STRUCTURE

Construction and Building Materials 47 (2013) 643–655

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Construction and Building Materials

j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c o n b u i l d m a t

Review

Production of bricks from waste materials – A review

0950-0618/$ - see front matter � 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.conbuildmat.2013.05.043

⇑ Tel.: +1 520 6260532; fax: +1 520 6212550. E-mail address: lyzhang@email.arizona.edu

Lianyang Zhang ⇑ Department of Civil Engineering and Engineering Mechanics, University of Arizona, Tucson, AZ 85721, USA

h i g h l i g h t s

� A wide variety of waste materials have been researched for production of bricks, including mainly fly ash and slags. � Methods for producing bricks from waste materials can be divided into 3 categories: firing, cementing and geopolymerization. � Commercial production of bricks from waste materials is still very limited due to different reasons. � Further research and development is needed to promote wide production and application of bricks from waste materials.

a r t i c l e i n f o

Article history: Received 17 February 2013 Received in revised form 27 April 2013 Accepted 5 May 2013 Available online 10 June 2013

Keywords: Bricks Waste materials Firing Cementing Geopolymerization Sustainable development

a b s t r a c t

Bricks are a widely used construction and building material around the world. Conventional bricks are produced from clay with high temperature kiln firing or from ordinary Portland cement (OPC) concrete, and thus contain high embodied energy and have large carbon footprint. In many areas of the world, there is already a shortage of natural source material for production of the conventional bricks. For envi- ronmental protection and sustainable development, extensive research has been conducted on produc- tion of bricks from waste materials. This paper presents a state-of-the-art review of research on utilization of waste materials to produce bricks. A wide variety of waste materials have been studied to produce bricks with different methods. The research can be divided into three general categories based on the methods for producing bricks from waste materials: firing, cementing and geopolymerization. Although much research has been conducted, the commercial production of bricks from waste materials is still very limited. The possible reasons are related to the methods for producing bricks from waste materials, the potential contamination from the waste materials used, the absence of relevant standards, and the slow acceptance of waste materials-based bricks by industry and public. For wide production and application of bricks from waste materials, further research and development is needed, not only on the technical, economic and environmental aspects but also on standardization, government policy and pub- lic education related to waste recycling and sustainable development.

� 2013 Elsevier Ltd. All rights reserved.

Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 644 2. Review of research on utilization of waste materials to produce bricks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 644

2.1. Production of bricks from waste materials through firing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 644 2.2. Production of bricks from waste materials through cementing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 647 2.3. Production of bricks from waste materials through geopolymerization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 651

3. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 652 4. Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 654

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 654

644 L. Zhang / Construction and Building Materials 47 (2013) 643–655

1. Introduction

Bricks have been a major construction and building material for a long time. The dried-clay bricks were used for the first time in 8000 BC and the fired-clay bricks were used as early as 4500 BC [1,2]. The worldwide annual production of bricks is currently about 1391 billion units and the demand for bricks is expected to be con- tinuously rising [3,4]. Conventional bricks are produced from clay with high temperature kiln firing or from ordinary Portland ce- ment (OPC) concrete. Quarrying operations for obtaining the clay are energy intensive, adversely affect the landscape, and generate high level of wastes. The high temperature kiln firing not only con- sumes significant amount of energy, but releases large quantity of greenhouse gases. Clay bricks, on average, have an embodied en- ergy of approximately 2.0 kWh and release about 0.41 kg of carbon dioxide (CO2) per brick [5,6]. It is also noted that there is a shortage of clay in many parts of the world. To protect the clay resource and the environment, some countries such as China have started to limit the use of bricks made from clay [7–9].

The OPC concrete bricks are produced from OPC and aggregates. It is well known that the production of OPC is highly energy inten- sive and releases significant amount of greenhouse gases. Produc- tion of 1 kg of OPC consumes approximately 1.5 kWh of energy and releases about 1 kg of CO2 to the atmosphere. Worldwide, produc- tion of OPC is responsible for about 7% of all CO2 generated [5,10– 12]. So the production of OPC concrete bricks also consumes large amount of energy and releases substantial quantity of CO2. In addi- tion, the aggregates are produced from quarrying and thus have the same problems as described above for clay.

For environmental protection and sustainable development, many researchers have studied the utilization of waste materials to produce bricks [8,9,13–15,17–66,80–85]. A wide variety of waste materials have been studied, including fly ash, mine tailings, slags, construction and demolition (C&D) waste, wood sawdust, cotton waste, limestone powder, paper production residue, petro- leum effluent treatment plant sludge, kraft pulp production resi- due, cigarette butts, waste tea, rice husk ash, crumb rubber, and cement kiln dust. Different methods have been used to produce bricks from waste materials.

This paper presents a state-of-the-art review of the research on utilization of different types of waste materials to produce bricks. The advantages and disadvantages of different methods for utiliz- ing waste materials to produce bricks are described. The concerns related to production of bricks from waste materials are also discussed.

2. Review of research on utilization of waste materials to produce bricks

The extensive research on utilization of waste materials to pro- duce bricks can be divided into three general categories based on the production methods: firing, cementing and geopolymerization, as detailed below.

2.1. Production of bricks from waste materials through firing

This method uses waste material(s) to substitute a portion or entire amount of clay and follows the traditional way to kiln fire the material(s) to produce bricks. Many researchers have studied the production of bricks from waste materials based on firing (see Table 1).

Chen et al. [8] studied the feasibility of utilizing hematite tail- ings and class F fly ash together with clay to produce bricks. Brick samples were prepared by using 77–100% tailings, 0–8% fly ash and 0–15% clay. Tests were performed to determine the compressive

strength, water absorption and bulk density of brick samples pre- pared at different conditions. Based on the results, they recom- mended a tailings:fly ash:clay ratio of 84:6:10, a forming water content of 12.5–15%, a forming pressure of 20–25 MPa, and a firing temperature of 980–1030 �C for 2 h, to produce good quality bricks.

Lingling et al. [9] investigated the production of fired bricks by using class F fly ash to replace clay at high volume ratios. Brick samples were prepared by mixing fly ash and clay at designed pro- portion, casting the mixture into bricks, drying the bricks at ambi- ent condition for 2 days, at 60 �C for 4 h and at 100 �C for 6 h, and firing the dried bricks in an electric furnace at 100 �C/h below 500 �C, 50 �C/h from 500 �C to highest temperature (1000, 1050, or 1100 �C), and at the highest temperature for 8 h. Tests were con- ducted on the fired bricks to evaluate their compressive strength, water absorption, bulk density, apparent porosity, cracking due to lime, frost and frost-melting. The results showed that when high percentages of fly ash were used, a firing temperature about 1050 �C should be adopted. The fired bricks with high percentages of fly ash had high compressive strength, low water absorption, no cracking due to lime, and high resistance to frost-melting. The study also indicated that the properties of fired bricks were im- proved by using pulverized fly ash (i.e., by decreasing the particle size of the fly ash).

Kute and Deodhar [13] studied the bricks manufactured in lab- oratory using class F fly ash and clay. The brick samples were pre- pared by mixing different amount of fly ash with clay and sufficient quantity of water, and then compressing the mixture in a mold. The molded bricks were dried in air for 2 days and then fired in a laboratory furnace respectively at 850 and 1000 �C for 24 h. Labo- ratory tests were conducted to evaluate the compressive strength and water absorption of the produced bricks. The results indicated that the inclusion of fly ash in general increased the compressive strength and decreased the water absorption of bricks. The highest compressive strength of 12.4 MPa (an average of eight samples) was obtained at 40% fly ash content, with the corresponding water absorption being 13.8%.

Chou et al. [14,15] conducted systematic study on utilization of class F fly ash to replace part of the clay and shale in production of bricks using the conventional kiln firing procedure. Paving bricks with up to 20 vol.% of fly ash and building bricks with up to 40 vol.% of fly ash were successfully produced in commercial-scale production test runs, with the properties exceeding the ASTM com- mercial specifications. They also conducted leaching study on the fired bricks from commercial-scale production following US EPA Method 1320 [16]. The results indicated that the amounts of lea- ched metals were well below the US EPA’s regulatory thresholds.

Kayali [17] studied the performance of FlashBricks, bricks pro- duced from fly ash. The bricks were produced by mixing fly ash with water and a small amount of commercially protected addi- tive, molding the mixture, drying the formed units for 3 days, and then firing them for hours. The FlashBricks were about 28% lighter than clay bricks and had a compressive strength greater than 40 MPa. Other important performance parameters such as water absorption, modulus of rupture, bond strength and durabil- ity also exceeded those pertaining to clay bricks.

Menezes et al. [18] evaluated the possibilities of using granite sawing wastes as alternative raw materials in the production of ceramic bricks and tiles. The results showed that the granite saw- ing wastes had physical and mineralogical characteristics that were similar to those of conventional raw materials for ceramic bricks and tiles and could be used to partially replace the conven- tional raw materials to produce ceramic bricks and tiles meeting the Brazilian standardizations.

Lin [19] studied the utilization of municipal solid waste inciner- ator (MSWI) slag to partially replace clay for the production of fired

Table 1 Studies on production of bricks from waste materials through firing.

No. Waste material (wt.%) Brick size (mm) Drying/firing condition Tests conducted Reference

1 Hematite tailings (77–100%) and class F fly ash (0–8%)

50 � 50 (cylinder)

Dried in an oven at 105 �C for 6–8 h and then fired in an electric furnace at 6 �C/min until 850–1050 �C for 2 h

Compressive strength, water absorption, bulk density

[8]

2 Class F fly ash (0, 50, 60, 70, and 80 vol.%)

60 � 60 � 25 Dried at ambient condition for 2 days, at 60 �C for 4 h and at 100 �C for 6 h, and fired in an electric furnace at 100 �C/h below 500 �C, 50 �C/h from 500 �C to 1000, 1050 or 1100 �C, and at the highest temperature for 8 h

Compressive strength, water absorption, bulk density, apparent porosity, cracking due to lime, frost and frost-melting

[9]

3 Class F fly ash (0%, 20%, 40%, and 60%)

95 � 45 � 45 Dried in air for 2 days and then fired in a laboratory furnace at respectively 850 and 1000 �C for 24 h

Compressive strength, water absorption

[13]

4 Class F fly ash (0–60 vol.%) Various sizes Following the process of a commercial clay brick plant

Compressive strength, water absorption, leaching

[14,15]

5 Fly ash (100%) - Dried for 3 days and then fired at 1000–1300 �C for hours

Compressive strength, water absorption, modulus of rupture, density, bond strength, durability

[17]

6 Granite sawing wastes (0–60%) Various sizes Fired at different temperatures between 750 and 1200 �C

Compressive strength, water absorption, modulus of rupture

[18]

7 Municipal solid waste incinerator slag (0–40%)

50 � 25 � 50 Air-dried at room temperature for 24 h, oven dried at 80 �C for 24 h, and finally fired at 800, 900, or 1000 �C for 6 h

Compressive strength, water absorption, density, firing shrinkage, weight loss on ignition, TCLP

[19]

8 Gold mill tailings (0–75%) 100 � 100 � 76 Dried at room temperature for 2 days, in the sun for 3 days, and then fired in an electric furnace at 750, 850, or 950 �C for 9 h

Compressive strength, water absorption, linear shrinkage

[20]

9 Kaolin fine quarry residue (50%), granulated blast-furnace slag (10– 40%), granite–basalt fine quarry residue (10–40%)

50 � 50 � 50 Dried in an electric dryer at 80 �C for 24 h, and then fired at different temperatures of 1100, 1125, 1150 and 1175 �C at 5 �C/min and 4 h soaking time in a muffle furnace under oxidizing condition

Compressive strength, water absorption, bulk density

[21]

10 Paper production residues (0%, 10%, 20%, and 30%)

85 � 85 � 10 Held overnight at room temperature followed by drying at 45 �C for 1 h in an oven, then fired in an electrical furnace at 2.5 �C/min until 600 �C and then at 10 �C/min until 1100 �C, for 1 h

Compressive strength, water absorption, bulk density, apparent porosity, thermal conductivity

[22]

11 Cigarette butts (0%, 2.5%, 5% and 10%)

300 � 100 � 50 Dried at 105 �C for 24 h, and then fired in a furnace at 1050 �C

Compressive strength, water absorption, density, thermal conductivity, leaching

[23]

12 Rice husk ash (0%, 5%, 10%, 15% and 20%)

50 � 50 � 50 Dried in the sun at 30 �C for 8 days, at 105 �C for 24 h in an oven, and then fired in a furnace continuously at 250, 500, 750 �C for 2 h each and finally at 1000 �C for 2, 4 or 6 h

Compressive strength, water absorption, density

[24]

13 Petroleum effluent treatment plant sludge (41%)

280 � 130 � 170 Dried at room temperature and then fired in a coal- fired Bulls trench commercial brick kiln along with usual commercial bricks at 1000–1100 �C

Compressive strength, water absorption, leaching

[25]

14 Kraft pulp production residue (2.5%)

33 � 40 (cylinder), 25 � 25 � 150

Dried at 21 �C for 72 h and then at 105 �C in the oven, and subsequently fired at 2 �C/min until 600 �C and then at 5 �C/min until 900 �C for 30 min

Compressive strength, water absorption, density

[26]

15 Waste tea (5%) 100 � 70 � 40 Dried at 21 �C for 72 h and then at 105 �C in the oven, and subsequently fired at 2 �C/min until 600 �C and then at 5 �C/min until 900 �C for 2 h

Compressive strength, water absorption, density

[27]

16 River sediments (15%) 60 � 220 � 220 Dried through a tunnel drier up to 80 �C and then fired through a tunnel kiln with a maximum temperature of 1000 �C

Compressive strength, water absorption, porosity, firing shrinkage, leaching, permeability, freeze–thaw

[28]

17 PC and TV waste glass (<2%) 100 � 20 � 10 Dried at ambient temperature in a non-controlled atmosphere for 48 h and then in an electric oven at 100 �C overnight, and finally fired in an electric chamber kiln at 100 �C/h until 900, 950 or 1000 �C for 4 h

Bending strength, water absorption, open porosity, bulk density, firing shrinkage, leaching

[29]

18 Municipal solid waste incineration fly ash (20%)

– Dried at around 60 �C and then fired at 950 �C Compressive strength, water absorption, shrinkage, leaching

[30]

19 Sawdust (0–10%), spent earth from oil filtration (0–30%), compost (0– 30%), or marble (0–20%)

30 � 10 � 60 Fired in a laboratory furnace at 3 �C/min up to 950 or 1050 �C for 4 h

Compressive strength, water absorption, bulk density, apparent porosity

[31]

20 Foundry by-products (0–50%) 150 � 30 � 15 Fired in a laboratory muffle at 2 �C/min up to 850, 950 or 1050 �C for 3.5 h

Flexural strength, water absorption, density, apparent porosity

[32]

21 Waste marble powder (20–100%) 41 � 8 � 8 Fired in an electrical furnace at 5 �C/min up to at 900, 1000 or 1100 �C for 3 h

Flexural strength, water absorption, bulk density, porosity

[33]

22 Waelz slag and waste foundry sand (20–40%)

100 � 80 � 20 Dried at 96–104 �C and fired in an industry tunnel kiln to a maximum temperature of 850 �C (heating rate �0.85 �C/min, cooling rate �1.14 �C/min, and soaking time of 1 h)

Flexural strength, water absorption, density, open porosity, leaching

[34]

23 River sediment (100% or 50%) 54 � 54 � (5–10)

Dried in an oven at temperature gradually increasing from 25 to 110 �C until no change in mass, and then fired in an electric laboratory furnace at different temperatures from 900 to

Compressive strength, water absorption, firing shrinkage, freeze–thaw

[35]

(continued on next page)

L. Zhang / Construction and Building Materials 47 (2013) 643–655 645

Table 1 (continued)

No. Waste material (wt.%) Brick size (mm) Drying/firing condition Tests conducted Reference

1000 �C with variations in heating rate and holding duration at the maximum temperature

24 Sugarcane bagasse ash waste (up to 20%)

25 mm (diameter)

Dried at 110 �C for 24 h and then fired in an electric kiln at 1100 �C (24 h cold to cold)

Linear shrinkage, water absorption, apparent density, tensile strength

[36]

646 L. Zhang / Construction and Building Materials 47 (2013) 643–655

clay bricks. Brick samples were heated to temperatures between 800 and 1000 �C for 6 h at a heating rate of 10 �C/min. Physical, mechanical and leaching tests were conducted on the brick sam- ples. The results indicated that the heavy metal concentrations in the leachate met the regulatory thresholds. Increasing the amount of MSWI slag resulted in a decrease in the water absorption rate and an increase in the compressive strength of the bricks. The absorption rate and compressive strength of the bricks sintered at 1000 �C met the Chinese National Standard (CNS) building requirements for second-class bricks. The addition of MSWI slag also reduced the degree of firing shrinkage. So the MSWI slag was suitable for partial replacement of clay in production of fired clay bricks.

Roy et al. [20] studied production of bricks by mixing different amount of gold mill tailings (0–75%) with black cotton soils or red soils. The soil-tailings bricks were dried at room temperature for 2 days and in the sun for another 3 days, and then fired in an elec- tric furnace respectively at 750, 850, and 950 �C. The fired bricks were tested to evaluate their compressive strength, water absorp- tion and linear shrinkage. The results indicated that 65%, 75%, 50% and 45% of tailings could be used respectively with the four differ- ent types of soils studied to produce bricks that pass the criteria in terms of compressive strength, water absorption and linear shrinkage.

El-Mahllawy [21] investigated the production of bricks using kaolin fine quarry residue (KFQR) combined with granulated blast-furnace slag (GBFS) and granite–basalt fine quarry residue (GBFQR). Brick specimens were prepared by mixing 50% of KFQR, 10–40% of GBFS and 10–40% GBFQR, and then placing the mixture into a 50 mm cubic mold and applying a forming pressure of 22 MPa. The formed specimens were dried in an electrical dryer at 80 �C for 24 h, and then fired at different firing temperatures of 1100, 1125, 1150 and 1175 �C at 5 �C/min firing rate and 4 h soaking time in a muffle furnace. Tests were performed to assess the physical, chemical and mechanical characteristics of the fired bricks against the requirements of the Egyptian standard specifica- tion (ESS). The results showed that the bricks containing 50% KFQR, 20% GBFQR and 30% GBFS fired at 1125 �C exhibited the most sat- isfying properties that meet the ESS requirements.

Sutcu and Akkurt [22] studied production of porous and light- weight bricks with reduced thermal conductivity and acceptable compressive strength by using paper processing residues as an additive to earthenware bricks. Mixtures containing brick raw materials and the paper processing waste were prepared at differ- ent proportions (up to 30% by weight). The granulated powder mixtures were compressed in a hydraulic press under a pressure of 10 MPa. The pressed specimens were held overnight at room temperature followed by drying at 45 �C for 1 h in an oven, and then fired in a laboratory-type electrical furnace at a rate of 2.5 �C/min until 600 �C and subsequently at a rate of 10 �C/min un- til 1100 �C for 1 h. Tests were performed to evaluate the dilatomet- ric behavior, drying and firing shrinkages, loss on ignition, bulk density, apparent porosity, water absorption, thermal conductivity, compressive strength and freeze–thaw performance of the fired brick specimens. The results indicated that the paper processing waste could be utilized together with brick raw materials to pro- duce porous and lightweight bricks with reduced thermal conduc- tivity and acceptable compressive strength.

Aeslina et al. [23] investigated the recycling of cigarette butts (CBs) into fired clay bricks. The CBs were disinfected by heat at 105 �C for 24 h and then mixed with soil at four different percent- ages. The mixture was placed in molds and compacted manually at the optimum moisture content which was found from standard compaction tests. The specimens were dried at 105 �C for 24 h, re- moved from the molds and fired in a furnace at 1050 �C. The fired specimens were tested for density, strength, thermal conductivity and leachate characteristics. The results indicated that cigarette butts could be regarded as a potential addition to raw materials used in the manufacturing of light fired bricks.

Rahman [24] made fired bricks using clay–sand mixes with dif- ferent percentages of rice husk ash. The firing durations at 1000 �C were respectively 2, 4 and 6 h. The effects of rice husk ash content on workable mixing water content, Atterberg limits, linear shrink- age, density, compressive strength and water absorption of the bricks were investigated. The results indicated that (1) the inclu- sion of rice husk ash increased the compressive strength of bricks, (2) the optimum firing duration was 4 h at 1000 �C, and (3) the bricks made of clay–sand–rice husk ash mixes could be used in load bearing walls.

Sengupta et al. [25] studied the utilization of petroleum effluent treatment plant sludge in preparing environmentally acceptable masonry bricks in a commercial brick plant. The sludge was mixed thoroughly with soil and sand at a ratio of 0.46:1:0.12. Mixtures were homogenized and used to prepare bricks by adopting the pro- cedure as practiced in common masonry brick manufacturing. The bricks were air dried at ambient condition to optimum moisture content and fired in a coal-fired Bulls trench commercial brick kiln along with the usual commercial bricks. The firing temperature ranged from 1000 to 1100 �C. The physical, chemical and mechan- ical properties of the bricks were evaluated. The results indicated that (1) the addition of the sludge reduced the requirement of pro- cess water and fuel, (2) the fired bricks containing the sludge met all the requirements of the Indian Standard Specification, and (3) most of the toxic metals were fixed in the vitrification pro- cess and the leachate values met the US EPA’s requirement for recycling of hazardous materials.

Demir et al. [26] investigated the potential of utilizing kraft pulp production residues in clay bricks. Different amounts of resi- dues were mixed with raw brick clay to produce bricks. Shaped brick samples were dried at laboratory conditions (21 �C and 40% relative humidity) for 72 h and then dried to constant weight at 105 �C in the oven. The dried samples were fired in a laboratory type electrically heated furnace at a rate of 2 �C/min until 600 �C and then at a rate of 5 �C/min until 900 �C for 30 min. The effect of including the sludge on shaping, plasticity, density, porosity, water absorption and mechanical properties were investigated. The results indicated that 2.5–5% residue additions were effective for the pore forming in clay body with acceptable mechanical properties. It was concluded that kraft pulp residues can be utilized in brick clay as an organic pore-forming agent.

Demir [27] studied the utilization of processed waste tea (PWT) together with clay to produce bricks. The effects of PWT addition on the durability and mechanical properties of bricks were investi- gated. Due to the organic nature of PWT, pore-forming (fired body) and binding (unfired body) ability in clay body was investigated. Different amounts of PWT were added to the clay to produce

L. Zhang / Construction and Building Materials 47 (2013) 643–655 647

bricks. The test brick specimens were produced by the extrusion method. The specimens were tested following the standard test methods. The results indicated that the inclusion of PWT signifi- cantly increased the compressive strength of the unfired and fired brick samples. As a result, it was concluded that PWT can be uti- lized in unfired and fired building bricks by taking advantage of low cost and environmental protection.

Samara et al. [28] investigated the use of polluted river sedi- ments after treatment in brick production by conducting a full- scale industrial experiment at a brick factory. The polluted sedi- ment was first stabilized by the Novosol� process and then intro- duced in the mix-design by replacing 15% of quartz sand used in normal brick production. Approximately 15,000 perforated sedi- ment-amended bricks were produced and the bricks were sub- jected to different qualification tests. The results indicated that the use of treated sediment resulted in significant increase in com- pressive strength and firing shrinkage and decrease in porosity and water absorption. The leaching tests showed that the quantities of heavy metals leached from crushed bricks were within the regula- tory limits.

Dondi et al. [29] studied the feasibility of utilizing PC and TV waste glass in production of clay bricks. The results indicated that addition of up to 2% of waste glass to the clay did not bring about significant changes to the properties of bricks. For low carbonate bricks, no significant release of Pb, Ba, and Sr was observed during the firing and leaching processes. However, for high carbonate bricks, some Pb volatilization during firing and Sr leaching were observed. One main constraint for the utilization of the PC and TV waste glass is that the glass must have a particle size below the limit of the pan mills used in brick production (<1 mm).

Haiying et al. [30] investigated the utilization of municipal so- lid waste incineration (MSWI) fly ash in production of ceramic bricks. It was found that the optimal mixture ratio of materials, MSWI fly ash:red ceramic clay:feldspar:gang sand, was 20:60:10:10, and the optimal sintering temperature was 950 �C. The results as a whole suggested that utilization of MSWI fly ash in production of ceramic bricks constituted a potential means of recycling MSWI fly ash.

Eliche-Quesada et al. [31] studied the application of a variety of waste materials together with clay to produce lightweight bricks: sawdust, spent earth from oil filtration, compost and marble. Brick samples were fabricated respectively with 0–10% sawdust, 0–30% spent earth from oil filtration, 0–30% compost, and 0–20% marble. A 54.5 MPa compression pressure was applied during the molding process. The brick samples were fired in a laboratory furnace at a rate of 3 �C/min up to respectively 950 and 1050 �C for 4 h. The re- sults showed that the bricks fired at 1050 �C had higher compres- sive strength, lower porosity and water absorption than those at 950 �C. The optimum amount of waste material which should be used was 5% sawdust, 15% spent earth from oil filtration, 10% com- post, or 15% marble.

Alonso-Santurde et al. [32] studied the production of bricks by mixing green and core foundry sand with clay in proportions 0– 50% and firing at 850–1050 �C. Brick specimens were prepared and evaluated physically and mineralogically. It was found that the clay–foundry sand bricks fired at 1050 �C had better physical property values while the mineralogy was not significantly af- fected. The optimum amount of foundry sand to produce bricks was found to be 35% green sand and 25% core sand.

Bilgin et al. [33] investigated the usability of waste marble dust as an additive material in industrial brick. Waste marble dust and industrial brick mortar were mixed in different proportions to pro- duce brick specimens for evaluating the effect of marble dust com- position on the physico-mechanical properties of bricks. The brick specimens were pressed and sintered at three different tempera- tures, 900, 1000 and 1100 �C. It was found that the amount of

added marble dust had positive effect on the physical, chemical and mechanical properties of the produced industrial brick.

Quijorna et al. [34] studied the utilization of Waelz slag and foundry sand to partially replace clay in the production of red clay bricks. A semi-scale industrial trial was conducted by incorporat- ing 20–40% additions to produce bricks and then evaluating their physico-chemical, mechanical and environmental properties. The results indicated that the incorporation of Waelz slag and foundry sand was beneficial for improved extrusion properties during forming, lower water absorption of the sintered brick due to re- duced connected porosity, significant reduction in CO2 and NOx emissions during firing, and improvements in potential leachabil- ity of some pollutants in relation to samples containing only Waelz slag or foundry sand. However, it was necessary to limit the addi- tion of Waelz slag to less than 30% in order to meet regulatory leaching limits for Mo. Other physico-chemical and mechanical parameters were not significantly affected by the addition of these industrial by-products.

Mezencevova et al. [35] conducted a laboratory-scale study to assess the feasibility of producing fired bricks by using dredged sediments as the sole raw material or as a 50% replacement for nat- ural brick-making clay. Brick samples were produced by firing at temperatures between 900 and 1000 �C. The test results indicated that the physical and mechanical properties of the dredged sedi- ment bricks generally complied with ASTM criteria for building bricks.

Faria et al. [36] investigated the recycling of sugarcane bagasse ash waste as a method to provide raw material for clay brick pro- duction. Brick samples were produced by using up 20% of sugar- cane bagasse ash waste to replace natural clay, and then tested to determine their physical and mechanical properties. It was found that the sugarcane bagasse ash waste was mainly composed of crystalline silica particles and could be used as a filler in clay bricks.

2.2. Production of bricks from waste materials through cementing

This method does not need kiln firing but relies on cementing from the waste material itself or other added cementing materials. Again, many researchers have studied the utilization of waste materials to produce bricks based on cementing (see Table 2).

Roy et al. [20] also used gold mill tailings to make bricks by mixing them with OPC in different proportions. The cement-tail- ings bricks were cured by immersing them in water for different periods of time and their compressive strengths were determined. The bricks with 20% of cement and 14 days of curing were found to be suitable. The cost analysis revealed that the cement-tailings bricks would be uneconomical compared to the soil-tailings bricks (see the related review in the previous section).

Malhotra and Tehri [37] investigated the development of bricks from granulated blast furnace slag, a byproduct of the iron and steel industry. The slag was first mixed with hydrated lime and then the lime–slag mixture with Badarpur sand thoroughly. Brick specimens were made by pressing the mixture in a hydraulic ma- chine at a pressure of 4.9 MPa and then curing the molded speci- mens at 270–272 �C and 95% humidity over a period of 28 days. The cured bricks were tested for compressive strength (in satu- rated conditions), bulk density and water absorption properties. The study revealed that good quality bricks could be produced from a slag–lime mixture and sand.

Poon et al. [38] studied the production of concrete bricks and paving blocks using recycled aggregates obtained from construc- tion and demolition (C&D) waste together with OPC and/or fly ash. A series of tests were carried out to determine the properties of the bricks and blocks prepared with and without recycled aggre- gates. The test results showed that the replacement of coarse and

Table 2 Studies on production of bricks from waste materials through cementing.

No. Waste material (wt.%)

Cementing material

Brick size (mm) Curing condition Tests conducted Reference

1 Gold mill tailings (0–75%)

OPC 100 � 100 � 76 Cured in water for different periods of time Compressive strength [20]

2 Granulated blast furnace slag (5–35%)

Hydrated lime 190 � 90 � 90 Cured at 95% humidity and at a temperature of 270–272 �C for 28 days

Compressive strength, bulk density, water absorption

[37]

3 Recycled aggregates (replacing 25– 100% of natural aggregates)

OPC alone or both OPC and fly ash

225 � 105 � 75 Bricks: cured in air at room temperature for 28 days; Blocks: cured in a steam bath at 65 �C for 6 h and then further cured in air at room temperature until 28 days

Compressive strength, density, drying shrinkage

[38]

4 Class F fly ash (60–90%)

Calcined phosphogypsum and mineral lime

220 � 110 � 75, 150 � 150 � 150 (hollow block)

Covered with wet gunny bags for a week and then cured in water filled tanks at 23�2 �C

Compressive strength, water absorption, density, durability

[39]

5 Class C fly ash (100%)

Fly ash itself 200 � 100 � 55 Cured in a moist room at 23 ± 2 �C and relative humidity not less than 95%

Compressive strength, water absorption, modulus of rupture, freeze– thaw

[40]

6 Class C fly ash (100%)

Fly ash itself 200 � 100 � 55 Cured in a wet environment (curing chamber) at room temperature for over 2 weeks

Compressive strength, water absorption, permeability, freeze–thaw, leaching

[41–45]

7 Copper mine tailings (8%, 12% and 15%)

OPC 190 � 90 � 90 Placed in well ventilated room at ambient temperature for 24 h and then cured in water

Compressive strength, water absorption [46]

8 Class F fly ash (50–80%)

Hydrated lime 45 (diameter) Pre-cured for about 24 h and then steamed autoclaved at pressure 0.5–2 MPa for 3– 12 h

Compressive strength, water absorption, unit weight, thermal conductivity

[47]

9 Wood sawdust and limestone powder (86–89%)

OPC 105 � 95 � 75 Cured at room temperature for 24 h, in lime-saturated water tank at 22 �C for 28 days, and then dried in ventilated oven at 105 �C for 24 h

Compressive strength, water absorption, flexural strength, unit weight, UPV test

[48]

10 Cotton waste and limestone powder (84–89%)

OPC 105 � 95 � 75 Cured at room temperature for 24 h, in lime-saturated water tank at 22 �C for 28 days, and then dried in ventilated oven at 105 �C for 24 h

Compressive strength, water absorption, flexural strength, unit weight, UPV test, thermal conductivity

[49,50]

11 Waste glass powder and limestone powder (89%)

OPC Various Cured at room temperature for 24 h, in lime-saturated water tank at 22 �C for 28 days, and then dried in ventilated oven at 105/115 �C for 24 h

Compressive strength, water absorption, flexural strength, unit weight, UPV test, abrasion resistance, freezing–thawing resistance, thermal conductivity

[51,52]

12 Crumb rubber (0–29%)

OPC 105 � 100 � 75 Cured in air for 6 h, in lime-saturated water tank at 22 �C for 28 days, and then dried in ventilated oven at 65 �C for 48 h

Compressive strength, water absorption, flexural strength, freeze– thaw resistance, unit weight, UPV test

[53]

13 Class F fly ash (95% and 100%)

Hydrated lime 15 � 65 � 10 Put in moist chamber at 98% RH for 3 days, and then autoclaved at 125–135 �C & 0.14 MPa pressure for 4 h

Compressive strength, water absorption, bulk density, leaching

[54]

14 Stockpiled circulating fluidized bed combustion ash (58.3–100%)

OPC, lime, and/or class F fly ash

90 � 65 � 90 Placed at 23 �C and 100% RH room for 1 day, and then cured in air at room temperature for different period of time

Compressive strength, water absorption density

[55]

15 Low-silicon tailings (83%)

Fly ash, slag, clinker dust and some activators

240 � 115 � 53 Sealed in plastic bag for 6 h, and then cured in autoclave for certain period of time

Compressive and bending strengths, freeze–thaw resistance, dry shrinkage

[56]

16 Limestone powder and class C fly ash (100%)

Class C fly ash itself

105 � 75 � 225 Cured at room temperature for 48 h, in water tank at 22 �C for 7, 28 and 90 days, and then dried in ventilated oven at 105 �C for 24 h

Compressive strength, water absorption, flexural strength, density, UPV test, thermal conductivity

[57]

17 Sludge from dyestuff-making wastewater coagulation (33– 50%)

OPC, ground silicate cement clinker, alumina cement, or slag cement

40 � 40 � 160 Cured at 20 �C in 100% humidity for 24 h, and then cured in water at 20 �C for 28 days

Compressive strength, freeze–thaw resistance, leaching

[58]

18 Low SiO2 content copper tailings (0–88%)

Lime 100 � 100 � 50 Heated-up for 2 h to 170–190 �C, stayed for 5–8 h, and then cooled-down for 3 h

Compressive strength, freeze–thaw resistance

[59]

19 Limestone powder, class C fly ash, and silica fume (100%)

Class C fly ash and/or silica fume

225 � 105 � 75 Cured by spraying additional water on the surface at room temperature for 48 h, and then cured in water for different times

Compressive strength, flexural strength, density, water absorption, porosity, thermal conductivity

[60]

20 Recycle paper mill waste (80–95%)

OPC 230 � 105 � 80 Solar dried Compressive strength, water absorption, specific weight, voidage, moisture content

[61]

21 Hematite tailings (70%)

Lime 50 � 23 (cylinder)

Pre-cured for about 24 h, and then steam autoclaved for certain period of time

Compressive strength, flexural strength, freeze–thaw resistance

[62]

648 L. Zhang / Construction and Building Materials 47 (2013) 643–655

Table 2 (continued)

No. Waste material (wt.%)

Cementing material

Brick size (mm) Curing condition Tests conducted Reference

22 CFBC fly ash (77–100%) and slag (0–20%)

OPC or lime 50 � 50 (cylinder) 240 � 115 � 53

Cured at 25–30 �C temperature and 80–90% humidity for a certain period of time, and then autoclaved for 3–8 h

Compressive strength, water absorption, dry-shrinkage, bulk density, freeze–thaw resistance

[63]

23 Waste phosphogypsum (75)

OPC and hydrated lime

240 � 115 � 53 Wet cured for 1 day, dried at 180 �C for 2 h, immersed in water for 1 h, and naturally cured

Compressive strength, bending strength, water absorption, freeze– thaw resistance

[64]

24 Coal combustion residues (70%, 90vol.%)

OPC 140 � 140 � 90 Moistened through water spraying and covered by a black plastic sheet

Compressive strength, unit weight [65]

25 Fly ash, quarry dust, and billet scale (85% and 90%)

OPC 200 � 90 � 60 Covered with wet burlap overnight, and then cured in plastic storage boxes at 22 �C and 95% RH

Compressive strength, water absorption, modulus of rupture, UPV, efflorescence and durability

[66]

L. Zhang / Construction and Building Materials 47 (2013) 643–655 649

fine natural aggregates by recycled aggregates at the levels of 25% and 50% had little effect on the compressive strength of the brick and block specimens, but higher levels of replacement reduced the compressive strength. Using recycled aggregates as the replacement of natural aggregates at the level of up to 100%, con- crete paving blocks with a 28-day compressive strength of not less than 49 MPa could be produced without the incorporation of fly ash, while paving blocks for footway uses with a lower compres- sive strength of 30 MPa and masonry bricks could be produced with the incorporation of fly ash.

Kumar [39] investigated the production of bricks and hollow blocks using class F fly ash together with calcined phosphogypsum and mineral lime. The brick and hollow block specimens were pre- pared by mixing different amounts of fly ash (60–90%), calcined phosphogypsum (5–30%) and mineral lime (5–30%) and then plac- ing the mixture in wooden molds. The molded bricks and hollow blocks were covered with wet gunny bags for a week and then transferred to water filled curing tanks at 21–25 �C. To investigate the durability, the bricks and hollow blocks were cured in an aggressive environment of sulfate solution. The cured bricks and hollow blocks were tested to evaluate their compressive strength, water absorption, density and durability. It was observed that these bricks and hollow blocks had sufficient strength for their use in low cost housing development.

Li and Lin [40] studied the production of bricks by compacting class C fly ash, both high grade with LOI (loss on ignition) = 0.03% and low grade with LOI = 9.1%, mixed with water. They tested the compacted bricks to evaluate their compressive strength, mod- ulus of rupture, freeze–thaw resistance, and water absorption. The results indicated that the bricks compacted from fly ash had higher compressive strength than ordinary commercial bricks, but lower freeze–thaw resistance. So they could be used in certain applica- tions. Analysis was also performed on the production cost for the compacted fly ash bricks and the results showed that the cost would be less than 2 cents per brick if the capital cost for a plant with a capacity of 100,000 tons per year did not exceed 1 million dollars.

Liu and his colleagues [41–45] developed a technique to pro- duce bricks by mixing class C fly ash with approximately 10% water, compressing the mixture at a pressure higher than 6.9 MPa and then curing the formed brick in a wet environment (curing chamber) at room temperature for over 2 weeks. This method relies on the self-cementing property of class C fly ash which contains a large amount of calcium and thus does not need the usage of other cementing material. The produced bricks had high compressive strength, good water absorption property and low permeability. To enhance the freeze–thaw resistance, they added small amount (0.2% by weight) of air-entrainment chemical into the bricks. They also performed detailed environmental study

and the results indicated that the produced fly ash bricks were environmentally safe.

Morchhale et al. [46] studied the production of bricks by mixing copper mine tailings with different amounts of OPC and then com- pressing the mixture in a mold at a pressure of 15 MPa. The molded bricks were transferred to a well ventilated room at ambient tem- perature for 24 h and then cured in water for different periods of time. The cured brick specimens were tested to evaluate their com- pressive strength and water absorption. The results indicated that the produced copper mine tailings-cement bricks satisfied the compressive strength and water absorption requirements as pre- scribed in Indian Standard (IS).

Cicek and Tanrverdi [47] investigated the production of light weight bricks by using class F fly ash together with sand and hy- drated lime. Brick samples were prepared under different condi- tions to study the effect of different factors. An optimum raw material composition was found to be a mixture of 68% fly ash, 20% sand and 12% hydrated lime. The optimum brick forming pres- sure was 20 MPa and the optimum autoclaving time and pressure were found to be 6 h and 1.5 MPa respectively. The results sug- gested that it is possible to produce good quality light weight bricks from fly ash.

Turgut and Algin [48] studied the potential use of wood saw- dust waste (WSW) and limestone powder waste (LPW) combina- tion together with Portland cement to produce lightweight bricks. Brick samples were prepared by mixing WSW and LPW with cement at specified proportions and then compacting the mixture in a mold for 4 h under specified pressures. The molded brick samples were cured at room temperature for 24 h, in a tank filled with lime-saturated water at 22 �C for 28 days, and then dried in a ventilated oven at 105 �C for 24 h. Tests were conducted on the bricks to evaluate their compressive strength, flexural strength, unit weight, ultrasonic pulse velocity and water absorp- tion. The results showed that the produced bricks satisfy the rele- vant international standards. The results also showed that the high-level replacement of WSW with LPW did not exhibit a sudden brittle fracture even beyond the failure loads, led to high energy absorption capacity, reduced the unit weight dramatically, and introduced smother surface compared to regular concrete bricks.

Algin and Turgut [49] tried to use cotton waste (CW) and lime- stone powder waste (LPW) together with Portland cement to pro- duce lightweight bricks. The study followed essentially the same method as used in [48] and similar conclusions were drawn (the only difference is that CW instead of WSW was used). Turgut [50] studied the thermal conductivity of the bricks produced from CW and LPW.

Turgut [51,52] studied the utilization of waste glass powder (WGP) and limestone powder waste (LPW) together with a small quantity of Portland cement to produce bricks following essentially

650 L. Zhang / Construction and Building Materials 47 (2013) 643–655

the same method used in [48–50]. The results indicated that the WGP used in LPW remarkably improved the compressive strength, flexural strength, modulus of elasticity, abrasion resistance, freez- ing–thawing resistance, and thermal conductivity of LPW bricks.

Turgut and Yesilata [53] examined the potential use of crumb rubber to partially replace sand aggregate for producing low cost and lightweight composite concrete bricks with improved thermal resistance. The physico-mechanical and thermal insulation proper- ties of the rubber-added concrete bricks were investigated. The ob- tained compressive strength, flexural strength, splitting strength, freeze–thaw resistance, unit weight and water absorption values met the relevant international standards. The experimental obser- vations also revealed that high level replacement of crumb rubber with conventional sand aggregate did not exhibit a sudden brittle fracture even beyond the failure loads, led to high energy absorp- tion capacity, reduced the unit weight dramatically, and intro- duced smoother surface.

Chindaprasirt and Pimraksa [54] studied the properties of fly ash–lime granule unfired bricks. Granules were prepared from mixtures of fly ash and lime at fly ash to hydrated lime ratios of 100:0, 95:5 and 90:10 and then used to make unfired bricks using hydrothermal treatment at temperature of 125–135 �C and pres- sure of 0.14 MPa. The microstructures, mineralogical compositions, mechanical properties and environmental impact of bricks were determined. The results revealed that the strength of unfired bricks was dependent on the fineness of fly ash and was higher with an increase in fly ash fineness. The strength of the fly ash–lime gran- ule unfired bricks was 47.0–62.5 MPa. In addition, the heavy ele- ments, in particular Cd, Ni, Pb and Zn, were efficiently retained in the fly ash–lime granule unfired brick.

Shon et al. [55] studied the utilization of stockpiled circulating fluidized bed combustion ash (SCFBCA) with OPC, lime, class F fly ash, and/or calcium chloride to manufacture compressed bricks. Brick specimens were prepared using a compaction pressure of 55.2 MPa and then placing the specimens at a 23 �C and 100% rel- ative humidity room for 1 day before air curing at room tempera- ture. Laboratory tests were conducted on the prepared brick specimens to determine their physical, chemical and mineralogical properties. The results indicated that SCFBCA could be used to manufacture compressed earth bricks.

Zhao et al. [56] investigated production of load-bearing bricks from low-silicon tailings by pressing and autoclaving, using fly ash, slag, clinker dust and some activators as the cementing mate- rial. The tailings were mixed with the cementing material and water and then pressure molded into brick samples under a form- ing pressure of 20 MPa. The formed bricks were sealed with plastic bags for 6 h and then placed into autoclave for cuing for certain period of time. The results indicated that good quality bricks con- taining 83% of tailings could be produced, having compressive strength up to 16.1 MPa, bending strength 3.8 MPa, low drying shrinkage and good freeze–thaw resistance.

Turgut [57] studied the production of masonry blocks using limestone powder (LP) waste and class C class fly ash (FA), without the addition of Portland cement. LP was mixed with FA at respec- tively 10%, 20% and 30% by volume, wetted and compressed under a pressure of 20 MPa in a steel mold for 1 min to produce block samples. The formed blocks were cured at room temperature for 48 h, in water tank at 22 �C for respectively 7, 28 and 90 days, and then dried in ventilated oven at 105 �C for 24 h. Tests were conducted on the produced blocks to evaluate their compressive and flexural strengths, ultrasonic pulse velocity (UPV), density, water absorption and thermal conductivity. The results indicated that masonry blocks could be produced using LP, FA and water.

Liu et al. [58] explored the feasibility of using the sludge derived from dyestuff-making wastewater coagulation for producing un- fired bricks. They tried four typical cements, OPC, ground clinker

of silicate cement, alumina cement, and slag cement, as the binder. The experimental results showed that the cement solidified sludge could meet all performance criteria for unfired bricks at a cement/ dry sludge/water ratio of 1:0.5–0.8:0.5–0.8. The compressive strength of alumina cement solidified sludge was the highest and exceeded 40 MPa.

Fang et al. [59] studied the utilization of low SiO2 content cop- per tailings to partially replace sand to produce autoclaved sand– lime bricks. Brick specimens were prepared by mixing the tailings with river sand and sand powder at different proportions, pressing the mixture in a mold under a pressure of 20 MPa and autoclaving the molded bricks. The produced bricks were tested to evaluate their compressive strength and freeze–thaw durability. The results showed that the copper tailings with low content of SiO2 could be used to produce autoclaved sand–lime bricks meeting the China National Standard, if the proportion of the copper tailings in the brick batch did not exceed 50% by mass and appropriate propor- tions of river sand and sand powder were added to compensate for the low SiO2 content.

Turgut [60] investigated manufacturing of bricks by utilizing limestone powder, class C fly ash, silica fume and water without any other components. Brick specimens were produced by mixing limestone powder, class C fly ash and silica fume with water, com- pacting the mixture and curing the formed units for periods of 7, 28 and 90 days. The brick specimens were tested to measure their physical and mechanical properties. The results indicated that the compressive and flexural strengths increased significantly when the silica fume content in the mixture was increased. At 20% silica fume content, the compressive strengths of the bricks after 28 and 90 days curing time reached 23 and 26.5 MPa respectively. It was also found that the production cost of the new bricks was 6.4-times lower than that of traditional fired clay bricks.

Raut et al. [61] studied the utilization of recycled paper mill waste (RPMW) together with OPC to produce light weight bricks. Brick specimens were produced by mixing RPMW and cement at different proportions, compressing the mixture using a hand oper- ated hydraulic press and then solar drying the formed bricks. The brick specimens were tested following ASTM C 67-03a standards. The results showed that bricks prepared using RPMW–cement combination was light weight, shock absorbing and met the ASTM C 67-03a compressive strength requirements.

Zhao et al. [62] investigated the possibility of using hematite tailings as main raw material to produce high strength autoclaved bricks. The orthogonal test results indicated that the optimum for- mulation was the mixture of 70% hematite tailings, 15% lime and 15% sand and the optimum autoclave pressure and time were respectively 1.2 MPa and 6 h. The produced hematite tailings auto- claved bricks had mechanical strength and durability conforming to the China Autoclaved Lime–Sand Brick Standard (GB11945- 1999) for MU20 autoclaved bricks.

Zhang et al. [63] studied the production of autoclaved bricks from circulating fluidized bed combustion (CFBC) fly ash and slag. It was shown that autoclaved bricks could be made using 77% CFBC fly ash, 20% CFBC slag and 3% cement, exhibiting good long-term volume stability and achieving a compressive strength up to 14.3 MPa. There was no dihydrate gypsum and ettringite formation in the autoclaved brick so that the destructive expansion could be avoided.

Zhou et al. [64] proposed and tested a novel process, called ‘‘hydration–recrystallization process’’, for producing non-fired bricks from waste phosphogypsum. In this process, the press- formed bricks were hot-dried at 180 �C to dehydrate gypsum into semi-hydrated gypsum, water-immersed to recrystallize gypsum crystals, and finally air-dried naturally to obtain the non-fired bricks. A series of experiments were conducted based on the novel process. The results showed that the optimal mix consisted of

Table 3 Studies on production of bricks from waste materials through geopolymerization.

No. Waste material (wt.%)

Alkali activator Brick size (mm) Curing condition Tests conducted Reference

1 Fly ash and bottom ash (100%)

Sodium silicate solution 40 � 57 (cylinder), 300 � 140 � 90

Cured in ambient air at 20–23 �C and RH 35–60% for 28 days

Compressive strength, water uptake, water absorption

[80]

2 Class F fly ash (100%)

Sodium silicate and sodium hydroxide solution

190 � 90 � 50 Treated in oven and steam at 40, 60, 80, 100 �C for 2, 4, 6, 24, 48, 72 h, and then cured at ambient condition

Compressive strength, density [81]

3 Bottom ash from circulating fluidized bed combustion (100%)

Sodium silicate solution, sodium hydroxide solution, potassium hydroxide solution, and lithium hydroxide solution

100 � 100 � 200 Cured at 40 �C and 100% humidity for different periods of time

Compressive strength [82]

4 Copper mine tailings (100%)

Sodium hydroxide solution 33.4 � 72.5 (cylinder)

Cured in an oven at 60–120 �C for 7 days

Compressive strength, water absorption, abrasion resistance

[83]

5 Copper mine tailings (90–100%) and cement kiln dust (0–10%)

Sodium hydroxide solution 33.4 � 72.5 (cylinder)

Cured in an oven at 90 �C for 7 days

Compressive strength, water absorption, durability

[84]

6 Fly ash (80% and 90%) and red mud (20% and 10%)

1:1 Mix of sodium hydroxide solution and sodium silicate solution

I shaped block Covered with plastic lid and cured at ambient temperature for 28 days

Compressive strength, water absorption, splitting tensile strength, flexural strength, abrasion resistance, leaching

[85]

L. Zhang / Construction and Building Materials 47 (2013) 643–655 651

75.0% phosphogypsum, 19.5% river sand, 4.0% Portland cement and 1.5% hydrated lime and the produced bricks at the optimal condi- tion met the requirements of MU20 grade bricks in the Chinese standard (JC/T422-2007).

Vinai et al. [65] studied the production of bricks using coal com- bustion residues (CCRs) together with cement, lateritic clayey soil and sand. 12 Dosages were tested and about 300 bricks were pro- duced with a hand-operated press. Unconfined compressive strength (UCS) higher than 7.5 MPa was observed for bricks with 20% of laterite and 10% cement after 45 days of curing. The pro- duced bricks showed good mechanical strength, low weight and no health threat.

Shakir et al. [66] investigated the production of bricks using fly ash, quarry dust, and billet scale. The procedure for producing the bricks included mixing the constituents along with cement and water, and then forming the bricks within molds without applying pressure over them. Results of mechanical property and durability tests were promising. The optimum ratio of both billet scale to fly ash and billet scale to quarry dust was found to be 1:1. It was indi- cated that the bricks developed in this study could be used as an alternative to conventional bricks.

2.3. Production of bricks from waste materials through geopolymerization

The different methods described above produce bricks from waste materials either using high temperature kiln firing or relying on cementing as in the OPC concrete and thus still have the draw- backs of high-energy consumption and large quantity of green- house gas emissions. Therefore, researchers have studied production of bricks from waste materials based on geopolymer- ization (see Table 3). Geopolymerization is a technology that relies on the chemical reaction of amorphous silica and alumina rich sol- ids with a high alkaline solution at ambient or slightly elevated temperatures to form amorphous to semi-crystalline aluminosili- cate inorganic polymer or geopolymer. Geopolymer possess three-dimensional silicoaluminate structures consisting of linked SiO4 and AlO4 tetrahedra by sharing all the oxygen atoms [67–74]. A general formula for the chemical composition of geo- polymer is as follows:

Mþn ½—ðSiO2Þz —AlO2 —�n ð1Þ

where M+ is an alkali cation (Na+ or K+); n is the degree of polymer- ization; and z is the Si/Al ratio. By tuning the Si/Al ratio (i.e., z = 1– 15, up to 300), geopolymers with different properties can be syn- thesized. Geopolymer not only provides performance comparable to OPC in many applications, but has additional advantages, includ- ing abundant raw material resources, rapid development of mechanical strength, good durability, superior resistance to chemi- cal attack, ability to immobilize contaminants, and significantly re- duced energy consumption and greenhouse gas emissions [72–79]. These characteristics have made geopolymer of great research interest as an ideal material for sustainable development.

Freidin [80] studied production of geopolymer bricks from fly ash and bottom ash by using sodium silicate solution as the alkali activator. Small cylinder specimens were prepared at different con- ditions to study the effect of sodium silicate content, compaction pressure and hydrophobic additive. The specimens were cured in ambient air at temperature of 20–23 �C and RH of 35–60% for 28 days before tested. The results indicated that concrete-like building materials can be produced from mixtures of fly ash and bottom ash by using sodium silicate solution as the alkali activator. The full size blocks made from the concrete-like building materials met the requirements of Israeli Standard for conventional cement concrete blocks.

Arioz et al. [81] investigated production of geopolymer bricks using class F fly ash, sodium silicate, and sodium hydroxide solu- tion. The bricks were produced using 30 MPa forming pressure and treated at various temperatures for different hours in oven and steam. Tests were performed to determine the compressive strength and density of the fly ash-based geopolymer bricks at ages of 7, 28 and 90 days. It was found that the compressive strength of the fly ash-based geopolymer bricks ranged between 5 and 60 MPa and the effect of heat treatment temperature and duration on the density of the bricks was not significant.

Chen et al. [82] studied production of geopolymer bricks using bottom ash from circulating fluidized bed combustion and four dif- ferent alkali activators: sodium silicate solution, sodium hydroxide solution, potassium hydroxide solution, and lithium hydroxide solution. Brick samples were produced by first mixing the bottom ash and an alkaline solution, placing the mixture into a mold until the mold was full, and applying a force of 60 kN at the top to com- press the mixture for 10 s. Then the brick was pushed out of the mold and stored at 40 �C and 100% humidity for curing. The same

652 L. Zhang / Construction and Building Materials 47 (2013) 643–655

liquid to solid mass ratio of 0.3 was used for all brick samples. The results indicated that the alkali activator used has a great effect on the compressive strength of bricks. The highest 7 day compressive strength of 18.8 MPa was obtained for brick samples prepared using 10 M potassium hydroxide solution.

Ahmari and Zhang [83] investigated utilization of copper mine tailings to produce geopolymer bricks by using sodium hydroxide (NaOH) solution as the alkali activator. They produced cylindrical brick specimens by using different initial water contents, NaOH concentrations, forming pressures and curing temperatures to study their effects on the physical and mechanical properties of the copper mine tailings-based geopolymer bricks. Scanning elec- tron microscopy (SEM) imaging and X-ray diffraction (XRD) analy- sis were also performed to investigate the microstructure and phase composition of the mine tailings-based geopolymer bricks prepared at different conditions. The results showed that by prop- erly selecting the preparation condition (initial water content, NaOH concentration, forming pressure and curing temperature), mine tailings-based geopolymer bricks could be produced to meet the ASTM requirements on compressive strength, water absorp- tion, and abrasion resistance for nearly all types of applications.

Ahmari and Zhang [84] studied the feasibility of using cement kiln dust (CKD) to further enhance the physical and mechanical properties and the durability of the copper mine tailings-based geopolymer bricks developed in [83]. The effects of CKD content (0–10%) on unconfined compressive strength, water absorption, and weight and strength losses after immersion in water were studied. To shed light on the mechanism for the contribution of CKD to geopolymerization, microscopic and spectroscopic tech- niques including scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX), X-ray diffraction (XRD), and Fou- rier transform infrared (FTIR) spectroscopy were used to investi- gate the micro/nano-structure and the elemental and phase composition of geopolymer brick specimens containing different amount of CKD. The results showed significant improvement of UCS and durability when CKD was used. Water absorption, how- ever, slightly increased due to the hydration of Ca in the added CKD.

Kumar and Kumar [85] studied the production of geopolymer paving blocks by using red mud together with fly ash. The influ-

Table 4 ASTM specifications for different applications of bricks.

Title of specification ASTM designation Type/gra

Structural clay load bearing wall tile C34-03 LBXa

LBX LBb

LB

Building brick C62-10 SWf

MWg

NWh

Solid masonry unit C126-99 Vertical Horizont

Facing brick C216-07a SW MW

Pedestrian and light traffic paving brick C902-07 SX MX NX

a LBX = load bearing exposed. b LB = load bearing non-exposed. c End construction use. d Side construction use. e Based on 1 h boiling water absorption. f Severe weathering. g Moderate weathering. h Negligible weathering. i Based on 5 h boiling water absorption.

ence of 0–40% red mud addition on the reaction, structure and properties of fly ash geopolymer was studied. An improvement in intensity of reaction was observed with the red mud addition at all replacement levels but the improvement in setting time and compressive strength was observed only in the samples containing 5–20% red mud. Structural characterization revealed that the rate of reaction was dependent on the NaOH concentration but the development of mechanical properties was related to the compact microstructure which was developed due to the combined effects of NaOH concentration, solubility of silicates and the presence of iron oxides. Based on the study results, paving blocks using 10% and 20% red mud were developed. These blocks met Indian Stan- dard (IS) 15658 and the leached toxic metals were within permis- sible limits.

It is noted that researchers have also studied many other types of waste materials for geopolymer production, including red mud and rice husk ash [86], fly ash and mine tailings [87], fly ash and concrete waste [88], blast furnace slag [89], and fly ash and blast furnace slag [90]. Although these studies are not specifically about brick production, the results indicate that many of these wastes are promising materials for production of geopolymer bricks.

3. Discussion

It is evident from Tables 1–3 that researchers have used various types of waste materials in different proportions and adopted dif- ferent methods to produce bricks. Different tests were conducted on produced bricks to evaluate their properties following the var- ious available standards. Compressive strength and water absorp- tion are two common parameters considered by most researchers as required by various standards. For example, Table 4 shows the ASTM specifications on minimum unconfined compres- sive strength (UCS) and maximum water absorption for different applications of bricks.

It is noted that although many of the studied bricks made from waste materials meet the various standard requirements and a number of patents have been approved (see Table 5 for a partial list), so far commercial production and application of bricks from waste materials is still very limited. Currently, the CalStar brick from CalStar Products Inc., which is produced from 99.5% fly ash,

de Minimum UCS (MPa) Maximum water absorption (%)

9.6c 16e

4.8d 16e

6.8c 25e

4.8d 25e

20.7 17 17.2 22 10.3 No limit

coring 20.7 NA al coring 13.8 NA

20.7 17i

17.2 22i

55.2 8 20.7 14 20.7 No limit

Table 5 Patents for production of bricks from waste materials.a

Patent no. Title Inventor/year Source material

US20120031306 Bricks and method of forming bricks with high coal ash content using a press mold machine and variable firing trays

Belden et al./2012 Fly ash

US7998268 Method to produce durable non-vitrified fly ash bricks and blocks Liu/2011 Fly ash US6440884 Composition and process for making building bricks and tiles Devagnanam/

2002 Clay, sludge and sand

US6068803 Method of making building blocks from coal combustion waste and related products Weyand et al./ 2000

Fly ash, bottom ash, & rock mineral fines

US5366548 Volcanic fly ash and kiln dust compositions, and a process for making articles therefrom

Riddle/1996 Volcanic fly ash and kiln dust

WO/1996/022952 Structural products produced from fly ash Strabala/1996 Fly ash US5362319 Process for treating fly ash and bottom ash and the resulting product Johnson/1994 Fly ash and bottom ash US5358760 Process for producing solid bricks from fly ash, bottom ash, lime, gypsum, and

calcium carbonate Furlong and Hearne/1994

Fly ash, bottom ash, gypsum, calcium carbonate, & lime

US4780144 Method for producing a building element from a fly ash comprising material and building element formed

Loggers/1988 Fly ash and slaked lime

US4476235 Green molded product containing asbestos tailings suitable for firing Chevalier/1984 Asbestos tailings US3886244 Method for producing bricks from red mud Bayer et al./1975 Red mud

a Based on the search on http://www.freepatentsonline.com/.

L. Zhang / Construction and Building Materials 47 (2013) 643–655 653

fine aggregates, water and less than 0.5% of proprietary material, is commercially available [91]. Sanjay Kumar from CSIR, Jamshedpur, India reported in July 2012 the commercial production of around 0.5 million geopolymer bricks from steel slag, fly ash and GBFS combination [92]. The possible reasons are related to the methods for producing bricks from waste materials, the potential contami- nation from the waste materials, the absence of relevant standards, and the slow acceptance of waste materials-based bricks by indus- try and public, as detailed below.

The method for producing bricks from waste materials through firing is very similar to the conventional clay brick production pro- cess. Therefore, this method can be easily executed without mak- ing major changes in the conventional clay brick production line. However, during the firing process, contaminants within the waste material may be released and cause new contaminations. Besides, making bricks through firing consumes significant amount of en- ergy and releases large quantity of greenhouse gases. Therefore, the methods for producing bricks without firing seem to be the trend to follow in terms of energy and environmental concerns.

The method for producing bricks from waste materials through cementing is based on hydration reactions similar to that in OPC to form mainly C–S–H and C–A–S–H phases contributing to strength. The cementing material can be the waste material itself or other added cementing material(s) such as OPC and lime. Since the man- ufacture of cementing material(s) such as OPC and lime consumes significant amount of energy and releases large quantity of green- house gases, the production of bricks from waste materials based on added cementing material(s) also has the drawbacks of high en- ergy consumption and large carbon footprint. When it relies on the self cementing of waste material, the waste material has to contain a large amount of calcium (such as class C fly ash). To ensure and accelerate the reaction kinetics, the curing process usually needs to be conducted under pressurized steam at 125–200 �C in an auto- clave, which translates itself into additional costs.

The method for producing bricks from waste materials through formation of geopolymer is based on the relatively new geopoly- merization technology which is different from the conventional

Table 6 Concentration limit on different leached elements based on different standards.

Standard Concentration limit (ppm)

Al Hg Ag Ba Cr Mn

USEPA NA 5.0 5.0 100 5.0 NA DIN NA NA NA NA NA NA Greek 2.5–10.0 NA NA NA NA 1.0–2.0

cementing technology in OPC concrete. Geopolymerization relies on the polycondensation of silica and alumina precursors and a high alkali content to attain structural strength whereas the conventional cementing depends on the presence of C–S–H and C–A–S–H phases for matrix formation and strength. Production of geopolymer bricks consumes much less energy and releases sig- nificantly lower quantity of greenhouse gases than production of conventional bricks. Besides, geopolymer bricks have favorable physical, mechanical and chemical properties. However, the utili- zation of alkali solutions brings about extra costs. The mild tem- perature required for curing in some cases also leads to additional costs for production. Although geopolymer is considered by many authors as a solution for ‘‘green’’ construction material, few studies have quantified the environmental impact of geopoly- mer [93,94]. Therefore, detailed environmental impact assessment of geopolymer brick production is necessary and should be com- pared with other brick production methods.

Since most waste materials contain contaminants within them, for production of bricks from waste materials using whatever method, it is important to ensure that the contaminants within the original waste material are effectively and safely immobilized. Leaching analyses can be conducted following USEPA, ASTM and/or other standard methods to check if the leached elements meet the related standard criteria such as those listed in Table 6. For exam- ple, Cengizler [95], Tanrıverdi, [96], Ahmari and Zhang [97], and Kumar and Kumar [85] respectively studied the leaching behavior of heavy metals from fired fly ash bricks, non-fired autoclaved fly ash–lime bricks, copper mine tailings-based geopolymer bricks, and red mud/fly ash-based geopolymer blocks.

The limited production and application of bricks from waste materials is also related to the absence of relevant standards and the slow acceptance by industry and public. Standardization plays an important role in disseminating knowledge, exploiting research results and reducing time to market for innovations [98]. To pro- mote the production and application of bricks from waste materi- als, relevant standards should be developed. Since the existing brick manufacturers have a vested interest in the conventional

Ni Cu Zn As Se Cd Pb

5.0 NA NA 5.0 1.0 1.0 5.0 NA 2.0–5.0 2.0–5.0 NA NA NA NA 0.2–0.5 0.25–0.5 2.5–5.0 NA NA NA NA

654 L. Zhang / Construction and Building Materials 47 (2013) 643–655

brick production technology, their interest in new technologies to produce bricks from waste materials has been tepid. As mentioned earlier, most waste materials contain contaminants within them. The ‘‘waste’’ feature of the waste material and the potential for causing contamination and being unsafe adversely affect public acceptance of waste material-based bricks. To promote production and application of bricks from waste materials, more work needs to done, not only on the technical, economic and environmental as- pects but also on the government policy and public education re- lated to waste recycling and sustainable development.

4. Conclusions

Based on the review of the various studies on production of bricks from waste materials, the following conclusions can be drawn:

� A wide variety of waste materials have been studied for produc- tion of bricks. � The different methods studied for producing bricks from waste

materials can be divided into three general categories: firing, cementing and geopolymerization. The firing and cementing (especially cementing based on added cementing materials) methods for producing bricks from waste materials still have the drawbacks of high energy consumption and large carbon footprint as the conventional brick production methods. The method for producing bricks from waste materials through geo- polymerization seems to be the trend to follow in terms of energy and environmental concerns. � Although much research has been conducted, the commercial

production of bricks from waste materials is still very limited. The possible reasons are related to the methods for producing bricks from waste materials, the potential contamination from the waste materials used, the absence of relevant standards, and the slow acceptance of waste materials-based bricks by industry and public. � For wide production and utilization of bricks from waste mate-

rials, further research and development is needed, not only on the technical, economic and environmental aspects but also on standardization, government policy and public education.

References

[1] Brick. http://en.wikipedia.org/wiki/Brick#cite_note-2. Visited 14.04.13. [2] Pacheco-Torgal F, Jalali S. Masonry units. In: Pacheco-Torgal, Jalali, editors.

Eco-efficient construction and building materials. London, UK: Springer; 2011. p. 131–42.

[3] Habla Zig-Zag Kilns Technology. The brick industry. <http:// www.hablakilns.com/industry.htm>. Visited 15.01.13.

[4] The Freedonia Group. Brick and block – US industry study with forecasts for 2014 & 2019. Study #2652; 2012.

[5] Reddy BVV, Jagadish KS. Embodied energy of common and alternative building materials and technologies. Energy Build 2003;35:129–37.

[6] Lippiatt BC. BEES 4.0 – Building for environmental and economic sustainability. Technical manual and user guide. NISTIR 7423; 2007.

[7] China Economic Trade Committee. Tenth five-year program of building materials industry. China Build Mater 2001;7:7–10.

[8] Chen Y, Zhang Y, Chen T, Zhao Y, Bao S. Preparation of eco-friendly construction bricks from hematite tailings. Constr Build Mater 2011;25:2107–11.

[9] Lingling X, Wei G, Tao W, Nanru Y. Study on fired bricks with replacing clay by fly ash in high volume ratio. Constr Build Mater 2005;9:243–7.

[10] Malhotra VM. Role of supplementary cementing materials in reducing greenhouse gas emissions. In: Gjorv OE, Sakai K, editors. Concrete technology for a sustainable development in the 21st century. London: E&FN Spon; 2000. p. 226–35.

[11] McCaffrey R. Climate change and the cement industry. Glob Cem Lime Mag (Environ Spec Issue) 2002:15–9.

[12] Rajamane NP, Nataraja MC, Lakshmanan N, Ambily PS. Literature survey on geopolymer concretes and a research plan in Indian context. The Masterbuilder 2012:148–60.

[13] Kute S, Deodhar SV. Effect of fly ash and temperature on properties of burnt clay bricks. J Civ Eng 2003;84:82–5.

[14] Chou MI, Patel V, Laird CJ, Ho KK. Chemical and engineering properties of fired bricks containing 50 weight per cent of class F fly ash. Energy Sources 2001;23:665–73.

[15] Chou MI, Chou SF, Patel V, Pickering MD, Stucki JW. Manufacturing fired bricks with class F fly ash from Illinois basin coals. Combustion byproduct recycling consortium. Project number 02-CBRC-M12. Final report; 2006.

[16] US EPA (US Environmental Protection Agency). Multiple extraction procedure for solid waste – method 1320; 1980.

[17] Kayali O. High performance bricks from fly ash. In: 2005 World of coal ash (WOCA). Lexington, Kentucky, USA: Center for Applied Energy Research; 2005.

[18] Menezes RR, Ferreira HS, Neves GA, Lira HdL, Ferreira HC. Use of granite sawing wastes in the production of ceramic bricks and tiles. J Eur Ceram Soc 2005;25(7):1149–58.

[19] Lin KL. Feasibility study of using brick made from municipal solid waste incinerator fly ash slag. J Hazard Mater 2006;137(3):1810–6.

[20] Roy S, Adhikari GR, Gupta RN. Use of gold mill tailings in making bricks: a feasibility study. Waste Manage Res 2007;25:475–82.

[21] El-Mahllawy MS. Characteristics of acid resisting bricks made from quarry residues and waste steel slag. Constr Build Mater 2008;22:1887–96.

[22] Sutcu M, Akkurt S. The use of recycled paper processing residue in making porous brick with reduced thermal conductivity. Ceram Int 2009;35:2625–31.

[23] Aeslina AK, Abbas M, Felicity R, John B. Density, strength, thermal conductivity and leachate characteristics of light weight fired clay bricks incorporating cigarette butts. Int J Civ Environ Eng 2010;2(4):179–84.

[24] Rahman MA. Properties of clay–sand–rice husk ash mixed bricks. Int J Cem Compos Lightweight Concr 1987;9(2):105–8.

[25] Sengupta P, Saikia N, Borthakur PC. Bricks from petroleum effluent treatment plant sludge: properties and environmental characteristics. J Environ Eng 2002;128(11):1090–4.

[26] Demir I, Baspinar MS, Orhan M. Utilization of kraft pulp production residues in clay brick production. Build Environ 2005;40:1533–7.

[27] Demir I. An investigation on the production of construction brick with processed waste tea. Build Environ 2006;41:1274–8.

[28] Samara M, Lafhaj Z, Chapiseau C. Valorization of stabilized river sediments in fired clay bricks: factory scale experiment. J Hazard Mater 2009;163(2– 3):701–10.

[29] Dondi M, Guarini G, Raimondo M, Zanelli C. Recycling PC and TV waste glass in clay bricks and roof tiles. Waste Manage (Oxford) 2009;29(6):1945–51.

[30] Haiying Z, Youcai Z, Jingyu Q. Utilization of municipal solid waste incineration (MSWI) fly ash in ceramic brick: product characterization and environmental toxicity. Waste Manage (Oxford) 2011;31:331–41.

[31] Eliche-Quesada D, Corpas-Iglesias FA, Pérez-Villarejo L, Iglesias-Godino FJ. Recycling of sawdust, spent earth from oil filtration, compost and marble residues for brick manufacturing. Constr Build Mater 2012;34:275–84.

[32] Alonso-Santurde R, Coz A, Viguri JR, Andrés A. Recycling of foundry by- products in the ceramic industry: green and core sand in clay bricks. Constr Build Mater 2012;27:97–106.

[33] Bilgin N, Yeprem HA, Arslan S, Bilgin A, Günay E, Marsoglu M. Use of waste marble powder in brick industry. Constr Build Mater 2012;29:449–57.

[34] Quijorna N, Coz A, Andres A, Cheeseman C. Recycling of Waelz slag and waste foundry sand in red clay bricks. Resour Conserv Recycl 2012;65:1–10.

[35] Mezencevova A, Yeboah NN, Burns SE, Kahn LF, Kurtis KE. Utilization of Savannah harbor river sediment as the primary raw material in production of fired brick. J Environ Manage 2012;113:128–36.

[36] Faria KCP, Gurgel RF, Holanda JNF. Recycling of sugarcane bagasse ash waste in the production of clay bricks. J Environ Manage 2012;101:7–12.

[37] Malhotra SK, Tehri SP. Development of bricks from granulated blast furnace slag. Constr Build Mater 1996;10:191–3.

[38] Poon CS, Kou SC, Lam L. Use of recycled aggregates in molded concrete bricks and blocks. Constr Build Mater 2002;16:281–9.

[39] Kumar S. A perspective study on fly ash–lime–gypsum bricks and hollow blocks for low cost housing development. Constr Build Mater 2002;16:519–25.

[40] Li Y, Lin Y. Compacting solid waste materials generated in Missouri to form new products. Final technical report to the solid waste management program, Missouri Department of Natural Resources (MDNR). Contact no. MDNR 00038- 1, submitted by Capsule Pipeline Research Center, University of Missouri- Columbia, USA; 2002. p. 90.

[41] Liu H. Compacting fly ash to make bricks. Final technical report, NSF-SBIR phase I project no. DMI-0419311. Freight Pipeline Company; 2005. p. 15.

[42] Liu H, Burkett W, Haynes K. Improving freezing and thawing properties of fly ash bricks. In: World of coal ash conference, April 14, 2005, Lexington, Kentucky, USA; 2005.

[43] Liu H, Watson JP, Banerji S, Burkett WJ. Test of mercury vapor emission from fly ash bricks. In: World coal ash conference, May 7–10, 2007, Northern Kentucky, USA; 2007.

[44] Liu H, Banerji SK, Burkett WJ, Van Engelenhoven J. Environmental properties of fly ash bricks. In: World of coal ash conference, May 4–7, 2009, Lexington, KY, USA; 2009.

[45] Liu H, Van Engelenhoven J. Use of ASTM standards for testing freeze–thaw resistance of fly ash bricks. In: World of coal ash conference, May 4–7, 2009, Lexington, KY, USA; 2009.

[46] Morchhale RK, Ramakrishnan N, Dindorkar N. Bulk utilization of copper mine tailings in production of bricks. J Inst Eng Indian Civ Eng Div 2006;87:13–6.

L. Zhang / Construction and Building Materials 47 (2013) 643–655 655

[47] Cicek T, Tanrverdi M. Lime based steam autoclaved fly ash bricks. Constr Build Mater 2007;2007(21):1295–300.

[48] Turgut P, Algin HM. Limestone dust and wood sawdust as brick material. Build Environ 2007;42:3399–403.

[49] Algin HM, Turgut P. Cotton and limestone powder wastes as brick material. Constr Build Mater 2008;22(6):1074–80.

[50] Turgut P. Research into artificial limestone composites with cotton waste. Jordan J Civ Eng 2013;7(1):126–31.

[51] Turgut P. Limestone dust and glass powder wastes as new brick material. Mater Struct 2008;41(5):805–13.

[52] Turgut P. Properties of masonry blocks produced with waste limestone sawdust and glass powder. Constr Build Mater 2008;22(7):1422–7.

[53] Turgut P, Yesilata B. Physico-mechanical and thermal performances of newly develop rubber-added bricks. Energy Build 2008;40:679–88.

[54] Chindaprasirt P, Pimraksa K. A study of fly ash–lime granule unfired brick. Powder Technol 2008;182:33–41.

[55] Shon CS, Saylak D, Zollinger DG. Potential use of stockpiled circulating fluidized bed combustion ashes in manufacturing compressed earth bricks. Constr Build Mater 2009;23:2062–71.

[56] Zhao F-Q, Zhao J, Liu H-J. Autoclaved brick from low-silicon tailings. Constr Build Mater 2009;23:538–41.

[57] Turgut P. Masonry composite material made of limestone powder and fly ash. Powder Technol 2010;204:42–7.

[58] Liu Z, Chen Q, Xie X, Xue G, Du F, Ning Q, et al. Utilization of the sludge derived from dyestuff-making wastewater coagulation for unfired bricks. Constr Build Mater 2011;25:1699–706.

[59] Fang Y, Gu Y, Kang Q, Wen Q, Dai P. Utilization of copper tailing for autoclaved sand–lime brick. Constr Build Mater 2011;25:867–72.

[60] Turgut P. Manufacturing of building bricks without Portland cement. J Cleaner Prod 2012;37:361–7.

[61] Raut SP, Sedmake R, Dhunde S, Ralegaonkar RV, Mandavgane SA. Reuse of recycle paper mill waste in energy absorbing light weight bricks. Constr Build Mater 2012;27:247–51.

[62] Zhao Y, Zhang Y, Chen T, Chen Y, Bao S. Preparation of high strength autoclaved bricks from hematite tailings. Constr Build Mater 2012;28:450–5.

[63] Zhang Z, Qian J, You C, Hu C. Use of circulating fluidized bed combustion fly ash and slag in autoclaved brick. Constr Build Mater 2012;35:109–16.

[64] Zhou J, Gao H, Shu Z, Wang Y, Yan C. Utilization of waste phosphogypsum to prepare non-fired bricks by a novel hydration–recrystallization process. Constr Build Mater 2012;34:114–9.

[65] Vinai R, Lawane A, Minane JR, Amadou A. Coal combustion residues valorisation: research and development on compressed brick production. Constr Build Mater 2013;40:1088–96.

[66] Shakir AA, Naganathan S, Mustapha KN. Properties of bricks made using fly ash, quarry dust and billet scale. Constr Build Mater 2013;41:131–8.

[67] Davidovits J. High-alkali cements for 21st century concrete. In: Metha PK, editor. Proceedings of V. Mohan Malhortra symposium: concrete technology, past, present and future. ACI SP-144; 1994. p. 383–97.

[68] Duxson P, Fernandez-Jimenez A, Provis JL, Lukey GC, Palomo A, Van Deventer JSJ. Geopolymer technology: the current state of the art. J Mater Sci 2007;42:2917–33.

[69] Majidi B. Geopolymer technology, from fundamentals to advanced applications: a review. Mater Technol 2009;24(2):79–87.

[70] Davidovits J. Soft mineralogy and geopolymers. In: Proceedings 1st international conference on geopolymers, vol. 1. Compiegne, France; June 1988. p. 19–24.

[71] Davidovits J. Geopolymers: inorganic polymeric new materials. J Therm Anal 1991;37(8):1633–56.

[72] Shi C, Krivenko PV, Roy DM. Alkali-activated cements and concrete. London and New York: Taylor & Francis; 2006.

[73] Dimas D, Giannopoulou I, Panias D. Polymerization in sodium silicate solutions: a fundamental process in geopolymerization technology. J Mater Sci 2009;44:3719–30.

[74] He J, Zhang J, Yu Y, Zhang G. The strength and microstructure of two geopolymers derived from metakaolin and red mud–fly ash admixture: a comparative study. Constr Build Mater 2012;30:80–91.

[75] Van Deventer JSJ, Provis J, Duxson P, Lukey GC. Technological, environmental and commercial drivers for the use of geopolymers in a sustainable material industry. In: International symposium of advanced processing of metals and materials; 2006. p. 241–52.

[76] Palomo A, Grutzeck MW, Blanco MT. Alkali-activated fly ashes: a cement for the future. Cem Concr Res 1999;29(18):1323–9.

[77] Li Z, Ding Z, Zhang Y. Development of sustainable cementitious materials. In: Proceedings of international workshop on sustainable development and concrete technology, Beijing, China; 2004. p. 55–76.

[78] Drechsler M, Graham A. Innovative material technologies: bringing resources sustainability to construction and mining industries. In: 48th Institute of quarrying conference, Adelide, SA, Australia; 2005.

[79] Shi C, Fernandez-Jimenez A. Stabilization/solidification of hazardous and radioactive wastes with alkali-activated cements. J Hazard Mater 2006;137(3):1656–63.

[80] Freidin C. Cementless pressed blocks from waste products of coal-firing power station. Constr Build Mater 2007;21:12–8.

[81] Arioz O, Kilinc K, Tuncan M, Tuncan A, Kavas T. Physical, mechanical and micro-structural properties of F type fly-ash based geopolymeric bricks produced by pressure forming process. Adv Sci Technol 2010;69:69–74.

[82] Chen C, Li Q, Shen L, Zhai J. Feasibility of manufacturing geopolymer bricks using circulating fluidized bed combustion bottom ash. Environ Technol 2012;33:1313–21.

[83] Ahmari S, Zhang L. Production of eco-friendly bricks from copper mine tailings through geopolymerization. Constr Build Mater 2012;29:323–31.

[84] Ahmari S, Zhang L. Utilization of cement kiln dust (CKD) to enhance mine tailings-based geopolymer bricks. Constr Build Mater 2013;40:1002–11.

[85] Kumar A, Kumar S. Development of paving blocks from synergistic use of red mud and fly ash using geopolymerization. Constr Build Mater 2013;38:865–71.

[86] He J, Jie Y, Zhang J, Yu Y, Zhang G. Synthesis and characterization of red mud and rice husk ash-based geopolymer composites. Cem Concr Compos 2013;37:108–18.

[87] Zhang L, Ahmari S, Zhang J. Synthesis and characterization of fly ash modified mine tailings-based geopolymers. Constr Build Mater 2011;25(9):3773–81.

[88] Ahmari S, Ren X, Toufigh V, Zhang L. Production of geopolymeric binder from blended waste concrete powder and fly ash. Constr Build Mater 2012;35:718–29.

[89] Hu S, Wang H, Zhang G, Ding Q. Bonding and abrasion resistance of geopolymeric repair material made with steel slag. Cem Concr Compos 2008;30:239–44.

[90] Nath SK, Kumar S. Influence of iron making slags on strength and microstructure of fly ash geopolymer. Constr Build Mater 2013;38:924–30.

[91] <http://calstarproducts.com/products/fly-ash-brick-fab/>. Visited 11.05.12. [92] Davidovits J. Keynote: state of the geopolymer R&D. The geopolymer camp

2012, IUT, University of Picardie, July 9–11, Saint-Quentin, France; 2012. [93] Habert G, d’Espinose de Lacaillerie JB, Roussel N. An environmental evaluation

of geopolymer based concrete production: reviewing current research trends. J Cleaner Prod 2011;19:1229–38.

[94] Pacheco-Torgal F, Abdollahnejad Z, Camões AF, Jamshidi M, Ding Y. Durability of alkali-activated binders: a clear advantage over Portland cement or an unproven issue? Constr Build Mater 2012;30:400–5.

[95] Cengizler H. Toxic elements leachability tests on light weight fly ash bricks. Asian J Chem 2009;21:2950–6.

[96] Tanrıverdi M. Toxic elements leachability tests on autoclaved fly ash–lime bricks. Asian J Chem 2006;18:2310–4.

[97] Ahmari S, Zhang L. Durability and leaching behavior of mine tailings-based geopolymer bricks. Constr Build Mater 2013;44:743–50.

[98] Sanjuán MA, Zaragoza A, Agüí JCL. Standardization for an innovative world. Cem Concr Res 2011;41:767–74.