Revisions are needed on the paper I submitted for school. I have uploaded a file titled default.pdf which explains. Any section that scored less than a 3 needs to be revised. Please read teachers comments. Aspects B3, B5, C2 - C2f, D1 and D2 require addre

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Chapter II illustrates the use of construction waste materials in the production of a lightweight concrete tile in Oman. Recently, there is a lot of construction projects undertaken by the Sultanate of Oman in order to develop the infrastructure, the construction waste has become a problem in the future. So it must find solutions to this problem, the production of light weight concrete tiles, it could be one solutions.

Literary reviews include 10 section, where each section contributes to achieving the objectives of research. Section 1.2 talking about the construction waste in general. Section 1.3 and Section 1.4 compare between developed and developing countries in the field of construction waste, and take both Australia and Malaysia as examples. While it is expanding more to talk about the management of construction waste in Oman in Section 1.5. Section 1.6 includes recycling of construction waste to make tiles. Section 1.7 discusses the proper materials produced from construction waste such as aggregate, wood, ect. In addition, the characteristics of tiles will be more broadly in Section 1.8.Advantages and disadvantages when using a concrete tile lightweight recycled is explained in Section 1.9. Section 1.10 clarify the challenges facing the preparation of light weight concrete tiles.

Overall, this chapter achieved 03 objectives fully, include objective 01: To identify the waste materials of construction that will be suitable for tiles production. Objective 02: To achieve the characteristics of lightweight concrete tiles. Objective 03. To assess the pros and cons to use of lightweight concrete tiles made from construction waste.

Waste is a derivative of such processes as extraction of raw materials, processing as well as consumption of finished goods. Construction waste is a disturbing problem for both developed and developing nations. However, the mode of generation and management of waste varies among countries. Construction activities that generate waste inclusive of rubbles are excavations, new constructions, buildings renovations, demolitions, road works and other construction-based activities (Silva et.al. 2014). The industry is traditionally regarded as an environmental hazard; given that contractors gain reward based on contractual speed as opposed to consideration for the environmental impact created by such works. Additionally, construction consumes large amounts of energy and raw materials while producing significantly high amounts of solid waste. On a global perspective, the industry consumes about 25% of sand, gravel and raw stone as well as 40% virgin wood on an annual basis. In the US for instance, 40% extracted materials are used to construct building components and during actual production (Fulford & Standing 2014). Other derivatives of construction works include various pollutions, generation of solid waste, depletion of natural resources, land deterioration and land development.

The construction industry accounts for approximately 35% of the global industrial waste. In the EU (European Union), this form of waste is about two to five times the amount of household waste quantities generated in the total waste output. Furthermore, the construction industry has significant labor wastage; about 30% of rework, while approximately 10% of all raw materials for construction are wasted on site for every construction project (Nagapan et al. 2013). This form of wastage has input to negative social, economic and environmental implications. Uncontrolled landfills lead to land deterioration, water and soil contamination. Contractors suffer financial burdens as a result of disposals, delays, costs of rework and new purchases for replacement of wasted materials. Social implications include safety, health as well as the image created by the industry at the societal level.

During waste management, construction waste is highly prioritized using such approaches as disposal, recycling or reduction. Construction waste managers propose that prior to disposal, recycling; sorting, reusing and reduction methods should be applied. Recycling is especially meaningful for future urban development and improvement and environmental protection. Other than recycling, inert end-of-life products are usable for such rationale as land fillers during reclamation. Inert materials include broken concrete, rocks, soil, slurry and earth while non-inert materials include plastics, timbers, metal and packaging (Ann et al. 2013). Amidst the alarming rate of construction waste, such waste has approximately 80% potential for recovery by recycling. In line with this, countries like Belgium, Netherlands and Denmark have embarked on recycling of construction waste and have yielded tremendous results; with the major drives to recycling being scarcity of disposal sites and raw materials. Even so, most of construction waste eventually culminates in landfills. In the UK for instance, about 89.6 million tons of such waste was generated in 2014, while about 27 million of the waste ended up in landfills (Evangelisti et al. 2014).

Governments of developed nations are increasingly shifting towards reduction of construction waste. From the construction and demolition waste stream, the governments have embarked on establishing a market for construction materials. According to the findings of the organization for Economic Co-operation and Development, buildings account for 25% solid waste, 20% water effluents, 40% atmospheric emissions, 12% land use, 25% water use, 42% energy use and 30% raw materials used (Saboori et al. 2014). Although, the statistics are not available for most developed countries, however, there are some developed countries do this statistics. Australia is one of the countries that recorded statistics, which can be as a case study.

1.1.1 Case study: Australia

According to National Waste Data Report 2014, Australia generates more than 48 megatons of waste annually (Gavilan & Benord 2014). During the period between 1997 and 2012, the Australian population experienced a growth of 22% and a corresponding waste generation increase of 145% (Gavilan & Benord 2014). However, the country recycles about 52% of all its waste. To promote recycling instead of landfills, the Australian government is increasing the levies payable for dumping in landfills by all councils and companies. As a result, expenditure by the companies on waste costs has increased from a previous 1% to between 2-3% in 2015(Gavilan & Benord 2014). Of course, such expenditure has a significant impact on profits and EBITDA of any company. The levies are entirely avoidable by recycling in place of landfilling. In Sydney for instance, the cost of landfilling one tonnage of waste is $300. The levies are proving useful for allocating resources to the infrastructure reform and investment projects. The levies are also significant revenue generators, rising up to $500 million annually for a single state. The NSW government has used the revenues to launch a four year recycling grants and infrastructure program worth $465.7 million. The funds have been allocated to councils and private companies up to $10 million and $5 million respectively (Gavilan & Benord 2014).

By 2056, the Australian population will have increased to about 35.5 million people. During the period 2013-2014, Australia generated about 53.7 million tons of waste, with the construction industry accounting for 16.5 million tons (31%), making the sector to be the largest generator of waste (Gavilan & Benord 2014). Masonry materials accounted for the largest generation of waste by households and industry, generating 19.8 million tons (38%). Organic waste was the second largest generator, producing 6.4 million tons of waste. During the period, about 97% of the household waste was recycled while 73 % of consumer items were reused (Gavilan & Benord 2014).

Australia manages her waste by landfilling, recovery or exporting. Of the total waste output of the period 2013-2014, 25.2 million tons were recovered locally, 3.7 million tons were exported while the rest was landfilled. Of the recovered 25.2 million tons, 10.9 million tons were from masonry while 6 million tons were organic matter (Gavilan & Benord 2014).

Construction wastes are increasingly becoming pressing issues for developing countries. This is alongside having social, economic and environmental effects. The main issue in most countries is illegal dumping of physical construction wastes; with expended intangible wastes such as time wasted and the attached costs of such wastes. Developing countries are experiencing socio-economic developments in terms of rapidly increasing populations, shifting consumer behaviors, high demands for infrastructural projects and improving living standards; leading to a rapidly growing construction industry (De Sousa 2014). This growth has had significant input to the rising levels of construction waste generation in these countries; resulting to a variety of implications to societal economic dynamics and drastic environmental effects.

The comparison to the developing world, waste can be addressed through the case study of Malaysia, that in situated in the same geographic region as Australia.

1.4.1 Case study: Malaysia

The country is currently facing the menace of illegally dumping construction waste; filling tropical mangrove swamps causing ecological disturbances and roadsides in the entire country. This is a clear reflection that Malaysia has neither significant policies nor practices for managing construction wastes. The existing regulators for solid waste management include PPSPPA (Public Cleansing and Waste Solid Management, (PMA) Pembinaan Malaysia Act 1994, (EQA) Environmental Quality Act 1974 and (SBW) Standard Specifications for Building Works (Mo & Manaff 2014). The ministries governing the bodies are (CIDB) Construction Industry Development Body, ministry of Environment and natural resources and Ministry of Housing and Local Government respectively. These bodies have limited impact in managing construction waste. Apparently, PPSPPA is mainly concerned with more with domestic waste while paying little or no attention to construction wastes. SBW focuses on the needs of the contractor’s alliancing with the Public Work Department. The contractors clean and clear construction waste and garbage twice a week and eventually disposing the waste into approved dumpsites or in landfills. PMA indulges in prevention, reduction and controlling of pollution as well as environmental conservation and preservation. PMA considers waste as gaseous, solid, liquid or radioactive; and either schedule or normal waste. The law only recognizes waste after it has been dumped illegally or has caused environmental pollution. Pembinaan Malaysian Act further serves to control construction activities in the country, enabling investigative officers to access construction sites at convenience for purposes of inspection. Hulu Selangor District is the most affected region in Malaysia, harboring about 39% of the total waste output in the country in about 87 illegal dumpsites (Mo & Manaff 2014). The Malaysian government has recently entered into alliances with the private sector waste management companies for a period of 22 years in order to curb the waste menace. However, the government has failed to give special attention to construction waste but has instead directed resources to domestic waste. This adds to the problem of managing construction waste.

Subsequently, cost and time overruns in the industry have resulted to abandonment of many construction projects in Malaysia. According to the Ministry of Housing and Local Government, about 35 projects holding more than 12,000 housing units were abandoned in 2014(Mo & Manaff 2014) . This is as a due to lack of enforcing current regulations on construction, construction delays, wrong construction specifications and ineffective financial management by project developers. As such, there is a tensed relationship between buyers and such developers; a reflection that intangible construction waste is in effect in Malaysia.

The Malaysian case study serves as a representation of how developing countries handle construction waste. It is evident that the existing policies and regulations in such countries, though effective, fail to directly address the issue of construction waste. In order for construction waste to be handled effectively, there is dire need for collaboration of all stakeholders. There should exist a streamlined communication and rapport among clients, consultants and contractors. Failure to establish such collaborations and communications will only lead to more waste in developing countries; to levels that may prove difficult to handle in future.

The composition of waste is a meaningful determinant of the recycling potential of the waste. Nevertheless, there exist numerous differences between developed and developing countries which have various implications on the potential for recycling.

Oman has a population of about 3.9 million people and generates about 1.7 million tons of solid waste annually with a per capita daily waste of about 1.2kg (Taha et al. 2013). Apparently, waste management is a disturbing issue in the country as a result of the scarcity of land as well as environmental and health impacts of the waste. The form of waste produced in Oman is potential to high recyclability inclusive of 4% glass, 1.8% metal, 20.9% plastics and 15% cardboard and paper (Taha et al. 2013). The country has however not tapped its full recycling potential, since most of its solid waste is dumped in both authorized and unauthorized landfills. The country has 350 landfills operated by the municipality, alongside many illegal dumping sites where all forms of waste is dumped illegally. Al Almerat Landfill is the most popular. Established in 2011, the landfill lies over 9.1 hectares piece of land with five cells that can hold about 10 million cubic meters of solid waste (Taha et al. 2013).

As a result of the construction project of urban development in the Sultanate of Oman, the construction waste represents 10-30% of waste dumped into landfills (Rawshan et al, 2006). In 2014 the amount of construction waste reached 735,341 tons (Taha et al. 2013), and is expected to increase in light of the upcoming development projects. The coastal road is the major projects in the current period will be demolished more than 2,000 homes (Taha et al. 2013). So Oman’s Government developed strategy to make use of these residues in the operations of the construction of roads, instead of wasting them, or disposed of in the valley streams or on the roads near residential areas.

Construction waste recycling is a successful sustainable strategy, where it can recycle 80-90% (Rawshan et al, 2006). Since the recycling lead to reduce the use of natural resources process, reduce the cost of production and transfer the raw materials and reduce waste transferred to landfills (Vivian et al, 2006). In addition, it reduce the health and environmental problems for this waste, where it caused a growing amount of pollutants resulting from dusting and concrete materials (Rawshan et al, 2006). The cause of this waste piles in the multiplication of rodents and insects that lead to the transfer of various diseases.

The construction industry uses myriad varieties of raw materials and in vast amounts. For this reason, as mentioned earlier herein, about 10% of the raw materials are wasted. Without proper waste management, these raw materials end up in landfills or in other dumpsites where they are potential to becoming environmental and health hazards. The construction industry, for this reason, is provided with a great opportunity to reuse, recycle or recover the wasted construction materials. The benefits attached to recycling construction waste include reduction of carbon emissions and disposal costs. Recycling is also useful as it assists the recycler to adhere to policies and legislations governing which waste should be taken to the landfills and which one should be left behind for reusing or recycling.

Tiles are recyclable from construction wastes such as floor tiles, ceramic walls, porcelain floor and wall tiles, stone marble, glass, slate and panel board products. Often, 8-10% tiles are wasted on walls and floors, 5-10% on floor rolling and 1-5% on flooring tiles (Bilgin 2012). This wastage is caused mainly by over ordering, breakages and cut-offs. To recycle tiles, the following processes are employable;

1) Fibresolving- wood fibers are subjected to pressurized steam in a vacuum at high temperatures and under mechanical agitation.

2) Microreleasing- the wood fibers are reclaimed from the resin by use of microwaves.

3) Thermohydrolic procedures- wood fibers are separated from the adhesive

4) Composting

To allow for more tiles to be recycled, it would be meaningful to; plan slow periods of demolition, provide training concerning how to handle the tiles for the staff, recovering materials instead of dumping them in the landfills, improvement of transportation procedures (Bilgin 2012).

In New Delhi, India, the Burari plant has proven the possibility of turning construction waste into tiles. In New Delhi, about 5,000 tons of construction and demolition as well as land clearing debris are generated on a daily basis (Bansal & Singh 2014). The plant, established with an initial processing capacity of 500 tons daily, has doubled its processing and production capacity. The plant processes about 1200 tons of waste per day and is set to expand to 2000 tons per day (Bansal & Singh 2014). Once the debris is brought to the plant, it is sorted to separate waste such as wood and plastic which are taken to another plant, Okhla for waste-to-energy recycling. The waste is then crushed and upon washing; used to make tiles and other products like manufactured sand, hollow bricks, pavement blocks, cement bricks and kerb-stones.

1.1.2 Perlite

It consists of steady silicates that are static and strong for use as a lightweight aggregate or for insulation. Its weakness is that it’s small in size, and has extreme lightness.

The small particle size requires more cement, while its light from 8 to 16 lbs per cu. ft. It has the tendency increase to soar out of the mortar. It’s helpful where maximum strength is not required, such as precast slabs and blocks and in floor fill, fireproofing and plaster (Sriwattanapong et al, 2013 p.227).

1.1.3 Vermiculite

Vermiculite is a micaceous mineral that expands on purpose of heat to as much as 30 times its original volume (Meszarosova et al, 2013 p.584). The dehydrated ore is passed through 1800 degrees temperature for 4 to 8 seconds, after which it weighs up to 6 to 12 lbs per cubic ft. It is used as an aggregate in concrete fireproofing steel, for floor and roof fill, and for audio and fire proof plaster (Youn et al, 2014, p.442).

1.1.4 Aggregates

Aggregate is a mixture of crushed rock, sand, gravel in their natural state or manufactured, where it is used to provide strength, wear resistance and bulk in construction (Barkdale, 2000, Robinson et al, 2004). Aggregates are used in asphalt paving, for the production of Portland reinforced concrete in the construction of roads and buildings in the United States. While in Europe, Aggregates are used to describe ceramics, bricks, and recycled concrete to be used in construction projects after it crushed. At the moment, Europe began to recycling aggregates to product new concrete (Weil et al, 2006).

Figure 1 shows that aggregates represent 75% of construction and demolition waste resulting from paving roads, building houses and demolished (Merino et al., 2010). As a result of this ratio, many states developed strategies for recycling aggregate and use them to fill the loose of infrastructure such as roads. Also use recycled aggregates in cement production, where it contributes to reducing the use of natural resources by more than 40% (Weil et al., 2006).

1.1.5 Wood

Clean and contaminated wood constitutes 11% (Figure 1) of the total waste produced resulting from the remnants of doors, window frames, etc (Merino et al., 2010). Clean wood is wood that has not been added to materials such as plastics, adhesives, chemicals, ect. While the contaminated wood has been added paint, glue, chemicals to maintain it against mold, etc. Since the contaminated wood cannot be recycled or used, due to the presence of hazardous substances may affect people's health in the long term (Dillon Consulting Limited, 2006).

1.1.6 Gypsum Board

Used gypsum board is often in the work of decoration and ornamentation. Where the white cement a large proportion in the mixture. Also, gypsum is considered part of the construction waste, where it is disposed of by landfill. However, it has been found that under certain conditions, the gypsum board can produce hydrogen sulfide gas (H2S), as well as leaking sulfide material if mixed with biodegradable waste (WRAP, 2006). As these toxic gases and flammable. During the past decade, it has become gypsum board is separated from the rest of the waste that is landfilled, in order to reduce the production of hydrogen sulfide gas (WRAP, 2006).

1.1.7 Metals

Metals are considered as a waste produced in the construction industry, because of the high cost of mineral products (Winkler, 2010). Minerals make up remnants of 5% of the total waste (Merino et al., 2010). These residues include iron, copper, aluminum. Usually, at construction sites are provided special containers to collect these residues. Where they can recycle these metals by melted down and re-production of new materials such as such as electric cables, copper pipes, etc. (Winkler, 2010).

1.1.8 Expanded shales and clays

These are light concrete that require heat in a kiln to a temperature near the blending point. The heated material softens and coalesces to a sticky mass (Bogas et al, 2014 p.2). The escaping gases are trapped forming cellular structures and expanding 50% volume of the material (Koshiro et al,2014).The crushing and firing operations are varied with different processes. The material is fired to a clinker then crushed and the size is often reversed with crushing operation. Examples of the materials involved are rocklite, dioatimte haydite and airox.

Aggregates are material suitable for use in the installation of tiles mixture. Since this material can be converted into softer material through the crushing more. In addition, it has produced a large proportion of construction waste, can also be obtained from concrete, bricks. Furthermore, the characteristics and features contained in aggregates such as strength will earn tiles hardness and strength of the ordinary tiles.

1.1.9 Characteristic of light weight aggregate concrete

An essential characteristic of lightweight concrete is the excellent attachment involving the aggregate and the adjacent hydrated cement paste. This is the outcome of several factors. Firstly, the coarse surface texture of many lightweight aggregates is positive to a fine mechanical join linking the two materials. In actual sense, there is frequent diffusions of cement pastes into the unwrapped surface holes in the coarse aggregate particles (Koshiro et al, 2014). Secondly, the moduli of flexibility of the lightweight concrete particles and of the toughened cement pastes do not modify much from the other (Bogas et al, 2014 p.269).

Lightweight concretes are beam due to the enclosure of air voids and their absorbance; expect a few with sealed cells. This absorbance plays a significant part in the way the concrete perform in its wet shape. Majority lightweight aggregates are artificial and they are produced in a careful, uniform and consistent manner that is important to mixing, placing and compaction (Bogas et al, 2014 p.1).

A diversity of normal and artificial porous solids, are available for use as lightweight aggregates (Koshiro et al, 2014 p.308). Generally, the upper the porosity of the aggregate, the low the thermal conduction, density and strength of the lightweight concrete completed with it. Concretes containing elevated absorbent such as vermiculite create lower-weight concretes of exceptional thermal shielding value but little resistance to stress (Meszarosova et al, p. 584). The less absorbent lightweight aggregates can make concretes which are strong enough to stand firm the structural pressure, but which are solid and less competent thermal insulators than those complete with the high-porosity aggregates (Koshiro et al, 2014 p. 38).

An appropriately intended concrete blend will have the preferred workability designed for the new concrete and the necessary toughness for the hard-edged concrete. Characteristically, a mix of 10 to 15 % of cement, 60 to 75 % concrete and 15 to 20 % water as reagent. Many types of concretes are cellular concretes prepared with bubbles or fluffy agents; some have lightweight aggregates and other lightweight aggregates (Moreno et al, 2014). Other lightweight concretes can have some standard weight sand.

1.1.10 Characteristic of light weight concrete tiles

a. Pumice concrete

It is a light weight concrete of volcanic origin that weighs 25 to 60 lbs per cu. ft. it is fit for use when it is hardened and well graded. The undesirable feature is that it absorbs a lot of water. In regard, this can be moderated by dripping in water before mixing with cement (Koshiro et al, 2014 p.308).

b. Coal cinder concrete

This type results from the burning of coal, they consist of ash components of coal with various amounts of unburned flammable matter. A few consists of explosive matter that have caused harmful expansion of concrete in which they have been used. Also have minimum amount of burnable material that are satisfactory for use in concrete but are not mainly weight reduction (Bogas et al, 2014 p.3).

c. Autoclaved Cellular concrete

This is a type of concrete tiles that are formulated so as to hold a large proportion of gas bubbles as an outcome of a chemical reaction that takes place in an atmosphere of stream (Meszarosova et al, 2013 p. 584). Autoclaved cellular concrete (ACC) is a lightweight pre-cast concrete building material that is alleviate under high weight inside particular kilns called autoclaves (Sriwattanapong et al,2013 p.227).The basic raw materials for ACC are cement, limestone, aluminum powder, water, and a large proportion of sand. The raw materials are assorted into slurry and poured into greased molds and the aluminum powders react chemically to produce millions of minute hydrogen gas bubbles.

The autoclave uses high-pressure steam heat of approximately 356° F (180°C) to speed up the hydration of the material and impel a second chemical reaction that provide ACC strength, rigidity, and dimensional constancy (Meszarosova et al, 2013 p. 584). Autoclaving in 8 to 14 hours can create concrete power equal to strengths acquired in a concrete alleviated moist for 28 days at 70° F (21°C). The end products are typically enfolded in artificial and elated straight to the construction site (Meszarosova et al, 2013 p. 584).

Light weight concretes has been exposed by examination and by performance to perform structurally in much the equal way as normal weight concrete. Some differ in characteristics since the variation are largely those of degree (Meszarosova et al, 2013 p. 584). Thus, the designers must reflect on the reimbursement of lighter weight and improved insulation in relative to the extra cost of the lightweight blend. The engineer must be familiar with the few different requirements relation to transporting placing and finishing. It is the characteristic mixture of functional and aesthetic properties that has made concrete the main construction material worldwide.

1.1.11 Advantages

a. Durability

Lightweight concrete tiles made from waste construction products are best known to be noncombustible. As such, the tile is proven to be a fire resistant construction material. Additionally, the lightweight concrete tiles are able to withstand wider range of climatic swings be it freezing temperatures or high temperatures. Considering the roofing tiles, the designed tiles are able to withstand seismic forces arising in earthquakes that are far greater to 0.8 gravity (Bremner, 2014). Thermal and radiant capability of the lightweight tile made from construction waste boost the durability of the concrete tile. According to a 2000 study conducted by the Florida Solar Energy Center, a constructed lightweight concrete roof tile reduces the transfer of solar heat by an almost 48% in comparison with other roofing types like black shingle (Libby, 2013). Such aspects make the lightweight concrete tiles from construction wastes to last to almost 100 years hence reducing construction waste due to limited possibilities of replacing the tiles (Chava, 2014). Additionally, the tiles are not made with petroleum based products like asphalt shingles hence the cost of making the product is not vulnerable to oil price flactuations

b. Workability

Concrete tiles made through construction wastes are essentially lightweight. The aspect makes it easier to place at the designed location in a building through an advantage of using less skilled labor. Additionally, the designed lightweight concrete tiles can be drilled and designed in to expected shapes through the use of standard hand tools, regular screws and nails (Desai, 2014).

c. Cost Efficient

The use of construction waste to manufacture lightweight tiles makes the end product be cost efficient through the manufacturing process to the end product hence cheaper in sell prices. This implies that the product is cheaper compared to other competitors like clay tiles which cost 30% more than concrete tiles yet concrete lightweight tile has a nice combination of the durability (Al, 2015). If a constructor is willing to save money, it is advisable to concrete lightweight tiles.

d. Savings in Materials

Lightweight concrete tiles construction from construction waste reduces materials used by 10%. This implies that no gravel is required for the production of the tile and only the sand and the cement mortar are embedded in form (air) for the production. For certain application of the tiles, no plaster is required but only gypsum putty is directly applied before painting hence saving on the materials. Using lightweight concrete tiles can cast walls as thin as 50mm (European Concrete, 2014)

1.1.12 Disadvantages

a. Compressive Strength

Basically, lightweight concrete aggregates are used to control the compressive strength performance in concrete tiles. The major two factors that determine the compressive of the concrete tile from the construction tile is the strength of the aggregates being used and the strength of the hardened cement-water paste. Considering the usual use of cement-water paste in making concrete tiles, the lightweight concrete tiles made from construction waste are weaker in regards to the usual range of cement content (American Society for Testing and Materials, 2013). As such, lightweight concrete tiles made from construction waste products are low in density and lower in the strength of the lightweight aggregates that essentially reduces the comprehensive strength of the tiles (Jones, 2012).

b. Cracks

Lightweight tiles constructed from waste construction materials crack easily especially in higher moisture conditions or walked on during construction or repairs. Moisture affects the lightweight tiles through regular freezing and thawing climatic cycle conditions resulting tile cracks because moisture sweeps beneath the surface of tile (Blair, 2014). During the drying or firing processes on making a tile, the lightweight tiles might develop shrinkage cracks hence creating weak points for easily breakage of the tiles. During the construction process the debris left in the interlocking channel creates load points that contribute towards tile cracks. Additionally, when exposing the lightweight tiles to rain, snow and sun, the tile begins to fade its color. As such, during the replacement of a broken or faded tile with a new one, it mismatches the rest of the tiles hence affecting the beauty pattern of the tiles.

c. Aging Process

The aging process of lightweight tiles constructed from waste materials makes the tiles to be completely saturated. This is due to the continuous erosion of the cement used and the mix aggregates used that makes the tiles to be more absorbent especially more moisture that makes them to age quickly. At this phase it is easier to observe pitting, cracking, displaced or missing tiles, thinning of the glaze, dripping of moistures from underneath of the tiles and continuous efflorescence forming on the tile (UNDP, 2013).

d. Installation Process

Working with lightweight tiles presents a number of challenges in installing process. It is a bit difficult to walk on and work within such tile with fear of breakages because the latent condition of the within environment is not well known. Additionally, it proves challenging in preventing waterproofing and the mounting penetrations at the underlayment level especially in lightweight concrete roofing tiles. As such, it is very important to embrace mounting technologies in any aspect of tile installation process that ensures the flashing of underlayment penetration hence enabling the tiles to last for decades regarding aspects like wide temperature differentials (Alfsen, 2013). Additionally, sealant and double flashing is needed during the installation process especially on the roof. This is purposefully done to try and repel water which is well known to be very expensive.

It is recommended that the results obtained through this project propose that there are numerous research issues with value to these materials that are worth for further analysis (Zhu et al, 2015 p. 620). The use of the waste materials from construction results in the formation of lightweight concrete (Yardim et al, 2013 p. 405). The usages of such waste materials cut down the price of constructing, but also add in secure disposal of the waste materials. The provisions and necessities on the results pass on to the usage of normal weight aggregates (Zhu et al, 2015 p.622). Hence, it is necessary to create further suggestion when lightweight aggregates are used to make structural concretes (Gesoglu et al, 2014 p.6). A broad variety of compactness and mechanical property may be achieved by considering the normal weight aggregate that may be changed light weight concrete in a fractional method, changing the coarse portion of the concrete (Ally et al, 2012 p.127).

1. Designation of aggregates

When locating the usage of waste materials for light concrete by mass, it must be taken into consideration that the granules metric charts may perhaps not be formed by weight for the light aggregates. In regard, it is essential to alter the description of an upper limit volume of an aggregate, and as an alternative of classification of the concrete by weight where it is distinct by volume.

2. Aggregate particle size grading

Notably with regard to the grading examination, the usual process for selection and formatting the weight of the preserved fraction is scarce since the disparity sized portions have diverse densities (Dunant et al, 2012 p.745). If the aggregate is of regular mass and its density does not depend on its size, it is probable to modify weight to volume openly (Khayat et al, 2014 p.145). The same process practical to light aggregates provide incorrect data since the diverse portions or mass possess various mass. This may be taken into consideration when determining the density of every part and if the resulting volume is considered. At this state, it is probable to regard the same grading limits recognized for fine aggregates of normal weight (Gesoglu et al, 2014 p. 6).

3. Physical-mechanical requirements

Light weight concretes are not tough compared to concretes of normal weight but equal under solidity and when subjected to the process of wear by abrasion and crushing (Ally et al, 2012 p.127). In this condition, the wear opposition of coarse aggregate shall not be assessed by the techniques or limitations of lightweight fine aggregate, evaluated in agreement with a micro-Deval test indicated (Khayat et al, 2014 p.145).

The combination ability of light weight concretes is usually high due to their low weight achieved through porous structures. The control of water absorption evaluation shall not be applied even if the processing presents a closed structure mainly if the absorption is articulated as a percentage of the aggregate or if the light weight concretes are less solid (De Brito, 2012). When the absorption is generally elevated the results of the properties of new concrete are drastically altered and different concrete methods or treatments shall be implemented during the concrete construction process (Ally et al, 2012 p. 128).

In regard to the frost opposition and structural light weight concretes, the occurrence of integrated air in the concrete assists to reduce corrosion in a similar mode with concretes of normal weight (Khayat et al, 2014 p.147). The concrete saturation level is a crucial aspect, as is the appropriate level of power. Evaluation of the ability of the light weight concretes to magnesium sulphate result due to the lower inherent power of the aggregates and its high combination of an isolated probability of compliance (Khayat et al, 2014 p.147). Generally, the fitness of the concretes shall be assessed under solidifying and melting process. Notably, the elevated power, adding of built-in air and a little level of diffusion concrete contribute to its performance (Gesoglu et al, 2014 p.6).

4. Composition

Composition of structural light concretes, usage of waste light aggregate, mixed saturation levels of light weight concretes and the kind and range of light aggregate have a straight influence on the properties of structural light concretes (Bissonnette et al, 2013 p.481). For this case, the composition of light weight concretes processes shall be inspected in advance, with no exceptions, to guarantee that it is capable to generate concretes that are automatic and solid for design needs (Yardim et al, p.405).

5. Concrete workability

The principles established in this project can be functional without the need for alteration. However, the uses of test methods ensure that the slump ability of light concretes is compacted (Khayat et al, 2014 p.145). Slump is the in a narrow cone that is suitable to the damage of concrete below its own mass (Long et al, 2012 p.38). The compactness of light concrete is lesser than that of standard concrete and for this reason it present a greater workability for equal slumps (Long et al, 2012 p.42). For the same basis, it is not measured practical to surpass the higher restrictions for solution uniformity even with the application of super fluidization preservatives.

6. Mixing of concrete

Generally, mixing of Structural Light Concretes takes lengthy time than conventional concrete (Khayat et al, 2014 p. 147). For that reason, lengthy time in mixing is necessary for the humidity of the concretes before adding up the cement and combination of the blend after adding preservatives following the adding of the total mixture of water. This occasion is mandatory to avoid quick absorption of water and preservatives and eliminate workability from the concrete combination and effectiveness from its admixtures (Khayat et al, 2014 p.150). The low mass of light concrete may cause it to soar at the start of the mixture, depending on the intensity of water diffusion it have when it come into contact with the mixing machine, which may establish effective application of the integration mechanism (Long et al,2012 p.38).

7. Compaction of light weight concrete

Compaction of the Structural Light Concretes needs an upper vibrating power than for normal concretes (Yardim et al, 2013 p. 405). As a result, solidification is passed out by dipping division connecting vibrator situations to 70% of the consumed standard light weight concretes (Dinakar et al, 2013 p.161). The surface coating of the face on which the concrete is located shall be shaped by suitable equipment used to compress the light aggregate and adjoin it to the mixture so that it is enclosed (Guneyisi et al, 2015 p.17).

Overall, the rapid increase of population and construction in the world is generated millions of tonnes of construction and demolition waste and this waste is growing with the passage of time. It became a construction waste now troublesome problem for both developed and developing countries. However, the method of generating and waste management are different between countries. Oman as other countries, is considered waste management in general, and construction and demolition waste is particularly challenging issue because of its negative effects on the environment and public health. Oman put its priority to reduce this waste by using recyclable approach.

Production of light weight concrete tiles is a form of recycling of construction waste. As this Tiles has several properties such as strength, corrosion resistance, sound insulation, ect.. Moreover, Tiles like any other product has advantages and disadvantages. The advantages in durability, workability, cost efficient and savings in materials. In contrast, the disadvantages include compressive strength, cracks, and installation process.

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