assignment 109

Final Frontier: Implementing Ultra High Performance Fibre

Reinforced Concrete (UHPFRC) in Marine Environments

[First Name]. [Last Name]1,*

1 Department Name, University Name, Address, United Kingdom

Problem statement

2. Fibre reinforcement:

3. UHPFRC - Current Limitations

Fibre Reinforced Concrete (FRC)

High Performance Concrete (HPC)

High Performance Fibre Reinforced Concrete (HPFRC)

Ultra High Performance Fibre Reinforced Concrete (UHPFRC)

The mechanical behavior of fibre reinforced concreted is governed by the mechanical properties of the interphase region between fibre and OPC matrix (including fracture toughness, critical strain energy release rate and interfacial shear strength = ISS) – these can change the trajectory of cracks propagating through the component, as well as modify the location of cracking. This is dependent on the fibre type, the most commonly used are Torex © (Figure iii) fibres

1. Concrete Evolution & Innovations

methodology

The use of Finite Element Analysis (FEA) modelling can speed up testing of exposure conditions – varying so the combination of high temperature and seawater exposures can be assessed individually.

Compressive & Split Tensile Strength

Finite Element Analysis (FEA)

Nanoindentation

The use of nanoindentation (xi) can probe the microstructural features, thus:

Assessing localized corrosion damage (Robert E. Melchers & Chaves, 2019) and corrosion damage penetration depths

Assessing parts of the composite which might be exposed but are not probed by standard EN 196-1 (2005) such as the edges of a beam

Investigating the separate effects of:

Fibre type (Torex fibres, PVA fibres etc..

Fibre aspect ratio (diameter to length ratio)

Matrix density (from manufacturing

Ethics, Health & safety

Cuadrf, F. (2017). Ultra High-Performance Fiber-Reinforced Concrete ( UHPFRC ) : a review of material properties and design procedures.

R.. Thyroff

Hussain, S., Bhunia, D., & Singh, S. B. (2016). An experimental investigation of accelerated carbonation on properties of concrete. Engineering Journal, 20(2), 29–38. https://doi.org/10.4186/ej.2016.20.2.29

Miguel, L. F. F., Riera, J. D., Iturrioz, I., & Aráoz, G. F. (2016). Influence of the Width of the Loading Strip in the Brazilian Tensile Test of Concrete and Other Brittle Materials. Journal of Materials in Civil Engineering, 28(11), 04016136. https://doi.org/10.1061/(asce)mt.1943-5533.0001628

References (Figures):

Sustainability & Ecological Impact:

Carbon cost for manufacturing OPC

Carbon cost for extracting aggregates for the matrix

Potential solutions:

Aggregates extracted from mineral waste instead (Suárez González et al., 2020)

Use of alkali-activated fly ash and slag (AAFS) mortars (Dong, Elchalakani, Karrech, & Yang, 2020) which enables higher degree of steel fibre protection

Acidification of the seawater environment from corrosion by-products

Negative impact on biodiversity

Increase in dystrophication

Differences in applications that are seawater and freshwater (including brackish waters)

Environment, Health & Safety (EHS) Ethics:

Already well-established (Van Broekhuizen, Van Broekhuizen, Cornelissen, & Reijnders, 2011) for UHPFRC

Ductility shown to even withstand seismic events with a 0.02 plastic drift ratio in design code (Liu, Shan, Lai, Liu, & Xiao, 2020)

Elevated production cost compared to elder versions of High Performance Concrete (HPC) and Fibre Reinforced Concrete (FRC).

Increase in cost associated with reduction in accessibility to stakeholders worldwide

Ethical concerns surrounding structural and social integrity if first-world countries have access to more advanced concrete structures first, widenign the inequality gap

Research Ethics:

Only a handful of groups are investigating the corrosion resistance of UHPFRC, could lead to biases in findings

Corrosion impact has been assessed as negligible when compared to other issues (Liu, Shan, Lai, Liu, & Xiao, 2020) around commercialisation of UHPFRC including:

Concrete shrinkage

Alkali-aggregate reactions

Structure cover deterioration

The setting of relevant testing standards follows previous research on HPC

Project progress & RESULTS

CONTACT EMAIL:

[Insert Email here]

or scan the following QR code:

[INSERT QR CODE TO EMAIL ADDRESS + NUMBER]

c.f. https://www.qr-code-generator.com/

Potential solutions to problems found in literature:

UHPFRC only used as a single layer within slabs (Menna & Genikomsou, 2021)

Use of a mixture of steel fibre lengths as reinforcement: to avoids interconnectivity of network

Use a mixture of fibre types such as relatively corrosive (steel) and less corrosive (PVA) micro fibres (Song, Yu, Shui, Chen, et al., 2020)

UHPFRC outperform their elder counterparts mechanically with ultimate tensile strengths at double those of ultrahigh (non-reinforced) concrete (Toledo Filho, Koenders, Formagini, & Fairbairn, 2012).

2 µm

Flexural strength (viii) of exposed composites can be assessed with the EN 196-1 (2005) standard.

Tensile and compressive strengths can be assessed using a variety of concrete-specific standards such as the tensile split test (ix) & the Brazilian disk tests.

Pre-mechanical testing checks for Friedel’s salt (x) and chloride binding (formed from reaction of chloride ions with alumina-rich matrix) to check for corrosion products.