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Abstract

The effects of steel rebars and cement which are the major constituents of conventionally reinforced concrete on the environment has been a major concern for all the stakeholders in the construction industry. Factors such as the cost of producing a cubic metre of SRRC, the high-energy required in the extraction and manufacturing of the constituent’s materials for its production and the effects of their end of life on the environment had made research on the use of alternative materials as part or full replacement of the two major constituents of SRRC a necessity. Therefore, this study is aimed at assessing and comparing the mechanical properties and environmental impacts of conventional reinforced concrete, steel fibre reinforced concrete, polypropylene fibre reinforced concrete and flax fibre reinforced concrete. The compressive, tensile splitting and flexural strengths which are considered as major properties are considered by reviewing past literatures while the life cycle assessments of the concretes were evaluated using past studies on life cycle assessment and simapro software. From the reviewed of existing literature, the mechanical properties of the fibre reinforced concrete are dependent on the length and diameter of the fibres (aspect ratio), the quantities of fibres used and their orientation. The addition of optimum quantity of 1.0% to 1.5% volume fraction of fibre gives a higher compressive strength of FRC than SRRC while fibre incorporation beyond the optimal volume fraction caused reduction in the compressive strength of the FRC. However, the more fibres incorporated in a concrete, the higher the tensile splitting and flexural strengths of such concrete. The tensile splitting strength of FRC in one of the past studies consulted showed an increase of 126.6% by increasing the fibre content from 0.5% to 2.0%. Another result showed that increasing the fibre contents from 0.5% to 2.0% caused an increase in the flexural strength from 18.96% to 98.28%. For the life cycle assessments, the environmental parameters of global warming potential, stratospheric ozone depletion, ionizing radiation, ozone formation (human health), fine particulate matter formation, ozone formation(terrestrial ecosystems), terrestrial acidification, freshwater eutrophication, marine eutrophication, terrestrial ecotoxicity, freshwater ecotoxicity, marine ecotoxicity, human carcinogenic toxicity, human non-carcinogenic toxicity, land use, mineral resource scarcity, fossil resource scarcity and water consumption were investigated using ReCiPe Methods (Endpoint and Midpoint)2016 H/ World 2010 H/ in Simapro 9.5 program. It was observed that concrete with conventional steel has the highest impact in 16 of the 18 environmental impact categories and has caused highest damage to human health and ecosystems. PPFRC has the highest index value in the damage to resources. All the environmental indices of FFRC were lower compared to other reinforced concrete types considered. It was concluded that the stakeholders in the construction industry work hand in hand to make use of eco-friendly materials such as fibres either as partial replacement or total replacement in concrete structures to reduce the quantities of steel and cement used in construction projects to help in achieving the limiting the impacts of global warming at 1.50C by year 2050.

Course: Civil Engineering - MSc - C0618

Date Deposited: 2025-01-15

URI/permalink: https://library.port.ac.uk/dissert/dis14636.html