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Abstract

Recycled fine aggregates (RFA) has been employed in the construction industry for sustainable concrete production in recent times in the quest to encourage sustainable development as part of the sustainable development goals and also gearing towards attaining net zero carbon emissions (climate change action) thus goals 11 and 13 respectively. The research aims to determine the best type and amount of RFAs to increase the compressive strength of concrete, with the ultimate objective being the reduction of greenhouse gas emissions and reduction of construction waste production. Based on a thorough analysis ofthe literature and laboratory experimental testing of concrete. A total of 42 ordinary concrete C30/37 and High Performance concrete C60/70 concrete cubes (100mmx100mmx100mm) were made out of two different types of recycled fine aggregates ; 1) manually Crushed 10mm recycled aggregates into SRFA and 2) Construction and Demolishing waste recycled fine aggregates(CDWRFA) with varying replacement percentages, control(0),25%,50% and 100% .These cubes were subjected to both wet and hardened mechanical testing (workability, Density and Compressive strength test).The study finds that the workability of SRFA performs poorly in high-performance concrete and works admirably in regular concrete. Equally, CDWRFA only exhibits intermediate workability in ordinary concrete, but it exhibits poor workability in high-performance concrete, requiring the use of superplasticizers to achieve better results for both high performance concretes. Compressive strength testing reveals that SRFA performs better, especially in Ordinary concrete. The greatest gains were seen when natural fine aggregates (NFA) were replaced with SRFA- 100% in high-performance concrete and 25% in regular concrete. On the other hand, both types of concrete in CDWRFA show compromised average compressive strength. It is suggested that in Ordinary concrete, NFA be replaced with CDWRFA to the tune of 25%, and in high-performance concrete, CDWRFA to the tune of 50%. These realisations help to minimise the carbon footprint of development projects, reduce waste production, and advance sustainable construction methods. Overall, the study supports the body of research that recycled fine aggregates has effect on compressive strength. These results demonstrate the extent and practicality of using RFAs in construction, if replacement percentages are carefully considered.

Course: Civil Engineering - MSc - C0618

Date Deposited: 2025-01-16

URI/permalink: https://library.port.ac.uk/dissert/dis14642.html