Open Collections

Hossain, F M Zahid

University of British Columbia

This research examined the impact of using recycled coarse aggregate (RCA), crumb rubber (CR), and polypropylene fibre (PPF) as partial replacements for traditional concrete coarse and fine aggregates. Through a series of experiments, the study assessed the compressive strength, tensile strength, and flexural response of recycled aggregate concrete with CR and PPF in comparison to natural aggregate concrete. Further tests examined the bond strength of concrete with steel reinforcement, aiming to optimise resource use, and investigated the shear behaviour of concrete beams containing RCA, CR, and PPF. The findings contributed insights into the potential of these recycled materials to create more sustainable concrete solutions. The study found that increasing crumb rubber (CR) content resulted in reduced compressive, tensile, and flexural strength while adding polypropylene fibre (PPF) improved these properties. For toughness and ductility, PPF had the most significant positive effect, with both RCA and CR enhancing these aspects when added incrementally. In bond analysis, combining CR and PPF reduced concrete’s bond with steel reinforcement, though using either material alone in certain RCA mixtures improved bond strength. Shear strength tests showed that CR reduced shear strength, post-diagonal cracking resistance, toughness, and deformability in concrete beams, but adding PPF enhanced these effects at up to 30% RCA replacement. The optimal composition (30% RCA, 5% CR, and 1% PPF) showed the best shear resistance, deformability, and toughness, with minor rubber additions (up to 5%) enhancing beam deformability and fibre increasing post-crack resistance. The research concluded that the optimal mix for sustainable concrete applications of recycled materials includes up to 30% recycled coarse aggregate (RCA), 5% crumb rubber (CR), and up to 2% polypropylene fibre (PPF). This combination demonstrated the best balance of mechanical and structural performance, making it a viable option for integrating recycled materials into concrete in future.

Text

2024-12-16

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/89889

Civil Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/