Effect of crumb rubber and silica fume on the fresh, hardened and concrete-steel bond strength properties of SCC

In recent years, the use of various industrial by-products and waste materials in concrete has attracted the attention of researchers around the globe to reduce their impact on the environment and to find sustainable solution to conserve natural resources. The use of end-of- life tires of vehicles in concrete is one such example. This research study investigates fresh and hardened properties, and bond stress-slip behavior of self-compacting rubberized concrete with and without silica fume. RILEM-FIP-CEB beam testing arrangement was employed to perform bond tests. The first part of the study focused on the development of self-compacting rubberized concrete (SCRC) with and without silica fume (SF) and investigating its fresh and hardened properties (compressive and tensile strengths). The second part focused on investigating bond stress-slip behavior of SCRC with different percentages of Crumb Rubber (CR) varying from 5% up to 30% as sand replacement by volume. Total 12 concrete mixes were prepared for this study. The experimental results showed that the replacement of sand with CR has negative effect on the fresh and hardened properties of SCRC. The bond strength was found to be decreased by 38% with 30% replacement of sand with CR. Further, presence of CR in the concrete mix caused detrimental effect on the bond stiffness and toughness. However, SF improved the mechanical properties and bond strength of SCRCs. This study found that replacement of sand with 10% CR by volume and addition of SF in concrete resulted in similar mechanical properties and bond strength as that of normal self-compacting concrete which demonstrates the potential use of SCRC in structural applications.

Automated summary

In recent years, researchers have focused on using various industrial by-products and waste materials in concrete to reduce environmental impact and conserve natural resources. This study investigates the properties, bond stress-slip behavior, and use of self-compacting rubberized concrete (SCRC) with and without silica fume. The results show that the replacement of sand with crumb rubber (CR) has a negative effect on the fresh and hardened properties of SCRC, but the addition of silica fume improves its mechanical properties and bond strength. By replacing 10% of the sand with CR and adding silica fume, the SCRC achieves similar properties and bond strength to normal self-compacting concrete, showing its potential for structural applications.