Practical Application of Crumb Rubber Concrete in Residential Slabs

Abstract

While there is extensive data now available for the performance of crumb rubber concrete (CRC) in laboratory mixes, it is essential to understand whether satisfactory performance can be replicated in real-world structures. This is particularly the case for the area of residential construction, which is a sector that is sometimes characterised by fairly average outcomes due to a sometimes-low skilled workforce operating with minimal supervision. To replicate a real-world situation, CRC research has been moved from “the lab to the slab” in this paper. Two large-scale (4 × 8 m each) reinforced concrete residential footing slabs were constructed. One was cast with CRC and the other with a standard residential mix of conventional concrete (CC). In addition, two reinforced concrete residential ground slabs of different dimensions were constructed out of CRC and CC mixes to assess abrasion resistance. These ground slabs were poured in high traffic entrances of a civil engineering laboratory. All mixes were provided by a commercial ready-mix company and the construction was undertaken by an experienced footing contractor. A large range of factors have been investigated and compared. Those related to construction requirements, included the effect of using rubber on concrete mixing, delivery, workability, pumpability, ease of surface finishing, and curing. The contractors reported easy screeding and less physical effort to do so, with no difference reported when finishing the concrete surface when using a concrete power trowel for footing slabs. Other factors that were investigated included: fresh and hardened density, compressive strength, modulus of elasticity, shrinkage, carbonation, chloride ingress, abrasion resistance, rising damp, and corrosion. The results show that CRC is a potentially viable and promising alternative to conventional concrete in the residential concrete market.