Incorporation of crumb rubber and air-entraining agent in ultra-lightweight cementitious composite: Evaluation of mechanical and acoustic properties

This research describes the usage of crumb rubber (CR) and air-entraining agent (AEA) to further reduce the density of lightweight cementitious composite into ultra-lightweight cementitious composites (ULCC), which has density lower than 800 kg/m(3). The effects of CR and AEA on workability, compressive strength, flexural strength, sound absorption and sound transmission loss of ULCC are evaluated. The dry densities of the ULCC produced are in the range of 711-857 kg/m(3). Compared with the control mix, the addition of 1% of AEA and inclusion 15% of CR have similar effect in reducing the density of ULCC, where the density is reduced by about 15%. Despite the decreased mechanical strength with the use of CR, the ULCC still possess good flexural strength of 2.4 MPa without AEA. Furthermore, the effect of CR is more significant than AEA in improving the sound absorption average (SAA) of ULCC which the SAA of the control mix is increased by 61.3%. Overall, the combination of CR and AEA reduced the density and improved the acoustic performance of ULCC.

Automated summary

The research shows that the combination of crumb rubber and air-entraining agent can effectively reduce the density of cementitious composite and improve its sound absorption performance. The use of CR and AEA together in ULCC production is efficient in reducing density and enhancing acoustic performance.