A comparative study on early-stage strength development and mechanical properties of cement emulsified asphalt mixture using brake pad waste

This paper aims to investigate the feasibility of using brake pad waste (BPW) in cement emulsified asphalt mixture (CEAM). The effects of BPW filler on early-stage strength, mechanical properties and durability of CEAM were experimentally studied, while mixtures with basic oxygen furnace (BOF), fly ash (FA), hydrated lime (HL) and conventional limestone filler (LF) were prepared and tested as comparison. Results indicate that strength of BPW mixture in early stage and after fully cured are smaller than that for the contrasting mixtures with common by-product fillers. The reason might be that BPW filler has no significant effect on hydration reaction of cement, due to its non-active characteristic. However, the engineering performance of BPW mixture is comparable to that with artificial by-product fillers. Moreover, result of dynamic modulus test implies that the temperature and frequency dependence of CEAM is weaker than the HMA. And there is no obvious difference in viscoelastic characteristics of CEAM mixes using various fillers concerned. The research demonstrates that BPW filler can be used as an alternative material for mineral filler in CEAM.