Microstructure characterisation and performance investigation of a rapid hardening emulsified asphalt seal mixture

In terms of longer hardening time of emulsified asphalt seal mixture, a rapid hardening seal mixture was prepared by adding cement and carbon fibre to the Styrene–Butadiene-Rubber (SBR)-modified emulsified asphalt. The mix proportion of mixture was determined by testing the mixable time, consistency, wet track abrasion value, adhered sand content, cohesion force and the cracking rate. The microscopic mechanisms of rapid hardening and cracking control were studied using the Scanning Electron Microscopy (SEM) and the Fourier Transform Infrared Spectroscopy (FTIR). It is found that the optimum contents of SBR-modified emulsified asphalt, added water, cement and carbon fibre in the prepared mixture are 12%, 13%, 4% and 4%, respectively. At 20°C, with a relative humidity of 90% and a wind speed of 10 km/h, the opening time to traffic of mixture adding 4% ordinary Portland cement can be 2 h earlier than that without cement.