Pretreatment and Modification Effects of Convenient Asphalt Concrete

The convenient asphalt mastic (CAM) is prepared by the pretreatment process of cationic rapid setting emulsified asphalt (CRS-1) with cement. The CAM is then mixed with the aggregate to produce the convenient asphalt concrete (CAC) mixture. The pretreatment is to mix sulphonated naphthalene formaldehyde condensates (SNF) with emulsified asphalt evenly. In the pretreatment process, the SNF generates a protective barrier outside the electrical double layer on the surface of the emulsified asphalt micelles, which can inhibit the demulsification of micelles and improve the stability of CRS-1 in the CAM preparation. The residual SNF in the pretreatment proceeding can also be used as a water reducing agent, which can improve the workability of CAM and provide a dosage ratio that can increase the cement content. The increase of cement content in CAM can significantly improve the mechanical properties of CAC. The results of this study show that as the SNF pretreatment dosage increases, CAM viscosity decreases, and the CAC mixture has better workability. The Marshall stability value of the CAC obtained by CRS-1 (pretreated with SNF) can reach about six times that of hot mixture asphalt (HMA) at 28 days of age. The compressive strength can reach more than three times and the 40°C resilient modulus can reach more than eight times. Clearly, the modification effect of the pretreated CAC significantly enhances the mechanical performance.