Prediction model of compaction process parameters for pavement of cement emulsified asphalt mixture based on effective compaction work

Abstract

Cement emulsified asphalt mixture (CEAM) is a semi-flexible pavement material, which is formed by the organic combination of aggregate, cement, emulsified asphalt and water. The compaction process of CEAM includes demulsification of emulsified asphalt, hydration of cement, evaporation of water, and formation of a three-dimensional interwoven network of aggregate, cement and asphalt. Therefore, it has different compaction deformation characteristics from the hot asphalt mixture. In order to explore the theoretical model of compaction process parameters for pavement (PCPP), which are based on compaction deformation characteristics and strain energy theory, effective compaction work (ECW) was defined as the compaction work consumed by viscoplastic compression displacement of the material. The mechanical response is studied by compressive testing and a calculation model for lab-scale effective compaction work (LECW) is established for CEAM. Furthermore, a calculation model for effective compaction work in pavement (PECW) is established based on the work-energy equivalence principle and roller compaction datas. In addition, a prediction model of PCPP for target dense degree (TDD) is obtained by the equivalence of LECW and PECW, and the introduction of energy absorption efficiency (EAE). Moreover, the PCPP combination modes during three stages, i.e., initial compaction, re-compaction and final compaction, of the roller are determined according to the compaction deformation characteristics of CEAM material. Based on the compaction combinations modes, the compaction process parameters combinations (CPPC) during the three compaction stages for the TDD are derived from the prediction model. The reliability of the proposed model is verified by a road compaction test. The CPPC results reveal the reliability of established LECW and PECW models. However, the EAE of vibration compaction in the prediction model is revised to be 76.05% after the road compaction test. The prediction model and introduction of EAE provide a theoretical baseline for the parametric design of compaction and construction process of CEAM and other pavement materials.