Effects of Anionic Asphalt Emulsion on Early-Age Cement Hydration
Cement-asphalt mortar (CAM) is a cement-based, asphalt-modified, inorganic-organic composite. In this study, the effects of anionic asphalt emulsion on early-age cement hydration of CAM pastes are investigated. The setting behavior, heat of hydration, and electrical resistivity of CAM pastes with different asphalt-to-cement (A/C) ratios are evaluated. The results indicated that the set time of cement paste was prolonged and the heat released from cement hydration was delayed with increased A/C. During the early state of cement hydration, the resistivity of the CAM paste studied was higher than that of the corresponding Portland cement paste, indicating that the asphalt emulsion hindered the ion dissolution of the cement in the CAM paste. However, during the acceleration period of cement hydration, the resistivity of the CAM paste studied was lower than that of the corresponding Portland cement paste, implying that the formation of microstructure of the CAM paste was delayed. This retardation phenomenon could be attributed to two mechanisms: (i) the active sites of cement particles that could have been occupied by asphalt emulsion through anionic emulsifier via electrostatic interaction and (ii) the most surfaces of the cement particles that might have been covered by asphalt membrane due to the demulsification of asphalt emulsion.
The present study is a part of the research project supported by the National Natural Science Foundation of China (No.51708483). This paper is modified from a part of publication of Ref. .