Early Hardening Process of CA Mortar Indicated by Electrical Resistivity

A non-contact electrical resistivity measurement device was employed to indicate the early hardening process of cement asphalt emulsified mortar (CA mortar). It was found that this process was analogous with the hydration process of cement and could be categorized into three parts: dissolving period, induction period and setting period. The mortar resistivity first decreased and then increased with the elapsed time. The effect of water/cement ratio (W/C), asphalt emulsified/cement ratio (A/C), cement types were also explored. Results indicated that the increase of W/C, dosages in SF (Silica fume) extended the induction period; replacement of Portland cementII with sulfoaluminate cement in CA mortar markedly increased the electrical resistivity and advanced the onset of setting period by 5∼6 h, making it possible to prepare CA mortar with high early strength, which can preventing distress such as peeling and bleeding during construction in winter and conformance to requirements in acceptance standard.