Investigation on the mixing stability of asphalt emulsion with cement through viscosity

Cement asphalt emulsion (CA) mortar is a key material in the nonballast slab track. Its properties are largely dependent on the compatibility between asphalt emulsion and cement. The mixing stability of asphalt emulsion with cement is investigated by analyzing the viscosity of CA paste. Viscosity and the critical particle volume fraction of CA paste are proposed as indexes in evaluating the mixing stability of asphalt emulsion with cement, and factors influencing the mixing stability of asphalt emulsion are studied. Mixing stability is dependent on mixing method, superplasticizer, and emulsion type. The premixing cement method, superplasticizer, and good asphalt emulsion can increase the critical particle volume fraction of CA paste, which is helpful in achieving a low water-to-cement mass ratio (W/C). Anionic emulsion has much better mixing stability with cement than does cationic emulsion. The critical particle volume fraction of CA pastes with anionic emulsion increases stably with the mass ratio of asphalt emulsion to cement (AE/C), but the critical particle volume fraction of CA pastes with cationic emulsion increases little with AE/C. This work proposes a method for choosing an asphalt emulsion with good mixing stability, and provides methods to improve the mixing stability of asphalt emulsion with cement.