Effect of early cement hydration on the chemical stability of asphalt emulsion

The effect of pH value, Ca2+ concentration and water loss induced by cement hydration on emulsion stability was investigated by measuring the Zeta potential of asphalt droplets. The microstructure of emulsion was also observed by optical microscope. The results indicate that the chemical stability of cationic emulsion is strongly affected by pH value increase and the addition of nonionic emulsifier improves the alkali resistance property of emulsion. However, the chemical stability of anionic emulsion was slightly improved by pH increase. Ca2+ slightly influences the cationic and anionic emulsions due to its small concentration in the cement paste pore solution. The Zeta potentials of both cationic and anionic emulsions were sharply decreased due to water loss. (C) 2013 Elsevier Ltd. All rights reserved.