Strength Mechanism of Cement-Asphalt Mortar

The strength mechanisms of two kinds of cement-asphalt (CA) mortar, which vary principally in their strength and elastic modulus, were investigated by environmental scanning electron microscopy, calorimetry, and strength tests. The results showed that the asphalt emulsion delayed the early hydration of the cement and the asphalt membrane had a negative effect on the further hydration of the cement, to some extent. The cement products could impale the asphalt membrane, and the cement could hydrate adequately because of the sufficient water supply in the CA mortar. The framework formed by the hardened cement paste was the primary structure skeleton in the CA mortar with a high elastic modulus and the asphalt phase, exhibiting as a filling phase, increased the weak phase of the structure system. For CA mortar with a low elastic modulus, the asphalt phase exhibited as a dominant phase. Two weak structure skeletons, formed by the asphalt membrane and the hardened cement paste, respectively, were responsible for the strength together.