Estimation of elastic modulus of cement asphalt binder with high content of asphalt

In this paper, the effects of asphalt-to-cement ratio (A/C) and water-to-cement ratio (W/C) on the elastic modulus Ec of cement asphalt (CA) binder were studied through measuring the stress-strain curves and phase volume fractions of various CA binder specimens. The results illustrate that the CA binder with high asphalt content (A/C ⩾ 0.6) is a two-phase composite with complicated microstructure formed by both cement hydrates and asphalt agglomerates. The elastic modulus of CA binder decreases with the increase of A/C and W/C, especially A/C. A composite model that describes the CA binder in terms of the properties of asphalt and volume fractions of cement phases is suggested, and Ec of CA binder can be predicted by this model according to A/C, W/C and properties of asphalt.