INVESTIGATION ON DYNAMICAL MECHANICAL BEHAVIORS OF CEMENT-ASPHALT BINDERS

The dynamic vicoelastic behaviors of cement asphalt gelled composites with varied asphalt content at the age of 7 days were investigated. The correlation between the storage modulus, loss modulus or loss angle and the loading frequency was obtained through testing dynamic mechanical properties of cement-asphalt binders (CABs for short) with different A/C ratios over a frequency range from 0.1Hz to 100Hz by Du Pond DMA 2980 at the temperature of 25℃, 25℃ or 75℃ respectively. Mater curves of the storage modulus of different CABs with frequency under normal temperature were established based on the frequency-temperature equivalence principle and Burgers constitutive relationship was used to simulate the dependency of a dynamic modulus on a loading frequency. Results indicated that, with the increase of A/C ratio or temperature, the storage modulus of CABs decreased and their viscoelaticity became increasingly remarkable. The storage modulus of CABs with a low A/C ratio or a high A/C ratio but under low temperature ascended linearly with a logarithmic frequency, while it behaves nonlinear growth when the A/C ratio or temperature turned higher. The frequency range for mater curves of CABs’ storage modulus got narrow with the A/C ratio, implying higher frequency sensitivity. The relationship between the dynamic modulus and frequency for three different CABs was successfully simulated by means of a Burgers mechanical model and the calculated results fitted well with experimental data.