Dynamic Characteristics of Asphalt Concrete as an Impervious Core in Embankment Dams under Varying Temperatures and Stress States

Abstract

To reveal the dynamic characteristics of asphalt core embankment dams (ACEDs), we carried out a dynamic triaxial experiment on hydraulic asphalt concrete (HAC) under different temperatures (T = 4 °C, 10 °C, 16 °C, and 22 °C) and stress states (Kc = 1.0, 1.2, 1.4, and 1.6; σ3 = 0.5, 0.6, 0.7, and 0.8 MPa). The results indicate that HAC’s maximum dynamic elastic modulus increased with decreasing temperature, increasing principal stress ratio, and increasing confining pressure. However, the damping ratio showed the opposite trend. Moreover, in order to study the deformation capacity of HAC, 300 cyclic loads were applied to some specimens. At a temperature of 22 °C, the specimens had a tendency to deform axially, but not significantly. With a decrease in temperature, the axial deformation tendency of the specimen gradually weakened or even disappeared. However, a small number of cracks appeared in the aggregate and between the asphalt and the aggregate of the specimen. In order to quantify the dependence of dynamic parameters on temperature, the temperature influence factor of the maximum dynamic elastic modulus and the temperature sensing factor of the damping ratio were defined. The variation in the temperature influence factor of the maximum dynamic elastic modulus with temperature can be described by a logistic function. The temperature sensing factor of the damping ratio increased with an increasing principal stress ratio and peripheral pressure. Finally, maximum dynamic elastic modulus and damping ratio computational models for the interaction of temperatures and stress states were developed using the normalization method. Upon comparison, the dynamic parameters were observed to be very close to those listed in the literature, which verifies the applicability of the computational models of the maximum dynamic elastic modulus and damping ratio.

Experimental Investigation of the Size Effect on Roller-Compacted Hydraulic Asphalt Concrete under Different Strain Rates of Loading

“…In many countries, lots of hydraulic structures are built in the alpine cold region; with low temperatures and frequent earthquakes, the dynamic mechanical safety performance of the RCHAC core wall has always been the concern of researchers. There have been many efforts to study the mechanical properties and failure mechanisms of RCHAC [ 2 , 3 , 4 , 5 , 6 ]; the majority of these, however, ignored the effect that size has on mechanical properties, while many studies showed that the size of the specimen has a significant effect on the mechanical properties of heterogeneous concrete-like materials [ 7 , 8 , 9 , 10 , 11 ]. Therefore, another noteworthy aspect is the influence of the specimen size on the mechanical properties and failure mechanisms in the mechanical research of HAC.…”