In order to study the fracture properties of dam concrete under
post-peak cyclic loading, wedge splitting tests with three loading rates
(0.001 mm/s, 0.01 mm/s, 0.1 mm/s) were performed on notched cubic dam
concrete specimens. Meanwhile, the acoustic emission (AE) and digital
image correlation (DIC) technologies were used to record the crack
propagation process of specimens. Test results show that the fracture of
dam concrete has a significant rate effect: with the loading rate
increases, the peak load increases, the slope of the post-peak P-CMOD
curve gradually decreases and the stiffness degradation of dam concrete
becomes more serious. The cumulative AE count shows a step increasing
trend and has a Kaiser effect. The Kaiser effect decreases with the
post-peak cyclic loading procedure, and with the loading rate increases,
the Kaiser effect increases. With the increasing of loading rate, AE
energy fluctuates violently and b value fluctuates frequently,
indicating the damage of dam concrete becomes more serious. As the
loading procedure, the damage of the specimen accumulates gradually, and
the strain recovery rate decreases gradually. With the loading rate
increases, the strain recovery rate decreases and the permanent crack
increases. Based on the fictitious crack model, the effective crack
length shows a gradual and steady rising trend. As the loading rate
increases, the growth rate of the effective crack length becomes large.
Study for the evaluation of fracture properties on silicon carbide under high temperature by means of an acoustic emission technique.
