Strain-Rate Effect on Mechanical Properties of Fully Graded and Wet-Screened Dam Concrete Based on Flexural and Compressive Tests

The dynamic mechanical properties of dam concrete play a critical role in the seismic design of dams. Conducting experiments on large-scale fully graded specimens to accurately obtain the mechanical properties of dam concrete is a challenging task. Dam concrete performance is typically evaluated using standard-sized wet-screened specimens. Therefore, it is essential to understand the relationship between the mechanical properties of fully graded and wet-screened specimens under dynamic loading; however, research in this field is scarce. This study investigated the dynamic flexural and compression tests of fully graded and wet-screened dam concrete specimens under strain rates corresponding to seismic loading. The strain rates for the flexural tests were set to 10−6 s−1, 2 × 10−4 s−1, 8 × 10−4 s−1, and 3 × 10−3 s−1, while the strain rates for the compression tests were set to 10−6 s−1, 5 × 10−4 s−1, 8 × 10−3 s−1, and 2 × 10−2 s−1. Failure modes and strain–stress curves were obtained for various strain rates. Based on the experimental data, the strength, elastic modulus, crack propagation velocity, cracking stress, cracking strain, peak compressive strain, and compressive energy absorption capacity of dam concrete under dynamic strain rates corresponding to seismic loading were determined. The effects of strain rate on these mechanical properties of dam concrete were analyzed. The relationship between fully graded and wet-screened concrete was explored, leading to a linear empirical formula for predicting the strength and elastic modulus of dam concrete based on wet-screened concrete test data. This study enriches the experimental research on the mechanical properties of dam concrete, deepens the understanding of the relationship between fully graded and wet-screened specimens, and provides scientific experimental data to support the seismic safety design of dams.

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