Chapter 10 - Research progress on dynamic mechanical behavior of high arch dam concrete

Abstract

Although there exists obvious differences in the size, volume, aggregate gradation, mix proportions, construction method, and working conditions of the concrete used in the high arch dam and the common concrete, the same characteristics also exist. Therefore, the researching progress in the dynamic mechanical behavior of concrete is introduced in this chapter, which includes dynamic strength of concrete, deformation, influencing factors, macro experiments, and X-CT techniques. The mechanisms for strain rate effect on concrete were also discussed. Combining the working state of high arch dams under earthquakes and the main characteristics of dam concrete, the dynamic tensile strength, strain rate effect, initial static loading effects on dynamic tensile strength, and elastic modulus was mainly demonstrated. Based on the above researching progress on the dynamic mechanical characteristics of concrete, the following key problems and technical methods on this area can be summarized as follows: the research on the property of large size, multigraded aggregate dam concrete is still seldom. There are some fundamental problems to be investigated and further researched. Under the action of earthquakes, the key point for the dynamic mechanical characteristic of dam concrete is the tensile behavior, especially for the dynamic flexural tensile strength and elastic modulus. For investigation on the internal damage mechanisms and explanation of the results from macro tests, the mesomechanical numerical analysis of concrete has been paid more attention. The research on the numerical concrete has the significant theoretical meaning and extensive application prospect. X-ray CT techniques are the direct, feasible, and effective methods to reveal the mechanisms for internal damage, explain the macro experimental results, and certify mesomechanical analysis. The strain rate effect is the key question in the dynamic mechanical characteristic of concrete and is a basic property for inhomogeneous concrete material. The rules are statistically summarized by experimental results in the current study. Although there are lots of results on the mechanisms, the consensus is still missing. Among them, the strain rate effect obtained by different testing methods is hard to be clarified as the natural characteristic or the influence of dynamic response from specimen structures.