Dynamic Fracture and Strain Rate Behavior of Aggregates Used in Transportation

Abstract

The static and dynamic uniaxial compressive strengths of coarse aggregate materials used in portland cement concrete (PCC) were determined under dry and saturated conditions for three blast furnace slags, three limestones, four dolomites, and two mafic igneous rocks. The slag aggregates exhibited the lowest compressive strength, followed by the carbonates (limestones and dolomites), and the mafic igneous rocks. Both the dry and saturated aggregates revealed a higher compressive strength under dynamic loads compared to the static loads. Based on the experimental data, a rate sensitivity parameter was defined to describe the increase in compressive strength as a function of strain rate. This parameter is deemed to have considerable relevance in evaluating the ability of a specific aggregate to resist dynamic loads such as in aggregate interlock in PCC cracks and joints, friction in asphalt, and also in the development of microfracture during rock blasting. Comparison of the compressive strength data to density and LA abrasion values revealed that the dynamic data have a better correlation to the above properties than the static data.