Analysis of the effect of aggregate type on the dynamic behaviour of concrete

Abstract

This paper focuses on how different aggregate types affect the dynamic response of concrete. While Split Hopkinson Pressure Bar (SHPB) is commonly used to assess dynamic behaviour through the dynamic increase factor (DIF), the specific influence of aggregate type, a major component of concrete, remains unclear. This influence is investigated using fast Fourier transform analysis of strain signals. Two different types of aggregates, sandstone and schist, with distinct geological origins and mineral compositions, are used to examine this effect. Energy analysis is performed to understand how aggregate type affects energy absorption. The fineness modulus of fractured specimens is also determined which allow the comparison of post-fracture grain sizes. A crucial link between aggregate type and dynamic response of concrete is observed. Stiffer aggregates lead to stiffer concrete, which influence the frequency of energy responsible for damage initiation. At lower strain rates, concrete with stiffer aggregates absorbs lower-frequency energy. However, as strain rate increases, the frequency of absorbed energy becomes more dependent on the extent of damage within the aggregates themselves. The type of aggregate also significantly affects the size distribution of the fractured material. To analyse the stress distribution under dynamic loading, numerical simulations are carried out. These simulations showed that the maximum stress in concrete is related to the stiffness of the aggregate.