Compressive behaviour and fragment size distribution model for failure mode prediction of rubber concrete under impact loads

Abstract

A 100-mm-diameter split Hopkinson pressure bar was used to obtain the dynamic compressive properties and strain-rate sensitivity of rubber concrete, as well as to analyse the reason for the difference in the strain-rate sensitivities of rubber concrete and ordinary concrete. Rubber contents of 0%, 10%, 20%, 30%, 40%, and 50% of the fine aggregate volume were used. The test results showed that the quasi-static strength of rubber concrete decreased primarily because of the weak interfacial bond of the rubber–cement matrix. The dynamic increase factor (DIF) of the rubber concrete for different rubber contents increased with the strain rate. In addition, the rubber particles could slow down the accumulation of damage and increase the deformation lag effect, which increased the DIF of the rubber concrete compared to ordinary concrete. The toughness of the rubber concrete was also greater than that of ordinary concrete under impact loads because the stress decreased slowly after the peak stress value for the rubber concrete was reached. The fragment size of the post-test specimens gradually decreased with an increase in the strain rate, and the ordinary concrete had a larger number of cracks compared to rubber concrete, under a similar strain rate. The fragment size of the specimens followed a Weibull distribution, and the fragment size distribution model could correlate the strain rate and rubber content for failure mode prediction.