Fragment theoretical model of concrete blocks subjected to blast loads

Abstract

Concrete, a typical engineering construction material, will fracture and fragment when subjected to blast loads. In this study, the blast experiments on concrete blocks were carried out using 30kg of explosive B at different stand-off distances, and the concrete fragments were recovered, sieved, weighed, and counted to obtain information of the fragments in different particle size groups. Moreover, the propagation process of the blast energy was analyzed based on the blast theory, and the deformation energy of the concrete blocks subjected to the blast loads was calculated according to the deformation energy theory. The Griffith fracture theory was employed to estimate the energy dissipation during the fragmentation of the concrete blocks, and the initial kinetic energy of the concrete fragments was determined by combining it with the kinematics theory. Subsequently, a fragment theoretical model was developed based on the principle of energy conservation. The validity of the proposed fragment theoretical model was verified by comparing the statistical data of the blast experiments. The present fragment theoretical model can predict the fragmentation degree of concrete members reasonably and effectively and calculate the particle sizes and quantity of concrete fragments under unknown blast load conditions.