Suitability of rock-filled concrete for constructing flexural structures

Several studies on rock-filled concrete (RFC) have been conducted to assess its suitability as massive concrete; hence, it is necessary to evaluate the possibility of using RFC as structural elements. The crack pattern and damage behavior of a structural element are significant for predicting its failure mode. In this study, a modified random rock model of an RFC beam based on its position and rotation was developed. In addition, a numerical model of four-point RFC beams with different rock volumes, percentages, shapes, and cohesion surface strength values was constructed and subjected to pure flexure stresses. A modified stirrup was designed to maintain the position of the rock around the minimum stress zone. The results indicated that the load capacity and traction damage decreased with increasing volume and percentage content of the rocks. The optimum diameter of the rock was 9.375–12.5 cm. The prepeak behavior and peak stress were insensitive to the spatial distribution of the rocks. However, the postpeak softening behavior was influenced by the spatial distribution of the rocks, although the RFC did not exhibit ductility failure. The cohesive surface characteristics significantly influenced the crack path.