When filling concrete into a CFT（Concrete Filled Steel Pipe）structure, hard concrete sometimes become stuck at the top and cause blockages. To investigate the cause of this, we used the MPS（Moving Particle Semi-implicit）method simulations to examine the differences in properties caused by the hardness of the concrete. Here, concrete with high yield stress that requires a large amount of force to start moving is referred to as hard concrete. We conducted simulations where both hard（yield stress 1000 N/m²）and soft（yield stress 10 N/m²）concrete were poured into a structure modeled after a CFT structure. By varying the order of pouring and comparing the results, we investigated how the hardness of the concrete affected the flow. The results showed that when hard concrete was poured later, it reached higher up in the structure. This suggests that hard concrete with high yield stress tends to accumulate in the upper layers, which could be a contributing factor to blockages.
KOYODA et al. (Wed,) studied this question.