活性粉末混凝土板抗冲击性能试验研究

为了研究常温养护条件下活性粉末混凝土(RPC)板的抗冲击性能,对3块RPC板和3块普通钢筋混凝土(RC)板进行14 m高度下的落锤冲击试验,利用高速动态采集系统对落锤冲击过程中动态加速度和动态支座反力、混凝土板的应变进行采集,通过记录数据并对比分析了RPC板和RC板抗冲击性能的差异。试验结果表明:与普通RC板相比,RPC板的落锤冲击持续时间明显延长,冲击速度增大,冲量明显增加;冲击加速度峰值、平均冲击力及最大冲击力均减小;RPC板四角所承受的动态反力幅值明显大于RC板;RPC板的最大应变均大于RC板。分析混凝土板的破坏情况,发现RPC板正面接触冲击部位只出现较小的冲击坑,未出现RC板的穿透性破坏,且RPC板背面的裂缝数量均少于RC板,宽度也明显小于RC板。试验结果,表明常温养护条件下RPC板的抗冲击性能明显高于RC板,且随着钢纤维掺量的增加,RPC板的抗冲击性能逐渐增强,相比较于普通混凝土,RPC材料更加适用于受落石冲击危害的地区。

Experimental study on impact resistance of reactive powder concrete slabs

To explore the impact resistance of reactive powder concrete(RPC) slabs at room temperature curing condition, the drop hammer impact tests at 14 m height were carried out to investigate the difference of impact resistance between the 3 pieces of RPC slabs and 3 pieces of reinforced concrete(RC) slabs. The high-speed dynamic acquisition system was used to collect the dynamic acceleration, the dynamic support reaction and the strain of the concrete slabs in the impact process of the drop hammer. Then, the difference in impact resistance between RPC and RC slabs were compared and analyzed.The results indicated that compared with the RC slabs, the impact time of the RPC slabs obviously prolonged, and the impact speed as well as impact energy increased. The peak value of the acceleration, the average impact force and the maximum impact force reduced. Additionally, the dynamic support reaction amplitude of the four corners of the RPC slabs were greater than that of the RC slabs apparently, and the maximum strain of the RPC slabs were also larger than that of the RC slabs. After analyzing the damaging degree of concrete slabs, we found only small impact pits on the front parts of RPC slabs, and the penetrating destruction of RC slabs was not appeared in RPC slabs. Moreover, the number of cracks on the front of RPC slabs was less than that of RC slabs and the width was also significantly less than the RC slabs. All of the results showed under the same room temperature curing condition, the impact resistance of RPC slabs were evidently higher than that of RC slabs. Furthermore,with the increase of steel fiber content, the impact resistance of RPC slabs could gradually improved,compared with ordinary concrete, RPC material is more suitable for areas affected by falling rock impact.