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作为混凝土材料的主要组成部分,骨料对混凝土力学性能具有重要影响。但骨料尺寸对混凝土层裂强度的影响仍缺少研究。本文利用大直径Hopkinson杆对混凝土细长杆件进行层裂实验,通过放置在试件后方吸收杆上的波形测量混凝土层裂强度。对两种不同尺寸骨料的混凝土进行了不同冲击速度下的层裂实验研究。实验结果表明,在相同加载条件下,骨料尺寸越大混凝土层裂强度越低,其主要原因是大尺寸骨料混凝土的界面过渡区强度更低;混凝土层裂强度具有率效应,即加载率越高其层裂强度也越高。但当加载波超过一定阈值时,由于压缩损伤演化和积累,层裂强度会降低。
As a major component of concrete materials, aggregate has an important impact on the mechanical properties of concrete. However, the effect of aggregate size on the spall strength of concrete is still lacking. In this paper, the large-diameter Hopkinson bar is used to test the splitting of concrete slender bars, and the concrete splitting strength is measured by the waveform placed on the back of the test bar. Experimental study on the splitting of concrete with two different sizes of aggregates under different impact velocities. The experimental results show that under the same loading conditions, the larger the aggregate size is, the lower the concrete spall strength is. The main reason is that the interface transition zone of large-size aggregate concrete has a lower strength. The concrete spall strength has a rate effect, that is, The higher the higher the spall strength. However, when the loading wave exceeds a certain threshold, the strength of the spalling will decrease due to the evolution and accumulation of compression damage.