砂胶比对海水拌合全珊瑚骨料混凝土动态力学性能的影响

Effect of Sand Binder Ratio on Dynamic Mechanical Properties of Seawater Mixed Coral Aggregate Concrete

珊瑚岛礁工程建设对于保障国家海洋权益具有重大战略意义。随着海洋资源的开发和建设,利用珊瑚骨料制备混凝土已在岛礁工程中得到广泛应用。为探究砂胶比对海水拌合全珊瑚骨料混凝土动态力学性能的影响,基于霍普金森压杆试验分析不同应变率、不同砂胶比(0.8—1.2)下试件的破坏模式、动态压缩强度、动态弹性模量和韧性指标等的变化规律。研究结果表明:动态压缩强度随砂胶比增大小幅度提高,当应变率为120 s^(-1)时,动态压缩强度提高6.7%;动态弹性模量变化规律与动态压缩强度变化一致,当应变率大于80 s^(-1)时,提高幅度最高可达24.1%;韧性指标和相对韧性指标随砂胶比增大而增大,当砂胶比增加到1.2时两者分别增大13.4%和37.8%。此外,通过试件破坏形态分析,海水拌合全珊瑚骨料混凝土在承受相同冲击荷载时,低应变率时试样破坏差异性不大,高应变率下砂胶比越高的混凝土破坏程度越低。由此可见砂胶比的增加确实会提升海水拌合全珊瑚骨料混凝土的抗冲击性能,导致其抗冲击性能、延性和抗压强度提高。

The construction of coral island reef project is of great strategic significance to protect national marine rights and interests.With the development and construction of marine resources,the preparation of concrete with coral aggregate has been widely used in island and reef engineering.The research on its basic mechanical properties and engineering application has also become one of the current hot topics.In order to explore the influence of sand binder ratio on the dynamic mechanical properties of seawater mixed full coral aggregate concrete,the variation laws of failure mode,dynamic compressive strength,dynamic elastic modulus and toughness index of specimens with different sand binder ratio(0.8—1.2)under different strain rates were analyzed based on Hopkinson compression bar test.The results showed that the dynamic compressive strength increased with the increase of sand binder ratio.When the strain rate was 120 s^(-1),the increase proportion of dynamic compressive strength was 6.7%.The variation law of dynamic elastic modulus was consistent with the change of strength,which increased with the increase of sand binder ratio.When the strain rate was greater than 80 s^(-1),the increase proportion reached 24.1%.The toughness index and relative toughness index increased with the increase of sand binder ratio.When the sand binder ratio increased to 1.2,the increase proportion was 13.4%and 37.8%respectively.In addition,through the analysis of specimen failure mode,when seawater mixed all coral aggregate concrete was subjected to the same impact load,there was little difference in specimen failure at low strain rate.Under high strain rate,the higher the sand binder ratio,the lower the damage degree of concrete.It can be seen that the increase of sand binder ratio will certainly improve the impact resistance of seawater mixed all coral aggregate concrete,resulting in the improvement of impact resistance,ductility and compressive strength.