高性能细石混凝土力学性能优化试验研究

MECHANICAL PROPERTIES OPTIMIZATION OF HIGH PERFORMANCE CONCRETE WITH FINE STONE BASED ON ENGINEERING DESIGN REQUIREMENTS

面向高轴压比工程构件的延性设计需求,文中采用正交试验法,针对28d抗压强度为70MPa左右的高性能细石混凝土进行力学性能优化试验研究。在常温养护条件下,通过三因素、三水平的正交法配合比试验,制备了混凝土拌合物9组,研究了砂率、钢纤维体积率、粉煤灰取代率对高性能细石混凝土力学性能的影响,并获取了一组最优配合比。通过X-CT观测了钢纤维和孔隙的分布情况,通过SEM电镜扫描分析了破坏断面的微观形成机理,为高性能材料的性能提升提供了理论依据。

For ductility design requirements of high axial compression ratio members in engineering structures, the orthogonal test method was used to optimize the mechanical properties of high performance fine stone concrete whose compressive strength is about 70MPa at 28d curing period. Under the condition of normal temperature curing,nine groups of concrete mixtures were prepared by orthogonal mixture ratio test with three factors and three levels.The effects of sand ratio, volume ratio of steel fiber, and replacement ratio of fly ash on mechanical properties of high-performance fine stone concrete were studied, and the optimal mixture ratio was obtained. X-ray CT was used to measure the distribution of steel fiber and porosity, and scanning electron microscope(SEM) was used to analyze the formation mechanism of fracture section, which may provide a theoretical basis for improving the performance of high-performance materials.