超高韧性混凝土配合比设计优化及力学性能研究

以最紧密堆积为出发点,采用“最小需水量法”和“骨料最紧密堆积模型理念”设计一种掺加混杂纤维的超高韧性混凝土配合比,并通过混凝土工作性和力学性能测试结果,对配合比中胶凝材料组分比例、石英砂的种类和比例、水胶比进行调整优化。试验结果表明:当m(水泥)∶m(矿粉)∶m(硅灰)=70∶15∶15、20~40目和40~120目石英砂按2.06∶1复配、水胶比控制在0.20左右、钢纤维体积掺量为2%、聚丙烯纤维体积掺量为0.1%时,混凝土的工作性和力学性能最佳,28 d抗折、抗压强度分别达35、130 MPa,且扩展度可以达到600 mm,满足实际工程需求。

Design optimization and mechanics study of mixture ratio of super high toughness concrete

Taking the closest packing as the starting point,adopting the"minimum water demand method"and the"closest packing model concept of aggregate"to design a super high toughness concrete mix ratio with polypropylene fiber,and through the workability and mechanical properties of the concrete,the proportion of the cementitious material,the type and proportion of the quartz sand,and the water-to-binder ratio in the mix ratio were adjusted and optimized.The test results showed that when the ratio of cement,mineral powder and silica fume was 70∶15∶15,quartz sand of 20~40 mesh and 40~120 mesh was 2.06∶1,the water-to-binder ratio was 0.20,the dosage of steel fiber was 2%of the volume of concrete and the polypropylene fiber was 0.1%of the volume of concrete,the workability and mechanical properties of concrete were the best,and the 28 days flexural strength and compressive strength was up to 35 MPa and 130 MPa respectively,and the extension could reach 600 mm,which could meet the actual engineering demand.