钢纤维增强大掺量再生骨料混凝土力学与断裂性能

Mechanical and Fracture Properties of Steel Fiber Reinforced Concrete with Large Amount of Recycled Aggregate

通过立方体抗压试验、劈裂抗拉试验与三点弯曲试验,探讨再生粗、细骨料较高取代率和钢纤维掺量对再生混凝土力学性能与断裂性能的影响。测试了试件28 d的立方体抗压强度、劈裂抗拉强度与双K断裂韧度,分析了再生混凝土基本力学性能与断裂性能之间的相关性,提出了钢纤维增强大掺量再生骨料混凝土起裂断裂韧度及失稳断裂韧度与劈裂抗拉强度的计算关系。结果表明:再生粗、细骨料以50%质量取代率分别替换天然碎石与河砂,钢纤维体积掺量为1.0%时,抗压强度与劈裂抗拉强度达到最高,分别达到天然混凝土的77.12%与93.97%。掺加1.0%的钢纤维后,试块的失稳断裂韧度明显增加,并且在再生细骨料掺量为50%时均超过了天然混凝土。

Through cube compression test,splitting tensile test,and three point bending test,the effects of high replacement ratio of recycled coarse and fine aggregate,and steel fiber content on the mechanical and fracture properties of recycled concrete were investigated.The cube compressive strength,splitting tensile strength,and double K fracture toughness of the sample for 28 d were tested,and the correlation between the basic mechanical properties and fracture properties of recycled aggregate concrete was analyzed.The computational relationships between the initiation fracture toughness,unstable fracture toughness,and splitting tensile strength of steel fiber reinforced concrete with large amounts of recycled aggregate were proposed.The results show that,the compressive strength and splitting tensile strength of recycled coarse and fine aggregate with a mass substitution ratio of 50%replace natural crushed stone and river sand and 1.0%volume fraction of steel fiber reach the highest,reaching 77.12%and 93.97%of those of natural concrete,respectively.After adding 1.0%volume fraction of steel fiber,the unstable fracture toughness of the test block significantly increases,and unstable fracture toughness exceedes that of natural concrete when the recycled fine aggregate content is 50%.