纤维再生混凝土力学性能试验及破坏分析

采用正交试验法研究了再生粗骨料掺量、粉煤灰掺量、减水剂掺量以及纤维类别对纤维再生混凝土抗压强度、劈拉强度及抗折强度的影响.利用扫描电镜及螺旋CT扫描技术分析纤维再生混凝土的内部破坏.结果表明：再生粗骨料掺量是影响纤维再生混凝土28d和90d抗压强度的重要因素；纤维类别是影响纤维再生混凝土28d劈拉强度和抗折强度的重要因素.以再生粗骨料掺量为50%(质量分数)、粉煤灰掺量(质量分数)为20%、减水剂掺量(质量分数)为0.5%和铣削波纹型钢纤维掺量(体积分数)为1.0%进行设计强度为C35的纤维再生混凝土的配制，可使其获得良好的和易性，并满足强度要求.再生粗骨料与砂浆界面处产生裂缝，导致了纤维再生混凝土强度较低.

Mechanical Properties Experiments and Failure Analysis of Fiber Recycled Concrete

The influences of four factors, including the contents of recycled coarse aggregate, fly ash, water reducing agent and sort of fiber, on the compressive strength, splitting tensile strength and flexural strength of fiber recycled concrete were investigated by utilizing the orthogonal testing method. Through the scanning electron microscopy and the screw CT scanning technique, the inner damage of fiber recycled concrete was analyzed. The results indicate that the content of recycled coarse aggregate is an prominent factor affecting 28d and 90d compressive strength of concrete and the sort of fiber play an important role in 28d splitting tensile strength and flexural strength of concrete. Adopting the mix proportion of 50%(by mass) recycled coarse aggregate, 20%(by mass) fly ash, 0.5%(by mass) water reducing agent and 1.0%(by volume) milling corrugated steel fiber, the fiber recycled concrete, of which the design strength grade is C35, reaches satisfactory workability and meets the requirements of strength. The cracks between the interfaces of recycled coarse aggregate and mortar lead to relatively low strength for the fiber recycled concrete.