碳纤维布约束下水泥砂浆动态力学及能量特征

Dynamic Mechanics and Energy Properties of Cement Mortar with CFRP Confines

为研究碳纤维复合材料(CFRP)对水泥砂浆的加固效果,针对普通水泥砂浆和CFRP布端面约束水泥砂浆,采用分离式霍普金森压杆(SHPB)分别进行恒定气压(0.3 MPa)和递增气压(0.2、0.3、0.4、0.5 MPa)循环冲击压缩试验,分析了试件的应力-应变曲线、破坏形态和能量特征.结果表明:与普通水泥砂浆试件相比,CFRP布端面约束水泥砂浆试件的循环冲击次数、峰值应力和峰值应变均有显著提高,且其峰值应力随着应变率的提高而增大;CFRP布的断裂部位主要发生在碳纤维横向连接处,CFRP布减缓了试件内部裂缝的产生,提高了试件的延性,表现出更好的抗冲击能力,试件的残余强度增加;端面粘贴CFRP布可以提高水泥砂浆的能量吸收能力,在相同冲击气压作用下,CFRP布端面约束水泥砂浆产生裂纹所需的能量高于普通水泥砂浆.

In order to explore the reinforcement effect of carbon fibre reinforced plastics(CFRP)pasted on cement mortar,the cyclic compressive impact tests were carried out on ordinary cement mortar and cement mortar with CFRP on the end faces with constant impact pressure(0.3 MPa)and increasing impact pressure(0.2,0.3,0.4,0.5 MPa)by using split Hopkinson pressure bar(SHPB)system.The stress‑strain curves,failure states,and energy properties of specimens under cyclical impact compression test were analyzed.The results show that compared with ordinary cement mortar,the number of cyclic impact,peak stress and peak strain of CFRP‑attached cement mortar are increased.The failure state shows that the fracture site of CFRP mainly occurred at the transverse connection of CFRP.The generation of cracks are slowed down and the ductility of specimens is improved.The impact resistance is obtained by the introduction of CFRP.CFRP can improve the energy absorption capacity of the specimens,so that the energy required for cracking of cement mortar with CFRP end face confines specimen under the same impact air pressure is higher than ordinary cement mortar.