Study On Axial Compressive Behaviors Of Concrete Columns Strengthened With TRC Under Conventional Environment And Chloride Salt Dry/wet Cycle

Textile reinforced concrete(TRC) is a new type of fiber-reinforced cement-based composite material, which is a combination of textile and high performance concrete. Compared with the conventional FRP reinforcement,TRC acting as a reinforcement material has the following advantages: high temperature resistance, compatible with the reinforced specimen, few limitation of the direction of fiber bundle, and lower cost. It is mainly due to the TRC providing hoop tension when TRC acts as reinforcement for concrete columns, so that the core concrete is in three-dimensional pressure state, improving the bearing capacity of the column. This paper focuses on the mechanical properties of square concrete columns reinforced with TRC under conventional environment and chloride salt dry/wet cycle. The specific contents are summarized as follows:1) An experiment was conducted under conventional environment to study the axis mechanical properties of plain concrete columns reinforced with TRC and RC columns reinforced with TRC. The results show that: plain concrete columns reinforced with TRC and RC columns reinforced with TRC perform well in increasing in ultimate bearing capacity and improving the failure mode and ductility. For RC columns reinforced with TRC, there is little difference in different reinforcement ratio; The reinforcement effect of TRC is improved with the increasing of the layers of textile; The lap length of the textile has little influence on reinforcement effect of TRC; Besides, the reinforcement effect of TRC was improved when chopped fiber high performance concrete was used as the matrix of TRC.2) Under the effect of chloride salt dry/wet cycle, compared with the unstrengthened RC column, the failure mode has little difference, while ultimate bearing capacity and ductility is decreased, and with the increasing number of dry/wet cycle, the decrease is more obviously. With the effect of load-chloride salt dry/wet cycle, the ultimate bearing capacity and deformation performance of RC column strengthened with TRC is declined with the increasing number of dry/wet cycles, and the extent of reduction is greater with the increasing of sustained load. The durability of reinforcement effect of TRC is improved slightly by using chopped fiber high performance concrete as the matrix of TRC.3) The formular for axial compression bearing capacity of RC columns reinforced with TRC under conventional environment was derived, and on this basis, chlorine salt dry/wet cycle influence coefficient was introduced. The formular for axial compression bearing capacity of RC columns reinforced with TRC under chlorine salt dry/wet cycle is fitted out, and the calculating results agree well with experimental ones.