Research On Flexural Behavior Of RC Beams Strengthened With Textile Reinforced Concrete After Elevated Temperature

Textile reinforced concrete(TRC)has good load-bearing capacity,crack limiting and impermeability capabilities.At present,there are more researches on TRC materials in conventional environments,and more mature theories have been formed,but there are few studies in elevated temperatures environments,especially the ISO standard heating curve for heating,to study the bending of TRC reinforced RC after elevated temperatures Performance studies are rarely reported.In order to further verify the feasibility and applicability of TRC in elevated temperatures environment,this paper mainly conducts experimental research on the flexural performance of RC beams reinforced with textile reinforced concrete after elevated temperatures,including the bonding performance and flexural performance after high temperature.The influence of high temperature time,number of reinforcement layers,initial cracks and other factors are considered.The specific conclusions are as follows:(1)The effects of reinforcement diameter and bond length on the bond behavior of TRC confined RC members after high temperature are studied.The results show that with the increase of bond length and reinforcement diameter,the bond stress between reinforcement and concrete decreases after high temperature.The results show that TRC members with 12 mm bar diameter exhibit good bond behavior after high temperature,including higher peak bond stress,smaller peak slip and cyclic decay stage of higher stress level.(2)In the process of high temperature test,when the elevated temperatures time is short,the TRC reinforcement layer has a good heat insulation effect,and the heat insulation effect increases with the increase of the number of textile layers.The thermal insulation effect of TRC gradually disappears with the increase of elevated temperatures time.(3)Regarding the effect of high temperature time,number of reinforcement layers,and initial cracks on the bending bearing capacity of TRC-reinforced RC beams after high temperature,the study found that: compared with unreinforced test beams,TRCreinforced beams have better bending performance and higher bearing capacity.The mid-span deflection and crack width of the beam before yielding are smaller.The elevated temperatures time has a great influence on the bending performance of the beam.The bending load capacity of the beam decreases significantly with the increase of time: for unreinforced beams,the descending mode tends to be linear;for TRC reinforced beams,it is nonlinear.The ratio of reinforcement has little effect on the bending capacity of the test beam after elevated temperatures,but it will change the failure mode of the beam.(4)According to the test results,considering the influence of elevated temperature time,and introducing the correlation coefficient,the theoretical calculation formula of TRC strengthened RC beam after elevated temperature is deduced.It is found that the calculated value obtained by using the theoretical calculation formula is in good agreement with the test value.The results have certain guiding significance for further analysis of the bearing capacity calculation of TRC strengthened RC beams after elevated temperature.There are 47 pictures,16 tables and 102 references in this paper.