EXPERIMENTAL STUDY OF BOND BETWEEN NEAR-SURFACE MOUNTED CFRP STRIPS AND CONCRETE UNDER FREEZE-THAWING CYCLES
The technique of prestressing near-surface mounted FRP(NSM FRP)has good potential and future prospects for structural strengthening due to its improvement on the bond between the FRP and concrete and its protection for FRP materials.However,notably few investigations have been conducted to study the bond durability of the NSM FRP-concrete interface.The present study is undertaken to increase the understanding of the durability of the interface between the NSM FRP and concrete under freeze-thawing cycles.Pull-out tests are conducted to investigate the influence of freeze-thawing cycles on the interface bond with ordinary concrete and concrete with high strength or additional frost resistance.Additionally,the mechanism of freeze-thawing cycles degrading the bond of the NSM FRP is discussed.Moreover,the influence of the distance between the concrete edge and the groove(edge distance)and the bond length on the bond durability are studied.It is found that(1)freeze-thawing cycling results in a decrease in strength of ordinary concrete,while the high strength concrete and the concrete with water-reducing agents and admixtures of air-entraining exhibit no significant deterioration under freeze-thawing cycles;(2)Freeze-thawing cycling also leads to a relatively significant decrease in the bond capacity and a transformation of the failure mode for the specimens with ordinary concrete.Nevertheless,this cycling has no substantial impact on the bond performance of specimens of concrete with high strength or frost resistance;(3)a decrease in the edge distance results in cone-shaped cracks at the loaded end;(4)when the failure mode remains debonding at the NSM FRP-concrete interface,increasing the bond length of the specimen leads to a more significant freeze-thawing induced decrease in bond capacity,because the residual friction stress at the debonding interface also decreases by freeze-thawing cycling,thus a longer bond length induces a great loss of residual friction force at the debonding zone.These findings indicate that the deterioration of the bond of NSM FRP under freeze-thawing cycles is caused by the degradation of concrete..
Near-surface mounted CFRP Bond performance Freeze-thawing cycles Concrete
Hui Peng Yang Liu C.S.Cai Jun Yu Jianren Zhang
Ministry of Education Key Laboratory of Safety Control of Bridge Engineering,School of Civil Enginee Dept.of Civil and Environmental Engineering,Louisiana State University,Baton Rouge,LA 70803,Changsha School of Civil Engineering,Central South University,Hunan Changsha,410075,China
国际会议
新加坡
英文
1-18
2017-07-19（万方平台首次上网日期，不代表论文的发表时间）