温度对玻璃纤维增强聚合物筋与混凝土黏结性能影响试验研究

Temperature effect on bond performance between glass fiber reinforcement polymer bars and concrete

为研究不同温度及不同升温(单调升温和循环升温)、降温方式(单调升温-自然冷却和单调升温-快速冷却)对玻璃纤维增强聚合物(GFRP)筋与混凝土之间黏结性能的影响,选取2种黏结长度共90个GFRP筋-混凝土立方体试件在温度为20~220℃范围进行拉拔试验,并在同样温度条件下对54个混凝土立方体试件(单调升温、单调升温-自然冷却)进行抗压、抗拉强度测试。结果表明,2种升温方式下,GFRP筋与混凝土随温度升高黏结性能退化严重,温度低于120℃时,单调升温对黏结强度退化影响超过循环升温;温度超过120℃时,升温方式对黏结性能衰减程度影响减小;2种降温方式下,单调升温-快速冷却随温度升高黏结性能退化明显,单调升温-自然冷却影响轻微。

The purpose of this study is to investigate the influence of temperature and heating/cooling modes(monotonous heating,cycle heating,monotonous heating-natural cooling,and monotonous heating-rapid cooling)on the bond performance between glass fiber reinforcement polymer(GFRP)bars and concrete.Totally 90 GFRP bars with a diameter of 10 mm and the concrete pull-out specimens with two bonded lengths were subjected to the tests at a temperature ranging from 20 to 220 oC.Totally 54 concrete cubic specimens were used to measure their ultimate compressive and tensile strength under the same conditions.The results indicated that the bond performance between the GFRP bars and concrete tended to deteriorate seriously with an increase in temperature under the two heating modes.The influence of monotonous heating on the degradation of bond strength was more significant compared to cyclic heating at a temperature below 120 oC.When the temperature exceeded 120 oC,the effect of heating mode on the attenuation of bond performance decreased.Under the two cooling modes,the bond performance between the GFRP bars and concrete seemed not to degrade significantly with an increase in temperature during the monotone heating-natural cooling process,whereas there was an evident degradation under the monotonic heating-rapid cooling process.