冻融后钢筋与页岩陶粒混凝土粘结性能试验研究

Experimental study on bonding behavior between steel bar and shale ceramsite concrete after freezing and thawing

通过试验研究了3种强度等级的页岩陶粒混凝土与普通螺纹钢筋、环氧涂层钢筋和玄武岩纤维(basalt fiber reinforced plastics,BFRP)筋在经受0、15、30、50次冻融循环作用后粘结性能的变化规律。结果表明:随着冻融循环次数的增加,各钢筋与页岩陶粒混凝土间的粘结强度均逐渐减小,峰值滑移量逐渐增加,且粘结强度随混凝土强度的提高而增大;其他试验条件均相同时,普通螺纹钢筋与页岩陶粒混凝土的极限粘结强度最高,环氧涂层钢筋次之,BFRP筋最小;当遭受冻融循环作用后,各钢筋破坏形态以混凝土劈裂破坏为主。最后,基于试验数据分析分别建立了不同影响因素下BFRP筋、普通螺纹钢筋、环氧涂层钢筋与页岩陶粒混凝土粘结强度计算公式,可为我国寒冷地区的工程实践提供理论支持。

Bonding behaviors of shale ceramsite concrete with three strength grades and common rebars,epoxy coated steel bars and basalt fiber reinforced plastics(BFRP)bars under 0,15,30 and 50 freeze-thaw cycles were analyzed.The results indicated that the bonding strength decreases and the peak slippage increases gradually with the increase of the number of freeze-thaw cycles,and the bonding strength increases with the increase of the concrete strength.When other test conditions were the same,the ultimate bonding strength of common rebar and shale ceramsite concrete was the highest,followed by epoxy coated steel bar,and the BFRP bar was the smallest.However,when subjected to the freezing-thawing cycle,concrete splitting was the main failure mode of steel bars.Finally,an analytical formula for calculating the bonding strength of BFRP bars,common rebars,epoxy coated steel bars and shale ceramsite concrete under different influential factors was proposed through experimental analysis,which may provide theoretical support for the engineering practice in cold areas of China.