低温下钢筋与混凝土黏结性能的试验研究

Experimental study on bond properties between reinforcement and concrete at low temperatures

最低降温至-80℃时,通过对69个黏结锚固试件的中心拔出试验,考虑温度、钢筋直径、相对保护层厚度、锚固长度和钢筋级别等参数的影响,分析不同低温条件下钢筋与混凝土黏结锚固的特征和黏结性能。试验研究表明:钢筋与混凝土的黏结性能受温度影响显著;随着温度的降低,极限黏结强度不断增大,且与温度基本呈线性;-40℃低温下黏结强度提高系数γ随钢筋直径d的增大而增大;-40℃时黏结强度提高系数γ随相对保护层厚度c/d增大而减小,且近似呈线性;低温下黏结强度提高系数γ与锚固长度la/d无明显相关;不同温度下黏结强度随钢筋屈服强度提高大体呈增大的趋势,但黏结强度受钢筋屈服强度影响的程度很小。

Based on the pull-out test of 69 specimens at the minimum temperature down to-80℃,the bond properties between reinforcing bar and concrete were analyzed.Several parameters,such as temperature,bar diameter,relative thickness of concrete cover layer,anchorage length and yield strength of rebar,were considered.Experimental studies indicate that the bonding behavior of the reinforced concrete is significantly affected by the temperature,and that the ultimate bond strength increases linearly with the temperature decreasing.At-40℃,the increasing coefficient of bond strength γ increases with the growth of diameter d and decreases linearly as the relative thickness of concrete cover layer c/d increases.However,the coefficient γ has no significant correlation with the anchorage length la/d.It also can be seen that the bond strength has an unobvious increasing tendency with the yield strength of rebar increasing.