带肋钢筋与灌浆料黏结性能试验

Experimental study on bond behavior for ribbed steel bars and grout

为灌浆料在预制装配式结构及加固改造领域提供理论依据,进行了27个带肋钢筋-灌浆料拉拔试验,研究了试件的破坏模式和黏结强度随变量的变化规律,分析了灌浆料开裂、压碎过程及与过程相对应的典型黏结-滑移曲线各阶段.基于试验数据,拟合了灌浆料黏结锚固强度公式、黏结强度对应的滑移值公式和黏结应力-滑移关系式,提出了钢筋在灌浆料中的锚固长度经验值.结果表明:随着保护层厚度增大,试件平均黏结强度不断增大,相比于混凝土,保护层厚度增大相同幅度,灌浆料黏结强度增长慢;随着钢筋直径增大,平均黏结强度减小;随着钢筋锚固长度增加,试件平均黏结强度降低,相比于自密实混凝土,锚固长度增加相同幅度,灌浆料黏结强度增长快;强度等级相同时,灌浆料黏结强度高于普通混凝土;钢筋与灌浆料间黏结性能和钢筋与混凝土间黏结性能有差异.

To provide theoretical data for the grout used in prefabricated structures and reinforcement reconstruction field. Pull-out tests were conducted on 27 specimens having grout with ribbed reinforced bars, and the failure mode and the variation of bond strength were studied. According to a typical bond-slip curve, the cracking, crushing and shearing process were analyzed. Based on the experimental data, the bond strength formula, the slip formula and the bond-slip formula were fitted. The empirical value of anchorage length of reinforcement in grout was presented. The result shows that the average bond strength increases with the increase of the cover thickness. While thickening the cover thickness, the increasing rate of bond strength is lower than that of concrete. In addition, increasing the bar diameter, the average bond strength decreases. Further-more, with the increase of the anchorage length, average bond strength decreases. The increase of anchorage length results in higher increment rate of the bond strength of grout compared to the self-compacting concrete. With the same compressive strength grade, the bond strength of grout is higher than that of ordinary concrete. In conclusion, the bond-slip behavior between ribbed steel bar and grout is different from that of concrete.