水泥基修复材料和老混凝土界面粘结性能

THE BOND STRENGTH BETWEEN OLD CONCRETE AND CEMENT-BASED REPAIR MATERIALS

混凝土服役过程出现力学性能或耐久性能退化,从而需要进行混凝土修复从而满足其使用功能或延长服役寿命。修复材料和老混凝土界面性能是发挥修复材料补强作用的关键影响因素。文中研究不同掺量膨胀剂和碳纤维的掺量对修复材料抗折和抗压界面力学性能的影响和修复界面力学性能的影响。试验采用修复界面劈拉试验,界面直接拉伸试验,直接剪切试验。结果表明碳纤维的加入由于其桥接作用使得修复材料的抗弯性能得到明显的改善,碳纤维的作用模式分为拔出和拉断。膨胀剂的加入可以提升修复界面粘结性能10%以上,碳纤维的加入可以改善修复界面粘结性能15%以上,最高可达27.6%,背散射观测表明膨胀剂的加入使得修复界面较为密实。

The mechanical properties and durability of concrete were degraded during the service life, which needs the reinforce to satisfy service function and extend service life. The bond strength between old concrete and repair materials is key factor to influence the reinforcement effect of repair materials. Therefore, this study aims to investigate effect of dosage of expansive agent and carbon fibre on the mechanical properties and bond strength.The results indicated that the bond strength improved with the increase of dosage of expansive agent and carbon fiber. The function of carbon fiber is divided into pull-out and pull-off. The addition of expansive agent can improve the bonding performance of repair interface by more than 10%, and the addition of carbon fiber can improve the bonding performance of repair interface by more than 15%, up to 27.6%. Backscatter images show that the addition of expansive agent makes the repair interface more dense。