Performance of interface between TRC and existing concrete under a chloride dry-wet cycle environment

Abstract

Textile-reinforced concrete (TRC) is suitable to repair and reinforce concrete structures in harsh environments. The performance of the interface between TRC and existing concrete is an important factor in determining the strengthening effect of TRC. In this paper, a double-sided shear test was performed to investigate the effects of the chloride dry-wet cycles on the average shear strength and slip at the interface between the TRC and existing concrete, also considering the existing concrete strength, bond length, textile layer and short-cut fiber arrangements. In addition, X-ray diffraction (XRD) technology was used to analyze the microscopic matter at the interface in the corrosive environment. The experimental results indicate that the interface performance between TRC and existing concrete would decrease with continued chloride dry-wet cycles. Compared with the specimen with a single layer of textile reinforcement, the specimens with two layers of textile with added PVA or AR-glass short-cut fibers could further improve the properties of the interface between the TRC layer and existing concrete. For the TRC with a single layer of textile, the average shear strength tended to decrease with increasing bond length. In addition, the strength grade of the existing concrete had a minor effect on the interface properties.

摘要

纤维编织网增强混凝土(TRC)适用于恶劣环境下混凝土结构的修补和增强。TRC 与既有混凝土 的界面性能是决定TRC 加固效果的重要因素。本文通过双面剪切试验研究了氯盐干湿循环对TRC 与 既有混凝土界面处平均抗剪强度和滑移的影响, 同时考虑了既有混凝土强度、粘结长度、加固层数和 掺加短切纤维等因素。此外, 还利用X 射线衍射(XRD)技术分析了腐蚀环境中界面处的微观物质。试 验结果表明, 随着氯盐干湿循环次数的增加, TRC 与既有混凝土的界面性能降低。与加固单层试件相 比, 加固两层且基体中掺入PVA 或AR-玻璃短切纤维的试件可以进一步改善TRC 层与既有混凝土的 界面性能。对于具有单层纤维编织网的TRC, 试件的平均抗剪强度随粘结长度的增加有减小的趋势。 此外, 既有混凝土的强度等级对TRC 与混凝土界面性能的影响较小。