Enhancement of the concrete-PCM interfacial bonding strength using silica fume
Enhancement of the concrete-PCM interfacial bonding strength using silica fume
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DOI：
10.1016/j.conbuildmat.2020.119774
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发表时间：
2020-10-30
影响因子：
7.4
通讯作者：
Matsumoto, Koji
中科院分区：
文献类型：
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作者：
Mizan, Mahmudul Hasan;Ueda, Tamon;Matsumoto, Koji
近年来，聚合物水泥砂浆(PCM)加铺法作为一种修补加固技术得到了广泛的应用。界面脱粘问题阻碍了这种加固方法在世界范围内的应用。随着界面脱粘的发生，相变材料的强化作用消失，承载能力骤然下降。为了防止早期剥离，本研究旨在通过使用硅灰来增强混凝土-PCM界面。试验方法为双面剪切试验，给出了3种表面粗糙度(喷砂最高、中等和最低)和两种不同混凝土抗压强度(低强类型为16.73 Mpa和正常强度类型为29.59 Mpa)的试验参数。当表面喷砂时，对于LS和NS类型的混凝土，添加5%二氧化硅PCM的试件比普通PCM试件的界面强度分别提高了36.84%和35.05%。钢丝刷毛(高、低)后，表面粗化的百分比增幅更大，分别提高了约135.35%和181.12%。这一事实表明，硅灰夹杂物可以增强混凝土-PCM界面的化学结合。掺入硅灰的PCM和较高的表面粗糙度使纯界面破坏(I)模式更接近于“LS”型混凝土的内聚力(C)破坏模式，而对于“NS”型混凝土则更接近于复合断裂模式(I-P)。综上所述，硅灰的加入增强了相变材料的界面结合强度。(C)2020爱思唯尔有限公司。保留所有权利。
Recently, the polymer cement mortar (PCM) overlaying method has gained popularity as a repair/retrofitting technique. The debonding issue at the interface hinders the worldwide application of this strengthening method. Accompanying the occurrence of debonding at the interface, the strengthening effect of the PCM is lost, causing a sudden decrease in the load-carrying capacity. To prevent premature debonding, this study aims to enhance the concrete-PCM interface by using silica fume. The bi-surface shear test was selected as the test method, and three levels of surface roughness (highest level with sandblasting, medium and lowest levels with steel wire brushing) and two different concrete compressive strengths (low strength type (LS) with 16.73 MPa and normal strength type (NS) with 29.59 MPa) were given as experimental parameters. When the surface is roughened by sandblasting, the specimens with 5% silica PCM increase the interfacial strength compared to that of the normal PCM cases by approximately 36.84% and 35.05% for the "LS" and "NS" types of concrete, respectively. The percentage increase is even higher when the surface is roughened by steel wire brushing (high and low), with an increase of approximately 135.35% and 181.12%, respectively. This fact indicates that silica fume inclusions can enhance the chemical bonding at the concrete-PCM interface. The mixing of silica fume in PCM and a higher surface roughness level shifts the pure interface failure (I) mode closer to the concrete cohesion (C) failure mode for "LS" type concrete and to the composite fracture mode (I-P) for "NS" type concrete. Conclusively, it is confirmed that mixing silica fume into PCM strengthened the interface bonding strength. (C) 2020 Elsevier Ltd. All rights reserved.