新旧水泥砂浆界面粘结性能试验研究

摘要/Abstract

摘要： 在荷载和环境因素作用下,混凝土结构产生不同程度的劣化。为了保证结构的安全性和耐久性,需要对损伤水泥基材料进行修复。基体的含水饱和度、界面粗糙度、修补砂浆的水灰比以及试件的养护条件都会影响修补砂浆与基体间的粘结强度。选取四种含水饱和度(0%、30%、70%、100%)的旧砂浆作为基体,浇筑水灰比为0.4和0.6的新砂浆,试件密封养护28 d,剪切试验结果表明:当新砂浆水灰比为0.6,旧砂浆含水饱和度按照70%、30%、100%、0%的顺序变化时,界面的剪切强度逐渐减小;当新砂浆水灰比为0.4,旧砂浆含水饱和度按照30%、0%、70%、100%的顺序变化时,界面的剪切强度逐渐减小。同时发现,新砂浆水灰比为0.4时的界面剪切强度普遍大于水灰比为0.6的数值。通过切槽法改变旧砂浆的界面粗糙度,然后浇筑水灰比为0.6的新砂浆,试件标准养护。剪切试验结果表明:当旧砂浆界面粗糙时,界面间的剪切强度是旧砂浆光滑时的1.26倍。选取两种含水饱和度(0%、100%)的旧砂浆作为基体,浇筑水灰比为0.4和0.6的新砂浆,分别进行标准养护和密封养护,剪切试验结果表明:在旧砂浆含水饱和度和新砂浆水灰比相同的情况下,标准养护下的界面剪切强度明显大于密封养护下的界面剪切强度。

关键词: 水泥砂浆, 粘结强度, 含水饱和度, 粗糙度, 密封养护, 剪切试验

Abstract: Under the load and environmental factors, concrete structures suffer from varying degrees of deterioration. In order to ensure the safety and durability of the structures, it is necessary to repair the damaged cement-based materials. The bonding strength between repair mortar and matrix was influenced by the moisture state of old mortar, the roughness of interface, the water cement ratio of repaired mortar and the curing condition. Old mortars with different moisture states (0%, 30%, 70% and 100%) were selected as the matrix and then new mortars with water cement ratio of 0.4 and 0.6 were poured. The composite specimens were cured in sealing condition for 28 d. The shear test results show that when the water cement ratio of new mortar is 0.6 and the moisture states of old mortar change in the order of 70%, 30%, 100%, 0%, the shear strength gradually decreases. When the water cement ratio of new mortar is 0.4 and the moisture states of old mortar change in the order of 30%, 0%, 70%, 100%, the shear strength gradually decreases. Moreover, when the water cement ratio of new mortar is 0.4, the interfacial shear strength is generally greater than that when the water cement ratio of new mortar is 0.6. The interfacial roughness was changed by grooving method, and then the new mortar with water cement ratio of 0.6 was poured. The composite specimens were cured in standard condition. The shear test results show that when the interface is rough, the shear strength is 1.26 times of that when the old mortar is smooth. Old mortars with different moisture states (0% and 100%) were selected as the matrix and then new mortars with water cement ratio of 0.4 and 0.6 were poured. The specimens were cured in sealing and standard condition respectively. The experimental results show that when the moisture states of old mortar and water cement ratio of new mortar are the same, the shear strength in standard condition is obviously higher than that in sealing condition.

Key words: cement mortar, bonding strength, moisture state, roughness, sealing curing, shear test

中图分类号:

TU528

孟繁强, 薛善彬, 张鹏, 王俊洁, 高世壮. 新旧水泥砂浆界面粘结性能试验研究[J]. 硅酸盐通报, 2020, 39(12): 3791-3798.

MENG Fanqiang, XUE Shanbin, ZHANG Peng, WANG Junjie, GAO Shizhuang. Experimental Study on Interfacial Bonding Property of New and Old Cement Mortar[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2020, 39(12): 3791-3798.

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