纤维聚合物水泥砂浆与基体界面粘结性能研究

Performance of the bonding between fiber reinforced polymer mortar and substrate

通过实验研究钢纤维、聚丙烯纤维、碳纤维等三种不同种类纤维和SBR乳液在单掺、复掺时对新拌砂浆与水泥混凝土基体之间界面粘结强度的影响,寻求适合于混凝土结构修补的新材料。在预先处理的基体表面浇筑不同类型的新拌水泥砂浆,在温度为(20±2)℃,湿度为(60±5)RH%的养护室中养护28d后,测试粘结面的粘结强度,通过粘结强度来反映不同种类纤维和乳液单掺、复掺对新旧水泥基体料粘结效果的影响。同时分析了纤维和乳液对新旧水泥基界面粘结性能作用的机理。研究结果表明,掺量为0.1%的碳纤维砂浆以及掺量不小于0.3%的钢纤维砂浆在复掺SBR(styrene-butadiene rubber)乳液的情况下对界面粘结性能作用效果比纤维、乳液单掺情况下均要好,而聚丙烯纤维与乳液复掺效果不明显。不同种类的纤维砂浆在复掺SBR乳液的情况下,均能有效改善新拌纤维砂浆与基体之间界面结性能,且随着乳液掺量的增加作用效果越好。钢纤维聚合物砂浆和碳纤维聚合物砂浆适用于混凝土结构修补。

The bonding strength of the interface between different types of new mortar and concrete substrate is studied in order to find out the most favorable repair materials for concrete structures. The steel fiber, polypropylene fiber, carbon fiber and SBR latex are mixed separately or fiber and latex are mixed together to compare the new types of mortars. New types of mortars are poured on the surface of the preprocessed concrete substrate. After 28d curing under the condition of （20 ± 2）℃ and （60 ± 5 ） RH%, the bonding strength between new mortars and the concrete substrate are tested. The diverse influences of fiber and SBR latex on the bonding performance are studied when fibers and latex are mixed separately or fibers and latex are mixed together. The bonding mechanisms between fiber reinforced polymer mortar and concrete substrate are briefly analyzed. The test results show that for mortar content 0. 1 % of carbon fiber （by volume of mortar） and mortar content not less than 0.3% of steel fiber, latex and fiber mixing together is better than mixing separately, while the effect is not obvious for polypropylene fiber and latex mixing together. It is concluded that for any type of fiber reinforced mortar, incorporation of SBR latex improves the bonding performance of the new mortar and the substrate, and the effect enhances with increasing content of the latex. Steel fiber and polypropylene fiber reinforced polymer mortar can be employed for repairing concrete structures.