新型聚合物水泥胶浆界面剂粘结性能及作用机理研究

采用新型聚合物水泥胶浆作为界面剂以提高新旧混凝土之间的粘结性能,通过拉拔粘结强度与劈裂抗拉粘结强度实验对5种不同类型的聚合物水泥胶浆界面剂的粘结性能进行了测试,并利用扫描电镜(SEM)分析研究了丁苯聚合物水泥胶浆的界面增强机理。实验结果表明,5种聚合物乳液中,丁苯聚合物水泥胶浆具有较好的拉拔粘结性能,当优选m(水泥)∶m(DB-1乳液)=3∶2时,其7d、28d拉拔粘结强度分别达到1.83MPa、2.41MPa,相比水泥净浆空白样分别提高了144%、96%;在劈裂抗拉粘结强度方面,水平方向浇筑时劈裂抗拉粘结强度相对较高,当聚合物水泥胶浆的优选m(水泥)∶m(DB-1乳液)=3∶2,水平浇筑时其28d劈拉粘结强度达到2.96MPa,明显高于不掺界面剂的试样以及掺加其它配比界面剂的混凝土试样;经过微观测试分析,丁苯DB-1聚合物水泥砂浆内部界面过渡区(ITZ)相比空白样明显致密,表明丁苯聚合物的加入有效填充了水泥基材料内部的宏观与微观缺陷,提高了界面过渡区的密实程度。

Study on the Interfacial Adhesive Performance and Enhancement Mechanism of Polymer Modified Cement Paste Interface Agent

Polymer modified cement paste interface agents was used to improve the bonding properties between the old and new concrete.The bond performance of five different types of polymer modified cement paste interface agents is tested by tensile bond strength and splitting tensile bond strength test.The interface enhancement mechanism of SBR polymer modified cement mortar was studied by the scanning electron microscopy(SEM) analysis.The test results show that: the SBR polymer modified cement paste has better tensile bonding properties among the five polymer emulsions.When m(cement)∶m(DB-1 latex)=3∶2,the 7d,28d of the tensile bond strength is 1.83MPa and 2.41MPa,respectively,compared to the blank samples of cement paste are increased by 144%,96%.In the splitting tensile bond strength,the splitting tensile horizontal pouring has relatively higher bond strength,when the quality of polymer cement paste m(cement)∶m(DB-1 latex)=3∶2,the 28d splitting tensile bond strength of horizontal pouring method is 2.96MPa,significantly higher than non-doped sample and binder interface admixture of other interface binder ratio of concrete specimens.The internal interfacial transition zone(ITZ) of DB-1 polymer modified cement mortar is dense compared to the blank sample,indicating that the added polymer cement-based materials to effectively fill the inside of the macro-and micro-defects and improve the interfacial transition zone of compaction.