聚合物改性抹灰砂浆抗裂性能初探

Research on Crack Resistance of Polymer Modified Plastering Mortar

通过测试4种市售建筑墙面找平用聚合物改性抹灰砂浆及1种修补砂浆的抗压强度、各龄期收缩率及开裂性能,研究了聚合物改性抹灰砂浆抗压强度与其开裂性的关系,同时研究了聚合物改性抹灰砂浆收缩率对其开裂性的影响,并提出采用Coutinho圆环测试评估砂浆开裂性能时的判定方法。结果表明:不同的聚合物改性抹灰砂浆材料,其抗裂性能存在差别;当砂浆抗压强度>12.2 MPa时,圆环开裂概率增加,但并非所有砂浆的抗压强度均与其抗裂性成正相关关系;Coutinho圆环测试结果与收缩率结果存在一致性;砂浆早期收缩发展越快,圆环开裂时所对应的收缩率越大,当收缩率>0.149%时,聚合物改性抹灰砂浆有较大的开裂风险。

By testing the compressive strength,shrinkage and cracking performance of 4 kinds of commercially available polymer-modified plastering mortar and 1 kind of repair mortar,this paper studies the relationship between the compressive strength and cracking properties of polymer-modified plastering mortar,and also studies the effect of shrinkage of polymer-modified plastering mortar on its cracking properties.And it proposes using Coutinho ring test to evaluate the cracking performance of mortar.The results show that there are differences in crack resistance of different polymer-modified plastering mortar materials.When the compressive strength of mortar>12.2 MPa,the probability of ring cracking increases,but not all mortars have a positive correlation between their compressive strength and their crack resistance.The Coutinho ring test results are consistent with the shrinkage results.The faster the mortar shrinks in the early stages,the higher the shrinkage when the Coutinho ring cracks.When the shrinkage>0.149%,the risk of cracking of polymer modified plastering mortar increases.