桥面用丁苯乳液改性水泥砂浆物理性能的研究

Physical Properties of Styrene-Butadiene Emulsion Modified Cement Mortar Used for Repair of Bridge Surface

摘要:

通过测定新拌砂浆保水性、含气率，硬化砂浆孔隙率、孔径分布、断面形貌以研究丁苯乳液D623对砂浆物理性能的改性效果，丁苯乳液D623对砂浆有良好的保水和引气作用，可使砂浆体积密度降低，孔径分布改变；聚合物成膜后形成网状结构，与水泥水化产物相互穿透；硬化砂浆的孔隙率与新拌砂浆的含气率没有对应关系，与新拌砂浆的体积密度反倒有一定的关系；砂浆抗压强度、抗折强度和弹性模量均与孔隙率、体积密度有对应关系，而粘结抗拉强度与它们的关系则不明确。

Abstract:

Modifying effects of carboxyl terminated styrene butadiene emulsion D623 on physical properties of cement mortar, such as water retention and air void content of fresh mortar and porosity, pore size distribution and fracture morphology of hardened mortar, were studied. D623 improves water retention of fresh mortar and entrains a large amount of micro air void which causes bulk density to reduce, pore size distribution to change. It is obvious that a network structure of polymer films has formed and crisscrossed with cement hydrates. Porosity of hardened mortar has no relation with air void content, but a little relation with bulk density of fresh mortar. Compressive strength, flexural strength and elastic modulus have good relations with porosity and bulk density. Tensile bond strength, however,is not same as the former.