丁苯胶乳水泥浆体系消泡剂优选与评价研究

Optimization of Defoamer of the Cement Slurry with Styrene-butadiene Latex

李早元[] 杨元意 程小伟 张 松 郭小阳

LI Zao-Yuan YANG Yuan-Yi CHENG Xiao-Wei ZHANG Song GUO Xiao-Yang

由于国产丁苯胶乳中含有大量的表面活性剂，在拌合过程中易导致气泡在水泥浆中形成并稳定存在，从而起泡严重，对水泥石密度和抗压强度产生较大的影响。本文对不同消泡剂的表面张力、胶乳稳定性以及不同温度下水泥浆流动性、密度进行了实验测试和讨论，并对添加复配消泡剂前后丁苯胶乳所形成水泥石的抗压强度和微观结构进行了分析。结果表明：丁苯胶乳浓度相对于消泡剂的种类对水泥浆体系影响较小，并且胶乳水泥浆高温下起泡比常温下严重；消泡剂异辛醇和二甲基硅油均具有较低的表面张力、不破坏胶乳稳定性以及对流动性影响较小，且在90℃下具有较好的消泡效果，加量为0.3%时的效果最佳；加入复配消泡剂（二甲基硅油和异辛醇质量比为1:1.5）后丁苯胶乳（加量为水泥质量的10%）所形成的水泥石抗压强度得到明显提高，气泡、孔量明显降低，结构更加致密。

Because there are many surfactants in the domestic styrene-butadiene latex, the foams could be produced and existed stably in the cement slurry though the mixing process, which would seriously influence the density and compressive strength of the cement pastes. In this paper, the surface tension and stability of the latex was tested and the flowability and density at different temperature was measured and the compressive strength and microstructure of the cement pastes with or without defoamers were studied as well. The results showed that the influence of the concentration of styrene-butadiene latex was lower than that of the type of the defoamers. Moreover, the foaming reaction of cement slurry with latex at high temperature was intenser than in room temperature. The surface tensile and defoamers of isooctanol as well as dimethicone was much lower than that of the others, and the both defoamers which had a good defoaming ability at 90℃would not effect the stability and flowability of the latex cement slurry, however, the defoaming effect was the best at the dosage of 0.3%. After adding the compound defoamers (the mass ratio of dimethicone to isooctanol was 1:1.5) in the latex cement slurry, the compressive strength of the obtained cement paste was much higher and the number of pore and bubble in the cement paste was fewer than that without defoamers, meaning that the microstructure of the cement paste with compound defoamers was denser.