有机硅憎水剂对混凝土强度与毛细吸水性能的影响

Effect of Organic Silicon Hydrophobic Agent on Strength and Capillary Absorption of Concrete

选取乳液型和粉末型各2种有机硅材料,分别将不同掺量(0、0.25%、0.50%、1.00%,质量分数)的有机硅材料整体内掺到混凝土中,通过接触角、抗压强度和毛细吸水试验,研究了内掺有机硅整体憎水混凝土的毛细吸水性能。结果表明:掺入新型有机硅后,乳液型有机硅相比粉末型有机硅对相同龄期下混凝土抗压强度的影响较小,特别是掺量为0.25%的乳液型有机硅对混凝土28d时抗压强度影响甚微,水灰比为0.53和0.35时,抗压强度分别降低了0.5%和7.8%。当有机硅在混凝土表面形成膜结构,接触角达到约100°以上,且随着掺量继续增加,接触角基本保持不变。相比普通混凝土,掺入有机硅的混凝土吸水72 h后,毛细吸水量至少降低了60%,且吸水36 h后,吸水速率便趋于稳定。

Two kinds of emulsion organic silicon and two types of powder organic silicon, with different contents(0, 0.25%, 0.50%, 1.00%, in mass fraction) were mixed into concrete. The water absorption behavior of hydrophobic concrete internally incorporating organic silicon was investigated by contact angle, compressive strength and capillary absorption measurements. The results show that the effect of emulsion organic silicon on the compressive strength of concrete at the same age is less than that of powder after the addition of organic silicon. The concrete with 0.25% emulsion organic silicon has a little effect on its compressive strength during 28 d curing. The compressive strength is reduced by 0.5% and 7.8% when the water-cement ratio is 0.53 and 0.35, respectively. After a silicon membrane is formed on the concrete surface, the contact angle reaches over 100° and is not affected by further increasing admixture amount of organic silicon. In addition, compared to ordinary concrete, the amount of absorbed water is reduced by 60% at least and the water absorption rate is stabilized for 36 h after the addition of silicon into concrete.