抗裂防水剂与矿物掺合料复合对混凝土Cl-扩散系数的影响

The Study on the Effect of Compound of the Crack-Resistance Waterproofing Agent and Mineral Admixtures to Concrete Chloride-ion-Diffusion-Coefficient

目的研究不同养护条件下抗裂防水剂与矿物掺合料复合对抗裂防水性能的影响,保证混凝土的耐久性.方法在化学分析实验中,采用BaSO4重量法测试样品不同龄期的可溶出SO42-量;在混凝土C l-扩散系数实验中,采用NEL法测试混凝土试件不同龄期的C l-扩散系数.结果有的抗裂防水剂在28d时仍有0.75%的可溶出SO42-;掺入粉煤灰的混凝土干空下的C l-扩散系数随着龄期的增长逐渐提高;掺入矿粉的混凝土干空和标养下的C l-扩散系数都随龄期的增长逐渐降低;掺入混凝土的抗裂防水剂SO3量越高,其干空下的C l-扩散系数越高.结论抗裂防水剂按推荐用量使用时,其28 d的可溶出SO42-量建议不大于0.72%;加入粉煤灰和SO3量较高的抗裂防水剂的混凝土易发生干缩开裂,即使养护良好,如果粉煤灰掺量较高,混凝土也可能发生膨胀开裂,粉煤灰适合和SO3含量较低的抗裂防水剂复合使用;掺加矿粉的混凝土不易发生干缩开裂,如果养护良好,SO3量较高的抗裂防水剂和矿粉复合使用可使混凝土内部密实得较快,矿粉适合和SO3量较高的抗裂防水剂复合使用.

The aim is to study the effect of the compound of crack-resistance waterproofing agent and mineral admixtures on the crack-resistance waterproofing agent and to guarantee the endurance of concrete. In chemistry analysis experiment, the BaSO4 weighted method is used to carry on chemistry analysis on the quantity of the dissolvable SO4^2- in different hydrated periods. In the concrete chloride-ion-diffusion-coefficient experiment, the NEL method is used to test the chloride-ion-diffusion-coefficient of concrete sample in different hydrated periods. Some crack-resistance waterproofing agent still has 0. 75 % dissolvable SO4^2- at 28 d;and the fly-ash concrete chloride-ion-diffusion-coefficient is gradually raising along with the hydrated period under air condition. The pulverized slag concrete chloride-ion-diffusion-coefficient is gradually decreasing along with the hydrated period under air condition and standard condition. The higher crack-resistance water- proofing agent SO3 quantity is added in the concrete, the higher the chloride-ion-diffusion-coefficient becomes in air condition. When the crack-resistance waterproofing agent is used according to the recommended dosage, its dissolvable SO4^2- quantity shouldn＇t be higher than 0.72% at 28d. The concrete added fly-ash and crack-resistance waterproofing agent with higher quantity of SO3 tends to have the crack of dried shrinkage. Even under standard condition,if the fly-ash amount is higher, the concrete also may have the crack of dried shrinkage, so the fly-ash is suitable to compound application with crack-resistance waterproofing agent with lower quantity of SO3. The pulverized slag concrete doesn＇t tend to have the crack of dried shrinkage ,under the standard condition, the compound application of crack-resistance waterproofing agent with higher quantity of SO3 and pulverized slag can make the inside of concrete dense more quickly. So it is suitable that the pulverized slag is used together with crack-resistance waterproofing agent with higher quantity of SO3.