论文部分内容阅读
引气剂是一种使混凝土在搅拌过程中产生大量微小气泡,从而改善薪拌混凝土工作性和硬化混凝土耐久性的外加剂。调凝剂则是调节水泥凝结时间的外加剂。1.引气剂的应用技术1.1 引气剂分类与引气剂成份引气剂根据水溶液的电离性质,可分为阴离子系、非离子系、阳离子系三大类。实际上,主要应用的引气剂都是阴离子型,即松香类引气剂。其制备方法是用碱将松香皂化,所以主要成份是皂化松香的产物。1.2 引气剂的作用与应用目的引气剂能使混凝土引进大量微小且独立的气泡,这些球形气泡象滚珠一般起着润滑作用,大大改善了混凝土的工作性。一般来说,当引气量控制适量时,掺引气剂的混凝土减水率可达7%～9%,同时减轻了离析与浮浆现象。减少浮浆,可防止粗骨料颗粒和预埋钢筋下面形成空洞,避免浆体与软弱
Air-entraining agents are admixtures that cause concrete to generate a large number of tiny bubbles during the mixing process, thereby improving the workability of the hardened concrete and the durability of the hardened concrete. The coagulant is an admixture that regulates the setting time of the cement. 1. Application technology of air-entraining agents 1.1 Classification of air-entraining agents and composition of air-entraining agents Air-entraining agents can be classified into anionic, nonionic, and cationic systems based on the ionization properties of aqueous solutions. In fact, the main application of air-entraining agents are all anionic, that is, rosin-based air-entraining agents. Its preparation method is to saponify rosin with an alkali, so the main component is the product of saponification of rosin. 1.2 The role and application of air-entraining agents Air-entraining agents can introduce a large number of small and independent air bubbles into the concrete. These spherical air bubbles act as a lubricant and greatly improve the workability of the concrete. In general, when the amount of air-entrainment is controlled properly, the water-reducing rate of concrete mixed with air-entraining agent can reach 7% to 9%, and the phenomenon of segregation and laitance can be reduced. Reducing laitance can prevent the formation of voids under the coarse aggregate particles and embedding rebar to avoid slurry and weakness