Views: 6 Author: Site Editor Publish Time: 2018-03-30 Origin: Site
Air-entraining admixtures are used to introduce microscopic air bubbles in concrete to improve the durability of concrete exposed to freeze/thaw cycles. According to ACI 212.3, there are two main types of air-entraining admixtures, which must meet the requirements of ASTM C 260. Water-soluble air-entraining admixtures are formulated from a variety of different organic substances, including among other things wood resin salts, synthetic detergents, and salts of petroleum acids. Solid materials with high internal porosity and a suitable pore size—such as hollow plastic spheres, crushed brick, expanded clay or shale, and diatomaceous earth spheres—can be added and seem to act like air voids.