The effect of calcium salts on air-void structure in air-entrained concrete – a statistical and simulated study

Abstract

AbstractThis paper analyzed the air-void system in air-entrained concrete in the presence of calcium salts and developed a new approach method, random “parking” method, for studying it. The foam index test studied indicated that the introduction of calcium salts did result in a drop in foaming power at 0.5 min, but the foam ability after 60 min was enhanced in surfactant-water solution. The Powers spacing factor in the air-entrained hardened concrete decreased gradually in the presence of CaCl2 or Ca(NO3)2. The probability density function of air-void distribution showed that the air-void size in air-entraining concrete was reduced with the addition of CaCl2 and Ca(NO3)2. The random parking method developed herein was compared with the experimental Powers spacing factor, and the concept of the alternative spacing factor, defined as the average distance between the surfaces of the two nearest air voids in concrete, was used. It was indicated that the alternative spacing factor is in close proximity to the experimental Powers spacing factor.