Freezing and thawing resistance of cellular concrete containing binary and ternary cementitious mixtures

Abstract

Cellular concrete (CC) is a foamed low-density and low-strength material made with cement and/or lime, silica-rich material (sand, slag, or fly ash), water, fine aggregate and a foaming agent. The CC containing millions of evenly distributed, uniformly sized macroscopic air-voids of approximately 0.1–1 mm in size is considered to have good freeze-thaw (F-T) resistance. In the present study, the CC of binary and ternary cementitious mixtures with varying proportions of portland cement, fly ash, and lime were explored in a comprehensive laboratory test program related to porosity, water absorption, dry density, compressive strength, and resistance to F-T including durability factor and loss of mass. For selected mixtures, air-void spacing factor and air-void distribution had been determined. Test results showed that compressive strength of CC was primarily as a function of the porosity and density regardless of type of cementitious material with respect to the combination of binary and ternary cementitious mixture. It was also found that higher porosity did not necessarily result in higher water absorption. CC was generally found to present good F-T resistance compared to non-aerated concrete although the CC with high porosity did not necessarily result in higher resistance of F-T. The addition of fly ash to mixture led to a decrease in the number of air voids smaller than 300 µm. It was also found the F-T resistance of CC was more affected by the size of the air-void. The number of air-voids smaller than 300 µm played a critical role on reducing the F-T damage in CC.