ABSTRACT
Malhotra and others (Langley et al. 1989; Giaccio and Malhotra 1988; Malhotra 1990; Alsali and Malhotra 1991; Bilodeau and Malhotra 1992; Bilodeau et al. 1994; Langley et al. 1992) have reported extensively on high-volume fly ash concrete. Concrete containing high volumes of Class F fly ash exhibited excellent mechanical properties, good durability with regard to repeated freezing and thawing, very low permeability to chloride-ions (Langley et al. 1989; Giaccio and Malhotra 1988; Malhotra
1990), and showed no adverse expansion when reactive aggregates were incorporated into concrete Malhotra (1990). Alasali and Malhotra (1991) reported that high-volume of Class F fly ash in concrete has proved to be highly effective in inhibiting the alkali-silica reaction. Superplasticized high-volume fly ash concrete containing up to 60% of fly ash of total cementitious materials, had poorer abrasion resistance than concrete without fly ash (Bilodeau and Malhotra, 1992). Air-entrained high-volume fly ash concrete exhibited excellent characteristics regardless of the type of fly ash (eight fly ashes from U. S.) and cements (two Portland cements from U. S.) (Bilodeau et al., 1994). For concrete blocks containing high volumes of low-calcium (ASTM Class F) fly ash, ratio of the 42 days core compressive strength to the 28 days laboratory-cured compressive strength ranged from 78% for the control concrete to 120% for the highvolume fly ash concrete. At 365 days, these ratios were 78 and 92 percent, and at 730 days, the respective ratios were 88 and 98 percent (Langley et al., 1992). Maslehuddin (1989) reported that addition of fly ash as an admixture increased the early age compressive strength and long-term corrosion-resisting characteristics of concrete. Tilasky et al. (1988) concluded that the abrasion resistance of concrete made with Class C fly ash was better than both concrete without fly ash and concretes containing Class F fly ash.
