Substantial study on use of Prefoam-type Air-entraining Admixture for Fly Ash Concrete

从有效利用自然资源和防止碱-硅反应的措施的观点来看，预计粉煤灰的使用量将增加。然而，很难充分控制粉煤灰混凝土的含气量，因为粉煤灰中所含的未燃烧碳会吸附引气剂，存在降低混凝土抗冻性的风险。在这项研究中，预发泡型引气剂的搅打奶油的一致性，这是不太容易未燃烧的碳的影响，被用来夹带细气泡到混凝土中，试图提高其抗霜冻损害。预发泡型引气剂能降低粉煤灰混凝土的空隙率，从而有效地抵抗冻融作用。

Increased use of fly ash is expected from the standpoint of the effective use of natural resources and measures against alkali-silica reaction. However, it is difficult to adequately control the air content of fly ash concrete, as unburnt carbon contained in fly ash adsorbs the air-entraining admixture, posing a risk of reducing the resistance of concrete to frost damage. In this study, a prefoam-type air-entraining admixture of a whipped cream consistency, which is less prone to the effect of unburnt carbon, was used to entrain fine air bubbles into concrete, in an attempt to enhance its resistance to frost damage. The prefoam-type air-entraining admixture was found to be capable of reducing the spacing factor of fly ash concrete and thus effective against freezing and thawing action.