CRACK REDUCING METHOD OF MASS CONCRETE FOR MAT FOUNDATION CONSIDERING THE COMBINED ADDITION OF FLY ASH, LIMESTONE POWDER AND CHEMICAL ADMIXTURE

摘要

A method of preventing cracks in a mass concrete foundation is provided to reduce the differences in hydration heat generation value between upper and lower concrete foundations for preventing tensile cracking of the mass concrete foundation by adding specific volume of retardant AE water reducing agent to a generic Portland cement on the upper concrete foundation and to the lower concrete foundation comprising a mixture of fly ash, fine limestone power and generic Portland cement. A method of preventing cracks in a mass concrete foundation includes dividing the mass concrete foundation into upper and lower foundations. On the upper foundation, generic Portland cement is poured and first chemical compound, comprising 0.01 to 1.5% of retardant AE water reducing agent or high AE water reducing agent by weight of the generic Portland cement, is added to the poured concrete. On the lower mass concrete foundation, concrete mixture containing 5 to 40% of fly ash and 5 to 30% of limestone powder by weight of the generic Portland cement respectively is poured, and a second chemical compound comprising 0.01 to 1.5% of retardant AE water reducing agent or high retardant AE water reducing agent by weight of the lower mass concrete mixture is added to the poured concrete. The first chemical compound includes 0.01 to 1.5% of generic or high generic AE water reducing agent by weight of the generic Portland cement, whereas second chemical compound includes 0.01 to 1.5% of retardant AE or high retardant AE water reducing agent by weight of the lower concrete mixture. The first chemical compound includes 0.01 to 1.5% of accelerator or high accelerator AE water reducing agent by weight of the generic Portland cement, and the second chemical compound includes 0.01 to 1.5% of retardant or high retardant AE water reducing agent by the weight of lower concrete mixture.