PREVENTIVE METHOD OF CRACK IN MASS CONCRETE

摘要

PURPOSE: To retard a hydration to prevent mass concrete from cracking, by placing an inner layer concrete in which no reducing agent of hydration heat is added and placing an outer layer concrete in which the reducing agent of hydration heat is added. ;CONSTITUTION: Inner layer concrete 1 without additives is placed in a form 3 and outer layer concrete 2 in which a hydrolyzable tannin is added as a retarding agent, is placed on the concrete 1 immediately thereafter. When concrete 12 is placed in layers, concrete 13 in contact with the form 20 at the periphery, in which a reducing agent of hydration heat is added, has been placed to heap up, and coincrete 12 without additives is placed in the middle. Many layers composed of the concrete 12, 13 are superposed and concrete 14 with the reducing agent of hydration heat is placed as the uppermost layer. The rising speed of the hydration heat and the setting and curing speed of the outer concrete 2 are made slower than those of the inner concrete 1. In this way, the difference of thermal deformation volume between the inner and outer concrete 1, 2 can be absorbed.;COPYRIGHT: (C)1996,JPO