CRACK PREVENTIVE WORK FOR MASS-CONCRETE STRUCTURE

摘要

PURPOSE:To prevent the cracking of mass-concrete structures by a method in which a cement mortar containing a coagulation retardant is placed in the lowermost layer in contact with the base of a structure and then cement mortar containing no coagulation retardant is placed there. CONSTITUTION:Cement mortar to which is added a coagulation retardant (e.g., an oxycarboxylate, etc.) in such an amount that the hydration reaction of cement with water is delayed by two days - two weeks is placed up to a height (h) of 3-30cm in the lowermost layer of a concrete wall 2 in contact with the base 1 of an existing structure. Then, ordinary cement mortar containing no coagulation retardant is placed up to a proper height H2 on said cement mortar. By this, during the period when the wall 2 is cooled and contracted, the lowermost layer 4 does not harden, and since the wall 2 is not related to the base 1, no tensile stress accompanying contraction by the base 1 occurs and also no cracking is produced in the concrete structure.