METHOD FOR REDUCING SHRINKAGE AND CRACKING OF MORTAR OR CONCRETE DUE TO DRYING

摘要

PROBLEM TO BE SOLVED: To control the drying of mortar or concrete and to reduce shrinkage and cracking due to drying by adding fine fibrous cellulose and a specified shrinkage suppressing material at the time of producing mortar or concrete. SOLUTION: One or more kinds of shrinkage suppressing materials are selected from among modified amido compds. each having a total amine value of 80-700 and compds. represented by the formula, RO(AO)n H [where R is 1-7C alkyl or 5-6C cycloalkyl, A is 2C alkylene and/or 3C alkylene and (n) is 1-10] and 100 pts.wt. of the materials are mixed with 0.5-5 pts.wt. fine fibrous cellulose having an aspect ratio of 250-5,000, <=3μm average fiber diameter, 5-300μm fiber length and 50-300m<2> /g specific surface area. The resultant mixture is added at the time of producing mortar or concrete.