The Effect of Heat Curing Methods on the Protection against Frost Damage at Early Age of the Concrete Under Extremely Cold Climate

Abstract

This study aimed to examine whether heat curing methods of concrete subjected to <TEX>$-10^{\circ}C$</TEX> could be effective by varying the combination of heating cable and surface heat insulations. Three different concrete specimens incorporating 30% fly ash with 50% W/B were fabricated to simulate wall, column and slab members with dimensions of <TEX>$1600{\times}800{\times}200$</TEX> mm for slab, <TEX>$800{\times}600{\times}200$</TEX> mm for wall and <TEX>$800{\times}800{\times}800$</TEX> mm for column. For heat curing combinations, Type-1 specimens applied PE film for slab, plywood for wall and column curing. Type-2 specimens applied double layer bubble sheet (2LB) and heating coil for slab, and 50 mm styrofoam for wall and column curing. Type-3 specimen applied 2LB for slab, electrical heating mat for wall and column inside heating enclosure. The test results revealed that the temperature of Type 1 specimen dropped below <TEX>$0^{\circ}C$</TEX> beginning at 48 hours after placement due to its poor heat insulating capability. Type 2 and 3 specimens maintained a temperature of around <TEX>$5{\sim}10^{\circ}C$</TEX> after placement due to favorable heat insulating and thermal resistance.