EFFECTS OF ACCELERATED CURING CONDITIONS ON STRENGTH PROPERTIES OF EPOXY-MODIFIED MORTARS WITHOUT HARDENER

ABSTRACT Epoxy resin without any hardener can harden in the presence of hydroxide ions in cement mortars and concretes at ambient temperature. However, the hardening rate of the epoxy resin at ambient temperature is slow, and the acceleration of the hardening reaction of the epoxy resin is requested for the manufacture of precast products. Epoxy-modified mortars without any hardener are prepared with polymer-cement ratios of 0 to 20%, subjected to an autoclaving or steam curing after a 1-d moist curing, followed by a 1-d heat curing, and tested for flexural and compressive strengths. As a result, the optimal curing conditions for the epoxy-modified mortars without any hardener are recommended as follows: (1) 1-d moist[20°C, 90%(RH)] + autoclaving(90 or 120°C, 3h) + 1-d heat(120°C) cure, and (2) 1-d moist[20°C, 90%(RH)] + 1-d steam(90°C) + 1-d heat(120°C) cure. Their flexural and compressive strengths can be predicted by the general equation expressed as a function of maturity.