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

摘要

Epoxy resin without any hardeners can harden in the presence of alkalis or hydroxide ions in cement mortar. This paper deals with the effects of curing conditions on the strength properties of epoxy-modified mortars without any hardeners. The epoxy-modified mortars without any hardeners are prepared with polymer-cement ratios of 0 to 40 percent, subjected to a dry cure, heat cure and hot water cure for 28d, and tested for flexural and compressive strengths. From the test results, the flexural and compressive strengths of the epoxy-modified mortars are markedly increased by applying the heat cure as compared to the strengths in case of the dry cure, because the hardening reaction of the epoxy resin is accelerated by the heat cure. In particular, the flexural and compressive strengths of the 28-d 90 deg C-heat-cured epoxy-modified mortars with polymer-cement ratios of 30 and 40 percent are about twice or three times those of the dry-cured epoxy-modified mortars. The flexural and compressive strengths of the heat-cured epoxy-modified mortars can be expressed as function of the product of the polymer-cement ratio and maturity at polymer-cement ratios of 10 to 20 percent and curing periods of 28 to 91d. A general equation for strength prediction is proposed by using the (polymer-cement ratio centre dot maturity)-strength relationships. The application of the hot water cure to the epoxy-modified mortars is difficult.