Effects of Accelerated Curing Conditions on Strength Properties of Polymer-Modified Mortars with SBR Latex and Hardener-Free Epoxy Resin
Yoshihiko OHAMA, Shinobu Takahashi and Masahiro OTA
Abstract:For the purpose of developing the early strength of concrete, accelerated curings such as steam and autoclave curings are widely applied to the manufacture of precast concrete products. The uses of polymer-modified mortar and concrete are also expected for precast products. The objective of the present study is to examine the application of effective accelerated curings to styrene-butadiene（SBR）-modified mortars with hardener-free epoxy resin. SBR-modified mortars with a hardener-free epoxy resin are prepared with various polymer-cement ratios, subjected to a 1-d 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,（steam+heat）-cured SBR-modified mortars with the hardener-free epoxy resin at polymer-cement ratios of 15% or more develop about three times higher flexural and compressive strengths than unmodified mortar. Such high strength development is attributed to the improved microstructures of interfacial transition zone by SBR-epoxy resin modification in the mortars. The optimal accelerated curing for the SBR-modified mortars with the hardener-free epoxy resin is recommended as follows: 1-d moist［20℃，90%（RH）］+1-d steam（90℃）+1-d heat（100 or 120℃）curing. Key Words:Polymer-modified mortars, SBR latex, Hardener-free epoxy resin, Steam curing, Steam+heat curing, Strengths, Polymer-cement ratio, Interfacial transition zone