EFFECT OF REDISPERSIBLE POLYMER POWDER ADDITION TO ULTRA RAPID HARDENING CEMENT MORTAR ON STRENGTH DEVELOPMENT

摘要

Several kinds of redispersible polymer powder have been recently used in prepackaged formulated cement mortars in Japan. Although the properties of polymer powder added cement mortar have already been investigated, few reports which deal the polymer powder added ultra rapid hardening cement mortar, provide. The effect of the polymer powder addition to ultra rapid hardening cement mortar on flexural, compressive and adhesive strengths were investigated in this paper. Comparison with those of the polymer powder added ordinary Portland cement mortar was also conducted. Three types of PAE and a type of VA/VeoVa, EVA and SBR as representative redispersible polymer powders in Japan were used with polymer cement ratio 5 and 10% in this study. The effect of the polymer powder addition on strength development was different according to the polymer type and in the same type of PAE it was different according to the product besides. Adhesive strength was improved by the polymer powder addition, even though it was not effective for improvement of flexural and compressive strength, particularly when the mortar thickness was thin. Furthermore, the effective polymer powder for ultra rapid hardening cement on strength development was not necessarily effective for ordinary Portland cement.