セメントの水和進行に伴うコンクリート内部の顕微鏡的形態変化について

Abstract

Microscopic features of cement hydrates in corcrete were observed by optical and scanning electron microscopy during long term progress of hydration. The characteristic shapes and structures are shown here, mainly by selected micrographs obtained in this study, and discussed briefly with special reference to the effects of curing temperature and to the developement of mechanical properties of concrete. Specimens for scanning electron microscopy were sampled directly from concrete test cylinders, immediately after the mechanical tests had finished. The features of cement hydrates were evaluated numerically from the micrographs by measuring several characters of the typical shapes, as was already reported in reference in detail. The comparison of the evaluations for microscopic features with mechanical properties of concrete pointed out that much attention should be paid to the massive gel-permeated structure of hardened paste, whose inside composition is invisible by scanning electron microscope. Optical microscope with polarizer attachment and specially devised specimens enabled to observe the inside of the structure. The result also indicates how largely the composition varies during rather long term of hydration.