2020 Volume 76 Issue 4 Pages 306-314
In this study, triaxial tests were performed on compacts of leached/unleached cement paste, calcium hydroxide, and synthesized C-S-H to understand the deformation mechanisms of cement paste and concrete under high pressure and also the mechanism of higher strength and density development of crushed concrete through compaction when the concrete powder is wet. It was found that compact of calcium hydroxide significantly reduced strength and stiffness when it was wet. The synthesized C-S-H reduced the stiffness under high confining pressure, but the effect of moisture was small compared with that of calcium hydroxide. Based on the obtained results, the process of the strength gain of crushed concrete through compaction is explained as follows: C-S-H, which deformed easily, was squeezed out, the calcium hydroxide structure was formed, and the structure deformation occurred readily when the concrete was wet. These findings are useful for understanding the deformation mechanisms of ordinary concrete and cement paste.