A Study on the Effects on Cement Hydration of Recyeled Mortar

• Main Authors: Jia-Hau Hou, 侯嘉豪
• Other Authors: Chung-Ming Ho
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/68158551349783144541

碩士 === 中原大學 === 土木工程研究所 === 97 === Abstract Recycled fine aggregates and powder obtained from crushed mortars were tested to assess the feasibility of using them to produce recycled cement mortar. By means of sieve analysis, recycled fine aggregates and powder were separated in order to replace natural fine aggregates and cement. Properties of recycled mortars on compressive strength and the strength reduction after elevated temperature exposure are carried out in this study. Tests of ultrasonic pulse velocity (UPV), loss of ignition (LOI) and x-ray diffraction (XRD) analysis of recycled mortars were carried out and compared with the associated compressive strength. Test results show that when more recycled aggregate were used, the development of compressive strength decreased, and the compressive strength and UPV of specimen subjected to high temperature exposure were came down. On higher water-binder ratio, compressive strength and UPV of specimen subjected to high temperature exposure were comparably descended. Since the recycled aggregates are crushed from laboratory mortar, the specimen contains raw and reused mortars. For replace fine aggregate, loss of ignition of cement paste was increased when more recycled materials were used. Instead of replacing cement, the test result of LOI was decreased when more recycled materials were used. Performance of mortar has no significant difference between A type and B type recycled aggregates. This could be attributed to the interval of curing age 28 days and 56 days, which is too closed. The performance of the recycled mortars had no divergence obviously.