Experimental Study on the Autogenous Shrinkage Behaviors of Different Portland Blast Furnace Slag Cements
In this study, the various autogenous shrinkage behaviors of Portland blast furnace slag (BFS) cements are experimentally investigated.Portland BFS cements that contain 40-45% BFS were collected from eight different plants in Japan and their autogenous shrinkage and temperature behaviors at early ages were measured with mortar specimens.The autogenous shrinkages were measured by an embedded strain gauge and measurement the results are processed to eliminate the effects of the expansions and the temperature histories shortly after the cement is laid.The experimental results showed that BFS cement had a larger autogenous shrinkage than ordinary Portland cement (OPC), and some BFS cements had a much larger shrinkage than others.The same class of Portland BFS cement can have different autogenous shrinkage behaviors, and the difference cannot be explained only from the Blaine values or other fundamental physical information.To study the cause of the different autogenous shrinkages, additional experiments were conducted.From the viewpoint of capillary pressure, the internal relative humidity and pore structure developments at an early age were observed.The results show that the capillary tension of the BFS cement seems lower than that of OPC, which is inconsistent with the measurement results of autogenous shrinkage.Subsequently, the reactive minerals in each powder and the reaction progress of cement and BFS in cement paste specimens were measured by thermal gravimetric analysis and X-ray deflection Rietveld analysis.The results show that there are differences in the reactive mineral content among the Portland BFS cements, and they are consistent with the shrinkage measurement results.Properties of cement hydrates can change because of the different reaction progress of BFS, and this can lead to the differences in autogenous shrinkage.
Autogenous shrinkage Portland blast furnace slag cement Reaction degree Internal relative humidity Thermo-gravimetric analysis X-ray deflection measurement
Y.Takahashi S.Suntharalingam
The University of Tokyo, Tokyo, Japan
国际会议
福州
英文
409-418
2018-11-04（万方平台首次上网日期，不代表论文的发表时间）