Abstract
This paper investigates hydrothermal synthesis of low water-to-powder light weight concrete containing cenosphere. Cenosphere is lightweight hollow sphere particle which is included in fly ash. The cenosphere in this study is collected from disposal water pool of coal ash in Japan where cenosphere float at the top. The density of cenosphere was about 0.75g/cm3 and median particle size was 159μm. Chemical composition of cenosphere was as same as that of ordinary fly ash in Japan. Cenosphere was mainly composed of glass（67％）and mullite（26％）. The amount of α-quartz in cenosphere（2.4％）was much smaller than fly ash. Using silica fume, viscosity agent and superplasticizer were effective to acquire both flowability of cement paste and prevention of material segregation for the hydrothermal reaction in Low Heat Cement-cenosphere system. The density and compressive strength of samples were ranged from 0.85 to 1.05g/cm3 and 15 to 22N/mm2 respectively. When comparing the specific strength of the present study with ordinary cementitious materials without cenosphere, it improved much higher with cenosphere. The surface of cenosphere was reacted, however the shell of cenosphere was remained firmly. In addition, the amount of through pore decreased by the usage of cenosphere and silica fume. Based on the above result, low permeability and high durabirity is expected for the present system.
