2013 Volume 62 Issue 8 Pages 473-478
Recently it has been pointed out that the phenomenon of “a heat island” as one of the social problem in Japan. The author et al. developed a special mortar that suppresses radiation during the nighttime by improving water-holding capability using the activated alumina. Activated Alumina is manufactured from aluminum hydroxide by de-hydroxylating it in a way that produces a highly porous material. It is made of aluminum oxide (alumina ; Al2O3). It has a very high surface-area-to-weight ratio. In the research, three sorts of experiments were carried out. Firstly we carried out the outdoor full-scale test having the real house using the mortar roof with activated alumina and white mortar roof without activated alumina. These mortars were made of white Portland cement. Secondly we carried out the laboratory test having halogen lights in order to explain the relationship between the evaporation heat and received heat of specimen. Finally we measured the pore size distribution in order to prove the porous body of mortar with activated alumina. As a result, it was considered that the special mortar mixing the activated alumina was able to suppress the temperature rise.