Abstract
In this study, the material properties, an index to evaluate the control function of heat island phenomenon, an appropriate mix proportion and temperature reduction effect of the porous concrete with 20 to 40% of void ratio used the lapilli which was lightweight and high absorption produced in Akita prefecture were clarified. The mass of unit volume of this concrete was about under half of ordinary concrete and compressive strength was 2N/mm2 but it was durable in the drying-wetting cycle test. There existed a paste coarse aggregate volume ratio having the maximum initial evaporation rate which was obtained from relationship between elapsed time and evaporation ratio. From the outdoor exposure test results and heat balance calculation, it was clarified that the temperature in the center of the cross sectional area and on the surface of the porous concrete plate manufactured by this mix proportion was 1 to 9 °C lower than that of ordinary concrete plate and this concrete had temperature reduction effect due to vaporization latent heat.
