Studies on Environmental Load Reduction and Surface Protection Effects of Porous Concrete Used Lapilliby Measuring Temperature in Outdoor Exposure Test

The outdoor exposure test of the porous concrete plate and beam used lightweight and high absorption lapilli produced in north of Akita Prefecture was carried out. Lapilli is one of the porous and light stone formed by volcanic activity. The temperature in the center of the cross section of the plate and the relative dynamic modulus of elasticity of the beam were measured. As the results of former measurement, the temperature in the center of cross section of the porous concrete plate was 4 degrees lower than atmospheric temperature at the maximum but that of the ordinary concrete plate was higher than the temperature during 2 months in summer. It was clarified that the porous concrete had temperature reduction effect due to vaporization latent heat of water by heat balance calculation. The control of temperature change in summer night and day, the reduction of the freezing and thawing cycle number and the rise of the minimum temperature in winter were observed when the porous concrete plate was covered on the ordinary concrete plate surface. It is considered that these results lead to the deterioration control effects. The relative dynamic modulus of elasticity of the porous concrete beam in the outdoor exposure condition did not decrease for one and half years in spite of its low strength characteristics