[A-GE28] Energy-Environment-Water Nexus and Sustainable Development

[AGE28-09] Experimental study to characterize valuation efficiency and solar reflectance of permeable pavement blocks made from recycled concrete aggregates blended with autoclaved aerated concrete grains

*Yuta Sakai¹, Akihiro Matsuno¹, Ken Kawamoto¹ (1.Graduate School of Science and Engineering, Saitama University)

Keywords:permeable pavement block, autoclaved aerated concrete, evaporation efficiency, solar reflectance, urban heat island

Due to rapid urbanization and population growth, the generation of construction and demolition waste (CDW) including concrete waste and autoclaved concrete (AAC) waste is increasing in developing countries. The urbanization as well as global warming cause. The urban heat island (UHI) problem. Permeable pavement (as well as water retentive pavement) contributes to mitigate the UHI effect decreasing the road surface temperature in urbanized areas and in widely spread in developing countries. The permeable pavement , however, has not been fully adopted in most of developing countries including Vietnam due to lack of reuse/recycling of CDW. In this study, therefore, investigated the evaluation efficiency and solar reflectance of permeable pavement blocks made from recycled concrete aggregates (RCA) blended with AAC grains, aiming the promotion of the CDW reuse/recycling and the mitigation of UHI at urbanized areas in Vietnam. The AAC grains is porous structure with high water absorbing ability and can be expected to retain water in permeable blocks. Four types of permeable blocks with design porosity of 20% were prepared by changing the blending proportions of AAC grains (0,5,10,15%). As control blocks, a permeable block (K-Ground Coat block, ECOSYSTEM Co. Ltd., Japan) and a water-retentive block (MOISTPAVE; DAIWA Ceramics Co. Ltd., Japan) were used. In a climate-controlled room, evaporation efficiency of tested samples was measured following a standard method (JSTM H 1001, 2015) and solar reflectance and thermal conductivity were also measured under the evaporation process.
The results showed that the measured evaporation efficiency and solar reflectance for permeable blocks blended with AAC grains satisfied well the Eco-standard of permeable and water-retentive interlocking blocks in Japan. Especially, the permeable block blended with 15% of AAC grains gave same evaporation performance with the control water-retentive block in Japan. Further studies are needed to examine the relationships between mechanical properties such as compressive and flexural strengths and the design porosity, but the blending porous AAC grains can be expected to develop the hybrid-type blocks (permeable and water-retentive) and to contribute the mitigation of UHI at urbanized areas in developing countries.