Influence of AAC grains on some properties of permeable pavement utilizing of CDW and industrial by-product

Abstract Construction and Demolition Waste (CDW) has been being accounted for a large amount of waste in urban areas around the world, especially for developing countries like Vietnam due to rapid urbanization and economic growth. The recycling and reuse of CDW are not only significant in reducing the consumption of natural materials but also can be a solution to improve the urban environment. In recent years, several studies have shown that the use of recycled materials from CDW in permeable pavement systems has a good effect on hydrological aspects and soil absorption capacity, thereby minimizing the risk of flooding and ground water depletion, increasing heat island effect. In this study, two main types of aggregates used are recycled aggregate (RA) and autoclaved aerated concrete (AAC) grains recycled from industrial by-products. The workability and forming ability are greatly affected by the moisture of the material before mixing. The results show that increasing AAC grain size leads to a slight decrease in the porosity of pervious concrete with the same AAC content. On the other hand, increasing AAC content from 5 to 10% results in significant fall in void content from 18% to 14.5%, thereby decreasing drainage speed. The compressive strength values show that without AAC, pervious concrete has the highest mechanical strength while increasing content and size of AAC leads to the compressive strength decreases. The surface temperature of pervious concrete samples is 4 – 5°C lower than that of normal concrete surface due to the increased effective surface area. The use of AAC grains helps to reduce the sample surface temperature by another 4°C.