Application Of Aggregate Recycled from Construction Waste to Highway Pavement

As aggregates recycled from various types of construction waste are continuously produced, interest has focused on how to apply them to highway pavement. This paper considers application of waste aggregates to lean concrete, based on basic mechanical property tests and environmental toxicity. Compared with natural aggregates, waste aggregates have low specific gravity and high water absorption characteristics. After testing their toxicity in the environment, it was found that when introduced to alkaline conditions, waste aggregates do not release any metallic ions, but when introduced to acidic solutions, they release a small but seemingly non-harmful amount of metallic ions. Concrete made with waste aggregates has significant limitations in strength, particularly in flexural strength, which is the main parameter of quality control and design for concrete pavement. It is therefore not practical to use waste aggregates for the surface layer of concrete, without using additives or special treatments. However, it is possible to apply concrete with waste aggregates for lean bases. In testing, lumps of asphalt, cement paste, bricks and glass were classified as impurities, and were observed for changes in strength based on the percentage of impurities used. If the amount is over 25%, the 7-day compressive strength does not meet strength requirements specified for lean concrete.