Performance Evaluation and Mix Proportion Design of Concrete Using Low-quality Recycled Aggregate in Vietnam

In Vietnam, the amount of generated construction waste is rapidly increasing along with economic and social development. According to a report from the World Bank, the amount of treated construction waste was 1.8 million tons in 2018, but the amount of untreated construction waste was considerably larger. If the construction waste is not recycled, it will become a huge environmental problem. According to the World Bank, the Vietnamese government envisions a construction waste recycle rate of 60% by 2025, most of which will be used as leveling material, roadbed material and non-fired brick. To improve the recycle rate of construction waste, a measurement for disseminating the use of low-quality recycled aggregate (recycled aggregate class L) in concrete is necessary. In this study, by mixing low-quality recycled and normal aggregates in a suitable replacement ratio, a relative quality index method was used for evaluating the concrete’s performance. Accordingly, a mix proportion of concrete using low-quality recycled aggregate can be designed that satisfies Vietnam’s required performance.