Construction and demolition waste generation and properties of recycled aggregate concrete: A global perspective

Concrete production and construction and demolition waste generation are some of the main contributors of constant carbon dioxide emission into the atmosphere. The main aim of this review is to present the status of construction and demolition waste generation around the world and subsequently provide a critical review of the recent studies conducted to improve the properties of recycled aggregate concrete through different supplementary materials. Information from 40 countries within six continents have been collated, critically analysed with the central focus being on the current construction and demolition waste generation and different policies adopted by the relevant government bodies. The future goals and targets of each country are briefly discussed. The overall construction and demolition waste generation in 40 countries worldwide reached more than 3.0 billion tonnes annually until 2012 and this trend is increasing constantly. The developing countries including India and China need to develop comprehensive system to monitor and utilize their huge C&D waste and government level initiative is required for mass awareness. Recycled aggregates obtained through construction and demolition waste are of inferior quality and use of different pozzolanic materials are recommended by several researchers to enhance its properties. Furthermore, it was also suggested to use the recycled aggregates from 30 to 50% to achieve the strength equivalent to natural aggregate concrete with supplementary cementitious materials. More research is imperative in the area of unconventional supplementary materials in recycled aggregate concrete and full structural analysis on long term scale. The uncertainty of its quality and absence of proper standards hinder its way of common adoption in real-world applications. Therefore, further research is necessary to endorse this waste in the construction industry and develop proper standards for its use in low-risk structural applications.