Abstract:
Any construction activity requires several materials such as concrete, steel, bricks, stones, glass, clay, mud and wood. However, the cement concrete remains the main construction material used in construction industry. For its suitability and adaptability with respect to the changing environment the concrete must be such that it can conserve the sources, protect the environment, economize and lead to proper utilization of energy. To achieve this, major emphases must be laid on to the use of wastes and by-products in cement and concrete used for new constructions. The utilization of recycled concrete waste is particularly very promising as 75% of concrete is made up of aggregates. In that case the aggregates considered are pavement, recycled concrete, quarrying wastes, culvert and burnt clay. The enormous quantities of demolished concrete are available at various construction sites which are now posing a serious problem of disposal in urban areas. This can easily be .recycled as aggregates and used in new constructions. Research investigation conducted by the Environmental Resources Ltd (1979) for European Environmental commission (EEC) envisages that there will be enormous increase in quantities of Construction and Demolition concrete waste from 55 million tons in 1980 to 302 tons by the 2020 in the EEC member countries. The main reasons for increase of volume of demolition concrete and masonry waste are as follows: i. Many old buildings, concrete pavements, bridges, and other structures have overcome their age and limit of use to structural deterioration beyond repairs and need to be demolished. iii. New construction for better economic growth. iv. Structures are turned into debris resulting from natural disasters like earthquakes, cyclones and floods. v. Creation of building wastes resulting from man made disasters.
