CONCRETE USING RECYCLED AGGREGATES

Worldwide, cities generate about 1.3 billion Tonnes of solid waste per year. Building materials account for about half of all materials used and about half the solid waste generated worldwide. The waste, generated in the construction, maintenance, repair and disposal phases of a building, is called Construction and Demolition (C&D) Waste. Management of C&D waste is a problem faced not only in India but by the global community and quantum of waste produced occupies a huge fraction of the total solid waste generation by mass. Furthermore, a continued environmental awareness instigates the pressure for reuse of construction materials instead of classifying them as waste materials. Using construction waste material as an aggregate for developing new concrete product is technically viable and may, in some circumstances, be environmentally beneficial. The recent government initiative to stop sand mining insists the need to recycle, reuse and substitute natural aggregates in order to ensure environmental sustainability. This research work aims at making one such experiment where recycled aggregates are produced from C&D waste thus paves a way, for the effective management of concrete debris. The concrete waste was collected from the waste yard in the college campus, segregated, crushed in jaw crusher, sieved, washed and used for concreting for a mix proportion of M25, as a replacement for natural course aggregates in proportions of 0%, 30%, 60% and 100%. On testing, the compressive strength was found to be increasing and split tensile strength and flexural strength were observed to be nearly equal to that of normal concrete mix. Therefore, use of recycled concrete aggregate showed acceptable performance with respect to mechanical properties. The recycled aggregates obtained from waste concrete are more angular and have higher absorption and specific gravity than natural coarse aggregates and it resulted in increased strength and improved load carrying capacity. However, further studies to determine the effect on durability and improvement on workability are necessary