Physical and mechanical properties of construction and demolition waste

Construction and demolition waste is produced every day around the world posing a great disposal problem. Thus, the idea of using wastes in different forms appears to be an effective approach to waste disposal. The various materials that can be reclaimed from construction and demolition waste include recycled concrete aggregates (RCA), crushed brick (CB), reclaimed asphalt pavement (RAP), waste excavation rock (WR), fine recycled glass (FRG). The assessment of the recycled concrete aggregates is identified by performing various tests, which indicate physical, chemical and mechanical properties of the materials. The physical properties test results indicated that the recycled aggregates showed good performance in comparison with the natural ones. The results of the test assessing mechanical performance of concrete with recycled aggregates also indicated better performance when required measures are taken, such as (i) The aggregates to be used are obtained from recycled materials the sizes of the fine aggregates can be controlled as per the requirement during demolition process and by sieving. (ii) The water absorption capacity of the recycled fine aggregates is higher than the natural fine aggregates and this water absorption capacity can be reduced by wetting and drying the aggregates. (iii) The performance of recycled coarse aggregates can be enhanced by removal and separation of the old hardened mortar which adhered to the aggregates obtained post-demolition. (iv) The performance can also be enhanced by the usage of suitable commercially-available plasticiser to reduce the higher water absorption ratio of the recycled aggregates to attain the required strength.