Effect of abrasion and chemical treatment of recycled aggregate on the workability, strength, and durability properties of concrete

Different treatment strategies have been explored in a quest to improve the properties of recycled aggregate concrete (RAC). The improvement strategies are directed towards the removal of residual layers of old mortar on the recycled coarse aggregate (RA). The removal of old mortar layer improves the bond between the new mortar and the RA that makes the quality of RAC better. Efforts have been made to remove the old mortar from the surface of the RA through abrasion process, however, there is a lack of detailed information, particularly about the beneficial effect of abrasion coupled with some chemical treatment. In the present work, the performance of RAC prepared with the RA subjected to abrasion (with the help of a Los Angeles abrasion test machine) was evaluated. The combined effect of abrasion and sodium silicate treatments of the RA on the fresh and hardened properties of RAC was also evaluated. A significant improvement in the workability, strength, and durability of RAC was noted due to abrasion treatment of the RA. Strength and durability of RAC increased significantly due to the combined effect of abrasion and sodium silicate treatment of the RA.