Testing recycled concrete aggregate suffering different levels of alkali-silica reaction for use in new structures

As concrete reaches the end of its service life, it is demolished and placed in landfills, which is not sustainable as this consumes land space. Many demolished structures are crushed into recycled concrete aggregate (RCA) and used in new construction work to reduce concrete waste. To be used in concrete, the effects of RCA on the new structures should be carefully examined. The RCA studied in this research is an alkali-silica reactive gravel from Sudbury, Ontario. The RCA was obtained from different elements of a 20-year old bridge that suffered different levels of deterioration. It was determined that the level of deterioration that affected the previous structure does not significantly affect the expansion that will occur in the new structure. It was also determined that the expansion could be mitigated through the use of supplementary cementing materials although higher levels are required compared those required for the virgin aggregate.