2015 CSCE Annual Conference Regina - Building on our Growth Opportunities Conference
Dr. Medhat Shehata, Ryerson University
Mr. Stephen Senior
Ms. Carole Anne MacDonald, Ministry of Transportation
In Canada there are a wide variety of environmental conditions, which aid in the deterioration of concrete. A number of accelerated lab tests have been created and modified over the years to stimulate a specific deterioration mechanism in order to accurately predict how different concrete mixes will react in a given environment. Although these tests provide data over a short period of time, the data obtained in the field is a more accurate measure of total deterioration due to multiple mechanisms working simultaneously, such as freeze-thaw deterioration and alkali-silica reaction (ASR). This is because conditions in the lab provide accurate results for a single deterioration mechanism, however in reality, multiple mechanisms are contributing to the deterioration simultaneously. The research presented in this paper compares lab and field expansion results, specifically ASR and freeze-thaw deterioration. Field measurements of expansion of concrete road barriers were taken and classified into two categories – high and low deteriorated. In the lab, expansion tests for ASR are being completed on samples that have been cast with the same natural coarse aggregate used in those road barriers along with recycled concrete collected from both high and low deteriorated road barriers. Cores that were extracted from the same barriers are also undergoing lab testing for ASR. In order to closely predict the deterioration mechanisms occurring in the road barriers, the expansion data obtained from the lab and field were compared. Thus, a prediction can be made about the contribution of additional mechanisms on the deterioration of the barriers.