For this project several sidewalk sections were placed using selected concrete mixtures and different finishing and curing practices. The objectives were to:
â€¢ Compare the field and laboratory de-icing salt scaling resistance of concretes incorporating different proportions of fly ash slag and ternary blends -with silica fume- .
â€¢ Determine the effect of various key parameters such as concrete mixture design finishing operations and curing on the de-icing salt scaling resistance of such concretes in both laboratory and field exposures;
â€¢ Explain the somewhat lower deicing salt scaling resistance of concrete incorporating SCMs;
â€¢ Suggest procedures modified concrete mixture proportioning or other field practices that will improve the de-icing salt scaling resistance of concrete incorporating fly ash slag or ternary blends
â€¢ Provide tools to better interpret the results of the current tests and suggest new or modified laboratory testing procedures that will better simulate the field performance of concrete incorporating SCMs exposed to de-icing salts.
The lab results showed that the use of curing compound especially during the fall significantly increased the scaling resistance of the concrete incorporating SCMs. The results also show that the specimens of the concrete incorporating SCMs -except those using ternary fly ash-SF cement- scaled significantly less when tested according to BNQ NQ 2621-900 -a standard-test of the province of Quebec Canada for evaluating de-icing salt scaling resistance- standard procedure in comparison to those tested according to ASTM C 672. The visual evaluation of the sidewalks after two winters -~20 freeze-thaw cycles- appeared to be more in line with the results of the specimens tested according to BNQ procedure.
Includes many tables images and diagrams documenting the results.
Case Study Report Author: Nabil Bouzoubaa, Alain Bilodeau, Benoit Fournier, CANMET Energy Technology Centre, Natural Resources Canada,