Deicer Scaling Resistance of Concrete Pavements, Bridge Decks, and Other Structures Containing Slag Cement Phase 1 TPF-5(100), September 2008

(2008) Deicer Scaling Resistance of Concrete Pavements, Bridge Decks, and Other Structures Containing Slag Cement Phase 1 TPF-5(100), September 2008. Transportation, Department of

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Abstract

The initial phase of this project was conducted to determine whether adding slag cement to concrete mixtures increases the surface scaling caused by the routine application of deicer salt. A total of 28 field sites that included Portland cement concrete pavements and bridge decks containing slag cement were evaluated. Laboratory testing was conducted on 6 in. diameter core samples extracted from 12 field sites and 3 sub-sites, including 6 pavement sites and 6 bridge decks. The laboratory testing program consisted of scaling tests, rapid chloride permeability tests, surface chloride profile tests, and petrographic examination. The results of this study suggest that construction-related issues played a bigger role in the observed scaling performance than did the amount of slag in the concrete mixture. • For the scaling tests, only cores extracted from one site exhibited scaling mass loss values that exceeded 1.5 lbs/yd2. It was also noted that the bridge deck cores tended to lose more mass during the scaling tests than the pavement cores. • For the rapid chloride permeability tests, the amount of charge passed did not appear to be directly related to the amount of slag in the mixtures. However, the different ages of the concrete at the various sites tended to complicate the interpretation of the test results. • For the surface chloride profile tests, the diffusion coefficients estimated for the various samples ranged. • Petrographic examinations indicated that four of the seven sites that exhibited scaling showed evidence of retempering. In addition, two of the scaling sites tended to have significantly higher water-cementitious material ratios than was expected from the nominal mixture design information that was provided.