Evaluation of methods for characterizing air void systems in Wisconsin paving concrete

Abstract

This research investigated primarily two methods of determining the air-void system parameters of hardened concrete. The methods investigated were the use of a flat-bed scanner and the use of a CT x-ray scanner. The flat-bed scanner proved to be an effective means of performing the analysis at a relatively low cost. The CT scanner proved to be technically feasible but not ready for general implementation outside of controlled laboratory conditions. The research also investigated the freeze-thaw performance of Wisconsin paving concrete mixtures prepared with vinsol resin air-entraining admixtures (AEA) and with non-vinsol (synthetic) AEAs. The mixtures prepared with vinsol resin based AEA performed in accordance with what has been historically reported in the literature. The mixtures prepared with synthetic AEAs performed better than the vinsol based AEA when the admixtures were used in low dosages (i.e. low air content). The results indicate that mixtures prepared with synthetic AEA could possibly be prepared with lower target air contents and a satisfactory level of freeze-thaw performance could be expected.