Durability of Concrete Structures Exposed to CaCl2 Based Deicing Salts

The authors point out that in addition to the steel corrosion, calcium chloride can specifically act as an aggressive agent for concrete through the formation of calcium oxychloride (3Ca0 CaCh 15 H20). This product is formed by reaction of CaCh diffusing through the cover and Ca(OH)2 produced by cement hydration. The main purpose of the present paper was to study the influence of the cementitious system (portland cement with and without a pozzolanic addition) on the damaging effect caused by CaCh used as a de-icing agent. In order to block both steel corrosion and concrete deterioration, the reduction of the water/cement ratio in the concrete mix should be accompanied by the utilization of slag cement or pozzolanic cement. The slag content should be at least 50% of the cement, whereas silica fume ( > 15% by weight of cement) instead of fly ash (30%) should be preferred.