Durability of Mortars Manufactured with Low-Carbon Binders Exposed to Calcium Chloride-Based De-Icing Salts

Abstract

Calcium chloride is one of the main de-icing salts for removing snow and ice from roads, infrastructures and service areas. It is well known that reinforced concrete structures, if exposed to calcium chloride, can suffer from severe damages due to both corrosion of steel reinforcement and chemical attack of the cement paste. This paper aims at evaluating the resistance to chemical attack of mortars manufactured with different low-carbon binders (alkali activated slag cements, calcium sulphoaluminate cement-based blends, high volume ultrafine fly ashes cements) in presence of CaCl2-based de-icing salts in cold weather (temperature about 4°C). Results indicated that alkali activated slag-based mortars are quasi-immune to calcium chloride attack due to their mineralogical composition. On the contrary, calcium sulphoaluminate-based blends show the total loss of binding capacity, especially when calcium sulphoaluminate cement is used with gypsum and Portland cement. Finally, the partial substitution of Portland cement with ultrafine fly ash strongly reduces the mass change and the strength loss of mortars submerged in 30 wt.% CaCl2 solutions due to the strong reduction of calcium hydroxide responsible for the calcium oxychloride formation in the cement paste.

An Overview of Smart Materials and Technologies for Concrete Construction in Cold Weather

“…As climate change and environmental concerns continue to drive the need for more sustainable and resilient infrastructure [238], the future of cold weather concrete construction is expected to focus increasingly on enhancing the sustainability and resilience of concrete materials, structures, and construction practices. The development and adoption of green concrete materials [239], such as those incorporating alternative binders like fly ash, slag, or geopolymers, can help reduce the environmental impact of concrete construction [240] while also improving the performance and durability of structures in cold weather environments [241]. These materials can offer enhanced material properties such as better resistance to freeze-thaw cycles [242], reduced permeability [243], and improved thermal performance [244].…”