Concrete production requires the use of fresh water to achieve better hydration, strength and durability, with an estimated consumption of around 1.7 % of the world’s freshwater withdrawals. Although this percentage is small, concrete construction is mainly concentrated in urban areas, and this leads to regional freshwater scarcity because wastewater purification is costly. Thus, it is essential to explore other alternatives, such as using industrial waste brine, to solve the freshwater-scarcity problem.

This work investigated four different mortar mixtures, which were ordinary Portland cement (CemI), CemI with 8 wt% fly ash, CemI with 8 wt% silica fume and Portland cement type III (CemIII) with slag, mixed with 2.56 M NaCl synthetic-brine water at a water-to-binder ratio of 0.55. For each, a mixture without chloride was also made for comparison. Fresh properties and hardened properties were measured. The amount of chloride in hardened mortars was determined. The corrosion behaviors of three embedded carbon steels were monitored using the linear polarization resistance measurement.

Results showed that mortars containing chloride had a higher slump flow and higher air content than mortars without chloride. The presence of chloride in mortars had a tendency to reduce bending and compressive strength and increase porosity, except in CemIII with slag, which showed similar bending and compressive strength as well as porosity regardless of the presence of chloride. Mortars with silica fume and slag showed a higher chloride-binding capacity, reducing the amount of free chloride ions available to initiate corrosion in embedded carbon steels. Among all the mixtures, CemIII with slag showed a lower mass loss and corrosion rate of embedded carbon steel compared to CemI, even with the presence of chloride in the mortar.

This study supports the feasibility of using waste brine as a mixing liquidtogether with pozzolanic materials for producing sustainable mortar and reducing steel corrosion.