Inorganic Salts:

The presence of different types of salts in water affects the properties of concrete in different ways depending upon their active participation in chemical reaction of cement with water. The presence of carbonates and bi-carbonates of sodium and potassium both considerably affect the setting time of cement. An excessive presence of these compounds might lead to reduction in strength of concrete also. Therefore, water with the concentration of these salts up to 1000 ppm (total sodium and potassium) can be used as such. Beyond this limit, it is essential to carry out the tests for setting time and strength to observe their actual effects.

The presence of calcium chloride accelerates the setting and hardening of cement/concrete while the presence of zinc chloride considerably retards the setting action of cement. A quantity of calcium chloride should be restricted to 1.5-2 percent through weight of cement. The presence of chlorides in water is also responsible for efflorescence and corrosion of reinforcement. A presence of lead nitrate is not desirable, as it is fully destructive for the concrete.