Calcium chloride intended for construction purposes should contain at least 73% CaCl2, about 22% water and not more than 2.5% sodium chloride (NaCl), 1,5%magnesium chloride, 1% calcium hydroxide (That(OH)2) and at the most 1% anhydrous calcium sulphate and components insoluble together. Crystalline calcium chloride are colorless crystals with a bitter taste, which melt under the influence of air, melting at about 30 ° C and hygroscopic (desiccant). The use of calcium chloride in mortars and concretes increases the setting temperature of the cement, shortening the setting period, increasing the strength and accelerating the hardening process of concrete in the initial period, increasing the degree of plasticity of concrete, lowering the freezing temperature of concrete and making concrete resistant to lack of moisture. 4% the addition of calcium chloride by weight enables the cement to set at minus 5 ° C (according to ITB). Calcium chloride is used in construction: a) in order to accelerate the setting and hardening of mortars and concretes; b) in order to ensure setting and hardening during winter works with little frost; c) as a drying agent.