Tips of the Production Attention of Concrete Mixtures

As a rule, concrete work should not be done during cold or freezing weather. However, there are times when it is unavoidable. The most satisfactory method of preventing concrete from freezing is to heat the ingredients and to protect the completed job form freezing until a large percentage of the water has evaporated and sufficient strength has developed. The water used in mixing the concrete must not be heated above 150 degree. The best method for heating the dry materials is to secure a piece of thin sheet metal and bend it to form an arch.

 

Place this bent form horizontally and build a fire at one end. Pile dry materials on the form and heat to a temperature of approximately 140 degree, then cover them with canvas or similar material to retain the heat. The concrete mixing should have an average temperature of 50 degree for at least a week. If a sudden cold snap is expected, protect the newly placed work with several layers of paper or canvas covered with approximately a 6 layer of straw, As ab added protection against a sudden freeze, spread a layer of earth on top of the straw.

 

Concrete must not be permitted to dry out too rapidly. Rapid drying will cause cracks and loss of strength. Because of the rapid evaporation of the water, freshly laid concrete must be protected from the sun or drying winds for a period of 7 to 10 days. If the layer of concrete is more than 4 layers in depth, adequate protection must be provided for at least 14 days. Cover it with burlap, straw, or similar material and keep the covering moist by occasional sprinkling with water as soon as the concrete has hardened sufficiently so that the water will not injure it. In cold weather newly laid concrete should be covered but need not be kept moist.