Proper implementation of concrete and reinforced concrete works

Here are the basic requirements for the implementation of concrete and reinforced concrete works. Neglect and improper storage often lead to contamination of the aggregates (sand, gravel), a variety of impurities (waste wood, gravel, broken bricks, slag, etc.). If the filler has at least double the strength of concrete, it is impossible to obtain a given concrete strength. A trapped organic matter leads to a decrease in strength, accelerating the corrosion of reinforcement. Debris caught in aggregate, leads to a decrease in frost resistance, durability, waterproofing and insulating properties of concrete. For example, the content of clay impurities in the sand is limited to three percent by volume (if such impurities 16%, the strength of concrete falls to 50%). The most simple analysis of the clay in the sand: Fill a glass jar with sand, and then 3 / 4 water. Intense shake the jar. About an hour later settled a layer of clay particles in thickness can be correlated with the entire volume. A very important point is the implementation of the recommendations on the composition of the solution. Excess or shortage of cement leads to a decrease in the strength increase in water permeability of concrete. You can not use "stale" cement, with the aging of the cement can occur due to improper storage. Even in the driest time of the cement can not be stored longer than three months, store bags of cement to the wooden flooring, the distance from floor to floor shall not be less than 0.3 m. Fig. 47 shows a device for washing sandy gravel from clay (Fig. 47a), and proper storage of cement (Fig. 47b). As already noted, during prolonged storage of cement loses the original strength. Portland cement 350 in storage in a brick warehouse at 20 ° C for a month to lose 25% strength in the open on all sides of the court under an awning - up to 50%. The date of manufacture of cement plant affixed to the outside of the bag, and if since its release more than three months, then use that cement should not be. The third component of concrete is water. Surface of the concrete during setting and hardening necessary to keep moist, if you do not, concrete "burn out" and reaches only a portion of the estimated strength. For mixing concrete need clean water, drinking tap water can be used without further study. Other water needs to be studied in the laboratory - not whether the water is harmful to concrete substances. As already mentioned, sulfate water destroy concrete.