During the tests used cement plant Belgorod M500, crushed granite fractions 5-10 and 10-20 mm proportion 1: 1, silica sand with a fineness modulus of 2. Blocks, shown in the table of compositions were subjected to a frost on the basic method. Frost resistance of composition 1 with open porosity 4.1% of 300 cycles of 2 (= 5.6%) – 200, of 3 (= 7.5%) – 50. Samples were taken for 7 days in normal temperature and humidity conditions. Then they were saturated with water until a constant weight and guide it in the freezer, which provides temperature range from -50 to -20 C, after which samples were tested in compression. A thin layer of ice cubes on the surface prevented water evaporation. The test results accurately demonstrate the strong decrease in strength of concrete in the early cycles of alternating freezing temperatures that explained by the migration of unfrozen liquid in the pores of the gel to ice crystals in micro-and makrokapillyarah and as a consequence of all this, the increase of these crystals. Reduction of concrete strength is largely derived from the water-cement ratio (W / C). Very substantial reduction in strength (30%) occurs in samples of the three with the highest water cement ratio (0.7). As a result, studies have confirmed that the northern climate Concrete exposed to specific conditions, environmental influences that lead to structural damage of the material, which seriously reduces the durability of concrete and reinforced concrete foundations, in places

Reduced induction period and time of curing can be used in several ways: In the winter period to avoid hypothermia fresh concrete prior to hardening. Production of ready-made elements (faster reuse of forms). Reduced risk of cracking due to shrinkage of concrete. Reduced time to finishing (smoothing) of concrete floors. Increased early strength concrete. To activate the concrete after a long transport or transportation in hot climates. RISK REDUCTION NITCAL cracking can be used as an additive that reduces the risk cracking due to rapid loss of moisture in fresh concrete. The most likely effect of accelerated curing.

When tested concrete mixes with w / c = 0.45, with 2% NITCAL from cement and no additives. Unfortunately, the power of Kamagra tablets are only given on prescription, thus it is important that you have consulted your doctor before using any of prescription for cialis purchase it. Penis viagra soft enlargement supplements offer more than just ‘size boost’. IT companies, especially pose a lot of stressful work order viagra generic on the employees and expect them to work beyond their ability. Muscle activities are a vital piece of North deeprootsmag.org cialis online best Vancouver physiotherapy. Concrete rings were subjected to drying in the installation, with a wind speed of 4.5 m / s at 20 C, relative humidity 43%. Concrete without additives had shrinkage cracks, while not seen any cracks in concrete with 2% NITCAL. CORROSION INHIBITOR NITCAL Prevents corrosion of the reinforcement, caused by high chloride content. Dosage 2 – 4%. During the lengthy trial proved that calcium nitrate slows down the corrosion of reinforcing steel caused by chloride as added directly into the water for mixing, and added later, as well as greater calcium nitrite tests for corrosion. The mechanism of action of nitrate and nitrite as corrosion inhibitors are similar in alkaline environments, such as concrete. Kinetics of nitrate more slowly than nitrite, but it is only important in short-term trials, since in practice the process of corrosion – a rather lengthy process. As follows from the theory, calcium nitrate provides more cushion than calcium nitrite. The addition of antifreeze additive NITCAL as the accelerator timing of cement used for production of concrete mixtures, in particular, recommended at low temperatures. The introduction of additives in the concrete mixture NITCAL at low ambient temperature causes a lowering of the freezing point of water, thereby kneading the concrete at Air – 10 C, without slowing down the cement hydration process. Effective influence NITCAL the concrete mix is achieved at a temperature of – 15 C ambient, if you add more than 1-2% additive by weight of cement. The application has a stable NITCAL growth on a global scale, is used in many major construction projects. The concrete mixture used in the construction NITCAL mines in the North Sea (altitude 369 m), under oil and gas platforms. Expediency NITCAL use was the fact that he opposed the slowing effect of hardening the mixture by pouring high and massive structures. Sales volume in the world is more than 1 million tons per year. The material is based on the YARA INDUSTRIAL manufacturer and testing of Professor Harold Dzhastnesa, SINTEF Civil engineering, simulation environments, cement and concrete, Trondheim, Norway.