Monolithic concrete and reinforced concrete structures are essential elements of any building. Therefore it is vital for these constructions to have correct and most importantly right shape.
Concrete is marked depending on the compressive of strength in kg per 1 sq. cm.
There are two identical classifier of concrete in compressive strength. The first is got from the builders in the distant past, their grades are M 50, 75, 100, 150, 200, 250, 350, 400.
We will tell about the second qualifier later.
Depending on what field the concrete will be used the preference is given to one or another grade.
M 150 is alight type of concrete used for installation of foundations for small buildings, as well as for pouring concrete monolithic slabs;
M 200 is universal concrete, applied to a variety of devices foundations, production of supporting walls. This grade is highly durable;
M 300 is a used in the forming of monolithic foundations and construction of walls;
M 350 is used in the formation of the foundation of slab apartment buildings, road slabs and load-bearing columns;
M 400 is the most durable and reliable brand of concrete, it has a very high cost, it is used in the construction of foundations of buildings with large areas.
for the foundation of three-storied administrative and domestic buildings, concrete of A 350 grade must be used. Concrete M400is needed for the production of reinforced concrete columns and trusses.
The special concrete is necessary for the construction of hydraulic buildings. Therefore, we wiill move on to the hydraulic concrete.
In actual operation proves that these concretes should have long service, comply with the terms of strength, water and frost resistance. Concrete for the installation and construction of concrete reinforced concrete structures of hydraulic structures or their parts must meet the special standards.
This material is used for building specialized engineering structures: dumbs, piers, breakwaters, cooling towers, water treatment, and bridge bearings.
There are three kinds of construction materials:
Underwater, which is constantly in the water;
Staying in an area where the water level varies from time to time;
Located above the water and washed by it.
Another difference divides concrete in nonmassive and massive as well as no power and power constructions. Also, depending on the use, hydro limited heat dissipation during solidification, limited shrinkage, deformability and resistance to abrasion and water sediments.
Strength, water frost resistance.
Concrete grade depends on its compressive strength and ability to withstand its stretching capacity on the contrary. Compressive strength at the age of 180 days, acting on a cube with sides of 15cm.
Grade of concrete except of above classifications in the modern regulatory framework start from B 3,5 B and finish in B80 5, and finish at D80, and mainly constrictors has to work with grades B10 and B40.
Tensile in strength eliminates the appearance of cracks. Samples were tested in the age of 180 days. Concrete grades increase from Vt0,8 to Vt3,2.
At the same age, hidroconcrete is tested on 4 types of waterproof: W8, W6, W4, W2. According to the standard tests, it should not leak under pressure 0,8MPa, 0,6MPa, 0,4MPa, 0,2MPa. There are also special additives to waterproof above W12.
Hydraulic engineering concrete is used in moderate, severe and very severe weather (weather) conditions. Frost-resistant hydraulic concrete can be of 5 brands: F300, F200, F150, F100, F50. Through special additives, the frost increases over F400. The classification is determined by the number of cycles of freezing and defrost of concrete age of 28 days, so that its strength is decreased to not more than 25%. Frost resistance is needed for objects that have a double effect of water and freezing temperatures.
For these characteristics of concrete, construction superintendent and / or the head of works on monolithic or precast concrete must know. From his knowledge and skills, the input quality of material and labor will depend on, as well as how reliable these materials and works, as well as how your building construction reliable will be.