Арматурой А3 называют особую горячекатаную сталь circular section with a periodic profile, designed for better adhesion to concrete. Such a rod is produced in compliance with the standards prescribed in GOST T5781-82.
Основной отличительной особенностью арматуры А3 is that on its surface there are two longitudinal ribs, between which there are corrugations in the form of a "fir-tree" (on one side the left screw, on the other - the right one). There is also a special purpose rod A3. The corrugations in this variant can go in one direction.
Diameter A3 can have different (6-40 mm).Thin rods (up to 10 mm) are supplied both in the form of cut rods and in coils. Thick products - only in rods. The length of the latter in both cases can be 6-12 m.
The valve A3 can be made of steel:
carbon of usual quality (ст.3пс, ст.3сп);
low-alloyed (35GS, 25G2S).
Steel grade 35GS has a short-termstrength 590 MPa, elongation at break 14% and yield strength 390 MPa. For the material 25G2S, these characteristics are the same in accordance with GOST 5781-82 and are equal to 980 MPa, 7% and 785MPa, respectively, according to GOST 10884-71. Used for the manufacture of reinforcement A3 steel can have in its composition elements such as boron, manganese and magnesium.
The field of application of reinforcement A3 is quite wide. Use this rod:
when building bridges and other loaded structures;
laying of road surfaces;
construction of underground engineering systems, tunnels for trains, subway, metro;
devices of various kinds of metal structures in moist soil;
in the construction of civil and military installations in areas with a harsh climate.
Of course, the first thing you pay attention to whenbuying rods is their price. Armature A3 in general is not too expensive. The price for it depends mainly on two factors: the diameter and the manufacturer. Wholesale suppliers usually indicate the cost of this material in tons. The price for the A3 armature, sold at retail, is determined for one running meter. Below we present to your attention a table with the prices for the most common variants of such a rod.
Diameter (mm) | Length (m) | Price per item (rubles) | Approximate cost of one ton (rubles) |
6 | 6 | 6 | 29 000 |
8 | 10-12 | 29 500 | |
10 | 11.7 | 17-18 | 28 500 |
12 | 24-25 | 28 000 | |
18 | 44-54 | 27 000 | |
25 | 90-100 | 2700-2800 | |
32 | 150 | ||
40 | 250-270 |
Above are given approximate prices for A3 bar of carbon steel. In some cases, its cost may be different. The price of reinforcement A3 depends mainly on the following factors:
Stamps used for the manufacture of steel.The reinforcement made of low-alloy steel is more expensive than the products from st.3ps and st.3sp. But at the same time it is characterized by the best performance characteristics.
Диаметра арматуры.With the decrease of this indicator, the price for A3 rods increases. At the same time, the most demanded diameters (for example, 12 mm) can sometimes be deficit. In this case, the price of the bar, of course, rises.
Season of sale. The most expensive A3 fittings are in the spring - in April-May, that is, when the construction season begins. The maximum discount for this product can be obtained in December.
The amount of purchase. When ordering a very large wholesale lot of the company, manufacturers and suppliers can make a good discount to the buyer. At retail, the armature, of course, costs a little more.
Places of purchase. At dealers, a ton of reinforcement will, of course, cost a little more than directly from the manufacturer.
Measuring fittings (with adjustable length parameters) are more expensive than immeasurable.
Consumers of these products are looking for it in the firstturn on the marking. For example, someone needs 12 A3 armature. This means that a person wishes to purchase a variant of A3 rod with a diameter of 12 mm. Products manufactured with exact compliance with all GOST standards, and should be marked according to certain rules. The diameter of the realized rod in millimeters is indicated in the first place. Next comes the specification of the actual product class (in our case A3). Then the number of reinforcement in the international classification (A400 for carbon steel or A500 for low-alloyed) is affixed. And in the last turn the GOST is indicated, according to which the armature (5781-82) was produced.
For example, the same rod with a diameter of 12 mm fromlow-alloy steel will be marked as follows: 12-A-III (A500) GOST5781-82. According to the regulations, no additional letters and numbers in the marking of the A3 valve should be used.
The final price of the reinforcement purchased sometimes also depends on the value of the additional services rendered by the supplier. It can be, for example:
Cutting of the reinforcement supplied in coils to rods of the right size;
delivery of purchased products.
Large batches of rebar are sold, as a rule, can be sent to any regions of the country. Small wholesale sellers deliver to a specific city or region.
When purchasing a material, among other things, you should ask the seller for a certificate. Armature A3 should have characteristics that exactly meet the requirements of GOST.
The popularity of A3 fittings from builders is explainedfirst of all by the fact that its use makes it possible to erect the most durable and durable reinforced concrete structures. In addition to the A3 rod, the modern industry produces option A1. Such reinforcement has no corrugation. And consequently, the degree of its adhesion to concrete is lower. Armature А3 and А1 is most often used for the erection of various types of reinforced concrete structures. In this case, the variant A1 is usually used in the construction of various auxiliary elements, and A3 - loaded. For example, it is the latter option that should be used when pouring the foundations of buildings. In addition to the high degree of adhesion to concrete, the A3 valve also has some other advantages.
Since the crescent and transverse edges of such bars do not intersect, the material with high strength is also characterized by plasticity.
The A3 valve, whose characteristics are simply excellent, can be used practically under any conditions. This rod does not lose its strength even at a temperature of -55 degrees.
The variant of A3 rod made of carbon steel is easily welded. Under certain circumstances, A3 bars from low-alloy steel can be joined in this way.
When manufacturing A3 fittings, the following GOST requirements must be observed:
Curvature of rods should not exceed 0.6% of the measured length.
On the surface of the ribs of the bars there should be no cracks, rolling captures or sunsets.
For the manufacture of the rod should be used carbon steel that meets the standards of GOST 380. The required characteristics of low-alloy steel are determined by special tables.
For bar steel A400 25G2S, the temporary resistance index can be reduced to 560 MPa.
The order of this procedure is also regulated by GOST. Armature A3 is packaged in compliance with such regulations:
the mass of bundles of reinforcement bars should not exceed 15 tons;
fasten the ligaments only with wire or wire;
upon customer's request, the bars can be packed in bundles of 3 tons or 5 tons;
each bundle should be labeled with a class A3.
A3 can be transported as an automobile,and by rail. When performing loading and unloading operations, it is necessary to ensure that the product is not deformed or destroyed for any reason.
Store A3 fittings in warehouses with normal orlow humidity. It is prohibited to store it directly on the ground with regulations. Store fittings should be packs on wooden pallets or shelves. When laying should ensure that no part of the material does not sag.
