Concrete is one of the most common building materials: it is used in the construction of residential and industrial buildings, in road works. However, tensile or flexural stress often results in structural failure. To cope with this inconvenience, reinforcement is used in construction work. One of the popular brands is A240 smooth reinforcement.
Describing fittings A240 GOST - 5781-82... It has the form steel rods with a smooth surface... They can be both thick and thin; there are 14 standard sizes of products in total. Diameter may vary from 0.6 to 4 cm, but length - from 6 to 12 meters... A suitable range of rebar 240 is selected for a specific task. Longer rods are also made to order (up to 25 m). Weight of products is directly related to their thickness. 1 m of a rod with a cross section of 2 cm will weigh 2.47 kg, with a diameter of 1 cm - 0.62 kg.
When studying the catalogs of manufacturers and reference books, it is sometimes noticed that products labeled A1 and A240 have identical characteristics. There really is no difference between them, it is just that the outdated name of the class (A1) has been replaced by something else. Numeral 240 indicates the yield strength of steel in MPa... The higher the number, the stronger the reinforcement and the greater the load it can withstand.
General classification
The armature is usually classified by such parameters:
manufacturing method: rope, wire, rod;
technology used: hot and cold rolled;
scope of application: assembly, work, distribution;
type of surface: smooth and grooved.
Rebar A240 - rod hot-rolled product... She is belongs to the mounting typerecommended for use in unloaded structures. You cannot use it in the frameworks of load-bearing structures. For this, products marked 300-400 and more are intended.
Assembly type products better for welding.
The surface of this reinforcement is smooth, which is rather a disadvantage in terms of the quality of adhesion to concrete.
Marking and decoding
On the markings of the rods after the figure indicating the yield strength, sometimes you can see such marks:
TO indicates the anti-corrosion treatment of the product.
FROM indicates weldability. Only those types of reinforcement that have this mark can be welded.
The number can be preceded by one of the following letters:
BUT indicates hot rolled products;
IN - cold-deformed;
TO - rolled.
Explanation of the name of fittings А240С - hot rolled rods with a limit of 240 MPa, suitable for welding. If the frame of the structure is made of more durable reinforcement, A240C and similar products can be used to form bundles. Welding is not used in this case.
Products marked 240 are produced by hot rolling. The most common raw materials are carbon steel... Sometimes low-alloyed metal with additions of manganese and chromium is also used. This protects the material from corrosion and increases its service life.
In accordance with GOST, the rods should have the most even surface without cracks, torn edges and other sloppy areas. Only traces of rust or traces of air bubbles are allowed.
Products must be accompanied by a passport and a valid certificate of conformity.
Thin rods (up to 1 cm in diameter) are supplied in hanks for easy handling, thicker ones - in a straightened form, while their length should be at least 2 m.
Application of reinforcing products
Due to the smooth surface and inferior to higher strength grades, such reinforcement is not used as a basis for supporting structures. But she well suited for connecting rods for knitting the frame, holding the main rods in the right places. As such an additional component, it is used in many types of structures, including underground and water.
Besides, the rods are used for the following purposes:
Reinforcement of columns - rods with a thickness of 1.5 cm or more are required here.
When arranging panels and beams, a suitable section is 1-3 cm.
As one of the components of the foundation reinforcement of a light house - the thicker the rods, the better.
Thin reinforcement 8 mm A240 is well suited for decorative structures. It is also used to reinforce screeds and plaster coatings.
Pros and cons of A240 fittings
Ease of welding due to the smoothness of the products
Resistance to aggressive chemical influences
Lower strength compared to A300, A400 and other products intended for the formation of load-bearing structures
Limited scope of application due to strength characteristics
Welded joints are particularly prone to corrosion and also have the lowest resistance
Like other types of rolled products, rods delivered in batcheswhich can weigh up to 70 tons (which is equivalent to a fully loaded freight train car). They are packed in bundles, tied in several places with a steel tape. Each pack usually weighs 5-8 tons.
Transport and storage
During transportation you should adhere to the rules:
The rolled metal is loaded and unloaded mechanically using cranes.
Thin rods (less than 1 cm in cross section) can be transported in the form of coils weighing up to 1.5 tons. Thicker rods are tied with wire.
The rods are stored only in closed warehouses, where precipitation and ultraviolet light do not penetrate. They cannot be laid directly on the floor.... A special stand is prepared for the reinforcement.
