- Types of steel reinforcement
- Advantages of steel fittings
- Types of fiberglass reinforcement
- Advantages of fiberglass reinforcement
- Comparison of technical indicators
- Comparison of expense and cost
Rebar is an important part of any reinforced concrete structure. It affects the strength characteristics. Market development does not stand still, and gradually reinforcing steel is being replaced by a composite material made of glass and plastic. But can composite rebar replace its steel counterpart??
Types of steel reinforcement
There are many different types of fittings. They can be classified according to:
- Accepted loads.
- Distribution method.
- The principle of action.
- Manufacturing method.
Typically, reinforced concrete structures are used for working, installation, distribution and anchor fittings. The working type of reinforcement perfectly perceives all tensile forces from external influences. She also accepts shear forces well. The distribution box fixes the working reinforcing bars in a predetermined position and evenly distributes the load between them. Mounting rods are designed for assembling the frame, anchor fittings are used as embedded parts. By the nature of the loads taken, the products can be divided into longitudinal and transverse ones. Longitudinal reinforcement absorbs tensile stresses, preventing vertical cracks from appearing in “narrow” places. Transverse products prevent the formation of inclined fractures arising from shear stresses near the supports.
Reinforced frames, meshes and piece rods are distinguished according to the distribution method. According to the manufacturing method, rod, rope and wire products can be distinguished. The armature is subdivided according to the principle of action into tensioned and non-tensioned. Before using a prestressing structure, a pre-tensioning procedure must be performed. This will help to reduce deflection, reduce metal consumption and prevent cracking. For reinforcement of prestressed structures, piece rods, strands of 3 mm wire and ropes of many steel strands are used.
Advantages of steel fittings
Metal products have been used in reinforced concrete structures for over a century. Despite the emergence of new types of reinforcement, in some reinforced concrete structures only steel rods, wire and ropes are used. Steel reinforcement is used in prestressed reinforced concrete. This type of material is designed to overcome tensile stress. In the production of such reinforced concrete, steel reinforcement with a high tensile strength is used. First of all, the steel rods are pulled with a special device, and then the concrete mixture is laid.
As a result of the release of the wire or rods, the pretensioning force is transferred to the concrete and a certain compressive stress is created, which allows you to get rid of tensile stresses. In addition to being used in prestressed concrete, iron reinforcement has a higher modulus of elasticity and thermal conductivity. It has a wider range of diameters, in contrast to fiberglass reinforcement. You can buy products with a diameter of six to forty millimeters.
Types of fiberglass reinforcement
SPA is a type of composite material. In addition to glass fibers for the production of composite reinforcing products, fibers are used:
Each type of fiber is impregnated with a polymer composition, usually with epoxy resin. After the impregnation procedure, the rods are sent to a special oven for drying. When the drying process is complete, a finished product is obtained from the oven, which can already be used..
It is worth highlighting the type of fiberglass reinforcement, in which polyethylene terephthalate acts as a binding polymer. Such products can be recycled, since the composition uses a thermoplastic polymer. ASPET has a low cost, but its strength indicators are significantly inferior to products made of fiberglass and basalt fibers.
Advantages of fiberglass reinforcement
Fiberglass rods have many advantages, but are not suitable for all types of concrete structures. They are best used for reinforcing brickwork, repairing buildings and structures, for the foundation of low-rise buildings. Fiberglass reinforcement has a number of obvious advantages:
- Less specific gravity.
- Excellent resistance to corrosion, warpage and decay.
- Material consumption is much lower.
- Resistance to aggressive environments, sea water.
- No need to use a welding machine to mount the frame.
- Installation without the use of construction equipment.
- Tear resistance allows use in road structures.
However, due to the low modulus of elasticity, the SPA is not recommended for the construction of floor slabs. At temperatures above 600 degrees, fiberglass rods are able to soften and lose their elasticity. To increase the fire resistance of the structure, it is worth using additional thermal insulation materials. The inability to weld fiberglass rods leads to additional labor costs for connecting parts.
Comparison of technical indicators
From the table below, it can be seen that fiberglass rods resist stretching better, but have a modulus of elasticity 4 times less than steel ones. SPA has a lower density and coefficient of linear expansion. The inability to conduct current has a positive effect on the service life of the concrete structure.
Specifications Armature Reinforcing steel, class A400 (A-III) Glass composite armature ASK “REBAR” Material Steel Fiberglass based on epoxy resin Standard tensile strength, MPa 390 1000 Elastic modulus, MPa 200,000 50,000 Thermal conductivity coefficient, W / (m ° С) 46 0.46 Linear expansion coefficient,? X10-five/ ° C 13-15 9-12 Density, t / m3 7.85 2.0 Corrosion resistance to aggressive media Low High Electrical conductivity Electrically conductive Dielectric Available diameters 6-10 4–20 Length Rods up to 11.7 m long According to the buyer’s request, up to 200 m Durability In accordance with building codes Predicted durability of at least 80 years
Steel reinforcement has a wider range of diameters than fiberglass, so it is advisable to use it on complex construction projects. Usually SPA is sold in bays of 50, 100, 150 meters.
Comparison of expense and cost
It was highlighted above that SPA has a lower specific gravity and consumption. Due to lower deflection strength for the same concrete structure requires a spa with a larger diameter.
Glass composite armature ASK “REBAR” Reinforcing steel A400 (A-III) Diameter, mm Weight, linear m in kg Number of meters per ton Diameter, mm Weight, linear m in kg Number of meters per ton 4 0.032 31 250 6 0.22 4,504.5 6 0.054 18 518 8 0.40 2,531.7 8 0.085 11,764 12 0.89 1 126.1 ten 0.135 7407 fourteen 1.21 826.5 12 0.20 5,000 sixteen 1.58 632.9 fourteen 0.26 3846 20 2.00 404.9 sixteen 0.35 2857 22 2.47 335.6 18 0.43 2 326 25 2.98 259.7 20 0.60 1667 28 4.83 207.0
The cost of composite reinforcement is several times less than the cost of steel reinforcement.
When building the foundation of a country house, a bathhouse, a low-rise building made of foam blocks and other types of cellular concrete, you can safely use fiberglass reinforcement. For complex construction of large facilities, it is still worth using time-tested steel reinforcement.