Concrete-reinforcing steel is divided into
- Reinforcing bars (rebars), reinforcing wire rod, reinforcing wire
- Welded mats and lattices
Reinforcing bars are steel products with a circular or nearly circular cross-section that are used for the reinforcement of concrete. Test methods for reinforcing bars, reinforcing wire rod and reinforcing wire are described in the ISO 15630-1 standard.
The smaller diameters are processed into mats or lattices before they are poured with concrete on site. Test methods for these products are described in the ISO 15630-2 standard.
A typical feature of concrete-reinforcing steel are ribs, which are coiled or rolled and serve to improve the bond between concrete and steel.
ISO 15630-1 specimen specifications
- Concrete-reinforcing steel is manufactured from a long product and its surface shape varies according to the manufacturing standard.
- The specimen has a constant cross-section over its length. In addition, the specimen's shape must be straight without curvature. Specimens with curvature must be straightened before testing.
- The cross-section of the specimen is significant for tensile tests. To determine the cross-section, the length of the specimen is measured and it is weighed. The cross-section is then mathematically calculated from these values.
The most important characteristic values
- Tensile strength Rm [MPa]
- Yield point Re [MPa]
- Yield point ratio of tensile strength Rm to yield strength Re
- Ratio of yield strength to nominal yield strength Re, actual / Re, nominal
- Total extension at maximum load Agt [%]
The nominal cross-sectional area is to be used for calculation of the strength properties, as long as this is not otherwise defined in the product standard concerned (see ISO 15630).
A test is not valid
- If the gradient of the measuring curve deviates >10% from the theoretical value of the Young's modulus
- In case of breakage within the specimen grips +20 mm or d (whichever is the higher value) distance to the specimen grips.