🔩 Reinforcing Steel Testing (Tensile, Bending)
In short
Testing mechanical properties of reinforcing steel: tensile test (Re, Rm, A), bending/reverse bending test. The test is performed according to PN-EN ISO 15630-1:2019; Yield strength Re: ≥500 MPa (B500SP). The procedure comprises 7 steps (about 58 min–1 h in total); it is used for: Reinforcing steel control on construction site (material acceptance), Factory production control at mills and rolling plants, Type testing of reinforcing steel (certification).
At a glance
- Standard: PN-EN ISO 15630-1:2019
- Category: Construction
- Procedure steps: 7
- Total time of stages: 58 min–1 h
- Yield strength Re: ≥500 MPa (B500SP)
- Tensile strength Rm: ≥575 MPa (B500SP)
- Ratio Rm/Re: 1.15–1.35 (B500SP)
Overview
Reinforcing steel must meet strictly defined mechanical requirements ensuring safety of reinforced concrete structures. Standard PN-EN ISO 15630-1 defines testing methods for bars, rods, and wire for concrete reinforcement.
Key tests: tensile test (yield strength Re, tensile strength Rm, elongation Agt) and bending test (ability to bend without cracks). Steel B500SP: Re ≥500 MPa, Rm/Re ≥1.15, Agt ≥8%.
These tests are performed with each steel delivery to construction site and within factory production control at mills. Results form the basis of mill certificates (3.1 per EN 10204) and quality documentation for reinforced concrete structures.
Method principle
Tensile test: bar section of length Lo = 5d or 10d is gripped in testing machine jaws and loaded with axial tensile force at constant strain rate until fracture. Force–elongation diagram is recorded. From diagram: Re (yield strength), Rm (tensile strength), Agt (total elongation at maximum force).
Bending test: bar is bent on mandrel diameter D (e.g., 4d for ø12–16) through angle 180°. No cracks = positive result.
Applications
- Reinforcing steel control on construction site (material acceptance)
- Factory production control at mills and rolling plants
- Type testing of reinforcing steel (certification)
- Control of steel for precast concrete products
- Assessment of steel from existing structures (diagnostics)
- Quality control of meshes and prefabricated reinforcement
Key parameters
| Parameter | Value |
|---|---|
| Yield strength Re | ≥500 MPa (B500SP) |
| Tensile strength Rm | ≥575 MPa (B500SP) |
| Ratio Rm/Re | 1.15–1.35 (B500SP) |
| Elongation Agt | ≥8% (B500SP, class C) |
| Bending test | Mandrel D=4d, angle 180°, no cracks |
| Tensile rate | 3–30 MPa/s (elastic zone) |
Standard
- Standard number
- PN-EN ISO 15630-1:2019
- Title (PL)
- Stal do zbrojenia i sprężania betonu — Metody badań — Część 1: Pręty, walcówka i drut do zbrojenia betonu
- Title (EN)
- Steel for the reinforcement and prestressing of concrete — Test methods — Part 1: Reinforcing bars, rods and wire
Step-by-step procedure
-
Sampling
Randomly sample bars from delivery per PN-EN 10080. Min. 3 specimens from each batch. Tensile specimen length: Lo + 2×grip length (min. 30 cm).
-
Dimension measurement
Measure nominal diameter, linear mass (weighing 500 mm section). Check rib geometry (height, spacing) — caliper, profilometer.
-
Machine mounting
Grip specimen in testing machine jaws. Install extensometer (gauge length Lo = 5d or 10d).
-
Tensile test
Load at constant strain rate (0.00025 s⁻¹ in elastic zone, 0.0067 s⁻¹ after Re). Record F-ε diagram until fracture.
-
Result reading
From diagram read: Re (0.2% or distinct yield), Rm (max force), Agt (elongation at Rm). Calculate Rm/Re.
-
Bending test
On separate specimen: bend bar on mandrel diameter D=4d through angle 180°. Inspection: no cracks visible to naked eye = positive result.
-
Reporting
Prepare report with results Re, Rm, Rm/Re, Agt, bending result. Compare with requirements PN-EN 10080 / PN-B-03264.
Required equipment and apparatus
| Equipment | Example | Indicative price |
|---|---|---|
| Testing machine (tensile) | Zwick Roell Z600, Instron 600DX, MTS 370 | 200,000–500,000 PLN |
| Contact extensometer | Zwick Roell makroXtens, MTS 634.31F | 15,000–40,000 PLN |
| Bending press | Zwick Roell BZ2.5, bar bending device | 30,000–80,000 PLN |
| Caliper | Mitutoyo, accuracy 0.01 mm, for diameter measurement | 200–800 PLN |
| Laboratory balance | For bar linear mass measurement, accuracy 1 g | 2,000–4,000 PLN |
Health and safety (OHS)
- Testing machine — enormous forces, absolute prohibition of inserting hands in testing zone
- Bar fracture — sudden energy release, use shields
- Sharp edges after fracture — protective gloves
- Bending — bar recoil risk, side shields
- Eye protection mandatory
Frequently asked questions
Which standard describes this test?
The test is performed according to PN-EN ISO 15630-1:2019 — “Steel for the reinforcement and prestressing of concrete — Test methods — Part 1: Reinforcing bars, rods and wire”.
How does this method work?
Tensile test: bar section of length Lo = 5d or 10d is gripped in testing machine jaws and loaded with axial tensile force at constant strain rate until fracture. Force–elongation diagram is recorded.
What is the measuring range and accuracy?
Yield strength Re: ≥500 MPa (B500SP); Tensile strength Rm: ≥575 MPa (B500SP); Ratio Rm/Re: 1.15–1.35 (B500SP); Elongation Agt: ≥8% (B500SP, class C).
How long does the test take?
The times given for the individual stages add up to approximately 58 min–1 h. The procedure comprises 7 steps.
What equipment is required?
Testing machine (tensile), Contact extensometer, Bending press, Caliper, Laboratory balance. Indicative cost of the core instrument (Testing machine (tensile)): 200,000–500,000 PLN.
Where is this test used?
Reinforcing steel control on construction site (material acceptance); Factory production control at mills and rolling plants; Type testing of reinforcing steel (certification); Control of steel for precast concrete products; Assessment of steel from existing structures (diagnostics); Quality control of meshes and prefabricated reinforcement.
What safety precautions apply?
Testing machine — enormous forces, absolute prohibition of inserting hands in testing zone; Bar fracture — sudden energy release, use shields; Sharp edges after fracture — protective gloves; Bending — bar recoil risk, side shields; Eye protection mandatory.
Which laboratory can perform this test?
The test is performed by laboratories accredited to ISO/IEC 17025. On LabCoda you can find them by the standard number PN-EN ISO 15630-1.