The rebar tensile and bend test verifies the mechanical properties of reinforcing steel — yield strength, tensile strength, elongation and ductility — to ISO 15630-1 and ASTM A615.
What the Test Measures
A universal testing machine pulls a full-size bar to failure to measure yield and tensile strength and elongation, while a bend (and rebend) test on a mandrel confirms the steel’s ductility and freedom from cracking.
Apparatus Required
- Universal testing machine of adequate capacity with tensile grips
- Extensometer for yield and elongation measurement
- Bend/rebend device with mandrels of specified diameter
- Gauge-length marking tools
NL Scientific manufactures the ELECTRO-HYDRAULIC Servo Control Universal Testing Machine and the full steel testing range, built to ASTM, EN, BS and AASHTO requirements with ISO/IEC 17025 accredited calibration.
Test Procedure
- Measure the bar and mark the gauge length.
- Grip the bar and apply tensile load, recording the yield point and maximum load.
- Continue to fracture and measure the final gauge length for elongation.
- On a separate sample, bend the bar around the specified mandrel to the required angle.
- Inspect the bend (and rebend, where required) for cracks.
Calculation & Reporting
Report yield strength (Re), tensile strength (Rm), the Rm/Re ratio and percentage elongation, plus a pass/fail for the bend test.
Acceptance Criteria
Values must meet the grade requirements (for example, ASTM A615 Grade 60 requires a minimum yield of 420 MPa) with no cracking on the bend test. The Rm/Re ratio confirms adequate ductility for seismic grades.
Frequently Asked Questions
Why is the bend test important?
Tensile strength alone does not prove ductility; the bend and rebend tests confirm the bar can be bent on site without cracking.
What machine capacity is needed for rebar?
Large-diameter and high-grade bars need a high-capacity servo-hydraulic universal testing machine; capacity is selected from the largest bar size and grade to be tested.
Need the right equipment for your laboratory? Contact NL Scientific for a quotation — Asia’s leading manufacturer of civil engineering and material testing equipment, shipping worldwide.
