ASTM D828
Line-Contact Tensile Grips for Paper and Paperboard
ASTM D828 Tensile Grip – Universal Grip Data Sheet (PDF)
ASTM D828 is the standard test method for tensile properties of paper and paperboard using constant-rate-of-elongation apparatus. A strip is clamped across its full width and stretched at a constant rate until it ruptures, giving tensile strength, stretch, tensile energy absorption and tensile stiffness in one test. Universal Grip builds line-contact grips that define the test span precisely and hold paper without the slippage and jaw breaks that flat jaws cause.
What ASTM D828 Measures
D828 reports tensile strength (breaking force per unit width), stretch at break, tensile energy absorption (the area under the force-elongation curve per unit test area), tensile stiffness, and the derived breaking length and tensile index. It applies to all types of paper, paperboard and related materials within the limits of the equipment, but not to combined corrugated board; towel and tissue have their own method. The TAPPI equivalent is T 494, and the two are run on the same constant-rate-of-elongation testers. Results are used in mill QC, packaging and converting specifications, and printing-grade comparisons, where machine- and cross-direction values are usually reported separately.
How the ASTM D828 Test Works
Cut strips of the specified width with clean, parallel edges, in both the machine and cross direction.
Condition the strips in the standard paper-testing atmosphere before testing.
Clamp each strip across its full width in the line-contact grips, set the test span and align the strip so it is pulled straight.
Apply a slight pretension so the strip is straight but not stretched, and zero the force.
Extend at a constant rate of elongation until the strip ruptures.
Record force and elongation and calculate tensile strength, stretch, TEA and tensile stiffness; test enough strips in each direction to meet the standard's count.
Specimens and Setup
Strip width and test span are set by the standard; TAPPI T 494 uses the same geometry, so one grip set serves both.
Cut with a precision strip cutter; ragged edges start tears and give low, scattered results.
Breaks within a few millimeters of the clamp line are jaw breaks and are discarded.
Use a low-capacity load cell; most papers break well under 200 N on a standard strip.
Confirm the elongation rate and specimen count in the current edition of the standard and in your product specification.
Universal Grip ASTM D828 Fixture
Line-contact faces clamp across the full specimen width
Aligned upper and lower faces prevent strip twisting
Quick-acting clamping for high-throughput testing
Faces designed to minimize slippage and jaw breaks
Lightweight for low-capacity load cells
Manual or pneumatic actuation, to suit the application
1 kN standard capacity; higher capacities on request; supplied as a matched pair
Applications
Paper and paperboard
Packaging and converting materials
Tissue and specialty papers
Pulp and paper mill QC
Related Standards and Products
Send us your specimen dimensions, required capacity and machine connection through our contact page and we will quote an ASTM D828 paper tensile grip set. Request a quote
ASTM D828 FAQ
What does ASTM D828 measure?
Tensile strength, stretch, tensile energy absorption and tensile stiffness of paper and paperboard, plus the derived breaking length and tensile index, using a constant-rate-of-elongation tensile tester. It excludes combined corrugated board.
Why line-contact grips?
Paper is thin and tears easily at a clamp edge. Line-contact faces grip across the full width along a narrow, well-defined line, so the test span is exact, the strip does not slip, and breaks start in the span rather than at the jaw.
Is D828 the same as TAPPI T 494?
They are equivalent constant-rate-of-elongation methods for the same four properties and use the same strip geometry, so the same grips and tester serve both. Report which one you followed.
What tester do I need?
Any constant-rate-of-elongation machine with a low-capacity load cell, vertical or horizontal. A Mark-10 tensile tester or a 1 to 2.5 kN benchtop universal testing machine with a 100 to 500 N cell covers paper and most paperboard.