Pull Test Methodology
We test installed anchor and adhesive combinations by applying a short-duration vertical pull and recording force and movement. This page describes the test procedure. For help interpreting the results, start with Understanding Anchor Strength and Guide Loads.
Test Installation
Section titled “Test Installation”Our reference test pavement is professionally installed PG64-16 asphalt, 3 inches thick over 3 inches of compacted road base, aged approximately one year, in Sonoma County.
Test anchors are installed following our installation instructions and allowed to cure for a minimum of 24 hours before testing. For field installations, follow the selected adhesive’s curing requirements for the installation temperature.
Test Equipment & Procedure
Section titled “Test Equipment & Procedure”We use a calibrated hydraulic jack with an integrated pressure gauge mounted in a custom three-point support stand. The stand is 12 inches tall, with legs spaced 18 inches apart in an equilateral triangle. The legs transfer the reaction force to the asphalt around the test anchor.
The anchor is connected through the center of the jack. We pull gradually over approximately one minute while logging force at 500 ms intervals. Each test is video recorded to observe movement. Force can decrease after the peak as the asphalt and anchor move.
Measurement Points
Section titled “Measurement Points”| Measurement | What it records |
|---|---|
| Peak pull force | The highest force recorded during the test. |
| Force at 1/8-inch displacement | The force when vertical movement reaches 1/8 inch. This is a measurement threshold, not the first possible movement. |
| Force at 1/2-inch displacement | The force when vertical movement reaches 1/2 inch. We treat this as functional failure in our test procedure. |
In most testing, peak force occurs with less than 1/4 inch of movement. Once the asphalt starts to move, the measured force generally decreases. Peak force and force at 1/2-inch displacement therefore describe different points in the test; the latter may occur after the peak.
The displacement thresholds describe test behavior. They do not establish acceptable movement for an attachment in service, which may tolerate much less movement. Continued resistance after the peak is not additional usable capacity or a guarantee of warning before failure.
Guide Loads and Test Results
Section titled “Guide Loads and Test Results”Our guide loads come from this test program. See how we set the guide loads.
Individual test results describe measured performance under the conditions tested. Keep the measured peak force, any force recorded at a displacement threshold, and the guide load separate when interpreting a result. See Understanding Anchor Strength and Guide Loads.
Temperature Comparisons
Section titled “Temperature Comparisons”We record the pavement temperature for each test and compare peak pull force across temperatures. See High Pavement Temperature and Anchor Capacity for how the results are grouped and normalized, and for the measured results.
Test Videos
Section titled “Test Videos”These videos show force and movement during individual pull tests. The behavior shown applies to those installations and test conditions.
Tests on Your Site
Section titled “Tests on Your Site”Site-specific tests can help evaluate local pavement and installation conditions. For an installation-verification test, the target load, loading duration, movement limit, and test temperature should be established for the application before testing. The destructive tests described here are not a proof-test procedure for anchors intended to remain in service.
A brief pull test measures performance under the conditions tested. It does not establish performance under sustained tension, repeated loading, or sideways forces. Contact us to discuss testing for your application.