RUT SUSCEPTIBLITY TESTING
Preventing rutting in asphalt pavements is a major concern when putting together an asphalt mix design. Emerging technology may improve our ability to prevent rutting in asphalt pavements. One new device is the Asphalt Pavement Analyzer (APA), which is a temperature controlled wheel-tracking device. It measures the rutting that occurs in laboratory compacted specimens. Rutting is induced with the use of a pneumatic hose loaded by an oscillating aluminum wheel. The hose is inflated to 100 psi and placed over the compacted asphalt specimens. A 100 pound load is then applied to the top of the hose by the oscillating wheel. A normal test is 8000 cycles of loading applied to specimens held at 64°C (147°F). Testing can be performed at other temperatures to model actual temperatures at a site. Proposed specifications would set a limit on the amount of rutting that can occur during this test.
Preventing rutting in asphalt pavements is a major concern when putting together an asphalt mix design. Emerging technology may improve our ability to prevent rutting in asphalt pavements. One new device is the Asphalt Pavement Analyzer (APA), which is a temperature controlled wheel-tracking device. It measures the rutting that occurs in laboratory compacted specimens. Rutting is induced with the use of a pneumatic hose loaded by an oscillating aluminum wheel. The hose is inflated to 100 psi and placed over the compacted asphalt specimens. A 100 pound load is then applied to the top of the hose by the oscillating wheel. A normal test is 8000 cycles of loading applied to specimens held at 64°C (147°F). Testing can be performed at other temperatures to model actual temperatures at a site. Proposed specifications would set a limit on the amount of rutting that can occur during this test.
ODOT currently requires rut susceptibility testing using the APA, for informational purposes, on all dense graded asphalt mixtures for use on ODOT transportation projects.
ASPHALT PAVEMENT ANALYZER RUT TESTING PROGRAM
1. General - The APAO is offering rut testing services using the new Asphalt Pavement Analyzer (APA). These services include the following:
- Rut Susceptibility Testing for ODOT Contracts per SP00745 QA. Requires mixing and compaction of test specimens using the APAO's SuperPave Gyratory Compactor.
- Rut Testing for APAO members on other mixes. Mixing and compaction may be by the member.
- Rut Testing for non-members on other mixes. Mixing and compaction may be by others.
2. Submitting Materials - For each HMAC blend tested, complete the attached 1) APA Services Request Form, 2) APA Material Submittal Information Form and submit the materials required to:
Attn: Kevin Berklund
Asphalt Pavement Association of Oregon
5240 Gaffin Rd. SE
Salem, OR 97317
Fx: (503) 363-5571
a. APAO Mixing and Compacting of Specimens - Submit the required batched aggregates, RAP, lime, asphalt cement and other materials as listed on the attached sheet. Submit a copy of the complete JMF including specimen heights, and intermediate mass determinations used to compute the bulk specific gravities (Gmb's).
b. Submitting Compacted Specimens for Test Only Requests - Mix and compact six (6) specimens per AASHTO T40. Indicate the top of each specimen as removed from the SuperPave Gyratory Compactor by marking with a large "T". Submit a copy of the JMF and the Gmm and Gmb's for the specimens prepared. (Please contact Kevin Burklund for information on attaining the necessary void requirements.)