1. Scope

1.1 This test method covers the procedures for preparing, testing, and measuring asphalt mixture rutting resistance at high temperatures using cylindrical laboratory prepared asphalt mix samples or pavement cores. The test method describes the determination of the rutting tolerance index RTIndex and other parameters determined from the load-displacement curve. These parameters can be used to evaluate the resistance of asphalt mixtures to rutting. 1.2 Units--The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. 1.3 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1.5 The within-laboratory repeatability standard deviation of rutting tolerance index has been determined to be 2.447, based on 1 laboratory, 24 test replicates, and 8 different samples. The between-laboratory reproducibility of this test method is being determined and will be available on or before May 31, 2023. Therefore, this standard should not be used for acceptance or rejection of a material for purchasing purpose.

Keywords

asphalt mixture rutting resistance; rapid rutting test; rutting tolerance index

Rationale

Many state Departments of Transportation (DOTs) are in the process of implementing balanced mix design method to improve asphalt mix performance with both rutting and cracking tests. There are many rutting tests developed in the past, but the two most often used rutting tests are the Hamburg Wheel Tracking Test and the Asphalt Pavement Analyzer (APA). However, neither of them is designed for quality control and quality assurance (QC/QA) testing at asphalt plants. Thus, there is an urgent need for a rapid shear rutting test for QC/QA so that the mix quality could be similar to what was designed in the laboratory. This standard introduces the rapid shear rutting test (RSRT). The RSRT has the following features: (1) simplicity: no instrumentation, coring, cutting, gluing, or notching samples; (2) efficiency: test completion within 1 min; (3) practicality: workable for both laboratory molded specimens and field cores; no sophisticated training needed for running the test; (4) low cost: use of existing test equipment with minimum cost; (5) repeatability: great repeatability and low coefficient of variation (COV) (10 % with three replicates); (6) sensitivity: sensitive to asphalt mix composition (aggregate, binder, recycled materials), air voids, and aging; (7) nanifesting rutting mechanism: RSRT measures shear stress resistance of asphalt mixes; and (8) good correlation with field rutting performance: the shear-resistance-based rutting parameter has good correlation with measured field-rutting performance. The rapidity, simplicity, and other features make the RSRT a great fit for field QC/QA testing.

The title and scope are in draft form and are under development within this ASTM Committee.