ASTM D7870/D7870M-13 - 1.6.2013
 
Significance and Use

3.1 This practice provides an accelerated conditioning method under cyclic loading. This system is capable of operating at higher than normal temperatures and creating pore pressure within a compacted asphalt mixture to achieve an acceleration of the effects that a mixture would experience over time from traffic at normal temperatures and conditions. The accelerated conditioning in this practice is intended to simulate the stresses induced in a wet pavement by a passing vehicle tire. The pulse shape produced by this system approximates a Lorentzian function with a half peak width of approximately 1 s at 276 kPa [40 psi].

3.2 The factors that influence the potential for moisture damage to occur include aggregate mineralogy, mixture air voids, water, cyclic applied stress, and elevated temperature. This practice provides a method and apparatus that is capable of producing three of these factors: water, stress, and high temperature. Aggregate mineralogy and air voids are mixture properties.

3.3 Specimens conditioned by this system can be tested using a variety of different tests including, Test Method D6931, Test Method D6927, bulk specific gravity difference obtained by Test Methods D6926 or D6752 for before and after conditioning, dynamic modulus, flow number, AASHTO TP 79 and visual inspection for stripped aggregates.

Note 1The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the capability, calibration, and maintenance of the equipment used. Agencies that meet the criteria of Practice D3666 are generally considered capable of competent and objective testing, sampling, inspection, etc. Users of this standard are cautioned that compliance with Practice D3666 alone does not completely assure reliable results. Reliable results depend on many factors; following the suggestions of Practice D3666 or some similar acceptance guideline provides a means of evaluating and controlling some of those factors.
 
1. Scope

1.1 This practice includes procedures for preparing compacted asphalt mixture specimens, exposing the specimens to hydrostatic pore pressure inside an enclosed chamber and guidance on testing the specimens for the effect of water on the tensile strength or change in other properties of the asphalt mixture, such as density, modulus, etc.

1.2 Specimens conditioned according to this practice can be tested using methods and test procedures referenced in this document and those results may provide information as to the effect of the moisture conditioning of this practice on the moisture sensitivity of those mixtures.

1.3 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.

1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

1.5 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.

 
2. Referenced Documents

D4867

Test Method for Effect of Moisture on Asphalt Concrete Paving Mixtures

D4013-09

Standard Practice for Preparation of Test Specimens of Bituminous Mixtures by Means of Gyratory Shear Compactor (Withdrawn 2013)

D3666-26

Standard Specification for Minimum Requirements for Agencies Testing and Inspecting Road and Paving Materials

D3665-24

Standard Practice for Random Sampling of Construction Materials

D2726-11

Standard Test Method for Bulk Specific Gravity and Density of Non-Absorptive Compacted Bituminous Mixtures

D1561-92(2000)

Standard Practice for Preparation of Bituminous Mixture Test Specimens by Means of California Kneading Compactor

D979-01

Standard Practice for Sampling Bituminous Paving Mixtures

D5361-06

Standard Practice for Sampling Compacted Bituminous Mixtures for Laboratory Testing

AASHTO TP 79

Standard Method of Test for Determining the Dynamic Modulus and Flow Number for Hot Mix Asphalt (HMA) Using the Asphalt Mixture Performance Tester (AMPT)

D6931-24

Standard Test Method for Indirect Tensile (IDT) Strength of Asphalt Mixtures

D6927-22

Standard Test Method for Marshall Stability and Flow of Asphalt Mixtures

D6926-20

Standard Practice for Preparation of Asphalt Mixture Specimens Using Marshall Apparatus

D6925-23

Standard Test Method for Preparation and Determination of the Relative Density of Asphalt Mix Specimens by Means of the Superpave Gyratory Compactor

D6752-09

Standard Test Method for Bulk Specific Gravity and Density of Compacted Bituminous Mixtures Using Automatic Vacuum Sealing Method