ASTM D6926-20 PDF Download

The ASTM D6926-20 standard provides guidelines for preparing and compacting asphalt mixture specimens for various physical tests. These tests include stability, flow, indirect tensile strength, fatigue, creep, modulus, density, and void analysis. The specimens are typically used in mixture design and evaluation of field compaction.

The standard specifies that the quality of the results obtained from this practice depends on the competence of the personnel performing the procedure and the calibration and maintenance of the equipment used. It is also noted that compliance with the applicable specifications alone does not guarantee reliable results, and factors such as testing, sampling, inspection, and other considerations should be taken into account.

The practice covers the preparation of cylindrical asphalt paving mixture specimens with a diameter of 4 inches and a height of 2.5 inches. It is intended for use with laboratory and plant-produced asphalt mixtures containing aggregate up to a maximum size of 1 inch. The practice also mentions the historical use of different numbers of blows per face during compaction, but cautions against applying excessive blows to avoid fatigue and damage to the apparatus components.

The standard describes three types of Marshall compaction apparatus, each with different hammer arrangements: manually held hammer handle (Type 1), restrained hammer handle (fixed laterally but not vertically) (Type 2), and restrained hammer handle with a slanted compaction foot on a rotating mold base (Type 3). Each type of apparatus may have different densities achieved even with the same number of blows, so the specific required number of blows should be established by the owner or specifier in relation to the field.

It should be noted that the standard includes references to notes and footnotes, which provide explanatory material but are not considered as requirements of the standard unless explicitly stated.