ASTM D6926-20 PDF

Full title and description

ASTM D6926-20 — Standard Practice for Preparation of Asphalt Mixture Specimens Using Marshall Apparatus. This practice describes the preparation and compaction of cylindrical asphalt paving mixture specimens (nominal 4 in. / 101.6 mm diameter by 2.5 in. / 63.5 mm height) using Marshall compaction equipment and procedures intended for laboratory and plant-produced asphalt mixtures (maximum aggregate size up to 1 in. / 25.4 mm).

Abstract

This practice specifies methods for molding and compacting Marshall specimens for physical testing (stability, flow, indirect tensile strength, fatigue, creep, modulus) and for density/voids analysis used in mix design and field compaction evaluation. It defines specimen size, describes three general types of Marshall compaction apparatus and hammer arrangements, and gives guidance on number of blows and apparatus considerations. Notes and SI conversions are informational only.

General information

• Status: Active.
• Publication date: 2020 (designation D6926-20; effective date listed as January 1, 2020).
• Publisher: ASTM International (Committee D04 — Road and Paving Materials / Subcommittee D04.20).
• ICS / categories: 93.080.20 — Road construction materials.
• Edition / version: D6926-20 (2020 edition).
• Number of pages: 8 pages (PDF edition).

Scope

The practice covers preparation and compaction of 4 in. (101.6 mm) diameter by nominal 2.5 in. (63.5 mm) high cylindrical asphalt paving mixture specimens. It is intended for laboratory and plant-produced asphalt mixtures with aggregate up to 1 in. (25.4 mm) maximum size and for recompaction of paving mixture samples. The document clarifies that there are multiple Marshall hammer/foot arrangements in use (three general types) and that the number of blows must be selected in relation to field conditions; SI unit conversions are provided for information only.

Key topics and requirements

• Specimen geometry: 4 in. (101.6 mm) diameter × nominal 2.5 in. (63.5 mm) height.
• Intended mixture size: aggregate up to 1 in. (25.4 mm) maximum.
• Marshall compaction apparatus: description of three hammer/foot arrangements (Type 1 hand-held, Type 2 fixed lateral restraint, Type 3 rotating mold/slanted foot — referee method distinctions noted).
• Compaction energy guidance: historical practice of 35, 50, and 75 blows per face is discussed; users/specifiers must establish the appropriate number of blows for their field equivalency and to avoid equipment fatigue/damage.
• Use of specimens: stability and flow testing, indirect tensile and resilient modulus testing, fatigue and creep evaluations, and density/voids analysis for mix design and field compaction evaluation.
• Notes and nonmandatory material: explanatory notes and SI conversions are informational and not normative requirements.

Typical use and users

Used by highway agencies, state and local DOT laboratories, independent testing laboratories, university research groups, pavement materials engineers, mix designers, and contractors for laboratory specimen preparation and for correlation of laboratory compaction to field compaction. Equipment manufacturers and calibrators also use the standard to design and verify Marshall compactors.

Related standards

Commonly used together with other asphalt and aggregate standards such as ASTM D6927 (Marshall stability and flow test methods), ASTM D2726/D2726M (bulk specific gravity and density of compacted bituminous mixtures), ASTM D4867 (moisture effect on mixtures), ASTM D6931 (indirect tensile strength) and related AASHTO or EN test methods for specimen preparation and performance testing. Users should consult current editions of these standards for test method details.

Keywords

Marshall apparatus, specimen preparation, asphalt mixtures, bituminous mixtures, compaction, Marshall compaction, mix design, stability, flow, density, voids, pavement materials.

FAQ

Q: What is this standard?

A: ASTM D6926-20 is the ASTM practice that specifies how to prepare and compact cylindrical asphalt (bituminous) mixture specimens using the Marshall apparatus for laboratory testing and mix evaluation.

Q: What does it cover?

A: It covers specimen dimensions, allowable aggregate size, Marshall compaction apparatus types and compaction procedures (including guidance on blows per face), and intended specimen uses (stability, flow, indirect tensile, density/void analysis, etc.).

Q: Who typically uses it?

A: State and local DOTs, municipal and commercial testing laboratories, researchers, pavement engineers, mix designers, and equipment manufacturers involved in asphalt mix testing and quality control.

Q: Is it current or superseded?

A: The D6926-20 edition (2020) is the active edition designated D6926-20; it supersedes earlier editions (for example D6926-16). Check with ASTM for the absolute latest status and any amendments if you need current compliance confirmation.

Q: Is it part of a series?

A: It is part of the ASTM road and paving materials suite (Book of Standards Volume 04.03) and is frequently used alongside other asphalt mixture and aggregate test standards (e.g., D6927, D2726, D4867, D6931).

Q: What are the key keywords?

A: Marshall compaction, specimen preparation, asphalt mixture, bituminous, stability, flow, density, voids, compaction energy.