ASTM C39/C39M-24 PDF

Full title and description

ASTM C39/C39M-24 — Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens. This test method covers the determination of compressive strength of cylindrical concrete specimens such as molded cylinders and drilled cores by applying an axial compressive load until failure and calculating strength as peak load divided by the specimen cross-sectional area.

Abstract

Provides procedures for preparing, capping/grinding, positioning, and loading cylindrical concrete specimens in a compression testing machine and for reporting results. The method is limited to concretes having unit weights greater than about 50 lb/ft³ (≈800 kg/m³) and presents both inch‑pound and SI units as independent systems. The standard also references accepted end‑preparation practices (capping or grinding) and requirements for load application rate, machine calibration, and specimen geometry.

General information

• Status: Current.
• Publication date: 2024 (ASTM C39/C39M-24, published June 2024).
• Publisher: ASTM International.
• ICS / categories: 91.100.30 — Concrete and concrete products.
• Edition / version: 2024 edition — designation C39/C39M-24.
• Number of pages: 8 pages (concise test method).

Scope

Specifies the procedure to determine compressive strength of cylindrical concrete specimens (molded or cored). It applies to typical structural concretes (unit weight > ~800 kg/m³) and sets requirements for specimen dimensions, end‑preparation (capping or grinding), alignment and seating in the test machine, rate of loading (expressed as stress rate), and reporting of results and deviations. The inch‑pound and SI unit systems are treated independently.

Key topics and requirements

• Specimen types: molded cylinders and drilled cores; minimum unit weight applicability (≈800 kg/m³).
• Specimen geometry and dimensional tolerances (diameter, length, end flatness/parallelism) and related acceptance criteria.
• End preparation: approved capping (unbonded caps) or grinding/capping practices; references to C617/C1231 and related practices for preparing end surfaces. Recent work items note adding alternative end‑grinding options and clarifying end‑preparation reporting.
• Loading procedure: alignment, platen contact, and controlled rate of loading (expressed as specified stress rate) until failure; machine calibration and verification practices.
• Calculation and reporting: compressive strength calculation (peak load ÷ cross‑sectional area), units, specimen identification, age, curing history, end treatment, and any departures from the method.
• Safety and laboratory practice notes: recommendations for guarding against sudden specimen failure and for maintaining machine calibration/verification records.

Typical use and users

Used by materials testing laboratories, quality control personnel on construction projects, concrete producers, research laboratories, and engineering consultants to determine and document compressive strength of concrete specimens for acceptance testing, quality control, and research. It is commonly referenced in construction specifications, quality plans, and laboratory test reports.

Related standards

Commonly referenced ASTM standards and practices include ASTM C617 / C617M and ASTM C1231 / C1231M (end preparation and unbonded caps), ASTM C31/C31M (making and curing test specimens in the field), ASTM C1077 (laboratory practice and testing agency criteria), and various calibration and hardness practices (E4, E74, etc.). Recent ASTM work items for C39/C39M indicate active revisions to clarify end‑preparation and loading machine requirements.

Keywords

compressive strength; cylindrical concrete specimen; concrete cylinder; drilled core; capping; end grinding; test method; ASTM C39; C39M; concrete testing; quality control.

FAQ

Q: What is this standard?

A: ASTM C39/C39M-24 is the ASTM test method that defines how to determine the compressive strength of cylindrical concrete specimens (molded cylinders and drilled cores) by axial compression testing.

Q: What does it cover?

A: It covers specimen types, dimensional requirements, accepted end‑preparation methods (capping or grinding), machine and platen seating/ alignment, rate of loading (stress rate), calculation of strength, and reporting requirements. The method applies to concretes of normal unit weight (≈800 kg/m³ and above) and treats inch‑pound and SI units separately.

Q: Who typically uses it?

A: Materials testing laboratories, QC/QA staff on construction projects, concrete producers, engineering consultants, and researchers who need standardized compressive strength measurements for specification compliance, acceptance testing, and investigation.

Q: Is it current or superseded?

A: The C39/C39M-24 edition (2024) is the current ASTM edition of this test method. ASTM subcommittee activity indicates ongoing work items to clarify end preparation and loading‑machine requirements, so small revisions may appear in future revisions.

Q: Is it part of a series?

A: It is part of the ASTM C09 committee suite of standards for concrete and concrete aggregates and is commonly used alongside related standards such as C31/C31M (making/curing specimens), C617/C1231 (end preparation), and C1077 (laboratory practice).

Q: What are the key keywords?

A: Compressive strength, concrete cylinder, drilled core, capping, end grinding, ASTM C39, quality control, specimen geometry, stress rate.