ASTM C452-21 PDF

Full title and description

ASTM C452-21 — Standard Test Method for Potential Expansion of Portland‑Cement Mortars Exposed to Sulfate. A short, prescriptive test method that defines preparation, curing, exposure, and length‑change measurement of mortar bars (portland cement + gypsum) to evaluate potential sulfate‑induced expansion and to support specification acceptance of sulfate‑resisting portland cements.

Abstract

This test method specifies how to make and measure mortar bars prepared from portland cement mixed with gypsum (to produce a 7.0 % SO3 content by mass) and to monitor their length change under controlled curing/exposure conditions. The expansion measured at specified ages is used for research and for assessing whether a portland cement meets sulfate‑resistance performance requirements referenced in cement specifications (for example, ASTM C150/C150M).

General information

• Status: Superseded (original designation C452‑21; superseded by ASTM C452/C452M‑25 published July 1, 2025).
• Publication date: April 1, 2021 (designation C452‑21).
• Publisher: ASTM International.
• ICS / categories: 91.100.10 (Cement. Gypsum. Lime. Mortar).
• Edition / version: ASTM C452‑21 (three‑page test method document).
• Number of pages: 3.

Scope

Applies to portland cements only. Covers determination of the potential expansion of mortar bars made from a mixture of portland cement and gypsum in proportions that give a sulfur trioxide (SO3) content of 7.0 % by mass. The standard defines units (SI and inch‑pound treated separately), specimen preparation (standard sand, molds), curing/exposure conditions, measurement intervals, and reporting of length change. It is intended for research and to demonstrate compliance of sulfate‑resisting portland cement with applicable performance specifications (e.g., ASTM C150/C150M).

Key topics and requirements

• Applicability: intended for portland cements (not formulated blends) — mortar bars made with added gypsum to reach 7.0 % SO3.
• Materials: use of ASTM standard sand (C778) and specified gypsum quality and proportions to control SO3 content.
• Specimen preparation: mixing, molding, compaction, and curing procedures referenced to related ASTM test methods (for example C109/C109M for mortar preparation/compressive strength procedures where applicable).
• Conditioning and exposure: controlled curing and storage conditions, immersion/exposure regime and temperature control required for reproducible expansion measurements.
• Measurement: initial and subsequent length readings using appropriate length‑comparator apparatus and reference bars (Practice C490 guidance), with reporting at specified ages (commonly 14 days and optionally extended intervals).
• Units and reporting: SI and inch‑pound units are each treated as independently standard; follow IEEE/ASTM SI‑10 conversion/rounding rules if converting.
• Acceptance guidance: used to evaluate sulfate resistance; industry practice references specific expansion limits (for example, limits cited for Type V cement in specification contexts), but acceptance limits are provided in the cement specification (ASTM C150/C150M), not within the test method itself.
• Safety note: fresh cementitious mixtures are caustic — users must follow appropriate health, safety, and environmental precautions.

Typical use and users

Used by cement manufacturers, quality control/quality assurance laboratories, independent testing laboratories, research organizations, transportation departments and materials engineers who need to evaluate the potential sulfate sensitivity of portland cements or to demonstrate compliance with sulfate‑resisting cement specifications. Also used in research comparing cement formulations or studying sulfate attack mechanisms.

Related standards

Commonly referenced standards and practices include ASTM C150/C150M (Specification for Portland Cement), ASTM C109/C109M (Compressive Strength of Hydraulic‑Cement Mortars), ASTM C1012 (Length Change of Hydraulic‑Cement Mortars Exposed to a Sulfate Solution), ASTM C778 (Standard Sand), ASTM C490 (practice for apparatus and use of length‑change comparators), and other ASTM C-series standards on cement and mortar testing.

Keywords

ASTM C452‑21; sulfate resistance; mortar bars; portland cement; gypsum addition; SO3 7.0%; expansion test; length change; C150; C1012; C109; C778; C490.

FAQ

Q: What is this standard?

A: ASTM C452‑21 is a short ASTM test method titled "Standard Test Method for Potential Expansion of Portland‑Cement Mortars Exposed to Sulfate" that prescribes how to prepare mortar bars (portland cement plus gypsum) and measure their length change to assess potential sulfate‑induced expansion.

Q: What does it cover?

A: It covers specimen materials and proportions (including adding gypsum to achieve 7.0 % SO3), specimen preparation, curing/exposure conditions, measurement technique and intervals, unit conventions (SI and inch‑pound treated separately), and reporting for the potential expansion of portland‑cement mortars exposed to sulfate.

Q: Who typically uses it?

A: Cement producers, QA/QC and independent testing labs, research institutions, DOT/materials engineers and anyone assessing the sulfate resistance of portland cement or confirming conformance with cement specifications that reference this test method.

Q: Is it current or superseded?

A: ASTM C452‑21 (published April 1, 2021) has been superseded — the active revision is ASTM C452/C452M‑25 published July 1, 2025. Users performing formal testing or procurement should refer to the latest active designation (C452/C452M‑25) for current scope or any scope changes.

Q: Is it part of a series?

A: Yes. C452 is one of the ASTM C (Cement, Lime, Gypsum, and Building Materials) family of standards maintained by Committee C01 and the subcommittee on sulfate resistance (C01.29). The method is used alongside related C‑series test methods and specifications (for example, C150, C1012, C109/C109M, C778, and C490).

Q: What are the key keywords?

A: Key keywords are: sulfate resistance, mortar bar expansion, portland cement, gypsum, SO3 7.0%, length change, ASTM C452, C150, C1012, mortar testing.