ASTM C1012/C1012M-24a PDF

Full title and description

Standard Test Method for Length Change of Hydraulic‑Cement Mortars Exposed to a Sulfate Solution — ASTM C1012/C1012M‑24a. This method defines procedures to prepare mortar bars, cure them under specified conditions, expose them to a sulfate solution, and measure length change to assess sulfate resistance of hydraulic‑cement mortars and blended cements.

Abstract

This standard specifies the preparation, curing, exposure, and measurement procedures for determining length change (expansion or contraction) of mortar bars immersed in a sulfate solution. It is intended to evaluate the relative sulfate resistance of portland cements, blended cements, and mixtures containing pozzolans or slag by monitoring dimensional change of standardized mortar specimens over time under controlled laboratory exposure conditions.

General information

• Status: Active (current edition designated C1012/C1012M‑24a; includes amendments through 20 Nov 2024).
• Publication date: Published Oct 15, 2024 (edition 24a; amendment/last update noted 20 Nov 2024).
• Publisher: ASTM International (formerly American Society for Testing and Materials).
• ICS / categories: 91.100.10 — Cement. Gypsum. Lime. Mortar (construction materials / cement testing).
• Edition / version: C1012/C1012M‑24a (24a indicates the 2024 edition with amendment).
• Number of pages: 9 pages.

Scope

This test method covers determination of length change of mortar bars immersed in a sulfate solution. Mortar bars are produced using the mortar described in Test Method C109/C109M, subjected to the specified initial curing period, then immersed in the standard sulfate exposure solution (normally 50 g/L Na2SO4) or other sulfate media as required to simulate the exposure of interest. The method provides a laboratory assessment of sulfate resistance for portland cements, blended cements, and cement blends containing pozzolans or slags.

Key topics and requirements

• Specimen preparation using mortar mix proportions consistent with Test Method C109/C109M.
• Controlled initial curing (standard text notes curing of bars for 7 days at 38 °C before immersion in the exposure solution under the 24a edition).
• Standard exposure solution concentration (typical: 352 moles Na2SO4 per m3, equivalent to ~50 g/L Na2SO4); allowance for alternative sulfate types or concentrations where relevant.
• Length‑change measurement procedures and schedule for monitoring expansion/contraction over time.
• Applicability notes differentiating this method from other sulfate or expansion tests (for example, C452 applicability differences and cross‑references to related practices and specifications).

Typical use and users

Used by cement and concrete laboratories, material suppliers, quality control personnel, research organizations, and standards bodies to evaluate sulfate resistance of cements and mortar formulations, support specification acceptance testing, and investigate durability performance in sulfate‑bearing environments.

Related standards

Typical related documents include Test Method C109/C109M (mortar strength and mortar preparation referenced in C1012), Test Method C452 (sulfate soundness/expansion tests for portland cements), Practice C490 (use of apparatus for length‑change determination), and other ASTM C01 committee standards on cement and concrete testing.

Keywords

sulfate resistance; length change; mortar bars; hydraulic cement; expansion; sulfate solution; Na2SO4; blended cements; pozzolans; slag; durability; C1012; C1012M; ASTM.

FAQ

Q: What is this standard?

A: ASTM C1012/C1012M‑24a is a standardized laboratory test method for measuring length change of hydraulic‑cement mortar bars immersed in a sulfate solution to assess sulfate resistance.

Q: What does it cover?

A: It covers specimen preparation (per C109/C109M), initial curing, immersion in a sulfate exposure solution (commonly 50 g/L Na2SO4), and periodic length measurements to quantify expansion or contraction over time and compare relative sulfate performance of cements and cement blends.

Q: Who typically uses it?

A: Cement and concrete test laboratories, material manufacturers, quality assurance/quality control staff, research groups studying sulfate durability, and specifiers writing or enforcing material acceptance criteria.

Q: Is it current or superseded?

A: It is the current active edition designated C1012/C1012M‑24a (published Oct 15, 2024, with amendment/last update recorded 20 Nov 2024), and supersedes prior editions (including earlier 2018/2019 editions).

Q: Is it part of a series?

A: Yes. It is part of the ASTM C01 committee standards on cement and related materials, developed by Subcommittee C01.29 on sulfate resistance, and is used alongside related methods such as C109/C109M and C452.

Q: What are the key keywords?

A: Sulfate resistance, length change, mortar bars, Na2SO4, expansion, blended cements, pozzolans, slag, durability, ASTM C1012/C1012M.