ASTM D4373-21 PDF

Full title and description

Standard Test Method for Rapid Determination of Carbonate Content of Soils. This method (designation D4373-21) describes a portable, gasometric procedure for rapid measurement of carbonate in soils and soft rock, reporting results as percent calcite equivalent.

Abstract

ASTM D4373-21 defines a quick field or laboratory gasometric technique to estimate carbonate (calcite-equivalent) content in soils that can be broken down by mechanical effort. The method uses a simple apparatus and reaction with dilute acid to evolve CO2; the evolved gas volume (or related gasometric measurement) is converted to percent calcite equivalent. The method notes limitations for certain carbonate species and for very low carbonate contents and refers users to complementary quantitative chemical analyses when species identification or higher accuracy is required.

General information

• Status: Active standard (current edition D4373-21).
• Publication date: Approved June 15, 2021; published June 2021.
• Publisher: ASTM International.
• ICS / categories: 13.080.10 — Chemical characteristics of soils.
• Edition / version: D4373-21 (2021).
• Number of pages: 5 pages (typical published PDF length).

Scope

This test method covers determination of carbonate content for soils and soft rocks that can be readily reduced to small pieces by mechanical effort. Results are reported as calcite equivalent (percent). The standard does not distinguish carbonate mineral species and recommends other analytical methods when identification or highly accurate quantification is required. It also directs users to follow appropriate laboratory safety and competency practices.

Key topics and requirements

• Gasometric technique using acid reaction to evolve CO2 and measurement of evolved gas to calculate carbonate as percent calcite equivalent.
• Use of a simple portable apparatus suitable for field or laboratory work; procedure suitable for soils and soft rock reducible by mechanical effort.
• Reporting requirement: state results as percent calcite equivalent (different carbonate minerals have different equivalencies).
• Limitations: low carbonate concentrations and presence of uncommon carbonates (e.g., cerussite, witherite) may affect interpretation; dolomitic material may require longer test times for similar accuracy.
• Reference to significance-digit practice and laboratory competence (referenced ASTM practices for reporting and laboratory qualification).

Typical use and users

Used by geotechnical and geoenvironmental laboratories, field engineering teams, construction materials inspectors, environmental consultants, and academic researchers for preliminary or rapid screening of carbonate content in soils and soft rock. Common applications include site characterization, preliminary design assessments, and screening prior to more detailed chemical or mineralogical analyses.

Related standards

ASTM D4373-21 references and is commonly used alongside other ASTM practices and standards such as Practice D6026 (use of significant digits in geotechnical data), Practice D3740 (competency of testing laboratories), Terminology D653, and other soil test methods addressing particle-size, organic content, and chemical analysis. Users should consult the referenced ASTM documents for complementary procedures and reporting conventions.

Keywords

carbonate content, calcite equivalent, gasometric, soils, carbonate soils, dolomite, field test, rapid determination, ASTM D4373-21.

FAQ

Q: What is this standard?

A: ASTM D4373-21 is a standard test method titled "Standard Test Method for Rapid Determination of Carbonate Content of Soils" that provides a rapid gasometric procedure to estimate carbonate expressed as percent calcite equivalent.

Q: What does it cover?

A: It covers a portable gasometric method for soils and soft rock that can be mechanically reduced, describing sampling considerations, test apparatus, procedure, calculation of calcite-equivalent percent, reporting, and limitations where species identification or higher accuracy is needed.

Q: Who typically uses it?

A: Geotechnical engineers, laboratory technicians, environmental consultants, construction materials labs, and researchers use this standard for quick field or lab screening of carbonate content.

Q: Is it current or superseded?

A: The current edition is D4373-21, approved June 15, 2021, and published in June 2021. It is the active edition as of the 2021 publication. Users should check ASTM or their national standards provider for any amendments or later revisions beyond 2021.

Q: Is it part of a series?

A: It is a standalone test method within ASTM Committee D18 (Soil and Rock) publications but is commonly used with related ASTM practices and test methods addressing soil characterization, laboratory competency, and data reporting (see Related standards above).

Q: What are the key keywords?

A: Carbonate content, calcite equivalent, gasometric, soils, dolomite, rapid field method, ASTM D4373-21.