ASTM C566-25 PDF

Full title and description

ASTM C566-25 — Standard Test Method for Total Evaporable Moisture Content of Aggregate by Drying. This test method describes the procedure for determining the percentage of evaporable moisture in an aggregate sample by oven drying, accounting for surface moisture and moisture in the pores of the aggregate; chemically combined water is excluded from the measurement.

Abstract

Provides a laboratory procedure for measuring total evaporable moisture in fine and coarse aggregates by drying to constant mass under specified conditions. The method is intended for routine quality control, batch adjustments for concrete production, and calibration of on-line moisture sensing equipment. Key elements include sample preparation, oven-drying conditions, mass measurements, and calculation of percent evaporable moisture.

General information

• Status: Active (published / active edition indicated as C566-25).
• Publication date: January 11, 2025 (edition year 2025).
• Publisher: ASTM International (American Society for Testing and Materials).
• ICS / categories: 91.100.01 — Construction materials / Aggregates and concrete testing.
• Edition / version: ASTM C566-25 (2025 edition).
• Number of pages: 3 pages (concise test method format typical of C566).

Scope

This test method covers determination of the percentage of evaporable moisture in a representative aggregate sample by oven drying. It addresses drying both surface moisture and pore moisture that is removable by evaporation; chemically combined water is not measured. The method is applicable to most normal-weight and lightweight aggregates, with user guidance for large particle sizes and considerations for rapid-drying alternatives where appropriate.

Key topics and requirements

• Sample collection, reduction to test size, and representative sampling procedures (see Practice C702/D75 related practices).
• Apparatus requirements: balance accuracy, sample container, and ventilated oven capable of maintaining the specified drying temperature (typically ~110 ±5 °C) and conditions for achieving constant mass.
• Drying procedure and time to constant mass, including notes on accelerating drying and handling large coarse aggregate particles.
• Calculation method for percent total evaporable moisture (mass loss basis) and reporting conventions (basis and precision reporting).
• Precision and bias statements and reference to Practice C670 for preparation of precision/bias information (recent editorial/format updates noted in the 2025 work program).
• Safety and handling considerations for hot ovens and heated samples; lab best practices for moisture testing.

Typical use and users

Used by materials testing laboratories, concrete producers and batch plants, aggregate producers, quality control/quality assurance personnel, and transportation/municipal agencies to determine oven-dry moisture content for mix design adjustments, moisture-sensor calibration, and verification of delivered aggregate moisture. The method is commonly cited in concrete and aggregate quality manuals and is used to calibrate electronic moisture meters and probes.

Related standards

Commonly referenced and complementary standards include: ASTM C127 (Specific Gravity and Absorption of Coarse Aggregate), ASTM C128 (Specific Gravity and Absorption of Fine Aggregate), ASTM C29/C29M (Bulk Density and Voids in Aggregate), ASTM C702 (Reducing Samples of Aggregate to Test Size), ASTM E11 (Test Sieves), ASTM C670 (Practice for Preparing Precision and Bias Statements), and ASTM D75 (Sampling Aggregates). These provide sampling, sizing, and precision/bias context for C566 results.

Keywords

aggregate; evaporable moisture; moisture content; oven drying; batch adjustment; quality control; C566; aggregate testing; drying method.

FAQ

Q: What is this standard?

A: ASTM C566-25 is the 2025 edition of the Standard Test Method for Total Evaporable Moisture Content of Aggregate by Drying — a short laboratory procedure to determine the percent evaporable (oven-removable) moisture in aggregate samples.

Q: What does it cover?

A: It covers procedures for sampling, oven drying to constant mass, calculation of percent evaporable moisture (surface plus pore moisture), apparatus and balance requirements, and reporting. Chemically combined water is excluded. The method also includes notes on limitations for large particles and references to precision/bias practices.

Q: Who typically uses it?

A: Materials testing laboratories, aggregate suppliers, concrete producers, QA/QC staff, and agencies that specify or verify aggregate moisture content for mix designs and process control. It is also used to calibrate moisture-sensing equipment.

Q: Is it current or superseded?

A: The C566-25 edition is listed as the active/current edition (publication date January 11, 2025). Historical editions include C566-19 and earlier versions; users should confirm they are using C566-25 for the latest editorial and precision/bias formatting updates.

Q: Is it part of a series?

A: C566 is part of ASTM Committee C09 on Concrete and Concrete Aggregates test methods and is grouped with other aggregate and concrete test methods (C127, C128, C29/C29M, C702, etc.) commonly used together for aggregate characterization and concrete mix control.

Q: What are the key keywords?

A: Aggregate, evaporable moisture, moisture content, oven drying, C566, quality control, aggregate testing, drying method.