ASTM C948-81(2023)
(Test Method)Standard Test Method for Dry and Wet Bulk Density, Water Absorption, and Apparent Porosity of Thin Sections of Glass-Fiber Reinforced Concrete
Standard Test Method for Dry and Wet Bulk Density, Water Absorption, and Apparent Porosity of Thin Sections of Glass-Fiber Reinforced Concrete
SIGNIFICANCE AND USE
2.1 Material properties determined by this test method are useful for quality control of glass-fiber reinforced concrete, ascertaining compliance with governing specifications, and research and development.
SCOPE
1.1 This test method covers the determinations of dry and wet bulk density, water absorption, and apparent porosity of thin sections of glass-fiber reinforced concrete.
Note 1: This test method does not involve a determination of absolute specific gravity. Therefore, such pore space as may be present in the specimen that is not emptied during the specified drying or is not filled with water during the specified immersion is considered “impermeable” and is not differentiated from the solid portion of the specimen for the calculations, especially those for percent voids.
Depending upon the pore size distribution and the pore entry radii of the specimen and on the purposes for which the test results are desired, the procedures of this method may be adequate, or they may be insufficiently rigorous. In the event that it is desired to fill more of the pores than will be filled by immersion, various techniques involving the use of vacuum treatment or increased pressure may be used. If a rigorous measure of total pore space is desired, this can only be obtained by determining absolute specific gravity by first reducing the sample to discrete particles, each of which is sufficiently small so that no impermeable space can exist within any of the particles.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
- Status
- Published
- Publication Date
- 30-Apr-2023
- Technical Committee
- C27 - Precast Concrete Products
- Drafting Committee
- C27.40 - Glass Fiber Reinforced Concrete
Overview
ASTM C948-81(2023), Standard Test Method for Dry and Wet Bulk Density, Water Absorption, and Apparent Porosity of Thin Sections of Glass-Fiber Reinforced Concrete, provides critical test procedures for evaluating essential physical properties of glass-fiber reinforced concrete (GFRC). Developed by ASTM International, this standard supports quality control, verifies compliance with project specifications, and facilitates research and development efforts for GFRC materials. By standardizing how to determine dry and wet bulk densities, water absorption, and apparent porosity, ASTM C948-81(2023) helps ensure durable, reliable concrete products for a range of construction and architectural applications.
Key Topics
- Dry and Wet Bulk Density Measurement
- Establishes procedures for accurately determining the weight per unit volume of GFRC in both its dry and water-saturated conditions.
- Water Absorption Testing
- Details steps for assessing how much water is absorbed by GFRC thin sections, reflecting the material's permeability.
- Apparent Porosity Calculation
- Describes how to quantify the proportion of pores accessible to water in GFRC, which correlates to durability and performance.
- Testing Methodology
- Covers requirements for specimen preparation, immersion, drying, and weighing.
- Notes the use of precise balances and containers for immersion, emphasizing accuracy.
- Standardization Assurance
- Developed according to internationally recognized principles for creating standards under the World Trade Organization TBT Committee.
Applications
ASTM C948-81(2023) holds practical value across various sectors involved with glass-fiber reinforced concrete:
- Quality Control in Manufacturing
- Enables consistent monitoring of bulk density, water absorption, and porosity for GFRC product lines.
- Compliance Verification
- Ensures that finished GFRC panels or components meet the governing specifications for strength, durability, and performance.
- Research and Development
- Supports the evaluation and comparison of new GFRC formulations or treatments in laboratories, assisting innovation and improvement.
- Architectural and Structural Applications
- Common in buildings, facades, and precast structures where reliable material properties impact both aesthetics and longevity.
- Teaching and Training
- Serves as an instructional reference in academic and vocational settings focused on advanced concrete technology.
Related Standards
To ensure comprehensive testing and specification for glass-fiber reinforced concrete and consolidated construction materials, these documents are often referenced alongside ASTM C948-81(2023):
- ASTM C150 / C150M - Standard Specification for Portland Cement
- ASTM C1185 - Standard Test Methods for Sampling and Testing Non-Asbestos Fiber-Cement Flat Sheet, Roofing, and Siding Shingles
- ASTM C1186 - Standard Specification for Flat Fiber-Cement Sheets
- ASTM C495 - Standard Test Method for Compressive Strength of Lightweight Insulating Concrete
- ASTM C496 - Standard Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens
Practical Value
Implementing ASTM C948-81(2023) enhances confidence in GFRC product quality and performance. By using standardized test methods, manufacturers and specifiers can compare results across projects, maintain compliance with regulatory and contractual requirements, and support ongoing development of innovative GFRC solutions. The standard’s rigorous methodology provides actionable data for durability assessment and helps prevent failures related to excessive water absorption and insufficient density in construction elements.
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ASTM C948-81(2023) - Standard Test Method for Dry and Wet Bulk Density, Water Absorption, and Apparent Porosity of Thin Sections of Glass-Fiber Reinforced Concrete
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Frequently Asked Questions
ASTM C948-81(2023) is a standard published by ASTM International. Its full title is "Standard Test Method for Dry and Wet Bulk Density, Water Absorption, and Apparent Porosity of Thin Sections of Glass-Fiber Reinforced Concrete". This standard covers: SIGNIFICANCE AND USE 2.1 Material properties determined by this test method are useful for quality control of glass-fiber reinforced concrete, ascertaining compliance with governing specifications, and research and development. SCOPE 1.1 This test method covers the determinations of dry and wet bulk density, water absorption, and apparent porosity of thin sections of glass-fiber reinforced concrete. Note 1: This test method does not involve a determination of absolute specific gravity. Therefore, such pore space as may be present in the specimen that is not emptied during the specified drying or is not filled with water during the specified immersion is considered “impermeable” and is not differentiated from the solid portion of the specimen for the calculations, especially those for percent voids. Depending upon the pore size distribution and the pore entry radii of the specimen and on the purposes for which the test results are desired, the procedures of this method may be adequate, or they may be insufficiently rigorous. In the event that it is desired to fill more of the pores than will be filled by immersion, various techniques involving the use of vacuum treatment or increased pressure may be used. If a rigorous measure of total pore space is desired, this can only be obtained by determining absolute specific gravity by first reducing the sample to discrete particles, each of which is sufficiently small so that no impermeable space can exist within any of the particles. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
SIGNIFICANCE AND USE 2.1 Material properties determined by this test method are useful for quality control of glass-fiber reinforced concrete, ascertaining compliance with governing specifications, and research and development. SCOPE 1.1 This test method covers the determinations of dry and wet bulk density, water absorption, and apparent porosity of thin sections of glass-fiber reinforced concrete. Note 1: This test method does not involve a determination of absolute specific gravity. Therefore, such pore space as may be present in the specimen that is not emptied during the specified drying or is not filled with water during the specified immersion is considered “impermeable” and is not differentiated from the solid portion of the specimen for the calculations, especially those for percent voids. Depending upon the pore size distribution and the pore entry radii of the specimen and on the purposes for which the test results are desired, the procedures of this method may be adequate, or they may be insufficiently rigorous. In the event that it is desired to fill more of the pores than will be filled by immersion, various techniques involving the use of vacuum treatment or increased pressure may be used. If a rigorous measure of total pore space is desired, this can only be obtained by determining absolute specific gravity by first reducing the sample to discrete particles, each of which is sufficiently small so that no impermeable space can exist within any of the particles. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
ASTM C948-81(2023) is classified under the following ICS (International Classification for Standards) categories: 91.100.30 - Concrete and concrete products. The ICS classification helps identify the subject area and facilitates finding related standards.
ASTM C948-81(2023) is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C948 − 81 (Reapproved 2023)
Standard Test Method for
Dry and Wet Bulk Density, Water Absorption, and Apparent
Porosity of Thin Sections of Glass-Fiber Reinforced
Concrete
This standard is issued under the fixed designation C948; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Significance and Use
2.1 Material properties determined by this test method are
1.1 This test method covers the determinations of dry and
useful for quality control of glass-fiber reinforced concrete,
wet bulk density, water absorption, and apparent porosity of
ascertaining compliance with governing specifications, and
thin sections of glass-fiber reinforced concrete.
research and development.
NOTE 1—This test method does not involve a determination of absolute
specific gravity. Therefore, such pore space as may be present in the
3. Apparatus
specimen that is not emptied during the specified drying or is not filled
with water during the specified immersion is considered “impermeable” 3.1 Balance, sensitive to 0.025 % of the mass of the
and is not differentiated from the solid portion of the specimen for the
specimen, suitable for determining the mass of the specimen in
calculations, especially those for percent voids.
water as well as in air.
Depending upon the pore size distribution and the pore entry radii of
the specimen and on the purposes for which the test results are desired, the 3.2 Container, suitable for immersing the specimen and
procedures of this method may be adequate, or they may be insufficiently
suitable wire for suspending the specimen in water.
rigorous. In the event that it is desired to fill more of the pores than will
be filled by immersion, various techniques involving the use of vacuum
4. Sampling
treatment or increased pressure may be used. If a rigorous measure of total
pore space is desired, this can only be obtained by determining absolute
4.1 Sampling method shall be in accordance with governing
specific gravity by first reducing the sample to discrete particles, each of
specifications.
which is sufficiently small so that no impermeable space can exist within
any of the particles.
5. Test Specimen
1.2 The values stated in inch-pound units are to be regarded
5.1 Whenever possible, the sample shall consist of indi-
as standard. The values given in parentheses are mathematical
vidual portions of glass-fiber reinforced concrete, each to be
conversions to SI units that are provided for information only
tested separately. The individual portions may be pieces of any
and are not considered standard.
desired shape or size, except that the volume of each portion
1.3 This standard does not purport to address all of the shall be not less than 25 cm (or 50 g nominal mass glass-fiber
safety concerns, if any, associated with its use. It is the reinforced concrete, approximately 1.7 oz, and shall not be
responsibility of the user of this standard to establish appro- greater than 650 cm or 1300 g nominal glass-fiber reinforced
priate safety, health, and environmental practices and deter- concrete, approximately 46 oz); and each portion shall be free
mine the applicability of regulatory limitations prior to use. of observable cracks, fissures, or shattered edges.
1.4 This international standard was developed in accor-
6. Procedure
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the 6.1 Immersed Mass and Saturated Surface—Dry Mass After
Development of International Standards, Guides and Recom-
Immersion:
mendations issued by the World Trade Organization Technical 6.1.1 Immerse the specimen in water at approximately 21°C
Barriers to Trade (TBT) Committee.
(70°F) for not less than 24 h and until two successive
determinations of mass of the surf
...




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