ASTM C128

Full Name

ASTM C128 – Standard Test Method for Relative Density (Specific Gravity) and Absorption of Fine Aggregate

Scope

ASTM C128 covers the determination of the following properties for fine aggregate:

  • Relative density (specific gravity): the ratio of the mass of a unit volume of aggregate to the mass of an equal volume of water. It is expressed in three forms:
    1. Oven-dry (OD) relative density: after the aggregate is dried in an oven.
    2. Saturated-surface-dry (SSD) relative density: after the aggregate is soaked in water for a specific duration and the surface moisture is removed.
    3. Apparent relative density: pertains to the solid material of the aggregate particles, excluding the pore space within the particles that can be filled with water.
  • Absorption: the increase in the mass of aggregate due to water absorbed in the pore spaces within the particles.

The scope of ASTM C128 includes:

  • Materials: fine aggregate passing a 9.5mm (3/8 inch) sieve and retained on a 75µm (No. 200) sieve.
  • Test method:
    • A sample of aggregate is immersed in water for a specified period to fill the pores.
    • The mass of the sample is determined in both oven-dry and saturated-surface-dry conditions.
    • The volume of the sample is determined using a pycnometer or a volumetric flask.
    • The relative density and absorption are calculated based on these mass and volume measurements.
  • Significance:
    • These properties are crucial for concrete mix design, as they affect the water demand and volume relationships of the mix.
    • The relative density is used to calculate the voids in aggregate in ASTM C29.
    • The SSD relative density is used for computations when the aggregate is assumed to be in a saturated-surface-dry condition.
    • The OD relative density is used for computations when the aggregate is dry or assumed to be dry.

ASTM C128 is a companion standard to ASTM C127, which covers the same properties for coarse aggregates.

ASTM C128 Accredited Laboratory

Applied Testing & Geosciences, LLC is accredited for performing tests using the ASTM C128 standard.

Our laboratory offers precise and reliable ASTM C128 testing services. Our experienced technicians utilize modern equipment and adhere to strict quality control measures to deliver accurate results. By entrusting your fine aggregate testing to us, you can ensure the quality and performance of your concrete projects.

Contact us today to learn more about our testing capabilities and how we can support your construction needs.

Resources

Keywords

relative density; specific gravity; absorption; fine aggregate; oven-dry; saturated-surface-dry; apparent relative density; pycnometer; volumetric flask

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