Home / Test methods / ASTM C127
ASTM International · Aggregate · Laboratory test
ASTM C127: Relative Density (Specific Gravity) and Absorption of Coarse Aggregate
Bulk, SSD, and apparent specific gravity plus absorption of coarse aggregate — the properties every concrete and asphalt mix design is proportioned around.
| Designation | ASTM C127 |
| Setting | Laboratory |
| Service line | Construction Materials Testing |
Testing is performed to the current edition of ASTM C127 referenced by your project specification. This page is a plain-language overview, not a substitute for the published standard.
What the ASTM C127 test measures
ASTM C127 determines the relative density, commonly called specific gravity, and the absorption of coarse aggregate. Three specific gravities are reported: oven-dry bulk, saturated-surface-dry bulk, and apparent. Absorption is the water the aggregate takes into its pores, expressed as a percentage of dry mass.
Every concrete and asphalt mix design uses these values to convert the batch masses of aggregate into the volume they occupy, and absorption sets how much of the batch water disappears into the rock instead of hydrating cement.
How the ASTM C127 test works, step by step
A washed sample retained on the No. 4 sieve is oven dried, then soaked in water for a set period. The particles are rolled in a towel to remove surface water and weighed in the saturated-surface-dry condition. The sample is then weighed submerged in water in a wire basket, and finally oven dried and weighed again. The three masses give the three specific gravities and the absorption.
What the numbers mean
Most natural gravels and crushed limestones run 2.55 to 2.75 bulk SSD specific gravity with absorption between 0.5 and 2 percent. High absorption, above about 3 percent, points to porous or weathered rock and is often paired with poor freeze-thaw and soundness performance. A shift in specific gravity between deliveries shows up in concrete as yield problems under ASTM C138.
What can throw the result off
Judging the saturated-surface-dry point is the main source of operator variation. Over-drying pushes the result toward apparent specific gravity and under-drying toward a wet bulk value. Trapped air on the submerged sample and temperature differences between soak water and weighing water also matter.
How we help with ASTM C127 testing
We run C127 and C128 together on each aggregate source so mix designers receive a complete set of specific gravities and absorptions, and we keep source histories so a change at the quarry is visible against previous results.
FAQ
Common questions about ASTM C127
Which specific gravity does a mix design use?
Bulk SSD for concrete mix proportioning under ACI 211; bulk dry for asphalt volumetrics along with the effective specific gravity from the asphalt side.
How often should it be retested?
Whenever the source, ledge, or product changes, and at the frequency the specification sets for source qualification. Many specifications require it annually per source at minimum.
What does ASTM C127 cover?
ASTM C127, Relative Density (Specific Gravity) and Absorption of Coarse Aggregate. Bulk, SSD, and apparent specific gravity plus absorption of coarse aggregate — the properties every concrete and asphalt mix design is proportioned around.
Is ASTM C127 a field test or a laboratory test?
Laboratory. ASTM C127 is performed in the Sugar Land, Texas laboratory on samples or specimens delivered under chain of custody, or in a mobile laboratory mobilized to large projects.
Which certification qualifies a technician to run ASTM C127?
NICET Construction Materials Testing (Concrete) work elements cover ASTM C127. Technicians running it are trained and checked on this method under the laboratory quality system, with the training record on file.
Which tests are usually run with ASTM C127?
ASTM C29 (Aggregate Unit Weight & Voids), ASTM C117 (Minus No. 200 by Washing), ASTM C128 (Fine Aggregate Specific Gravity), ASTM C131 (LA Abrasion). A project specification usually calls for them together, and one technician visit or one laboratory sample covers the set.
How do I schedule ASTM C127 testing?
Call (346) 420-5425 for dispatch, or send the specification sections and quantities through the proposal request form for a written scope. Same-day or next-morning scheduling is typical in the Houston metro; other metros are scheduled through the nearest regional hub.
Scheduling & proposals
Need ASTM C127 testing?
Call to schedule a technician, or send project documents for a written proposal.