ASTM C948-81 (R2016) PDF Download

The ASTM C948-81 (R2016) standard is used to determine the dry and wet bulk density, water absorption, and apparent porosity of thin sections of glass-fiber reinforced concrete. These material properties are important for quality control, compliance with specifications, and research and development purposes.

It is worth noting that this test method does not involve a determination of absolute specific gravity. The pore space in the specimen that is not emptied during drying or not filled with water during immersion is considered "impermeable" and is not differentiated from the solid portion of the specimen in the calculations for percent voids. The adequacy of the procedures may depend on the pore size distribution and entry radii, as well as the intended use of the test results. Additional techniques involving vacuum treatment or increased pressure may be required to fill more of the pores if desired. For a rigorous measure of total pore space, absolute specific gravity needs to be determined by reducing the sample to discrete particles.