Comparative Study of Methods to Measure the Density of Cementitious Powders

The accurate measurement of the density of hydraulic cement plays an essential role in the determination of concrete mixture proportions. As more supplementary cementitious materials (SCM), such as fly ash and slag, or cement replacement materials, such as limestone and calcium carbonate, are used in blended cements, knowledge of the density of each powder or of the blended cement would allow a more accurate calculation of the proportions of a concrete mixture by volume instead of by mass. The current ASTM standard for measuring cement density is ASTM C188-14 "Test Method for Density of Hydraulic Cements," which utilizes a liquid displacement method to measure the volume of the cement. This paper examined advantageous modifications of the current ASTM test by alcohol substitutions for kerosene. In addition, a gas (helium) pycnometry method was evaluated as a possible alternative to the current standard. The described techniques were compared to determine the most precise and reproducible method for measuring the density of hydraulic cements and other powders.