Date of Award
Master of Science in Civil Engineering (MS)
College, School or Department Name
Department of Civil and Environmental Engineering
Stanley J Vitton
Density is a basic property of a material that is equal to the objects mass divided by its volume. However the determination of an accurate density for some rock materials can difficult. This difficulty comes from many sources such as irregular volume, porosity, moisture content of the material, permeability of the material and the lack of a clear definition of density itself. This research investigated a common industry method used to determine the bulk density of rock core samples typically encountered in the mining industry. The main problem in determining the bulk density of rock core is obtaining an accurate estimate of the rock core’s total volume. The research investigated four common techniques used to measuring the bulk density of materials. The research also investigated the issue of moisture saturation into the rock core. This is an important parameter in the portioning of concrete mixes. This density is known as the saturated-surface-dry density.
Testing was completed using a suite of seven different kinds of rock that ranged from highly competent granite and dolomites to highly permeable sandstone and blast furnace slag that contained a large volume of internal pore space.
Four different methods commonly used in the aggregate and mining industries to determine the bulk density of materials were examined. These methods were the caliper method, instantaneous water immersion method, wax immersion method, and wax-shrink wrap immersion. Of the four methods tested the wax-immersion method was determined to be the most accurate method. This was due to the liquid waxes ability to closely mold into the surface pore of the sample which gives the most accurate estimate of the volume of the sample.
The particle density of the materials used in this research were determined using an automated helium gas pycnometer, which is considered an industry standard. The saturated-surface-dry density used in the aggregate industry is outlined in ASTM C127-07 (Standard Test Method for Density, Relative Density (Specific Gravity), and Absorption of Coarse Aggregate). Testing revealed that ASTM C127-07 does not accurately represent the particle density of the material due to the large surface pores where, mainly in the blast slag samples.
Crawford, Kacy Mackenzey, "DETERMINATION OF BULK DENSITY OF ROCK CORE USING STANDARD INDUSTRY METHODS", Master's report, Michigan Technological University, 2013.