CMT 1 (C127-07)

• The C127-07 is a test method covers the determination of the average density of a quantity of coarse aggregate particles (not including the volume of voids between the particles), the relative density (specific gravity), and the absorption of the coarse aggregate.
• The OD density and OD relative density are determined after drying the aggregate.
• The SSD density, SSD relative density, and absorption are determined after soaking the aggregate in water for a prescribed duration.
• C127-07 is a test method is used to determine the density of the essentially solid portion of a large number of aggregate particles and provides an average value representing the sample.
• Distinction is made between the density of aggregate particles as determined by this test method, and the bulk density of aggregates as determined by Test Method C 29/C 29M, which includes the volume of voids between the particles of aggregates
• C127-07 is a test method is not intended to be used with lightweight aggregates.
• C 29/C 29M - Test Method for Bulk Density (Unit Weight) and Voids in Aggregate
• C 125 - Terminology Relating to Concrete and Concrete Aggregates
• C 128 - Test Method for Density, Relative Density (Specific Gravity), and Absorption of Fine Aggregate
• C 136 - Test Method for Sieve Analysis of Fine and Coarse Aggregates
• C 566 - Test Method for Total Evaporable Moisture Content of Aggregate by Drying
• C 670 - Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• C 702 - Practice for Reducing Samples of Aggregate to Testing Size
• D 75 - Practice for Sampling Aggregates
• D 448 - Classification for Sizes of Aggregate for Road and Bridge Construction
• E 11 - Specification for Wire Cloth and Sieves for Testing Purposes
• AASHTO No. T 85 - Specific Gravity and Absorption of Coarse Aggregate
• absorption, n—the increase in mass of aggregate due to water penetration into the pores of the particles during a prescribed period of time, but not including water adhering to the outside surface of the particles, expressed as a percentage of the dry mass.
• oven-dry (OD), adj— related to aggregate particles, the condition in which the aggregates have been dried by heating in an oven at 110 ±5 °C for sufficient time to reach a constant mass.
• saturated-surface-dry (SSD), adj—related to aggregate particles, the condition in which the permeable pores of aggregate particle are filled with water to the extent achieved by submerging in water for the prescribed period of time, but without free water on the surface of the particles.
• density, n—the mass per unit volume of a material, expressed as kilograms per cubic metre (pounds per cubic foot).
• density (OD), n—the mass of oven dry aggregate per unit volume of aggregate particles, including the volume of permeable and impermeable pores within the particles, but not including the voids between the particles.
• density (SSD), n—the mass of saturated-surface-dry aggregate per unit volume of the aggregate particles, including the volume of impermeable pores and permeable, water-filled voidspores within the particles, but not including the poresvoids between the particles.
• apparent density, n—the mass per unit volume of the impermeable portion of the aggregate particles.
• relative density (specific gravity), n—the ratio of the density of a material to the density of distilled water at a stated temperature; the values are dimensionless.
• relative density (specific gravity) (OD), n—the ratio of the density (OD) of the aggregate to the density of distilled water at a stated temperature.
• relative density (specific gravity) (SSD), n—the ratio of the density (SSD) of the aggregate to the density of distilled water at a stated temperature.
• apparent relative density (apparent specific gravity), n—the ratio of the apparent density of aggregate to the density of distilled water at a stated temperature.
• A sample of aggregate is immersed in water for 24±4 h to essentially fill the pores.
• the volume of the sample is determined by the displacement of water method.
• Relative density (specific gravity) is the characteristic generally used for calculation of the volume occupied by the aggregate in various mixtures containing aggregate, including portland cement concrete, bituminous concrete, and other mixtures that are proportioned or analyzed on an absolute volume basis.
• Relative density (specific gravity) is also used in the computation of voids in aggregate in Test Method C 29/C 29M
• Relative density (specific gravity) (SSD) is used if the aggregate is wet, that is, if its absorption has been satisfied
• the relative density (specific gravity) (OD) is used for computations when the aggregate is dry or assumed to be dry
• Apparent density and apparent relative density (apparent specific gravity) pertain to the solid material making up the constituent particles not including the pore space within the particles which is accessible to water.
• Absorption values are used to calculate the change in the mass of an aggregate due to water absorbed in the pore spaces within the constituent particles, compared to the dry condition, when it is deemed that the aggregate has been in contact with water long enough to satisfy most of the absorption potential.
• Aggregates mined from below the water table commonly have a moisture content greater than the absorption determined by this test method, if used without opportunity to dry prior to use.
• some aggregates which have not been continuously maintained in a moist condition until used are likely to contain an amount of absorbed moisture less than the 24-h soaked condition.
• For an aggregate that has been in contact with water and that has free moisture on the particle surfaces, the percentage of free moisture is determined by deducting the absorption from the total moisture content determined by Test Method C 566.
• The general procedures described in this test method are suitable for determining the absorption of aggregates that have had conditioning other than the 24-h soak, such as boiling water or vacuum saturation