Soundness

Soundness

Aggregate is considered to be unsound when volume changes in the aggregate induced by weather, such as alternate cycles of wetting and drying or freezing and thawing, result in concrete deterioration.

Bulk Density (ASTM C 29)

Defined as the mass per unit volume an aggregate including the volume of voids present in it. The typical bulk density used in making normal concrete ranges from 1200 to 1750 kg/m³.

§  The void contents range between 30% to 45% for coarse aggregate and 40% to 50% for fine aggregate. Void content increases with angularity and decreases with well graded aggregate.

Absolute Density

Defined as mass per unit volume of a material (aggregate) excluding the volume of voids.

For example if:

V_T = V_solid + V_voids=Total volume of the sample

V_void = Volume of the voids only

m = Mass of the sample

Then the absolute density p_abs would be:

p_abs = m/ V_solid whereas bulk density will be;

p_abs = m/ (V_solid + V_voids)

Relative Density

Defined as the ratio of the density of a material to the density of water.

Relative Density = Density of material / Density of water

Thus the value of relative density will be less than 1 if the material is lighter than water and will be greater than 1 if it’s heavier than water.