# MATERIAL TESTING Bulk Density (Unit Weight) and Voids in Aggregate

### Bulk Density (Unit Weight) and Voids in Aggregate

Standard AASHTO T 19-14 / ASTM C 29M-09

Bulk density and calculated voids between particles in fine, coarse, or mixed aggregates in a compacted or loose condition is determined based on AASHTO T 19-14/ASTM C 29M-09 test method. This test method is not applicable to aggregates exceeding 125 mm [5 in.] in nominal maximum size.

Bulk Density: Mass of a unit volume of bulk aggregate material, in which the volume includes the volume of the individual particles and the volume of the voids between the particles. Expressed in kg/m3 (lb/ft3).
Unit Weight: Mass per unit volume of aggregates or density.
Voids: The space between particles in an aggregate mass not occupied by solid mineral matter. It may be noted that, permeable or impermeable voids within particles, are not included in voids as determined by AASHTO T 19.
Three procedures are specified for the determination of bulk density;
• Shoveling procedure: used only when specifically stipulated
• Rodding procedure: for aggregates having a nominal maximum size of 37.5 mm [1½ in.] or less
• Jigging procedure: for aggregates having a nominal maximum size greater than 37.5 mm [1½ in.] and not exceeding 125 mm (5 in.).

Weigh Balance of sufficient capacity, readable to 0.1 percent of the sample mass, or better.

Tamping Rod - 16 mm (5/8 in.) dia., 600 mm (24 in.) long, rounded end.

Cylindrical Metal Measure of height approximately equal to the diameter, but in no case shall the height be less than 80 percent nor more than 150 percent of the diameter. The capacity of the measure shall conform to the limits in Table below for the relevant aggregate size to be tested.

Nominal Maximum Size, mm (in.) Capacity of Measure, L (ft3)
12.5 (½) 2.8 (1/10)
25.0 (1) 9.3 (1/3)
37.5 (1½) 14 (½)
75 (3) 28 (1)
100 (4) 70 (2½)
125 (5) 100 (3½)

Shovel/Scoop for filling the measure with aggregate

Calibration Equipment - Plate Glass, Grease, Thermometer.

1. Determine the mass of the plate glass and measure to the nearest 0.05 kg (0.1 lb) after applying a thin layer of grease on the rim of the measure.

2. Fill the measure with water that is at room temperature. Cover it with the plate glass in such a way as to eliminate bubbles and excess water. Determine the mass of the water, plate glass, and measure to the nearest 0.05 kg (0.1 lb).

3. Measure the temperature of the water to the nearest 0.5°C (1°F) and determine its density. Density (of water) to temperature correlation tables are provided in AASHTO T 19-14 / ASTM C 29M-09. The tables provide correlation temperatures for a range of 15.6°C (60°F) to 29.4°C (85°F). However, to avoid interpolation and to follow an established correlation, density (of water) to temperature correlation provided in ASTM D 854-14 (given below) has been adopted for calculations in this TransCalc tool.

$ρ w = 1 .00034038-(7 .77 × 10 − 6 ) × T − ( 4.95 × 10 − 6 ) × T 2$

where;
ρw=Density of water in g/mL,
T=Test temperature in °C.

4. Calculate the volume (V) or Factor (F) of the measure using the following equation.

$V = B − C D$

$F = D B − C$

where;
V = volume of the measure, m 3 (ft3);
B = mass of the water, plate glass, and measure, kg (lb);
C = mass of the plate glass and measure, kg (lb);
D = density of the water for the measured kg/m3 (lb/ft3); and
F = factor for the measure, 1/m3 (1/ft3).

## RODDING

Choose the weight measure appropriate for the size of aggregate to be tested and fill the measure one-third full and level the surface with the fingers. Rod the layer of aggregate with 25 strokes of the tamping rod. Rodding shall be evenly distributed over the surface. Next, fill the measure two-thirds full and again level and rod as described above. Finally, fill the measure to overflowing and rod again in the manner previously mentioned. Level the surface of the aggregate with the fingers or a straightedge. Levelling shall be done in such a way that any slight projections of the larger pieces of the coarse aggregate approximately balance the larger voids in the surface below the top of the measure.
Determine the mass of the measure plus contents, and the mass of the measure alone and record the values to the nearest 0.05 kg [0.1 lb].

## JIGGING

The measure is filled in three approximately equal layers, compacting each layer by placing the measure on a firm base, such as a cement-concrete floor. Raise the opposite sides of the measure alternately about 50 mm [2 in.], and allow the measure to drop to the floor. Compact each layer by dropping the measure 50 times in the manner described, 25 times on each side. Level the surface of the aggregate with the fingers or a straightedge in such a way that any slight projections of the larger pieces of the coarse aggregate approximately balance the larger voids in the surface below the top of the measure.
Determine the mass of the measure plus contents, and the mass of the measure alone. Record the values to the nearest 0.05 kg [0.1 lb].
The aggregate particles, by this procedure, will arrange themselves in a densely compacted condition.

## SHOVELLING

In this procedure, the measure is filled to overflowing by means of a shovel or scoop. The aggregate is discharged from a height not exceeding 50 mm [2 in.] above the top of the measure. Level the surface of the aggregate with the fingers or a straightedge in such a way that any slight projections of the larger pieces of the coarse aggregate approximately balance the larger voids in the surface below the top of the measure. Determine the mass of the measure plus contents, and the mass of the measure alone. Record the values to the nearest 0.05 kg (0.1 lb).

# Calculation:

1. Bulk density for the rodding, jigging, or shoveling procedure is calculated based on the following equation.

$M = ( G − T ) V M = ( G − T ) × F$ where:
M = bulk density of aggregate, kg/m3 (lb/ft3);
G = mass of aggregate plus the measure, kg (lb);
T = mass of the measure, kg (lb);
V = volume of measure, m3 (ft3); and
F = factor for measure, m-3 (ft-3).

2. Bulk Density in terms of saturated surface-dry (SSD) condition is calculated based on the following formula.

$M S S D = M [ 1 + A 100 ]$ where:
MSSD = bulk density in SSD condition, kg/m3 (lb/ft3); and
A = absorption, percent, determined in accordance with AASHTO T 84 or AASHTO T 85.

3. Void Content for the rodding, jigging, or shoveling procedure is calculated based on the following equation.

$v o i d s % = 100 [ ( S × W ) − M ] ( S × W )$ where:
M = bulk density of aggregate, kg/m3 (lb/ft3);
S = bulk specific gravity (dry basis) as determined in accordance with AASHTO T 84 or AASHTO T 85; and
W = density of water, 998 kg/m3 [62.3 lb/ft3].

Calibration of Measure

Please enter the temperature in °C.

Output:

Volume of Measure, m3:

Factor for the Measure, 1/m3:

Bulk Density and Voids in Aggregate

Please enter either Volume of Measure or Factor of Measure.

Please enter Bulk Specific Gravity (Dry basis) of the aggregate as determined in accordance with AASHTO T 84 or T 85.

Bulk Density and Voids in Aggregate: Results

Compaction Procedure:

Bulk Density of Aggregate, kg/m3:

Bulk Density of Aggregate in SSD condition, kg/m3:

Void Content, % Voids:

Report Section

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