AGGREGATES - Materials for Civil and Construction Engineers - page 195

5.7 A sample of wet aggregate weighed 19.682 N. After drying this sample
in an oven it weighed 18.365 N. The absorption of this aggregate is
4.8%. Calculate the percent of free water in the original wet sample.
5.8 Samples of coarse aggregate from a stockpile are brought to the labo-
ratory for determination of specific gravities. The following weights
are found:
Mass of moist aggregate sample as brought to the laboratory:
5298 grams
Mass of oven dried aggregate: 5216 g
Mass of aggregates submerged in water: 3295 g
Mass of SSD (Saturated Surface Dry) Aggregate: 5227 g
Find
a. The aggregate bulk specific gravity
b. The aggregate apparent specific gravity
c. The moisture content of stockpile aggregate (report as a percent)
d. Absorption (report as percent)
5.9 Base course aggregate has a target dry density of 124.9 lb/cu ft in
place. It will be laid down and compacted in a rectangular street re-
pair area of The aggregate in the stockpile
contains 2.7 percent moisture. If the required compaction is 95 per-
cent of the target, how many tons of aggregate will be needed?
5.10. Calculate the percent voids between aggregate particles, which have
been compacted by rodding, if the dry-rodded unit weight is 88.0
lb/cu ft and the bulk dry specific gravity is 2.701.
5.11. Coarse aggregate is placed in a rigid bucket and rodded with a tamp-
ing rod to determine its unit weight. The following data are obtained:

1000 ft * 52 ft * 6 in.

1

2 ft 3

Volume of bucket =

Weight of empty bucket = 20.3 lb

Weight of bucket filled with dry rodded coarse
a. Calculate the dry-rodded unit weight
b. If the bulk dry specific gravity of the aggregate is 2.620, calculate
the percent voids between aggregate particles.
5.12 The following laboratory tests are performed on aggregate samples:
a. Specific gravity and absorption
b. Soundness
c. Sieve analysis test
What are the significance and use of each of these tests?
5.13 The specific gravity and absorption test (ASTM C128) was per-
formed on fine aggregate and the following data were obtained:
Mass of SSD
Mass of pycnometer with water
Mass of pycnometer with sand and
Mass of
Calculate the specific gravity values (dry bulk, SSD, and apparent)
and the absorption of the fine aggregate.

aggregate = 69.6 lb

sand = 500.0 g

only = 623.0 g

water = 938.2 g

dry sand = 495.5 g