By: Sarchia Khursheed

1. 1
Soran University
Faculty of Engineering
Civil Engineering Department
Specific Gravity of Coarse
Aggregate
Student: Sarchia Khursheed
Group: 2
Experiment NO.: 2
Date: 4.11.2015
Supervisor: Arianfar Haji

2. 2
Introduction
The coarse aggregate specific gravity test is used to calculate the
specific gravity of a coarse aggregate sample by determining the ratio
of the weight of a given volume of aggregate to the weight of an equal
volume of water.
The coarse aggregate specific gravity test measures coarse aggregate
weight under three different sample conditions:
 Oven-dry (no water in sample).
 Saturated surface-dry (SSD, water fills the aggregate pores).
 Submerged in water (underwater).
Using these three weights and their relationships, a sample’s apparent
specific gravity, bulk specific gravity and bulk SSD specific gravity as
well as absorption can be calculated.
Aggregate specific gravity is needed to determine weight-to-volume
relationships and to calculate various volume-related quantities such
as voids in mineral aggregate (VMA), and voids filled by asphalt (VFA).
Absorption can be used as an indicator of aggregate durability as well
as the volume of asphalt binder it is likely to absorb.
Objective
To determine the specific gravity of given sample of coarse
aggregates.
Apparatus
 A balance or scale of capacity not less than 3 kg, readable and
accurate to 0.5 g and of such a type and shape as to permit the
basket containing the sample to be suspended from the beam
and the weighed in water.
 A well ventilated oven thermostatically controlled to maintain a
temperature of 100oC to 110oC.
 A wire basket of not more than 6.3 mm mesh or a perforated
container of convenient size.
 A stout water tight container of convenient size.
 A glass container

3. 3
 Two dry soft absorbent cloths each not less than 75×45 cm
 A shallow tray of area no less than 650 cm2
Materials
 Coarse aggregate
 Distilled water
Procedure
1. Obtain a sample of coarse aggregate material. This sample size
is based on nominal maximum aggregate size (NMAS).
2. Prepare the material.
 Wash the aggregate retained on the No. 4 (4.75 mm) sieve.
This discards small aggregate particles clinging to the retained
large particles.
 Dry the material until it maintains a constant mass. This
indicates that all the water has left the sample. Drying should
occur in an oven regulated at 110°C.
 Coolthe aggregate to a comfortable handling temperature.
 Immerse the aggregate in water at room temperature for a
period of 15 to 19 hours.
3. Dry the sample to a saturated suface dry (SSD) condition.
Rolling up the aggregate into the towel and then shaking and
rolling the aggregate from side to side is usually effective in
reducing the sample to a SSD condition. It may be necessary to
wipe the larger particles separately. Once there are no visible
signs of water film on the aggregate particle surfaces, determine
the sample mass.
4. Place the entire sample in a basket and weigh it underwater. The
basket should be pre-conditioned to the water bath temperature.
Shake the container to release any entrapped air before
weighing. The container overflow needs to work properly to
compensate for the water displaced by the sample.
5. Remove the aggregate from the water and dry it until it
maintains a constant mass. This indicates that all the water has

4. 4
left the sample. Drying should occur in an oven regulated at
110°C.
6. Cool the aggregate in air at room temperature for 1 to 3 hours
then determine the mass.
Data and Results
Weights
Groups
A B C D
1 306 g 1556 g 1856 g
2 351 g 1665 g 1886 g
3 325 g 1665 g 1870 g
A = Weight of aggregate in saturated surface dry condition (SSD), in
g.
B = Weight of glass container filled by water, in g.
C = Weight of glass container + aggregate sample + water, in g.
D = Weight of the oven dry aggregate in air (100 – 110 oC)
Calculations
Bulk specific gravity (SSD) =
𝐴
𝐴+𝐵−𝐶
=
351 𝑔
351 𝑔+1665𝑔−1886𝑔
= 2.7
Absorption (%) =
𝐴−𝐷
𝐷
× 100 =