PAVEMENT DESIGN EXAMINATION REPORT

MODUL 9

SPECIFIC GRAVITY AND ABSORPTION OF COARSE AGGREGATE

GROUP 1A

Daniel Wibisana 1306437076

Sabrina Nurul Hidayah 1306437145

Raihan Alisha Nabila 1306437126

Rafitya Rahisa 1306437063

Jean-baptiste Davies 1506796580

Date of Experiment : November 15, 2015

Name of Assistant : Alfisahr Ferdian

Date of Approval :

Score :

Assistant Signature :

LABORATORIUM OF STRUCTURE AND MATERIAL

DEPARTMENT OF CIVIL ENGINEERING

ENGINEERING FACULTY

UNIVERSITAS INDONESIA

DEPOK 2015

J-09 SPECIFIC GRAVITY AND ABSORPTION OF COARSE AGGREGATE

(PB – 0202– 76)(AASHTO T – 85 – 81)(ASTM C – 127 – 04)

I. Objective

This examination is intended to determine the specific gravity (bulk), specific gravity of

saturated surface dry (SSD), the apparent specific gravity (apparent) of coarse aggregate

a) Density (bulk specific gravity) is the ratio between the aggregate weight of dried and

distilled water whose content is equal to the aggregate in the saturated state at a certain

temperature.

b) Weight of saturated surface dry (SSD), which is the ratio between the weight of saturated

surface dry aggregate and the weight of distilled water which content is equal to the

aggregate in the saturated state at a certain temperature.

c) Apparent specific gravity (apparent specific gravity) is the ratio between weight and dry

aggregate weight of distilled water with the same content with the content of the

aggregate in the dry state at a certain temperature.

d) Absorption is the percentage by weight of water that can be absorbed by the pores of the

weight of dry aggregate.

II. Apparatus

1. Wire basket size of 3.35 mm or 2.36 mm (6 or 8) with a capacity of approximately 5

kg.

2. Place water with capacity and form suitable for inspection. This place should be

equipped with a pipe so that the water level always remains.

3. Scales with a capacity of 5 kg and accuracy of 0.1% of the weight of the sample was

weighed and fitted with a basket hanger

4. Oven, equipped with temperature control to heat up (110 + 5) ° C

5. Separator sample

6. Sieve No. 4

III. Material

The test object is retained coarse aggregate sieve no.4 obtained from the separator sample or

how the quarter of approximately 10000 g (2 x 5000 grams).

IV. Procedure

1. Washing the specimen to remove any dust or other materials that glue on the surface.

2. Drying the specimen in an oven at 105 ° C until the weight remains.

3. Cooling the specimen at room temperature for 1-3 hours, then weighed to the nearest

0.5 gram (Bk).

4. Soaking the specimen in water at room temperature for 24 + 4 hours.

5. Removing the specimen from the water, wipe with an absorbent cloth until the water

on the membrane surface is lost (SSD condition), for which a large grain drying

should be one by one.

6. Weighing saturated surface dry test object (Bj).

7. Placing the specimen in the basket, roll the stone to remove the air and set the air

captive and determine its weight in water (Ba). Measure the water temperature to

adjust the calculation of the standard temperature (25 ° C).

V. Data Calculation

The equations below are needed to determine the weight for Bulk Specific Gravity,

Saturated Surface Dry, and Apparent Specific Gravity.

Weight of surface saturated specimen, Bj = 2567 gram Weight of wet specimen, Ba = 1568.5 gram Weight of oven dry specimen, Bk = 2500 gram

1. Bulk density (Bulk Specific Gravity) Bk

Bj−Ba= 2,500

2,567−1,568.5=2,50 4

2. Saturated surface dry density (SSD) Bj

Bj−Ba= 2,567

2,567−1,568.5=2 , 57 1

3. Apparent Specific Gravity Bk

Bk−Ba= 2,500

2,500−1,568.5=2,68 4

4. Absorption Percentage Bj−Bk

Bk×100 %=2,567−2,500

2,500× 100 %=2.68%

VI. Analysis

i. Experiment Analysis

The purpose of this experiment is to determine the specific gravity of bulk, saturated

surface dry and apparent specific gravity. First, the coarse aggregates are obtained

from aggregates retained by sieve no. 4. The amount of aggregate used in this

experiment is 2,500 grams. The specimen would have to be in oven dry condition, so

the specimen would be placed and heated in the oven first. After that, the specimen is

taken out and placed in a room temperature to cool for a couple of hours. Then using

a weight scale, the students take 2,500 grams of the specimen to be used for the whole

experiment. Now the weight of oven dry specimen is obtained. After that, the

specimen is soaked in water at room temperature for 24 hours. The specimen is

simply placed into a container and water is poured into the container until it is full.

On the next day, the water is removed from the container. The students have to be

careful during this process because some aggregates could also fall and be thrown out

with the water. Once the water is removed, the aggregates are wiped with a piece of

absorbent cloth to remove the water on the surfaces of the aggregates. This drying

process has to be done manually using hands. So only a couple of coarse aggregates

can be dried at one time. After the specimen is dry enough, the weight is measured

again as saturated surface dry specimen. Then finally, the specimen is placed in

another container with water. Shake the specimen so that no air is trapped, and

measure the weight once more. There are 3 weights obtained from this experiment

which are weight of specimen oven dry, saturated surface and wet. The data is

collected to be processed in the calculation.

ii. Result Analysis

By applying a variety of treatment to the sample, students are able to obtain various

data that will be used for data processing. The results of the data processing are very

influential on what students obtained from experiments. From the calculations, the

bulk of its specific gravity of 2.50, saturated surface dry density of 2.57, the apparent

specific gravity is 2.68, and the absorption of 2.68%.

iii. Error Analysis

In the lab the specific gravity and absorption of fine aggregate, there are some errors

that ultimately affect the acquisition of data. These errors include errors when

transferring aggregates. The smaller sized aggregates might fall to the ground or other

places, so it would affect the final weight of the aggregates. An error can occur while

measuring the aggregates because the scale reading is not accurate. During the

process of drying the aggregates by hands, some aggregates can be lost or fall during

the process, which would affect the weight and calculation also.

VII. Conclusion

From the experiments conducted, coarse aggregate used as the sample has the following

characteristics:

1. Bulk Specific Gravity of sample is 2.50

2. Saturated Surface Dry of sample is 2.57

3. Apparent Gravity Specific of sample is 2.8

4. The absorption of the sample is 2.68%

VIII. Reference

http://www.pavementinteractive.org/article/theoretical-maximum-specific-gravity/

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