UNIVERSITY OF THE EAST – CALOOCAN

COLLEGE OF ENGINEERING

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CIVIL ENGINEERING DEPARTMENT

EXPERIMENT 1A

SPECIFIC GRAVITY AND ABSORPTION OF COARSE AGGREGATES

SUBMITTED BY:

Arcon, Michael Luis

Fontanilla, Patrick Kelly

Macasaquit, Kenneth

Manalili, Ferdinand Jr.

Castro, Christian

Pulanco, Michael Angelo

Reyes, Sean Drexxtler

SUBJECT AND SECTION:

NCE 414 – 3CE

SUBMITTED TO:

Engr. John Rei Gomez

I.       INTRODUCTION.. 1
SPECIFIC GRAVITY. 1
BULK DRY SPECIFIC GRAVITY. 1
BULK SSD SPECIFIC GRAVITY. 1
APPARENT SPECIFIC GRAVITY. 1
ABSORPTION.. 1
COURSE AGGREGATE (GRAVEL). 2
A. OBJECTIVES. 2
B. HYPOTHESIS. 2
II.           MATERIALS. 2
III.         METHODOLOGY. 2
IV.         COMPUTATION.. 3
V.          RESULT. 4
VI.         DISCUSSION.. 4
VII.        CONCLUSION.. 4
VIII.      BIBLIOGRAPHY. 4
IX.         APPENDICES. 5
A. APPARATUS. 5
B. DATA.. 5
C. DOCUMENTATION.. 6

EXPERIMENT 1A:

SPECIFIC GRAVITY AND ABSORPTION OF COARSE AGGREGATE

I.             INTRODUCTION

“Aggregates have different sizes and could be identify by sieve analysis. These sizes could be from a small as a dust or up to 2 in diameter or higher. Aggregate is divided into two groups, fine aggregate and course aggregate.” (Somayaji, 2001)

SPECIFIC GRAVITY

“Specific gravity is the ratio of the weight of a specimen with respect to the volume it occupies to the weight of water at the same temperature and volume as material” (Somayaji, 2001)

“Specific gravity is used to calculate the ratio of voids or pores to the solid volume of aggregates to be used in Portland Cement Concrete.” (AASHTO)

BULK DRY SPECIFIC GRAVITY

Bulk dry specific gravity is the ratio of the weight of dry aggregates alone to the weight of the water in an equal volume of the occupied space of the aggregates including the volume of its voids either permeable or not. (AASHTO)

BULK SSD SPECIFIC GRAVITY

The ratio of the weight of saturated aggregates, weight of the aggregates and weight of the water in permeable voids, to the weight of the water in an equal volume of the occupied space of the aggregates INCLUDING the volume of its voids either permeable or not. (AASHTO)

APPARENT SPECIFIC GRAVITY

The ratio of the weight of the dry aggregates alone to the weight of the water in an equal volume of the occupied space of the aggregates only, volume of permeable voids are NOT INCLUDED. (AASHTO)

ABSORPTION

“Water absorption is the capacity of a material to absorb water in its permeable voids. This is expressed as the ratio of the weight of the water found in permeable voids to the weight of the oven-dried material” (Somayaji, 2001)

Increase on the weight of the aggregates when its permeable pores or voids are filled with water. (AASHTO)

COURSE AGGREGATE (GRAVEL)

The following are the values of Specific Gravity and Absorption of gravel presented by AASHTO.

Bulk SG = 2.737

Bulk SSD SG = 2.756

Apparent SG = 2.790

Absorption = 0.693 %

The results of the test present relationship between Bulk Specific Gravity, Bulk Specific Gravity at SSD and Apparent Specific Gravity. Among the three, the bulk dry specific gravity will give the least value because it is the ratio of the weight of material to the weight of water in equal volume of material with its voids. While the bulk specific gravity at SSD is in between and the apparent specific gravity is the highest, because the weight of water taken is just in equal volume of the material only.  (AASHTO)

A.    OBJECTIVES

The experiment aims to measure the specific gravity and absorption of coarse aggregate, gravel.

B.    HYPOTHESIS

The bulk specific gravity is the least value, the apparent specific gravity is the highest value and the bulk specific gravity at SSD condition is in between the two. (AASHTO)

The bulk specific gravity of gravel will be at the range of 2.4 up to 2.9. (Nemati, 2015)

II.            MATERIALS

·         Specific Gravity Apparatus

·         Weighing Scale

·         Pale

·         Water

·         Course Aggregates

·         Cloth

·         Sieve No. 4

·         Tray

·         Container

·         Scoop

III.          METHODOLOGY

1.       Prepare at least 1 kg of coarse aggregates and soak it in the water for at least 24 hours.

2.       Collect the soaked course aggregates and properly sieve it using Sieve No. 4. Collect 1 kg of retained sample at Sieve No. 4.

3.       Wipe the sample using dry cloth then put it on the tray and cover it with wet cloth to prevent further air drying.

4.       Obtain the mass of the container to be used. Then transfer the sample from the tray to the container.

5.       Weigh the saturated surfaced dry (SSD) sample with the container.

6.       Tare scale the specific gravity apparatus with wire basket in the water. Remove the basket from the apparatus and put the SSD inside. Return the basket in the apparatus and make sure that the whole sample is submerged in the water.

7.       Record the submerged weight of the sample.

8.       Remove the sample from the basket and return it to the same container used before. Oven-dry the sample for 24 hours.

9.       After 24 hours, measure the weight of the oven-dried sample with container.

IV.          COMPUTATION

Specific Gravity and Absorption of Coarse Aggregates with accordance to ASTM C127

Where:

A = Dry weight

B = SSD weight

C = Submerged weight

V.           RESULT

The bulk specific gravity at dry condition, bulk specific gravity at SSD condition, apparent specific gravity and absorption of the tested coarse aggregate are 2.74, 2.78, 2.87, and 1.68%, respectively.

VI.          DISCUSSION

The result of bulk dry specific gravity of 2.74 means that in every 1 unit weight of water with respect to the volume of aggregates and its voids, there is a 2.74 unit weight of the aggregates.

In line with the result of the bulk SSD specific gravity compare to the bulk dry specific gravity, it means that in every 1 unit weight of the water with respect to the volume of aggregates and its voids, there is a 0.04 unit weight of water in the permeable voids of the aggregates.

The apparent specific gravity result shows that in 1 unit weight of water, there is 2.87 unit weight of aggregate.

The 1.68% absorption of the aggregates shows that if the given 1000 grams of aggregates are become saturated, the resulting weight will become 1016.8 grams.

The bulk dry specific gravity is the lowest at 2.74, the apparent specific gravity is the highest at 2.87 and the bulk SSD specific gravity is the intermediate at 2.78 which verify the statement from AASHTO.

The result is also valid because the computed values of specific gravity of gravel are in between the set range of 2.4 to 2.9.

VII.        CONCLUSION

The specific gravity of the gravel which are 2.74 for bulk dry specific gravity, 2.78 for bulk SSD specific gravity and 2.87 for apparent specific gravity was valid based on the “values presented ranges from 2.4 to 2.9.” (Nemati, 2015)

The bulk dry specific gravity was the smallest and the apparent specific gravity was the highest while the bulk SSD specific gravity was in the middle of the two.

VIII.       BIBLIOGRAPHY

AASHTO. (n.d.). Specific Gravity of Course Aggregate. Retrieved December 19, 2017, from www.in.gov

Nemati, K. (2015). Aggregates for Concrete. Retrieved December 19, 2017, from http://courses.washington.edu/cm425/aggregate.pdf

Somayaji, S. (2001). Civil Engineering Materials. Prentice-Hall, Inc.

IX.          APPENDICES

A.    APPARATUS

Figure 1. Specific Gravity Apparatus

B.    DATA

Table 1. Measured weight of gravel in different conditions

Course Aggregate

A

Dry weight

950.0 g

B

SSD weight

966.0 g

C

Submerged weight

619.0 g

Table 2. Computed values of specific gravity and absorption of gravel

Bulk Dry s.g

Bulk SSD s.g

Apparent s.g

Absorption (%)

2.74

2.78

2.87

1.68

C.    DOCUMENTATION

Figure 2. Measurement of the weight of the container to be used in the experiment

Figure 3. Gathering of 1kg of soaked coarse aggregates

Figure 4. Wiping of surfaces of coarse aggregates

Figure 5. Measurement of the weight of SSD sample with container

Figure 6. Measurement of the submerged weight of coarse aggregates

Figure 7. Drying of coarse aggregates into the oven

Figure 8. Measurement of the weight of dry coarse aggregates with container