EXPERIMENT NO. 4SPECIFIC GRAVITY AND ABSORPTION OF AGGREGATESOBJECTIVESTo determine the specific gravity and absorption of aggregates in accordance with ASTM C127 and C128.

DISCUSSION OF PRINCIPLESAn aggregate refers to any crushed rock product, plus some naturally fragmented materials such as river gravel and sand. Coarse aggregates is that which is larger than about 5 mm, and fine aggregate comprises particles from 5 mm down to 0.075 mm. Particles finer than 0.075 mm are referred to as filler, binder, or dust. The purpose of aggregates testing is to provide a basis for comparison with satisfactory or failed materials used in the past and also to ensure compliance with specification.Aggregate specific gravity test and absorption is a common test used to calculate the volume the aggregate particles (absolute volume) occupy in concrete in mixture proportioning.

PROCEDURESTick each step if it has been performed

A. Specific Gravity and Absorption of Fine Aggregates____1.1 Soak 1000 g of the sample in water for 2 hours. (Or test in the moist condition that it will be used in concrete.)____1.2 Spread sample on a flat surface.____1.3 Pour the excess water and bring the aggregate to a saturated surface dry condition by using forced air and a heat lamp.____1.4 Test for surface moisture of aggregates using the cone test for surface moisture.____1.4.1 Fill the cone fully with partially dry aggregate to overflowing in the cone____1.4.2 Lightly tamp in the aggregate with 25 drops of the tamper.____1.4.3 Remove the loose sand from the base.____1.4.4 Lift the cone.Note: Saturated surface dry condition is reached when the sample just slumps on removing the cone.____1.5 Weigh 500 g of the surface dry aggregates.____1.6 Partially fill the pycnometer with 100 mL of water.____1.7 Bring in the sand into the pycnometer.____1.8 Roll on the pycnometer with aggregates in a flat surface to remove its bubbles.____1.9 Place the pycnometer with aggregates in a water bath maintained at 20 C for about 1 hour.____1.10 Fill the pycnometer with water to 500 mL.____1.11 Mark and weigh the pycnometer.____1.12 Remove sample from pycnometer.____1.13 Dry to constant weight.____1.14 Determine the oven dry weight.

Calculations (fine aggregates)

Where:Wo = weight in air of oven-dry sampleW1 = weight in air of saturated surface-dry sampleW2 = weight of pycnometer filled with water to 500 mLW3 = weight of pycnometer-water-sample in bottle

B. Specific Gravity and Absorption of Coarse Aggregates

____2.1 Pass 5 kg of the sample through a 3/8 sieve, reject portion passing____2.2 Wash portion retained to remove dust or other coating____2.3 Soak in water at 20 C for 24 hours (or use in the moist condition that it will be used in concrete)Note: The sample you will use in this test have been dried and weighed. You will be provided with the oven dry weight. Be extremely careful not to lose any of the sample while determining the specific gravity.____2.4 Be sure the bucket of water below the scale is filled to overflowing.____2.5 Check the water temperature. It should be 73.4 +/- 3 F____2.6 Tare the scale with empty wire basket hanging in water.____2.7 Remove samples from water____2.8 Wipe all visible films of water with an absorbent cloth.Note: Sample is now in surface-dry condition.____2.9 Weigh surface-dry sample in air.____2.10 Place the sample in the wire basket.____2.11 Determine its weight in water.Note: Shake the container before weighing to ensure that all air has been removed.____2.12 Record the weight on your data sheet.

Calculations (coarse aggregates)

Where:Wo = weight in air of oven-dry sampleW1 = weight in air of saturated surface-dry sampleW2 = weight of flask filled with water to 500 mLW3 = weight of sample in wire basket in water

APPARATUS1. Pycnometer or volumetric flask2. Conical mold, 1-1/2 in. top diameter, 3-1/2 in. bottom diameter, 2-7/8 in height.3. Tamping rod, weighing 12 oz. with a flat circular tamping face 1 in. diameter4. Wire basket of no. 4 mesh5. Water bath6. Thermometer7. Balance beam and set of weights

SET UP OF APPARATUS

1 Tamping Rod 2 Volumetric Flask 3 Fine Aggregates

Fig. 4-1 Set up for determining the Specific Volume of Fine Aggregates

Engineering Materials and Testing Laboratory

Experiment No. 4

Specific Gravity and Absorption of Aggregates

Preliminary Data Sheet

Name: Festin, Daniel Joshua N.Date: May 26, 2015

Section: B3Group No.: 2

Fine Aggregates

Trial Number12

Weigh in air of oven-dry samplewo939939

Weight in air of saturated surface-dry samplew111841150

Weight of pycnometer filled with H2O to 500 mLw2835835

Weight of pycnometer-H2O-sample in bottlew318351835

Bulk specific gravity (dry)5.10336.26

Bulk specific gravity (SSD)6.43487.6667

Apparent specific gravity (SSD)-15.3934-15.3934

% absorption26.091622.4707

Coarse Aggregates

Trial Number12

Weigh in air of oven-dry samplewo992994

Weight in air of saturated surface-dry samplew110191031

Weight of flask with H2Ofilled to 500 mLw2835835

Weight of sample in wire basket in waterw318351835

Bulk specific gravity (dry)52.210532.0645

Bulk specific gravity (SSD)53.157933.2581

Apparent specific gravity (SSD)-124-171.8333

% absorption27.21773.7223

Assisted by:

Vergel S. RodriguezME-UTM EngineerApproved by:

Engr. F. GaleraInstructor

QUESTIONS1. Define Aggregates.

2. What is a fine aggregates?

3. What is a coarse aggregates?

4. What are the main functions of aggregates in concrete mixtures?

5. How important is the high absorption quality of the aggregates particularly in the design of concrete mix?

6. What is purpose of determining the specific gravity of the aggregates used in the concrete mixtures?

SAMPLE COMPUTATION (use another sheet of paper; engineering lettering)

DISCUSSION (use another sheet of paper; engineering lettering)

CONCLUSION (use another sheet of paper; engineering lettering)

RECOMMENDATION (use another sheet of paper; engineering lettering)

REFERENCES (use another sheet of paper; engineering lettering)

13 Festin, Daniel Joshua N.

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