SPECIFIC GRAVITY, VOID RATIO, POROSITY AND BULK DENSITY OF COARSE AND FINE AGGREGATES

 SPECIFIC GRAVITY, VOID RATIO, POROSITY, AND BULK DENSITY OF COARSE AND FINE AGGREGATES

(IS 2386 PART III-1963)

 AIM:

To Fine the specific gravity, void ratio, porosity, and bulk density of given coarse and fine aggregates as per IS 2386 PART III-1963.

 Instrument Required:

 10 Kg capacity balance with weights, cylindrical containers of 1 liter and 5-liter capacities, measuring jar of 1000ml capacity.

 INTRODUCTION:

The specific gravity of an aggregate is generally required for calculations in connection with cement concrete design work for the determination of moisture content and for the calculations of volume yield of concrete. The specific gravity also gives information on the quality and properties of aggregate. The specific gravity of an aggregate is considered to be a measure of the strength of the quality of the material. Stones having low specific gravity are generally weaker than those with higher specific gravity values. The bulk density of an aggregate is used for judging its quality by comparison with normal density for that type of aggregate. It is required for converting proportions by weight into proportions by volume and is used in calculating the percentage of voices in the aggregate.

एक स्पेसिफिक का विशिष्ट गुरुत्व आमतौर पर नमी की मात्रा के निर्धारण के लिए और कंक्रीट की मात्रा की उपज की गणना के लिए सीमेंट कंक्रीट डिजाइन के काम के संबंध में गणना के लिए आवश्यक है। विशिष्ट गुरुत्व कुल की गुणवत्ता और गुणों के बारे में भी जानकारी देता है। एक स्पेसिफिक के विशिष्ट गुरुत्व को सामग्री की गुणवत्ता की शक्ति का माप माना जाता है। कम विशिष्ट गुरुत्व वाले पत्थर आमतौर पर उच्च विशिष्ट गुरुत्व मूल्यों वाले लोगों की तुलना में कमजोर होते हैं। एक स्पेसिफिक के थोक घनत्व का उपयोग उस प्रकार के स्पेसिफिक के लिए सामान्य घनत्व के साथ तुलना करके इसकी गुणवत्ता को पहचानने के लिए किया जाता है। यह अनुपात द्वारा भार द्वारा अनुपात में परिवर्तित करने के लिए आवश्यक है और इसका उपयोग स्पेसिफिक में आवाज़ों के प्रतिशत की गणना करने में किया जाता है।

1. Specific gravity is the weight of aggregate relative to the weight of an equal volume of water.

2. Void ratio is the ratio of the volume of voids to the volume of solids in an aggregate.

3. Percentage of voids or porosity is the ratio of the volume of voids to the total volume of a    sample of an aggregate.

4. Bulk density or unit weight is the weight of material per unit volume.

 1.  Specific gravity पानी के बराबर मात्रा के वजन के सापेक्ष कुल का वजन है।

2.Void ratio एक कुल में ठोस की मात्रा के लिए voids की मात्रा का अनुपात है।

3. voids या porosity का प्रतिशत किसी समुच्चय के नमूने की कुल मात्रा के लिए voids की मात्रा का अनुपात है।

4. Bulk density या इकाई का वजन प्रति यूनिट आयतन का भार होता है।

PROCEDURE:       

  Coarse aggregate

1.         Find the weight of the empty container W1.

2.         Take coarse aggregate in the container up to approximately half of the container and find out the weight W2.

3.         Fill the container with water up to the level of the coarse aggregates so that all void space inside the aggregate is filled with water. Find its weight W3.

4.         Fill the container with water after emptying it from a mix of coarse aggregate and water.

5.         Water should be up to the mark, up to which coarse aggregate is filled. Find its weight W4.

6.         Repeat the same process for another trail by taking the aggregate upto the full of the container and by filling the water up to the same point.

1. खाली कंटेनर W1 का वजन ज्ञात करें।

2. लगभग आधे कंटेनर में कंटेनर में मोटे कुल ले लो और वजन W2 का पता लगाएं।

3. कंटेनर को मोटे एग्रीगेट के स्तर तक पानी से भरें ताकि एग्रीगेट के अंदर सभी शून्य स्थान पानी से भर जाए। इसका भार W3 ज्ञात कीजिए।

4. मोटे एग्रीगेट और पानी के मिश्रण से खाली करने के बाद कंटेनर को पानी से भरें।

5. पानी को निशान तक होना चाहिए, जिस पर मोटे एग्रीगेट भरे जाते हैं। इसका वजन W4 ज्ञात कीजिए।

6. कन्टेनर के पूर्ण भाग तक और उसी बिंदु तक पानी भरकर दूसरे निशान के लिए भी यही प्रक्रिया दोहराएं।

 OBSERVATIONS:

S. No			Trail 1	Trail 2
1.	Weight of empty container	W1
2.	Weight of container with material	W2
3.	Weight of container + material + water	W3
4.	Weight of container + water	W4

 i)                    Void ratio =  Vol. of Voids / Vol. of solids

W3 - W1 / ((W4 - W1)-(W3-W2))

ii)                  Porosity = Vol. of Voids / Total Vol. of aggregate *100

W3 - W2 / (W4 - W1) * 100

iii)                Specific gravity = W2 - W1 / ((W4 - W1) - (W3 - W2))

 

iv)                Bulk density = W2 - W1 / (W4 - W1)

 

Fine aggregate: Void Ratio and porosity

 1. Take 150 ml of dry sand (v1 ml) in clean measuring jar of 1000 ml capacity.

2. Add a measured quantity of 100 ml clean water to the above sample (v2 ml) i.e. v2=100 ml

3. Shake the jar thoroughly till all air bubbles are expelled.

4. Now note the readings against the top surface of water in the jar (V3 ml)

Void ratio = v1 + v2 - v3 / v3 - v2

Porosity = v1 + v2 - v3 / v1

। 1000 मिली क्षमता के जार को साफ करने के लिए 150 मिली सूखी रेत (v1 मिली) लें।

2. उपरोक्त नमूने (v2 ml) यानी v2 = 100 ml के लिए 100 मिली स्वच्छ पानी की मापी हुई मात्रा डालें

3. सभी हवा के बुलबुले निष्कासित होने तक जार को अच्छी तरह से हिलाएं।

4. अब जार में पानी की ऊपरी सतह (V3 मिली) के खिलाफ रीडिंग पर ध्यान दें।

The specific gravity of fine aggregates:

 1. Weigh the empty measuring jar of 1000 ml capacity = W1

2. Take the weight of an empty measuring jar with 150 ml of sand

1. 1000 मिलीलीटर की क्षमता = W1 की खाली माप जार का वजन

2. एक खाली मापने वाले जार का वजन 150 मिलीलीटर रेत के साथ लें

Empty jar + sand =W2

3. Take the weight of an empty measuring jar with 150 ml of sand and 100 ml of water

3. एक खाली मापने वाले जार का वजन 150 मिलीलीटर रेत और 100 मिलीलीटर पानी के साथ लें

Empty jar + sand + water = W3

4. Remove the mix of sand and water from the bottle and fill it with water up to volume V3 then

weigh it.

4. बोतल से रेत और पानी का मिश्रण निकालें और पानी के साथ इसे तब तक V3 तक भरें इसे तौलना।

Empty jar + water = W4

Specific gravity = Weight of solids / Volume of Solids

W2 - W1 / ((W4 - W1) - (W3 - W2))

 PRECAUTIONS:

 While filling the container with water in determining the void ratio and porosity of coarse aggregate care should be taken that water should not be in excess of the level of course aggregate.

 RESULT:

 1) Specific gravity of course aggregate.

 2) Void ratio of course aggregate.

 3) Porosity of coarse aggregate.

 4) Bulk density of course aggregate.

 5) Specific gravity of fine aggregate.

 6) Void ratio of the given fine aggregate.

 7) Porosity of the given fine aggregate.

 COMMENTS:

 

 

 

 

 

 

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PARTICLE SIZE DISTRIBUTION

(IS: 2386, PART-1 -1963)

OBJECT: To find fineness modulus of coarse and fine aggregate

Instruments: Sieves, Fine aggregate, coarse aggregate, and Weighing Machine.

 

THEORY:

This strategy decides the fineness modulus of solid fine total utilized in the assessment of normal and manual sands for Portland cement concrete. The standard meaning of fineness modulus is as per the following: An empirical factor obtained by adding the total percentages of a sample of the aggregate retained on each of a specified series of sieves and dividing the sum by 100. all in all a little worth showed a fine aggregate while a huge worth demonstrates a coarse aggregate. The limit for fine totals usually goes from 2.00 to 4.00 and for a coarse total from 6.50 to 8.00.

PROCEDURE:

Coarse aggregate:

1.          From the quartering, we take random 5kg aggregate size 20 mm

2.        Carry out sieving by hand, shake each sieve in order 75mm ,40mm, 20mm, 10mm, and No's 480, 240, 120, 60, 30, & 15 over a clean dry tray for a period not less than 2 min.

3.        The shaking is finished with a fluctuated movement in reverse and forward, left to right, round, clockwise, and anticlockwise and with continuous jostling. 

4.         so the material is continued moving over the sifter surface is regularly evolving ways. 

5.         Discover the weight held on each strainer taken all together.

Fine aggregate:

1.         From the quartering, we take a random 1kg fine aggregate 

2.         Arrange the sieves in order of No. 480, 240, 120, 60, 30 and 15 keeping sieve 480 at top and 15 at the bottom.

3.        Fix them in the strainer shaking machine with the container at the base and spread at the top. 

4.    Keep the sand in the top strainer no 480, do the sieving in the arrangement of sieves, and organized before for at the very least 10 minutes. 

5.       Discover the weight held in each strainer..

6.      Plot a chart of percent passing by weight versus strainer size, with the cutoff points determined in CSA standard A23.1 for fine and coarse total sizes superimposed.

 Coarse aggregate:      Wt. of coarse aggregate taken:                      Kgs.

S. No	Sieve size (mm)	Weight retained	% Weight retained	% weight passing	Cumulative %Weights retained
1	75
2	40
3	20
4	10
5	4.75
6	2.36

 

Fine aggregate:          Wt. of fine aggregate is taken:               Kgs

S. No	Sieve size	Weight retained	% Weight retained	% weight passing	Cumulative % Weights retained
1	4.75 mm
2	2.36 mm
3	1.18 mm
4	600 micron
5	425 micron
6	300 micron
7	150 micron
8	75 micron
9	Pan

 

CALCULATION-

·         Calculate the Fineness Modulus (FM) as the sum of the percents retained on the series of sieves divided by 100:

FM =        (∑Cumulative percent retained) / 100

 

Safeguards 

1. The Sample ought to be in air-dry condition, if not, might be dried at room temperature or by warming at a temperature of 1000-1100 C. 

2. Sieves ought to be dry and clean before use. 

3. Each sieve ought to be shaken for a period at the very least 2 min. 

4. Try not to compel the material through Sieves by hand pressure.

RESULT:

The fineness modulus of given fine aggregate:         

 The fineness modulus of given coarse aggregate:

  COMMENTS: Limits of fineness modulus of aggregates.

Maximum size of aggregate	Minimum retained	Maximum retained
Fine aggregate	2	3.5
Coarse aggregate	2	3.5
20 mm	6	6.9
40 mm	6.9	7.5
75 mm	7.5	8.0
150 mm	8.0	8.5

 

 

 

 

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