Effect of Silt Content on the Strength Property of Concrete – A Case Study

Effect of Silt Content on the Strength Property of Concrete A Case Study

Effect of Silt Content on the Strength Property of Concrete A Case Study

1. Tauseef Bashir,

Student,

Department of structural engineering, Indo Global Group of Colleges Mohali, Punjab 140109

2 Manjit Kour Science

Assistant Professor, Department of Structural Engineering, Indo Global Group of Colleges Mohali,

Punjab 140109

Abstract – This project is robust with the effects of different quantities of silt content present in fine aggregates on the strength of concrete. The 3 days, 7 days, & 28 days compressive strength of concrete is checked. 36 samples were tested. For different tests such as compressive strength, split tensile strength, flexural strength on different shaped samples (cube, cylinder, & beam). Each 9 samples casted with different fine aggregates found in the river Jehlum at different locations namely, Qamarwari, Pampore, and Lasjan. Each sample is casted with design mix of M30 ratio.

INTRODUCTION

1. : SILT:

   Silt consists of small particles or grains of soil and minerals that are easily carried and deposited by water. Each particle is smaller than a grain of sand but larger than a clay particle. When heavy rains pound the soil some of these fine granular particles are carried by the runoff water as silt. Silt carried by water runoff is deposited in lowlands, rivers or ponds as sediment. The environmental impact of silt is enormous, as once it settles into a river or lowland it provides valuable nutrients for plants and insects in the sediment it creates.

   Silt carried down the Nile River, for example, created an oasis of rich, fertile soil for the ancient Egyptians. Silt is carried down the Mississippi and other rivers to the ocean where it also provides a rich habitat for plants and fish. But silt can also be a source of problems by clogging pipes and drains. When too much silt is dumped into waterways or rivers, it can become a pollutant known as siltation. This can cause a number of environmental problems, including killing fish by clogging their gills, and by reducing the water's dissolved oxygen level

2. : Properties and characteristics of Silt:

Silt is granular material of a size between sand and clay, whose mineral origin is quartz and feldspar. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water (also known as a suspended load) and soil in a body of water such as a river. It may also exist as soil deposited at the bottom of a water body, like mudflows from landslides. Silt has a

moderate specific area with a typically non-sticky, plastic feel. Silt usually has a floury feel when dry, and a slippery feel when wet. Silt can be visually observed with a hand lens.

Silt particles range between 0.0039 and 0.0625 mm, larger than clay but smaller than sand particles. ISO 14688 grades silts between 0.002 mm and 0.063 mm. In actuality, silt is chemically distinct from clay, and unlike clay, grains of silt are approximately the same size in all dimensions; furthermore, their size ranges overlap. Clays are formed from thin plate-shaped particles held together by electrostatic forces, so present cohesion. According to the U.S. Department of Agriculture Soil Texture Classification system, the sand-silt distinction is made at the

0.05 mm particle size. The USDA system has been adopted by the Food and Agriculture Organization (FAO). In the Unified Soil Classification System (USCS) and the AASHTO Soil Classification system, the sand-silt distinction is made at the 0.075 mm particle size (i.e., material passing the #200 sieve). Silts and clays are distinguished mechanically by their plasticity

1. Effects of silt on hardened concrete:

   Effect of silt fines on the durability properties of concrete. Silt fines are fine aggregate particles smaller than the 75 m (No. 200) sieve. … The compressive strength, however, when silt fine content is small than 5%, increases only 1 MPa. But decreases from 3 MPa to 5 MPa when the silt content increases from 7% to 9%…were cast and tested in this study. Moreover, chloride transport tests were conducted to investigate the properties of concrete. Test results indicate a decrease in durability when the ratio of silt content to fine aggregate exceeds 5%. The compressive strength, however, when silt fine content is small than 5%, increases only 1 MPa. But decreases from 3 MPa to 5 MPa when the silt content increases from 7% to 9%. These results could serve as a reference in concrete production as well as quality control of fine aggregate containing a large amount of silt fines.

   1. SOURCE OF MATERIALS AND TEST DATA

      S.No	Name of Materials	Source	Specific Gravity	Water Absorption (%)	Silt Content(%)
      1	Cement OPC 43 Brand TCI		3.15	–	–
      2	Coarse Aggregates (20.mm)	QAMARWARI	2.84	–	–
      3	Fine Aggregates	QAMARWARI, LASJAN, PAMPORE	2.64 2.64 2.64	7.5 4.17 2.5	6.65 4.65 4.8
      4	Water	1	–	–	–

   2. OBSERVATION AND CALCULATION OF SILT CONTENT AS PER IS 383 FOR QAMARWARI SAMPLE

      Description	Sample Numbers
      	Sample-1	Sample-2	Sample-2
      Volume of sample, V1 (ml)	75	75	75
      Volume of silt after 3 hours, V2(ml)	5	6	4
      % silt by volume =(V2/V1)*100	6.67	8	5.3

      Average of above three values =6.65%

   3. OBSERVATION AND CALCULATION OF SILT CONTENT FOR LASJAN SAMPLE AS PER IS 383

      Description	Sample Numbers
      	Sample-1	Sample-2	Sample-2
      Volume of sample, V1 (ml)	82	82	82
      Volume of silt after 3 hours, V2(ml)	3	5	4
      % silt by volume =(V2/V1)*100	3.4	5.8	4.8

      Average of above three values =4.65%

   4. OBSERVATION AND CALCULATION OF SILT CONTENT FOR PAMPORE SAMPLE AS PER IS 383

      Description	Sample Numbers
      	Sample-1	Sample-2	Sample-2
      Volume of sample, V1 (ml)	82	82	82
      Volume of silt after 3 hours, V2(ml)	5	4	3
      % silt by volume =(V2/V1)*100	6.0	4.8	3.6

      Average of above three values =4.8%

      1. Details of Lasjan Sample

   5. SAMPLE DETAILS

      Ingredients: Qantity

      Cement 23Kg

      Coarse Aggregates 74Kg

      Fine Aggregates 35Kg

      Water 9Kg

      Zone of Sand IV

      Silt Content 4.65%

      Water Content in Sand 4.17%

      1. Details of Pampore Sample

         Ingredients: Quantity

         Cement 22.97Kg

         Coarse Aggregates 70Kg

         Fine Aggregates 33.21Kg

         Water 9.45Kg

         Zone of Sand IV

         Silt Content 4.8%

         Water Content in Sand 4.8%

      2. Details of Qamarwari Sample

      Ingredients: Quantity

      Cement 22.97Kg

      Coarse Aggregates 70Kg

      Fine Aggregates 33.21Kg

      Water 7.45Kg

      Zone of Sand IV

      Silt Content 6.65%

      Water Content in Sand 7.5%

      1. Tests Performed

         • Compressive strength test

         • Split tensile test

         • Flexural strength test

      SPECIMEN USED, RESULTS AND DISCUSSION

      Compressive strength test

      1. cubes of 15 cm size Mix. M30 Split tensile test

         Concrete cylinder 15 cm diameter & 30cm long Flexural strength test

         Beam mould of size 15 x 15x 70 cm (when size of aggregate is less than 38 mm)

         8. RESULTS OF LASJAN SAMPLE

         The compressive strength, split tensile strength, flexural strength test of concrete with silt content of 4.65% is shown in this table of different specimen.

         Test date	CUBE(COMPRESSIVE STENGTH TEST) (N/ mm2 )	CYLINDER(SPLIT TENSILE TEST) (N/ mm2 )	BEAM(FLEXURAL STRENGTH TEST) (N/ mm2 )
         3-days	435	110	8
         7-days	480	160	13
         28-days	722	185	15

         The 3-days, 7days and 28 days compressive strength of lasjan sample is shown in the graph below:-

         Cube Compressive Strength of Lasjan Sample

         Compressive Strength (N/mm2)

         Compressive Strength Lasjan(N/mm2)

         800

         700

         600

         500

         400

         300

         200

         100

         0

         3-days 7-days 28-days

         Days

         Compressive Strength

         Lasjan

         The 3-days, 7days and 28 days Split Tensile Strength of lasjan sample is shown in the graph below:-

         Cylinder Split Tensile Strength of Lasjan Sample

         CYLINDER(SPLIT TENSILE TEST) (N/ mm2 )

         Split Tensile Strength(N/mm

         200

         180

         160

         140

         120

         100

         80

         60

         40

         20

         0

         3-days 7-days 28-days

         Days

         CYLINDER(SPLIT TENSILE TEST) (N/ mm2 )

         The 3-days, 7days and 28 days Flexural strength of lasjan sample is shown in the graph below:-

         Beam Flexural Strength of Lasjan Sample

         BEAM(FLEXURAL STRENGTH TEST) (N/

         mm2 )

         16

         Flexural Strength

         14

         12

         10

         8

         6

         4

         2

         0

         3-days 7-days 28-days

         Days

         BEAM(FLEXURAL STRENGTH TEST) (N/

         mm2 )

         1. DETAILS OF PAMPORE SAMPLE

            The compressive strength, split tensile strength, flexural strength test of concrete with silt content of 4.80% is shown in this table of different specimen.

            Test date	CUBE(COMPRESSIVE STENGTH TEST) (N/ mm2 )	CYLINDER(SPLIT TENSILE TEST) (N/ mm2 )	BEAM(FLEXURAL STRENGTH TEST) (N/ mm2 )
            3-days	420	80	7
            7-days	472	120	12
            28-days	705	150	14

            The 3-days, 7days and 28 days compressive strength of pampore sample is shown in the graph below:-

            Cube Compressive Strength of Pampore Sample

            Compressive Strength(N/mm

            Cube Compressive Strength Pampore(N/mm2)

            800

            700

            600

            500

            400

            300

            200

            100

            0

            3-days 7-days 28-days

            Days

            Cube Compressive Strength Pampore

            The 3-days, 7days and 28 days Split Tensile Strength of pampore sample is shown in the graph below:-

            Cylinder Split Tensile Test of Pampore Sample

            Cylindrical Split Tensile Test Pampore(N/mm2)

            160

            Tensile Strength(N/mm

            140

            120

            100

            80

            60

            40

            20

            0

            1. days 7-days 28-days

               Days

               Cylindrical Split Tensile Test Pampore

               The 3-days, 7days and 28 days Flexural strength of Pampore sample is shown in the graph below:-

               Beam Flexural Strength of Pampore Sample

               BEAM(FLEXURAL STRENGTH TEST)

               (N/ mm2 )

               16

               14

               Flexural Strength

               12

               10

               8

               6

               4

               2

               0

               3-days 7-days

               Days

               BEAM(FLEXURAL STRENGTH TEST) (N/

               mm2 )

               From above results it is observed that sand from pampore with silt content 4.80 %, compressive strength, split tensile strength, and flexural strength is increased as days of curing increased. If results are compared with sand from Lasjan with silt content (4.65%), it is observed that all strength is decreasing as slit content is increased.

         2. RESULTS OF QAMARWARI SAMPLE

The compressive strength, split tensile strength, flexural strength test of concrete with silt content of 6.65% is shown in this table of different specimen.

Test date	CUBE(COMPRESSIVE STENGTH TEST) (N/ mm2 )	CYLINDER(SPLIT TENSILE TEST)( N/ mm2 )	BEAM(FLEXURAL STRENGTH TEST)( N/ mm2 )
3-days	320	70	6
7-days	450	110	10
28-days	630	130	13

The 3-days, 7days and 28 days compressive strength of Qamarwari sample is shown in the graph below:-

400

300

200

Cube Compressive Strength

Qamarwari

100

0

Compressive Strength (N/mm2)

Cube compressive Strength of Qamarwari Sample

700

600

500

Cube Compressive Strength

Qamarwari(N/mm2)

3-days

7-days

28-days

Days

The 3-days, 7days and 28 days Split Tensile Strength of qamarwari sample is shown in the graph below:-

Cylinder Split Tensile Test of Qamarwari Sample

CYLINDER(SPLIT TENSILE TEST)( N/ mm2 )

Tensile Strength (N/mm2)

200

180

160

140

120

100

80

60

40

20

0

3-days 7-days 28-days

Days

CYLINDER(SPLIT TENSILE TEST)( N/ mm2 )

The 3-days, 7days and 28 days Flexural strength of Qamarwari sample is shown in the graph below:-

Beam Flexural Strength of Qamarwari Sample

BEAM(FLEXURAL STRENGTH TEST)(

Flexural Strength(N/mm2)

N/ mm2 )

14

12

10

8

6 BEAM(FLEXURAL

4 STRENGTH TEST)( N/

2 mm2 )

0

3-days 7-days 28-days

Days

From above results it is observed that sand from pampore, Lasjan and qamarwari with silt content 4.80 %, 4.65% and 6.65% compressive strength, split tensile strength, and flexural strength is increased as days of curing increased. If results are compared with sand from Lasjan with silt content (4.65%), it is observed that all strength is decreasing as slit content is increased.

• At the end, all the strengths are compared with each other .

In below graph comparison of compressive strength of sand from different location having different percentage of silt content are shown.

Compressive Strength of Three samples Take at Different Locations

800

700

Compressive Strength(N/mm2)

600

500

400

300

200

100

compressive strength of lasjan sample

compressive of Pampore sample

compressive strength of Qamarwari sample

0

3-days 7-days 28-days

No. of Days(curing)

In Below split tensile strength of all the samples taken from three different locations are compared with each other having different percentage of silt content.

Split Tensile Strength OF Three Samples Taken From Different Locations

200

Split Tensile Strength (N/mm2)

180

160

140

120

100

80

60

40

20

0

3-days 7-days 28-days

No. of Days(Curing)

Split Tensile Strength of Lasjan Sample

Split Tensile Strength of Pampore Sample

Split Tensile Strength of Qamarwari sample

In below Bar Chart flexural strength of all the samples taken from three different locations are compared with each other having different percentage of silt content .

Flexural Strength of Three Samples Taken From Different Locations

16

14

12

Flexural Strength (N/mm2)

10 Flexural Strength of Lasjan

sample

8 Flexural Strength of Pampore

6 Sample

Flexural Strength of Qamarwari

4 sample

2

0

3-days 7-days 28-days

No. of Days(Curing)

From above graphs, it is observed that all types of strengths are decreases as the silt content is increases.

CONCLUSION:

Based on the experimental investigations, the following conclusions were drawn.

1. The control mix for M30 grade with the varying quantity of silt content by 6.65%, 4.65%, & 4.80% were designed.

2. It is concluded that with the increase in 0.15% of silt content in fine aggregates, the compressive strength of concrete mixes decreases by 0.15%,0.08%,and 0.17% after 3,7 and 28 days respectively comparing Lasjan and Pampore samples.

3. It is concluded that with the increase in 1.85% of silt content in fine aggregates, the compressive strength of concrete mixes decreases by 1%, 0.22%, and 0.75% after 3,

   1. and 28 days respectively comparing pampore and qamarwari samples.

4. ) It is concluded that with the increase in 2% of silt content in fine aggregates, the compressive strength of concrete mixes decreases by 1.15%,0.30%,and 0.92% after 3,7 and 28 days respectively comparing Lasjan and Qamarwari samples.

5. ) It is concluded that with the increase in 0.15% of silt content in fine aggregates, the Split Tensile strength of concrete mixes decreases by 0.3%,0.40%,and 0.35% after 3,7 and 28 days respectively comparing Lasjan and Pampore samples.

6. It is concluded that with the increase in 1.85% of silt content in fine aggregates, the Split Tensile strength of concrete mixes decreases by 0.1%, 0.1%, and 0.2% after 3,

   7 and 28 days respectively comparing qamarwari and Pampore samples.

7. ) It is concluded that with the increase in 2% of silt content in fine aggregates, the compressive strength of concrete mixes decreases by 1.4%,0.5%,and 0.55% after 3,7 and 28 days respectively comparing Lasjan and Qamarwari samples.

8. ) It is concluded that with the increase in 0.15% of silt content in fine aggregates, the flexural strength of concrete mixes decreases by 0.01%,0.01%,and 0.01% after 3,7 and

   28 days respectively comparing Lasjan and pampore samples.

9. ) It is concluded that with the increase in 1,85% of silt content in fine aggregates, the compressive strength of concrete mixes decreases by 0.01%,0.02%,and 0.01% after 3,7 and 28 days respectively comparing pampore and Qamarwari samples.

10. ) It is concluded that with the increase in 2% of silt content in fine aggregates, the flexural strength of concrete mixes decreases by 1.02%,0.03%,and 0.02% after 3,7 and

28 days respectively comparing Lasjan and Qamarwari samples.

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