Introduction of Modified Proctor Test
Important Point
Bearing capacity of the soil is one of the most important factors which should be considered during the construction of any structure or building.
Before starting construction it is necessary that the bearing capacity of the soil should be checked on the site.
In this article, you will get to know about the Modified Proctor Test and the difference between the Modified Proctor test and Standard Proctor test.
If the bearing capacity of the soil which is available on the site, is not as per the requirement then there are only two solutions.
The first solution is to construct the foundation at the greater depth so that the total load can transmit into the deep underground strata of the soil.
The second solution is to improve the bearing capacity of the soil by using various methods. Compaction of the soil is one of the most widely used methods for the improvement of soil bearing capacity.
Compaction of the soil is increasing the density of the soil by the application of Mechanical energy.
In the compaction process, the density of the soil is increased by reducing the air voids in the soil.
The Theory of compaction was firstly developed by the R. Proctor while building a dam in the United States of America.
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Purpose of Compaction
The Compaction of soil is done for the various purposes which are as follows
- The compaction of the soil is done to increase the density.
- Compaction process help to decrease the permeability of the soil.
- It will help to increase the shear strength of the soil and bearing capacity of the soil.
- It will reduce the settlement of the structure after the construction.
- Compaction also helps to reduce the danger of piping which is required for seepage control of the Dams.
- Compaction process to increase the resistance towards the erosion of soil.
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Modified Proctor Compaction Test
The Modified proctor test is widely used for the determination of the compaction of the different types of soils and their properties with a change in the water content.
The Modified proctor compaction test also determines the relationship between dry density and the water content of the soil.
The one of the main purpose of the process of compaction is to increase the shear stress of the soil by reducing its permeability and compressibility.
Modified proctor test is also known as heavy compaction test and widely used in situations where heavy compaction is needed.
Apparatus Required for the Modified Proctor Compaction Test
There are various Apparatus are required for performing the modified proctor compaction test are as follows.
- The cylindrical metal mould which is either 100 mm diameter and 1000 cubic cm volume or 150 mm diameter and mm 2250 cubic cm.
- Thermostatically controlled oven with the interior of non-coding material to maintain the temperature between 105-degree celsius and 110-degree celsius.
- The sample extruder which consists of Jack extruding compacted specimen from the mould.
- Sieves of 75 mm, 19 mm, 37.5 mm IS sieves.
- Balance of capacity 15 kg and sensitivity of 1 gram.
- Metal rammer and mixing tools.
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Modified Proctor Test Procedure
The step by step procedure of modified proctor test is as follows
Step 1. Take the representative sample of dried soil of about 5 kg.
Step 2. Sieve the sample properly through the 19 mm sieve.
Step 3. Add a suitable amount of water in the soil and mix it thoroughly.
Step 4. In case of sandy or gravel soil at about 3 % to 5 % of water and for cohesive soil such as clay soil ad 12% to 15% percent water in the soil.
Step 5. Take the weight of the mould with the base plate attached to the nearest one gram. Record the weight as W1.
Step 6. Attach the extension collar with the mould.
Step 7. Take the volume of the soil in the mould in each layer such that it’s compacted height is about one-third of the total height of mould.
Step 8. Compact the moist soil into the mould that different five layers which should be approximately equal.
Step 9. Each player should be compacted with 25 number of blows with the help of 9 kg rammer.
Step 10. The rammer should be a drop from the minimum height of 450 mm above the soil so that it should be compacted properly.
Step 11. After the completion of the compaction process remove the extension collar and level up the top of the mould properly with the help of straightedge.
Step 12. Take the weight of mould with the compacted soil to the nearest 1 gram and note it as W2.
Step 13. Remove the compacted soil from the mould and place it on the tray.
Step 14. Now take out a sample from that specimen for determining water content in that soil.
Step 15. Take a number of the result by adding an increment of water in the soil sample such as for the gravel and sandy soil add water 1% to 2%.
Step 16. For cohesive and clayey soils add water about 2% to 4%.
Step 17. The minimum 5 reading should be taken, then the graph is plotted between the dry density of the soil and moisture content.
Step 18. The graph will give the value of optimum moisture content at the maximum dry density.
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Calculations of Modified Proctor Test Procedure
Calculate the bulk density Yw in g /cm3 of each compacted specimen from the equation is as follows
Yw = (m2 – m1) / Vm
m1 = Weight of mould with the base plate.
m2 = Weight of mould with the compacted soil.
Vm = Volume of mould in cm3
Calculate the dry density Yd in g/cm3 from the equation are as follows
Yd = Yw / (1+W/100)
Ye = Bulk density
W = % of moisture content
- The percentage of the moisture content of the soil which is corresponding to the maximum dry density shall be reported as the optimum moisture content.
- The optimum moisture content of the soil is defined as the water content at which the soil can be compacted to the maximum dense state.
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Standard Proctor Test Procedure as Per Is Code: Is:2720
- Standard proctor test is also known as Light compaction Test. Standard proctor test is used to achieve controlled compaction of the soil in the field.
- Standard Proctor Test is used to determine the optimum moisture content at the maximum dry density. This test gives the relation between dry density and moisture content for the particular soil sample.
The step by step procedure of standard proctor test is as follows
- First, upon, take the sample of 16 kg of air-dried which passes through 20 mm IS sieve.
- Applied water to bring the water contains about 10 % which is less than the estimated optimum water content.
- Keep the soil sample in the airtight container for about 20 hours to ensure thorough mixing of the water with the soil.
- Divide the sample into the six equal parts and clean the mould and take the weight of it.
- Apply grease to the inside of the mould base plate and collar and assemble properly the mould and the Base plate together.
- Take one part of the sample and filled mould in three layers and apply 25 number of blows to each layer.
- The hammer which is used for blowing should weight 6 kg any two-beat drop from the height of 310 mm.
- Then scratch each layer with a spatula before putting in the next layer.
- Remove the collar and trim the compacted soil flush with the top of the mould with a straight edge.
- Take the weight of the mould with the soil to the nearest gram and extract the soil from the mould with the extruder.
- Cut the soil sample in the middle and take the represented you sample in the airtight container from the middle of the cut surface.
- Calculate the water container and bulk density.
- Then calculate the dry density using bulk density and water content values.
Standard Proctor Vs Modified Proctor
The difference between the standard proctor test and modified proctor test is as follows
| Sr.No. | Standard Proctor test | Modified Proctor test |
| 1 | The standard proctor test was developed by R.R Proctor | The modified proctor test was developed by the American Association of state highways. |
| 2 | The weight of rammer which is used in the standard proctor test is 2.6 kg | The weight of hammer which is used in the modified proctor test is 4.89 kg |
| 3 | Standard proctor test is also known as light compaction test. | The modified proctor test is also known as heavy compaction test. |
| 4 | In the standard proctor test the height of free fall of the rammer is 310 mm | In the modified proctor test the height of free fall is 450 mm. |
| 5 | In the standard proctor test the soil is compacted in the mould in three layers. | In the modified proctor test the soil is compacted in the mould in 5 layers. |
| 6 | The compactive effort of the standard proctor test is 592 kg/m3 | The compactive effort of the Modified Proctor test is 2700 kg/m3 |
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Modified Proctor Test
Modified Proctor Test is used to determine the compaction of different types of soil and the properties of soil with a change in moisture content; and the relationship between Dry Density and Moisture Content.
Standard Proctor Vs Modified Proctor
In Standard Proctor test soil sample is compacted in 3 layers whereas in the Modified Proctor Test soil sample is compacted in 5 layers. A higher value of dry density is obtained in the Modified Proctor test as compared to the Standard Proctor test.
Proctor Test of Soil
The Proctor compaction test is a laboratory method of experimentally determining the optimal moisture content at which a given soil type will become most dense and achieve its maximum dry density. This process is then repeated for various moisture contents and the dry densities are determined for each.
What Is Modified Proctor Test?
Modified Proctor Test is used to determine the compaction of different types of soil and the properties of soil with a change in moisture content; and the relationship between Dry Density and Moisture Content.
What Is Modified Proctor?
Modified Proctor Test is used to determine the compaction of different types of soil and the properties of soil with a change in moisture content; and the relationship between Dry Density and Moisture Content.
What Is the Standard Proctor?
Proctor, a student at the University of California, Berkeley, established a laboratory procedure that easily defines the practical maximum density of a soil sample along with the optimum moisture content needed to achieve that density.
Why Is the Standard Proctor Test Used?
Standard Proctor Test is used to determine the compaction of different types of soil and the properties of soil with a change in moisture content.
How Do You Do a Modified Proctor Test?
- Take about 4 kg of air-dried soil passing No. 4 sieve and mix it with an optimum quantity of water.
- Weigh the empty mold without a collar, with base plate attached.
- Place the mold With the collar attached on a solid base and compact the soil mass into the mold using standard compaction in five layers with 25 blows per layer; and with a 4.5 kg rammer dropping from a height of 45 cm. Take care to distribute the blows uniformly over the surface of each layer, and to let the rammer fall freely.
- Remove the collar carefully strike off the projected part of the compacted soil by steel straight edge. Then weigh the mold + soil.
- Extrude the compacted soil specimen from the mold and split it on a large tray. Take a sample for moisture content determination.
- Break-up the specimen to No.4 sieve size, and mix it with the remainder of the original sample. Add suitable increments of water, and mix thoroughly for at least six trials. Then repeat 3 to 5 steps for each trial.
- Draw compaction curve on a graph with dry density on ordinate and moisture contents on the x-axis. Maximum dry density shall be at the apex of the curve and optimum moisture content (OMC) at which maximum dry density is obtained.
Where Is Standard Proctor Test Used?
Standard Proctor Test is used to determine the compaction of different types of soil and the properties of soil with a change in moisture content. In this article, you’ll know Standard Compaction Proctor test in details from Apparatus, Theory, to Result and much more.
Procter Compaction Test
The Proctor compaction test consists of compacting soil samples at a given water content in a standard mould with standard compaction energy. The standard Proctor test uses a 4-inch-diameter mould with the compaction of three separate layers of soil using 25 blows by a 5.5 lb hammer falling 12 inches.
In the Proctor test, the soil is first air dried and and then separated into 4 to 6 samples. The water content of each sample is adjusted by adding water (3% – 5% increments or more depending on the type of the soil).
The soil is then placed and compacted in the Proctor compaction mould in three different layers where each layer receives 25 blows of the standard hamer. Before placing each new layer, the surface of the previous layers is scratched in order to ensure a uniform distribution of the compaction effects.
How Do You Do a Soil Proctor Test?
The soil is usually compacted into the mold to a certain amount of equal layers, each receiving a number of blows from a standard weighted hammer at a specified height. This process is then repeated for various moisture contents and the dry densities are determined for each.
Why Proctor Test Is Done?
The Proctor Compaction Test establishes the maximum unit weight that a particular type of soil can be compacted to using a controlled compactive force at an optimum water content.
How Do You Do a Soil Proctor Test?
The soil is usually compacted into the mold to a certain amount of equal layers, each receiving a number of blows from a standard weighted hammer at a specified height. This process is then repeated for various moisture contents and the dry densities are determined for each.
How Do You Test for Compaction?
The best way to test is to probe the soil with a compaction tester to a depth of 36″ to 48″. The testing rod should move down through the soil with steady, even pressure, Hard, compacted soils resist penetration with the rod. Often penetration abruptly stops at a fairly uniform depth across a field or landscape area.
What Is the Difference Between Standard Proctor Test and Modified Proctor Test?
In Standard Proctor test soil sample is compacted in 3 layers whereas in the Modified Proctor Test soil sample is compacted in 5 layers. A higher value of dry density is obtained in the Modified Proctor test as compared to the Standard Proctor test.
How Is Proctor Density Calculated?
The soil must be poured in three equal layers with each layer compacted uniformly by standard proctor hammer. … The weight of the soil sample is then divided by the standard volume of the mold for determination of wet or bulk density. By using the moisture content, the dry density can be calculated.
What Is the Aim of Proctor Compaction Test of Soil?
The Proctor compaction test is a laboratory geotechnical testing method used to determine the soil compaction properties, specifically, to determine the optimal water content at which soil can reach its maximum dry density.
How Is Soil Compaction Test Calculated?
The percent compaction for the field density test is calculated by dividing the dry density of the soil by the maximum dry density from the proctor test.
What Is a Standard Proctor?
The standard Proctor is a laboratory test performed in order to determine the maximum dry density and optimum moisture content of a given soil. This test usually conforms to ASTM D698. The modified Proctor (ASTM D1557) is a different, but similar, laboratory test used for the same thing.
Where Is Standard Proctor Test Used?
Standard Proctor Test is used to determine the compaction of different types of soil and the properties of soil with a change in moisture content.
How Is Compaction Factor Calculated?
By dividing the value of partially compacted concrete by the value of fully compacted concrete, the compaction factor is calculated and to the nearest second decimal place, it shall normally be stated.
Which Equipment Is Used in Proctor Test?
Cylindrical Metal Mold, having internal diameter 4” (10.16 cm) or 6” (15.24 cm), the internal effective height of 4.6” (11.7 cm); and the mold should have detachable base plate & collar of 2 inches (5.08 cm).
How Many Types of Compaction Tests Are There?
The most commonly used laboratory test is called the Proctor compaction test and there are two different methods in obtaining the maximum density. They are the standard Proctor and modified Proctor tests; the modified Proctor is more commonly used. For small dams, the standard Proctor may still be the reference.
What for a Proctor Needle Is Used?
Proctor needles are used for quick evaluation of maximum soil density in the field. Standard Compaction curves showing moisture contents versus densities are drawn in laboratory using standard compaction method and penetration of the proctor needles are correlated.
What Is Difference Between Compaction and Consolidation?
Compaction is a process where a mechanical pressure is used to compress the soil mass for the purpose of soil improvement. Consolidation is a process where steady and static pressure causes compression of saturated soil.
What Is Compaction in Soil Mechanics?
Soil compaction is the practice of applying mechanical compactive effort to densify a soil by reducing the void space between soil particles. Compaction occurs when particles are pressed together to reduce the space between them. Highly compacted soils contain very few spaces resulting in soil with higher unit weight.
What Is Standard Proctor Compaction Test?
The Proctor Compaction Test establishes the maximum unit weight that a particular type of soil can be compacted to using a controlled compactive force at an optimum water content. In-place measured densities of the compacted fill are compared to the Proctor test results to determine the degree of soil density.
What Is the Purpose of Standard Proctor Test?
Standard Proctor Test is used to determine the compaction of different types of soil and the properties of soil with a change in moisture content.
What Does It Mean by 95% Compaction?
For example, specifications often require compaction to be 95 percent of Standard Proctor. This means the on-site soil density must be equal to 95% of the maximum achievable compaction. • Compaction is achieved by applying three basic types of force to the soil mass.
What Are the Practical Applications of Standard Proctor Compaction Test?
Standard Proctor Test is used to determine the compaction of different types of soil and the properties of soil with a change in moisture content.
What Is the Free Fall Height in a Standard Proctor Test?
In the Standard Proctor Test, the soil is compacted by a 5.5-lb hammer falling a distance of 1 foot into a soil-filled mold. The mold is filled with three equal layers of soil, and each layer is subjected to 25 drops of the hammer.
What Is the Best Soil for Compaction?
Cohesive (clay), granular (sand) and organic (for planting) are the three basic soil groups, but only two of these—cohesive and granular—are suitable for compaction. Cohesive soils have particles that stick together, while granular soils crumble easily.
How Do You Calculate Volume of Proctor Mold?
γm = (W2-W1)/V. Vm = Volume of mould i.e. 1000 cm3. Dry density, γd in g/cm3 of each compacted specimen is calculated from the following equation.
Which Parameters Information Can Be Known from Standard Proctor Test?
The two parameters involved in the compaction process are water content and dry density of the soil. The relationship between the amount of water used and the resulting dry density is rather straightforward. Water acts as a lubricant and orients the soil grains into a densely packed state.
When Testing for Compaction What Is the Standard Proctor Test?
Modified Proctor or standard Proctor tests are performed and the optimum moisture content as well as the maximum dry density is determined from the compaction curves. At the same time and for each Proctor test, modulus tests are performed to obtain the lab soil modulus.
Why Do We Use Standard Proctor Test?
Standard proctor test is also known as Light compaction Test. Standard Proctor Test is used to determine the optimum moisture content at the maximum dry density. This test gives the relation between dry density and moisture content for the particular soil sample.
Standard Vs Modified Proctor
In Standard Proctor test soil sample is compacted in 3 layers whereas in the Modified Proctor Test soil sample is compacted in 5 layers. A higher value of dry density is obtained in the Modified Proctor test as compared to the Standard Proctor test.
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