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Download Proctor Compaction Test for Maximum Dry Density. What Is Compaction? Compaction is the process of increasing the bulk density of a soil or aggregate by

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  • Slide 1
  • Proctor Compaction Test for Maximum Dry Density
  • Slide 2
  • What Is Compaction? Compaction is the process of increasing the bulk density of a soil or aggregate by driving out air. Compaction is the process of increasing the bulk density of a soil or aggregate by driving out air.bulk densitybulk density For any soil, at a given compactive effort, the density obtained depends on the moisture content. For any soil, at a given compactive effort, the density obtained depends on the moisture content. For any soil, an optimum water content exists at which it will achieve its maximum density. For any soil, an optimum water content exists at which it will achieve its maximum density.
  • Slide 3
  • Soils are compacted for the following reasons: 1. To increase strength and stability 2. To decrease permeability 3. To enhance resistance to erosion 4. Decrease compressibility under load and minimize settlement
  • Slide 4
  • Common Equipment Shown: Sheepsfoot Sheepsfoot Padfoot Padfoot Vibratory Roller Vibratory Roller Grid Roller Grid Roller
  • Slide 5
  • Dynamic Compaction: Profile of Overlap
  • Slide 6
  • Definition: Maximum Dry Density The peak dry unit weight is called the "maximum dry density. The peak dry unit weight is called the "maximum dry density. The Optimum Water Content, w opt, is the water content at the soils maximum dry density. The Optimum Water Content, w opt, is the water content at the soils maximum dry density.
  • Slide 7
  • Achieving Maximum Compaction In The Field Proctor Compaction Test determines the optimum water content and maximum dry density of for a soil. Proctor Compaction Test determines the optimum water content and maximum dry density of for a soil. A required range for moisture is often specified by the engineer: A required range for moisture is often specified by the engineer: Ie, 3% below and 2% above optimum. Ie, 3% below and 2% above optimum. For example, if optimum water content is 16%, the acceptable range would be from 13% to 18%. For example, if optimum water content is 16%, the acceptable range would be from 13% to 18%. Percent compaction is also specified: Percent compaction is also specified: Meaning required percentage of max dry density Meaning required percentage of max dry density % Compaction = dry field / dry max
  • Slide 8
  • Dry Density Curve: Proctor Test
  • Slide 9
  • How Does A Contractor Modify Compaction in the Field? Adjust Water Content Adjust Water Content More Passes More Passes Thinner Lifts Thinner Lifts Bigger Rollers Bigger Rollers
  • Slide 10
  • Sand Cone Test Sand Cone Test Nuclear Densometer Nuclear Densometer How Do We Determine Actual Field Density?
  • Slide 11
  • Getting Back To The Proctor Compaction Test Test developed to help specify levels (%) compaction (1933). Test developed to help specify levels (%) compaction (1933). Ralph R. Proctor first defined this standard compaction test in Engineering News Record Ralph R. Proctor first defined this standard compaction test in Engineering News Record
  • Slide 12
  • Proctor Compaction Procedure Soil is air dried, pulverized Soil is air dried, pulverized & passed thru #4 sieve. & passed thru #4 sieve. Separated into 4 to 6 samples. Separated into 4 to 6 samples. Adjust the water content of each sample by adding water. Adjust the water content of each sample by adding water.
  • Slide 13
  • Using the proctor mould (1/30th cubic foot) place & compact soil in 3 layers. Using the proctor mould (1/30th cubic foot) place & compact soil in 3 layers. Each layer should receive 25 drops of the compaction hammer. Each layer should receive 25 drops of the compaction hammer. Proctor Compaction Procedure
  • Slide 14
  • After the last layer, use a straight edge to trim the excess soil leveling to the top of the mould.
  • Slide 15
  • Proctor Compaction Procedure Determine the weight of the mould with the compacted moist soil. Extrude from mould and collect a sample for water content determination. Repeat for each sample over a range of moisture contents.
  • Slide 16
  • Proctor Compaction Procedure After collecting all pertinent weights, calculate dry density and plot vs. water content After collecting all pertinent weights, calculate dry density and plot vs. water content
  • Slide 17
  • Typical Proctor Data 12 3 4 5 6 7 8 9 Mold (lbs) Mold + Wet Soil (lbs)Moist Soil (lbs) Moist Unit Wt. (pcf) Mass of Can (g) Mass Can + Moist Soil (g) Mass of Can + Dry Soil Moisture ContentDry Unit Wt. 9.3113.233.92117.6061.00273.50249.700.13104.43 9.2013.604.40132.0061.00280.00249.200.16113.44 9.3113.524.21126.3061.00242.90214.900.18106.86 9.3013.344.04121.2061.00306.70265.600.20100.93 9.2013.254.05121.5061.00222.60190.200.2597.14 9.3113.163.85115.5061.00212.20178.100.2989.45 (Line 3)/(1/30) (Line 4)/(1+Line 8)
  • Slide 18
  • Graph from Proctor Data
  • Slide 19
  • Achieving Maximum Compaction For any job requiring fill/compaction the engineer will specify the compaction requirements: For any job requiring fill/compaction the engineer will specify the compaction requirements: ODOT Roadway Embankment Requirements: Maximum Laboratory Dry Weight [lb/ft 3 ] Minimum Compaction Requirements in Percent of Laboratory Maximum 90 to 104.9102 105 to 119.9100 120 and higher98
  • Slide 20
  • Achieving Maximum Compaction Since the maximum dry density is material specific, Since the maximum dry density is material specific, AND AND Since material being hauled in may change from truck to truck, Since material being hauled in may change from truck to truck, It is necessary to verify the maximum dry density number for the material being placed. It is necessary to verify the maximum dry density number for the material being placed.
  • Slide 21
  • One-Point Proctor Thus, the one-point proctor is used to verify the maximum dry density of soils in the field. Thus, the one-point proctor is used to verify the maximum dry density of soils in the field. One proctor test is done to determine the wet density vs. moisture content. One proctor test is done to determine the wet density vs. moisture content. Then a family of curves is used to determine the maximum dry density. Then a family of curves is used to determine the maximum dry density.
  • Slide 22
  • ODOT Family of Curves
  • Slide 23
  • Percent Compaction Then, comparing the maximum dry density to the ACTUAL density being achieved (nuclear densometer), we can calculate % compaction. Then, comparing the maximum dry density to the ACTUAL density being achieved (nuclear densometer), we can calculate % compaction. % Compaction = dry field / dry max % Compaction = dry field / dry max

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