compaction factor
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Transcript of compaction factor
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Proctor Compaction Test
for Maximum Dry Density
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What Is Compaction?
Compaction is the process of increasing the bulkdensityof a soil or aggregate by driving out air.
For any soil, at a given compactive effort, thedensity obtained depends on the moisturecontent.
For any soil, an optimum water content existsat which it will achieve its maximum density.
http://en.wikipedia.org/wiki/Bulk_densityhttp://en.wikipedia.org/wiki/Bulk_densityhttp://en.wikipedia.org/wiki/Bulk_densityhttp://en.wikipedia.org/wiki/Bulk_density -
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Soils are compacted for the
following reasons:1. To increase strength and stability
2. To decrease permeability
3. To enhance resistance to erosion4. Decrease compressibility under load and
minimize settlement
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Common Equipment
Shown: Sheepsfoot Padfoot Vibratory Roller Grid Roller
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Definition: Maximum Dry Density
The peak dry unit weight is called the"maximum dry density.
The Optimum Water Content, wopt, is thewater content at the soils maximum drydensity.
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Dry Density Curve: Proctor Test
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How Does A Contractor Modify
Compaction in the Field?
Adjust Water Content
More Passes Thinner Lifts
Bigger Rollers
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Getting Back To The Proctor
Compaction Test
Test developed to helpspecify levels (%)compaction (1933).
Ralph R. Proctor firstdefined this standardcompaction test inEngineering News Record
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Proctor Compaction Procedure
Soil is air dried, pulverized& passed thru #4 sieve.
Separated into 4 to 6 samples.
Adjust the water content of each sample by addingwater.
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Using the proctor mould (1/30th cubic foot)place & compact soil in 3 layers.
Each layer should receive 25 drops of thecompaction hammer.
Proctor Compaction Procedure
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Proctor Compaction Procedure
After the last layer, use a straight edge totrim the excess soil leveling to the top ofthe mould.
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Proctor Compaction Procedure
Determine the weight of the mould withthe compacted moist soil.
Extrude from mould and collect a samplefor water content determination.
Repeat for each sample over a range ofmoisture contents.
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Proctor Compaction Procedure
After collecting allpertinent weights,calculate dry density
and plot vs. watercontent
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Typical Proctor Data
1 2 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
Content Dry Unit Wt.
9.31 13.23 3.92 117.60 61.00 273.50 249.70 0.13 104.43
9.20 13.60 4.40 132.00 61.00 280.00 249.20 0.16 113.44
9.31 13.52 4.21 126.30 61.00 242.90 214.90 0.18 106.86
9.30 13.34 4.04 121.20 61.00 306.70 265.60 0.20 100.93
9.20 13.25 4.05 121.50 61.00 222.60 190.20 0.25 97.14
9.31 13.16 3.85 115.50 61.00 212.20 178.10 0.29 89.45
(Line 3)/(1/30) (Line 4)/(1+Line 8)
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Graph from Proctor Data
80
85
90
95
100
105
110
115
120
0.00 0.10 0.20 0.30 0.40
D
ryDensity(pcf)
Water Content
Proctor Compaction Results
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Achieving Maximum
Compaction For any job requiring fill/compaction the engineer will
specify the compaction requirements:
ODOT Roadway Embankment Requirements:
Maximum Laboratory
Dry Weight
[lb/ft3]
Minimum Compaction
Requirements in Percent of
Laboratory Maximum
90 to 104.9 102
105 to 119.9 100
120 and higher 98
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Achieving Maximum
Compaction Since the maximum dry density is material
specific,
AND
Since material being hauled in maychange from truck to truck,
It is necessary to verify the maximum drydensity number for the material beingplaced.
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One-Point Proctor
Thus, the one-point proctor is used toverify the maximum dry density of soils inthe field.
One proctor test is done to determine thewet density vs. moisture content.
Then a family of curves is used todetermine the maximum dry density.
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ODOT Family of Curves
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Percent Compaction
Then, comparing the maximum drydensity to the ACTUAL density beingachieved (nuclear densometer), we can
calculate % compaction.
% Compaction = dry field/dry max