ITEM 205 CHEMICALLY STABILIZED
EMBANKMENT
205.01
Description
205.02
Materials
205.03
Submittals
205.04
Construction
205.05 Mixture
Design for Chemically Stabilized Soils
205.06 Method
of Measurement
205.07 Basis of
Payment
205.01 Description. This work consists of
constructing a chemically stabilized embankment by mixing cement, lime, or lime
kiln dust into the embankment soil using the method for the specified chemical.
The
Contract Documents include an estimated quantity for the specified chemical.
205.02 Materials. Furnish materials conforming to:
Portland
cement....................................................... 701.04
Lime (quick
lime)................................................. 712.04.B
Lime kiln
dust...................................................... 712.04.C
Furnish
water conforming to 499.02. Furnish
suitable natural soil, from on or off the project site, conforming to 703.16 and 203.03.
205.03 Submittals. Submit, for the Engineer’s
acceptance, a report that lists the type of equipment to be used, speed of the
intended equipment usage, rate of application of the chemical, and calculations
that demonstrate how the required percentage of chemical will be applied.
Submit the report to the Engineer for acceptance at least 2 workdays before the
stabilization work begins.
If
the pay item for Mixture Design for Chemically Stabilized Soils is included in
the Contract Documents, prepare and submit reports according to Supplement
1120.
205.04 Construction. Perform chemically
stabilized embankment work when the air temperature is 40 °F (5 °C) or above
and when the soil is not frozen.
Do
not perform this work during wet or unsuitable weather.
Drain
and maintain the work according to 203.04.A.
A. Spreading. If the pay item for Mixture Design for Chemically
Stabilized Soils is not included in the Contract Documents, use the following
spreading percentage rate for the specified chemical. The percentage is based
on a dry density for soil of 110 pounds per cubic foot (1760 kg/m³):
Chemical |
Spreading Rate |
Cement |
6 % |
Lime |
5 % |
Lime Kiln Dust |
7 % |
Spread the chemical
uniformly on the surface using a mechanical spreader at the approved rate and
at a constant slow rate of speed.
Use a distribution bar
with a maximum height of 3 feet (1 meter) above the ground surface. Use a
canvas shroud that surrounds the distribution bar and extends to the ground
surface.
Minimize dusting when
spreading the chemical. Control dust according to 107.17. Do not spread chemical when
wind conditions create blowing dust that exceeds the limits in 107.19.
Do not spread the
chemical on standing water.
B. Mixing. Immediately after spreading
the chemical, mix the soil and chemical by using a power driven rotary type
mixer. If necessary, add water to bring the mixed material to at
least optimum moisture content for cement and lime kiln dust, and to at least 3
percent above optimum moisture content for lime. Continue mixing until
the chemical is thoroughly incorporated into the soil, all soil clods are
reduced to a maximum size of 2 inches (50 mm), and the mixture is a uniform
color.
For areas not under
pavements or paved shoulders, the Contractor may use a spring tooth or disk
harrow in place of the power-driven rotary type mixer by modifying the above
procedure as follows:
1.
Open the soil with a spring tooth or disc harrow before spreading.
2.
Spread the chemical.
3.
Use a minimum disc harrow coverage of ten passes in
one direction and ten passes in the perpendicular direction to thoroughly
incorporate the chemical into the soil. Continue mixing until all soil
clods are reduced to a maximum size of 1 inch (25 mm) and the mixture is a
uniform color.
C. Compacting. Construct and compact
chemically stabilized embankment according to 203.07,
except use 98 percent of the maximum dry density for acceptance.
Determine the maximum
dry density for acceptance using the Ohio Typical Moisture Density Curves, the
moisture density curves from the Contractor’s mixture design submittal, or the
maximum dry density obtained by test section method.
205.05 Mixture Design for Chemically Stabilized Soils. When
included in the plans, perform a mixture design for chemically stabilized soils
according to Supplement
1120.
205.06 Method of Measurement. The
Department will measure chemically stabilized embankment by the number of cubic
yards (cubic meters) used in the complete and accepted work, as determined by
Item 203.
The
Department will measure cement, lime, and lime kiln dust by the number of tons
(metric tons) incorporated in the complete and accepted work.
205.07 Basis of Payment. The Department will pay
lump sum for all work, labor, and equipment described in 205.05. The Department will pay two-thirds of
the lump sum amount bid when the sampling and testing is complete and the
report is accepted by the Department. The Department will pay one-third of the
lump sum amount bid when the chemically stabilized embankment is completed and
accepted by the Department, and the field verification test results are all
submitted.
The
Department will pay for accepted quantities at the contract prices as follows:
Item
Unit
Description
205
Cubic
Yard
Cement Stabilized Embankment
(Cubic Meter)
205
Cubic
Yard
Lime Stabilized Embankment
(Cubic Meter)
205
Cubic
Yard
Lime Kiln Dust Stabilized
(Cubic
Meter)
Embankment
205
Ton (Metric
Ton) Cement
205
Ton (Metric
Ton) Lime
205
Ton (Metric
Ton) Lime
Kiln Dust
205
Lump
Sum
Mixture Design for Chemically
Stabilized Soils