ITEM 205 CHEMICALLY STABILIZED EMBANKMENT
205.05 Contractor Designed Chemically Stabilized Embankment
205.01 Description. This work consists of constructing a chemically stabilized embankment using the method specified, which will either be cement stabilized embankment (CSE) or lime stabilized embankment (LSE), including designing the percentage of chemical in the stabilized embankment.
The Contract Documents will contain an estimated quantity for the specified chemical for the project, based on using 4 percent for cement and 5 percent for hydrated lime, per dry unit weight of a soil weighing 110 pounds per cubic foot (1760 kg/m3).
205.02 Materials. When CSE is specified, furnish portland cement conforming to the requirements of 701.04.
When LSE is specified, furnish hydrated or quick lime conforming to 712.04.B.
Furnish suitable soil, from on or off the project site, conforming to Item 203.
205.03 Limitations. 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.
A. Spreading. Prepare a report denoting the type of equipment to be used, speed of the intended equipment usage, rate of application of the chemical, and calculations to produce the required percent chemical. Submit this report 2 workdays before the work for approval.
If a 205.05 Contractor Designed Chemically Stabilized Embankment is not specified, use the following spreading percentage for the specified chemical. This percentage is based on a dry unit weight of soil of 110 pounds per cubic foot (1760 kg/m3):
|
Cement |
4 percent |
|
Lime - Hydrated |
5 percent |
|
- Quick |
4 percent |
Spread the specified chemical uniformly on the subgrade 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 subgrade. Use a canvas shroud that surrounds the distribution bar and extends to the subgrade.
Minimize dusting when spreading the specified chemical.
Do not spread the specified chemical on standing water.
Do not apply the specified chemical if wind conditions are such that blowing cement or lime exceeds the limits in 107.19.
B. Mixing. Immediately after spreading the specified chemical, mix the soil and chemical by using an approved power driven rotary type mixer. If necessary, add water to bring the mixed material to above the following moisture contents, for the specified chemical:
|
Cement |
optimum |
|
Lime - Hydrated |
optimum |
|
- Quick |
3 percent over optimum |
Continue mixing until the specified 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 elect to use the spring tooth or disk harrow in place of the power-driven rotary-type mixer by modifying the procedure as follows:
1. Open the soil with a spring tooth or disc harrow before spreading.
2. Spread the specified chemical.
3. Use a minimum disc harrow coverage of ten in one direction and ten in the perpendicular direction to thoroughly incorporate the chemical into the soil. Continue mixing until all soil clods are less than 1 inch (25 mm) and the final mixture is a uniform color.
C. Compacting. The Department will perform the compaction testing according to Supplement 1015.
Construct and compact chemically stabilized embankment according to Item 203. The Engineer will use at least 98 percent of the maximum dry unit weight for acceptance of the chemically stabilized embankment compaction.
205.05 Contractor Designed Chemically Stabilized Embankment. When specified in the Contract Documents, design the percent of specified chemical in the soil according to 206.06.
205.06 Method of Measurement. The Department will measure Cement Stabilized Embankment or Lime 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 by the number of tons (metric tons) incorporated in the complete and accepted work.
The Department will measure Lime by the number of tons (metric tons) incorporated in the complete and accepted work. The contract quantities contain the amount of hydrated lime estimated to complete the work. When the Contractor uses quick lime, calculate the equivalent amount of hydrated lime incorporated in the completed and accepted work according to 206.07.
The Department will not measure Contractor Designated Chemically Stabilized Embankment.
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 one-third of the lump sum amount bid when the chemically stabilized embankment 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 moisture density curves of the chemically stabilized embankment are 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.
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 Embankment
(Cubic
Meter)
205 Cubic Yard Chemical
Mixture Stabilized Embankment
(Cubic
Meter)
205 Ton (Metric Ton) Cement
205 Ton (Metric Ton) Lime
205 Ton (Metric Ton) Lime
Kiln Dust
205 Lump Sum Contractor Designed Chemically Stabilized
Embankment