217.01Description
This work shall consist of drying soils by uniformly mixing fly ash or lime with soil to aid in achieving the workability of soils as shown on the plans or as directed.
MATERIALS
217.02Materials
Materials shall be in acco rdance with the following: 10
Fly ash ......................................................................... 901.02 Lime ............................................................................ 913.04(b) Water ........................................................................... 913.01
Soils containing organic content greater than 6% by dry weight or having a maximum dry density of less than 95 pcf, or with soluble sulfate content greater than 1,000 ppm shall not be used. The maximum dry density shall be determined in accordance with AASHTO T 99, the organi c content shall be determined in accordance with AASHTO T 267, and the sulfate content shall be determined in 20 accordance with ITM 510.
CONSTRUCTION REQUIREMENTS
217.03Testing and Mix Design
The Contractor shall be responsible for all tests required to determine the chemical modifier type and the relationship between the soils, chemical modifier, and moisture content. The modifier selection, laboratory testing, and mix design shall be performed by a qualified geotechnical c onsultant in accordance with the Department’s Design Procedures for Soil Modification or Stabilization. 30
Chemical modifier, mix design, test results, and the geotechnical consultant recommendations shall be submitted to the Engineer and to the Department’s Geotechnical Engineering Division for approval at least three business days prior to 217.03
use. Fly ash and lime shall be selected from the Department’s QPLs of Pozzolan Sources and Soil Modifiers, respectively.
The quantity of chemical modifier may be adjusted for different soil types and moisture content.
217.04Storage and Handling
The chemical modifier shall be stored and handled in accordance with 215.04.
217.05Weather Limitations
The chemical soil treatment shall be performed when the soil has a minimum temperature of 35°F, measured 4 in. below the surface, and with the air temperature rising. The chemical modifier shall not be mixed with frozen soils or with soil containing frost. When the soil temperature is expected to fall below 35°F prior to the next lift being placed, chemically treated soils shall be protected from freezing by placing a minimum of 12 in. thick soil. 50
217.06Preparation of Soils
The preparation of the soil shall be in accordance with 215.06. The maximum loose lift shall be no more than 12 in.
217.07Spreading of Chemical Modifiers
The specified quantity of chemical modi fier shall be spread on the surface. The chemical modifier shall be distributed uniformly by a cyclone, screw-type, or pressure manifold type distributor. Where Type A-7 soils are encountered, the soil shall be scarified prior to spreading the chemical modifier. The chemical modifier shall not be 60 applied when wind conditions create problems in adjacent areas or create a hazard to traffic on any adjacent roadway. The spreading of the chemical modifier shall be limited to an amount which can be incorporated into the soil within the same work day. The chemical modifier spreading rate shall be adjusted to the current soil moisture content. If weather causes stoppage of work or exposes the chemical modifier to washing or blowing, additional chemical modifier may be spread when the work resumes. Any materials wasted or disturbed by the Contractor’s actions shall be repaired or replaced at no additional cost.
217.08Mixing 70
The chemical modifier, soil, and water when necessary, shall be thoroughly mixed by rotary speed mixers. The mixing shall continue until a homogenous layer of the required thickness has been obtained. One hundred percent of the material, exclusive of rock particles, shall pass a 1 in. (25 mm) sieve and at least 60% shall pass a No. 4 (4.75 mm) sieve. The mixing depth shall not exceed 12 in.
217.09Compaction
The moisture content of the mixture sha ll be at the optimum moisture content or above the optimum moisture content as dete rmined by the mix design in accordance with 215.03. Moisture content will be de termined in accordance with ITM 506. 80 217.04
Aeration or drying by further mixing may be done to obtain the required moisture content. Compaction of the mixture shall begin as soon as practical. Compaction shall be in accordance with 203 or 207.03, as applicable.
Acceptance of chemically modified soils will be performed on the finished grade with a Dynamic Cone Penetrometer, DCP, in accordance with ITM 509. The chemically treated soil lift shall meet the following requirements for compaction:
modification. 90
chemically treated soil for each two-lane pavement section.
for each two-lane pavement section.
lime soils mixing. A moisture test shall be performed if soil changes.
During embankment construction, placing of the second 12 in. lift is allowed when the first lift meets the blow counts requirements of 203.23. A third lift will not be allowed until the first lift complies with 217.09(a).
Construction traffic or equipment will be allowed after the minimum DCP blow count is obtained. Construction traffic or equipment shall be routed in one direction so that the chemically modified soil does not pump or rut.
217.10Method of Measurement
The accepted quantity for drying soils will be measured by the ton of chemical 110 modifier complete in place. Soils required to construct the fill will be measured in accordance with 203.
217.11Basis of Payment
The accepted quantity of chemically modified soils will be paid for by the ton of chemical modifier used for drying. Soils required to construct the fill will be paid for in accordance with 203.
Payment will be made under:
Pay Item Pay Unit Symbol
Drying Soils for Embankment ................................................... TON
The cost of performing the laboratory tests, providing a qualified geotechnical consultant, scarification of in-situ soil, spreading, pulverization, mixing of the 217.11
chemical modifier and soil, moisture compaction of the resultant mixture, shaping the grade, work required due to adjustments of modifier proportioning, correction of deficient areas, water required for the modification process, and all operations needed to meet the requirements of this specificatio n shall be included in the cost of the pay 130 item of this section.
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