232.03 Construction Requirements.
mixing, and processing as required to incorporate the stabilizing material to the specified depth, to obtain and maintain the required grade, section, and density of the roadbed until covered by an overlying layer of ordered material and includes all equipment, tools, labor, and incidentals necessary to complete the work. The contract unit pric e for Stabilizing Roadbed with In -Place Material, shall be full compensation for all equipment, tools, labor, and incidentals required for mixing, and processing, as required to incorporate the stabilizing material to the specified depth. It shall also be full compensation for obtaining and maintaining the required grade, section, and density of the roadbed until covered by an overlying layer.
b.Payment will be made under Item No .: 231-A Roadbed Stabilizing Material, Type Material - per cubic yard {cubic meter} 231-B Roadbed Stabilizing Material, Type Material - per ton {metric ton} 231-C Stabilizing Roadbed with In -Place Material per Roadbed Station LIME STABILIZED ROADBED
232.01 Description.
This Section shall cover the work of preparing a roadbed for an overlying base and paving structure by stabilizing it with a lime treatment. The work shall consist of scarifying the roadbed, incorporation of lime, and the necessary p rocessing thereof in accordance with one of the following methods to the proper grade, section, and density. Class 1 Lime Stabilization shall consist of spreading and incorporating the specified percentage of lime in two increments in the following sequenc e: spreading the first increment, initial mixing, mellowing, spreading the second increment, final mixing, compacting, and finishing in accordance with these specifications. Mellowing is defined as the process of softening to a loamy consistency. Class 2 L ime Stabilization shall consist of spreading the specified percentage of lime, initial mixing, mellowing, final mixing, compacting, and finishing in accordance with these specifications. Class 3 Lime Stabilization shall consist of spreading the specified p ercentage of lime, mixing, compacting, and finishing in accordance with these specifications.
232.02 Materials.
All material furnished for use shall comply with the requirements of the appropriate Sections of
Division 800 — , Materials . Water shall meet the r equirements of Article 807.03; lime shall meet the
requirements of Section 817. The soil used in the stabilization shall consist of existing roadbed material or material added as directed. Particles of aggregate larger than those passing the 3 inch {75 mm } sieve, and deleterious substances such as roots, stumps, grass turfs, and other vegetable matter shall be removed from the soil.
232.03 Construction Requirements.
a.General . The basic requirement for work under this Section is to obtain a completed lay er or layers of roadbed material containing a uniform lime mixture, with a smooth, closely knit surface, free from cracks, loose or segregated areas, and constructed to the proper depth, width, and surface requirement as specified. Quantities and percentages of lime shown on the plans and proposal are based on preliminary soil investigation and dry laboratory sample tests. The actual application rate will be established from dry density tests made just prior to beginning stabilization work. The ini tial tests are based on Hydrated lime. If Quicklime is used and placed directly on the roadbed in pebble form, the percentage will be adjusted by the Engineer based on a factor of 0.833 times the hydrated lime percentage required. While either hydrated lim e or quicklime may be used on different segments of the project, a second application of lime must be of the same type used in the first application. It is necessary to the quality of lime treated materials that all such materials be kept moist at all times. It shall be the Contractor's responsibility to provide sufficient equipment and keep all partially constructed or completed lime stabilized layers sufficiently and continuously moist until a succeeding layer has been placed thereon or until final accept ance of the project.
232.03 Construction Requirements.
b.Equipment . Choice of equipment to perform the work required under this Section shall, in general, be that of the Contractor provided such produces the desired results.
c.Preparation of the Roadbed . The roadbed shall have been prepared in accordance with the provisions of Section 210. The roadbed shall be scarified to the depth required for the stabilization prior to the lime application. The depth of scarification shall be carefully controlled so that the surface of the roadbed below the scarified material shall remain undisturbed and conform to the established cross -section. The scarified material shall be partially pulverized and all existing unsuitable material and material retained on a 3 inch {75 mm} sieve shall be removed.
d.Application of Lime . The rate of application of lime shall be as specified by the Engineer. When the lime is to be placed in two applications as designated for Class 1 Lime Stabilization and the design percentage equals 5 %, 3 % shall be placed in the first application unless noted otherwise on the plans. When the lime is to be placed in two applications as designated for Class 1 Lime Stabilization and the design percentage equals 7 %, at least 3 % but not more than 3.5 % shall be placed in the first application unless noted otherwise on the plans. No lime shall be applied between October 1 and April 1 without written authorization of the Construction Engineer. Application of the lime shall be accomplished by either an approved "dry application" or "sl urry application" method. The slurry application method shall be used unless shown otherwise on the plans. "Dry Application" - Lime applied by this method shall be spread uniformly and shall be sprinkled with water sufficient to prevent loss of lime by win d. Spreading of the lime when wind and weather conditions are unfavorable will not be permitted nor will spreading of the lime by motor patrol be acceptable. "Slurry Application" - Lime applied by this method shall be mixed with water in approved agitating equipment and applied to the roadbed as a thin water suspension of slurry. The distributing equipment shall be equipped to provide continuous agitation from the mixing site until applied on the roadbed. The proportion of lime shall be such that the "Dry S olids Content" shall be at least 30 percent by weight {mass}. NOTE: When quicklime is used, it shall be turned under by an approved means prior to application of water so as to reduce the harmful exposure to the heat of hydration by the quicklime. The dist ribution of lime at the rate specified shall be attained by successive passes over a measured section until the specified percentage of lime has been spread. After each successive pass, the material shall be incorporated into the soil with the mixing equip ment. Additional water, if necessary, shall be added and mixed into the mass to hasten mellowing. Payment will not be made for any lime that has been spread and exposed before mixing for a period of six hours or more. Such areas shall be treated again with the full required rate of application. Additional lime shall be added at the Contractor's expense to any section on which excessive loss has occurred due to washing or blowing prior to mixing. The quantity of lime applied on any section shall be spread un iformly and shall not vary more than plus or minus five percent of the quantity ordered for that section. No payment will be made for lime application exceeding the five percent plus tolerance. When the quantity applied is deficient by more than the allowa ble minus tolerance, additional lime shall be applied prior to mixing.
e.Mixing .
1.Initial Mixing . The lime and water shall be incorporated uniformly into the soil. The mixing and watering operation shall be continued until a homogeneous mixture that will pass a 3 inch {75 mm} sieve is obtained. After satisfactory mixing is obtained, the layer shall be reshaped to approximate line, grade and section and sealed with a light roller, if mellowing is required. For Class 1 and 2 stabilization, the mixt ure shall be left to mellow for a minimum period of three days but not to exceed 21 days. During this period the entire surface of the stabilized layer shall be kept moist by sprinkling and at no time allowed to become dry or dusty. For Class 3 stabilizati on, the moisture content during the mixing operation shall not vary more than two percent, plus or minus, from the laboratory specified optimum moisture. After mixing this material shall be compacted and finished as specified in Subarticles (f) and (g) bel ow.
232.04 Me thod of Measurement.
2.Final Mixing. After the required mellowing period (Class 1 and 2), the layer shall be scarified and in the case of a Class 1 treatment, the second application of lime added. The layer shall then be remixed as prescribed in the initial mixing operati ons adding water. Mixing shall be continued until 100 percent of material by dry weight {mass}, exclusive of gravel and stone, will pass a 2 inch {50 mm} sieve and 60 percent will pass a Number 4 {4.75 mm} sieve. The percent moisture shall not vary more th an two percent, plus or minus, from the laboratory specified optimum moisture during this mixing operation. If mixing cannot be completed in the same day begun, the surface of the layer shall be sealed by rolling with a rubber -tired roller before suspendin g that day's operation and the processing continued the following day, weather conditions permitting.
f.Compaction . Compaction of the mixture shall begin immediately after the required mixing operation noted above has been completed. Compaction operations shall be completed within 72 hours after it was begun and so conducted as to provide uniform compaction from bottom to top of the layer. The mixture shall be aerated or watered as necessary to obtain the spec ified moisture content within two percent, plus or minus, of the laboratory specified optimum moisture. If compaction cannot be completed in the same day started, the surface shall be sealed by rolling with a rubber -tired roller before suspending that day's operation and the compaction continued the following day. Throughout the entire compaction operation, depressions, defective areas, or soft spots which develop shall be corrected immediately by scarifying the area, adding lime when required, or removing the material and reshaping and compacting in accordance with these specifications at the expense of the Contractor. Density requirements will be as specified in Section 306. Standard weights {masses} will be established on the project using material from t he completed mixture, as directed by the Materials and Tests Engineer. The standard weight {mass} sample will be obtained and the standard weight {mass} established the same working day as the compaction tests are run. If compaction cannot be obtained with in the 72 hour limit noted herein in this Subarticle, the section involved shall be reprocessed adding additional lime in the increment directed by the Engineer and the compaction operation restarted, all of which shall be at the sole expense of the Contra ctor.
g.Finish and Testing . The surface of the layer shall be smooth and conform to the lines, grades, and cross sections shown on the plans or established by the Engineer. Surface requirements shall be as specified in Subarticle 230.03(e). The thickness of the lime stabilized layer will be determined from measurements taken at intervals not to exceed 200 feet {60 m}. The thickness of the entire layer(s) shall not vary more than 1 inch {25 mm} plus or minus from that shown on the plans. Any section defici ent by more than 1 inch {25 mm} shall be reconstructed immediately in accordance with these specifications. Any section exceeding the 1 inch {25 mm} tolerance shall have additional lime added to correct the deficiency and shall be remixed to the specified depth and width in accordance with these specifications. In each case, such reconstruction and additional lime added shall be at the sole expense of the Contractor.
h.Protection, Curing and Maintenance . Upon completion of the compaction and finishing of each layer, no vehicles or equipment other than watering equipment shall be permitted on the finished layer for a period of seven days unless otherwise authorized. During this curing period, the surface of the layer shall be lightly watered at frequent int ervals to prevent drying. The Contractor may, on a layer to be covered by a conventional base or subbase layer, substitute at his expense an acceptable prime coat in lieu of watering during the curing period noted above. Regardless of the method of curing used, the Contractor shall be responsible for the protection and maintenance of the treated layer until it is covered by another layer or the completion of the project. Any damage to the treated layer due to other phases of construction or any cracking or other defects that may occur due to any cause or reason before being covered by the next layer shall be repaired without additional compensation.
232.04 Method of Measurement.
The actual area of the roadbed stabilized as ordered, for each specified compact ed depth, completed to the thickness and cross -section shown on the plans or directed, will be measured in square
232.05 Basis of Payment.
yards {square meters}. All calculations of areas measured for payment shall be based on measurements made to the nearest 0.1 yard {0.1 meter} with areas calculated to the nearest square yard {square meter}. The length will be measured along the surface of the completed roadbed at its center point. The width will be the top surface width of the completed roadbed specified on the plans or directed , measured perpendicular to the center line of roadbed. Additional areas required for cross overs, turnouts, etc., shall be measured by length and width along the surface of area processed. Lime actually incorporated in the work will be measured by the ton {metric ton}. In cases where Pure Quicklime (CaO) is slaked on the jobsite to produce a lime slurry, the pay quantity for lime will be measured in tons {metric tons} of hydrated lime as calculated using the certified lime purity for each truckload as foll ows: TOTAL TONS {METRIC TONS} HYDRATED LIME PRODUCED = (A x B x 1.32) + A (1.0 - B) Where: A = tons {metric tons} of Quicklime delivered B = certified percent purity Note: 1.32 = ratio of Molecular weights {masses} for Hydrated Lime (74) and Pure Quic klime (56)
232.05 Basis of Payment.
a.Unit Price Coverage . The ordered and accepted area of lime stabilization, measured as noted above, will be paid for at the contract unit price bid per square yard {square meter} of the class and depth specified. Said unit price bid shall be full compensation for all scarifying, pulverizing, mixing, shaping, watering, compacting, and application of lime and for all equipment, tools, labor, and incidentals necessary to complete and maintain the work. The accepted quantity of lime actually incorporated in the work except as noted herein, measured as provided above, will be paid for at the contract unit price per ton {metric ton} for lime, which price shall be payment in full for furnishing, transporting, st oring, handling, preparation of slurry, and spreading; and for all equipment, tools, labor, and incidentals needed for completion of the work. Any additional soil material required to bring the roadbed to plan grade and section, and any unsuitable material excavated, will be measured and paid for under the appropriate item of Unclassified Excavation or Borrow. No direct payment will be made for blading, shaping, compacting, and like operations.
b.Payment will be made under Item No .: 232-A Lime Stabilizat ion, Class ____ , ___ inches {mm} Thick - per square yard {square meter} 232-B Lime - per ton {metric ton} SECTION 235 DETOUR BRIDGES
235.01 Description.
The work under this Section shall cover the work of furnishing all materi als, construction, maintenance, and removal (unless otherwise directed) of any temporary detour bridge structure at the approximate location shown on the plans or directed.
235.02 Materials.
All timber used shall be a minimum of dense No. 1 structure grade pine or equivalent grade of other wood. Steel or other types of bridging material may be used; however, the grade of material used must be approved by the Bridge Engineer. Other materials shall conform to the requirements noted elsewhere in these Specific ations for the type material used.
235.03 Construction Requirements.
a.General . The alignment, length of bridge, grade, and typical cross -section will be shown on the plans. All construction shall be consistent with the requirements for the type work inv olved as noted in other portions of these Specifications.
Source: Alabama Standard Specifications for Highway Construction, 2022 Edition. Pages 148–150 of 934.