224.01 Description.
TREATMENT OF LIME SINKS
224.01 Description.
The work under this Section shall cover the treatment required to correct conditions occurring when lime sinks are found within or adjacent to construction limits of the work. The application and extent of the treatment will be in accordance with plan details or as directed.
224.02 Materials.
Material furnished for use under this Section shall be of the quality and character noted on the plans or ordered by the Engineer, suitable for the purpose intended, and consistent with the requirements for such materials as may be noted in other parts of these Specifications.
224.03 Construction Requirements.
a.General . Choice of equipment to perform the work required under this Section shall in general be that of the Contractor provided such will produce the desired results within the limits directed by the Engineer.
b.Sequence of Work . To properly evaluate the limits of the corrective treatment required to effectively bridge a lime sink, the work shall be performed in the following sequence:
1.Exploration of the lime sink area to lo cate the sink hole will be as directed by the Engineer; the size of the exploratory excavation shall be kept to a minimum.
2.The sink hole, once located, shall be enlarged to the size and depth as directed by the Engineer to expose the solution cavity.
3.After exposing the solution cavity, it shall be plugged with a rock boulder or a plug of suitable material capable of sealing the cavity, yet maintaining proper ground water drainage.
4.After installation of the plug, a strata of selected material that will permit proper ground water drainage shall be placed to a depth of approximately one- half the excavated hole depth, but not in excess of 7 feet {2 m}. The material used for this "Special Backfill" shall be of the type shown on the plans or directed. Th is special backfill material shall be placed in approximately equal uniform layers, not to exceed 2 feet {600 mm} in thickness, for the depth specified or directed. No compaction or density tests will be required.
5.The remainder of the backfill for the l ime sink excavation shall then be constructed of Unclassified Excavation, Borrow, or other designated material in accordance with the requirements for Embankments as required in Section 210.
6.In the event a sink hole occurs in the immediate vicinity of t he finished subgrade elevation, the use of concrete seal may be directed. In such case the same process noted before shall be used up to the bottom elevation designated for the concrete seal. The concrete shall be Class A concrete of the thickness shown on the plans or as directed. Steel reinforcement, if required, will be as provided by the plans or as directed.
224.04 Method of Measurement.
a.Lime Sink Excavation . Measurement for this item will be in cubic yards {cubic meters} computed from field measurements of the material actually removed as directed.
b.Special Backfill for Lime Sink . Special backfill material, furnished as directed, will be measured in cubic yards {cubic meters}, loose measurement, or per ton {metric ton} in the transporting vehicle. The boulder or plug will be measured for payment as an estimated number of cubic yards {cubic meters} or an estimated tonnage {metric tonnage}.
c.Concrete Seal . When the use of a concrete seal is ordered, measurement will be made i n cubic yards {cubic meters} computed from field measurement of concrete actually placed. All reinforcement required will be measured in accordance with Section 502, Steel Reinforcement.
230.03 Construction Requirements.
224.05 Basis of Payment.
a.Unit Price Coverage .
1.The accepted vol ume of Lime Sink Excavation, measured as provided above, will be paid for at the contract unit price bid which shall be payment in full for the removal and disposal of the excavated material in a manner satisfactory to the Engineer, and for all equipment, tools, labor, and incidentals necessary to complete the work in accordance with the plans and this Specification.
2.The accepted volume of Special Backfill material, including the plug, measured as noted above in accordance with the method provided in the contract (cubic yard {cubic meter} or ton {metric ton}), will be paid for at the contract unit price bid which shall be payment in full for the item complete in place and shall include all costs incidental to procurement, excavating, hauling, dumping, spr eading, and formation of the embankment and for all equipment, tools, labor, and incidentals necessary to complete the work in accordance with the plans and these Specifications.
3.The accepted volume of concrete for the seal, measured as noted above, will be paid for at the contract unit price bid which shall be full compensation for the preparation of the concrete bed, furnishing of all materials, mixing, hauling and placing, and for all labor, tools, equipment, and incidentals necessary to complete t he item. Steel reinforcement will be paid for under Item 502, Steel Reinforcement.
b.Payment will be made under Item No .: 224-A Lime Sink Excavation - per cubic yard {cubic meter} 224-B Special Backfill for Lime Sink, Type Material - per cubic yard {cu bic meter} 224-C Special Backfill for Lime Sink, Type Material - per ton {metric ton} 224-D Concrete Seal for Lime Sink - per cubic yard {cubic meter} SECTION 230 ROADBED PROCESSING
230.01 Description.
This Section shall c over the operations required to provide a satisfactory roadbed for receiving a base or pavement structure layer. Roadbeds will be of two types: (1) Improved Roadbeds when designated on the plans or (2) Modified Roadbed whenever Improved Roadbed is not spec ified on the plans. This Section covers the additional work above that required for regular earthwork construction specified under Section 210. Improved Roadbed . Improved roadbed shall require the top layer, or layers, of the graded earth of both cuts and fills, with the upper surface at subgrade elevation, to be constructed of selected material from Unclassified Excavation or Borrow. Each layer of the plan designated thickness shall be processed and compacted as specified in Article 230.03. Modified Roadbe d. Modified roadbed shall require that the existing top layer of the graded earth of both cuts and fills below subgrade elevation be processed and compacted as specified in Article
230.03 This procedure is to establish a proper subgrade before constructin g an overlying layer.
230.02 Materials.
a.Improved Roadbed Materials from Unclassifed Excavation . Materials for Improved Roadbed that are from Unclassified Excavation shall be the best available materials, as determined by the Engineer, meeting the requi rements given in Item 210.02(c)2.
b.Improved Roadbed Materials from Borrow Excavation . Materials for Improved Roadbed that are from Borrow Excavation shall meet the requirements given in Item 210.02(c)2.
230.03 Construction Requirements.
a.General . 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. Construction of the roadbed shall be conducted so that earth or other material does not prevent immediate drainage of water to the side ditches.
Source: Alabama Standard Specifications for Highway Construction, 2022 Edition. Pages 143–143 of 934.