Taylor County
July 2011
SECTION 02515 – STABILIZED SUBGRADE
PART 1 - GENERAL
1.1
SCOPE OF WORK
A.
1.2
The work specified in this Section includes all labor, materials, transportation and equipment
necessary to properly construct a Type B stabilized roadbed having a Limerock Bearing Ratio
(LBR) of 40. The required LBR shall be obtained by stabilizing the roadbed material with
crushed limerock, oyster shell, coquina shell or any other material specified in Section 914 of
the FDOT Standard Specifications for Road and Bridge Construction.
RELATED WORK
A.
The following items of related work are included and specified in other Sections of these
Specifications.
1.
2.
3.
4.
1.3
Section 02200:
Section 02512:
Section 02516:
Section 02520:
Earthwork
Concrete Curbs, Curbs and Gutters, And Sidewalks
Limerock Base
Asphalt Concrete Surface Course
COMPLIANCE WITH STANDARDS
A.
1.4
Except as modified or supplemented herein, all work in this section shall meet the requirements
and standards listed. In case of conflict between the referenced Specifications or standards, the
most stringent requirement shall govern.
1.
American Association of State Highway and Transportation Officials – AASHTO
2.
Florida Department of Transportation – FDOT
SUBMITTALS
A.
Submit reports to Engineer demonstrating materials comply with requirements herein.
B.
Test Results: Submit results of all tests conducted to the Engineer.
PART 2 - PRODUCTS
1.
All materials used for subgrade stabilization shall meet the requirements of Section 914,
FDOT Standard Specifications.
PART 3 - EXECUTION
STABILIZED SUBGRADE
02515 - 1
Taylor County
3.1
July 2011
APPLICATION
A.
The stabilizing material shall be spread, mixed and compacted in accordance with Section 160
of the FDOT Standard Specifications.
B.
The stabilized subgrade shall be stabilized to a bearing value of LBR 40.
C.
The stabilized subgrade shall be processed in one course to a depth of 12 inches below the
bottom of the proposed limerock base material. There shall be no adjustment or extra payment
for additional thickness of subgrade material.
D.
The stabilized subgrade shall be shaped and compacted to conform to the proposed finish grade.
E.
The stabilized subgrade shall extend six inches (6”) beyond proposed finished edge of finished
base course.
3.2
TESTING
A.
Contractor shall comply and pay for the services of an independent testing laboratory in
accordance with Section 01400.
B.
Bearing Value Tests
C.
1.
Perform LBR testing for stabilized subgrade at a frequency of four tests per lift per
roadway mile (4/lift/rdwy mile), or at a minimum of two tests per roadway segment,
whichever is greater.
2.
For widening and stabilized shoulders only, perform LBR testing for stabilized subgrade
at a frequency of one test per roadway mile per side (1/rdwy mile/side), or at a minimum
of two tests per roadway segment, whichever is greater.
3.
Perform LBR testing for stabilized subgrade for non-roadway areas at a frequency of one
test per 500 square yards of pavement area.
Density Requirements
1.
Minimum density requirements at any location in the stabilized subbase area will be as
shown on the plans and set forth in Section 02200 – “Earthwork”. The contractor shall
undercut unsuitable materials and/or dewater the subbase, if required, to ensure proper
compaction.
2.
Perform compaction testing for stabilized subgrade and fill the full depth at a frequency
of one test per lift per 500 foot section (1/lift/500’). Non-roadway areas shall be tested at
a frequency of one test per 500 square yards of pavement area. A minimum of two tests
per roadway and non-roadway segments shall be taken.
END OF SECTION 02515
STABILIZED SUBGRADE
02515 - 2