283-1 Description.
Construct a base course composed of reclaimed asphalt pavement (RAP) material. Use RAP material as a base course only on non -limited access paved shoulders, shared use paths, or other non-traffic bearing applications.
283-2 Materials.
Obtain the RAP material by either milling or crushing an existing asphalt pavement. Use material so that at least 97% (by weight) pass a 3 -1/2 inch sieve and is graded uniformly down to dust. When the RA P material is from a Department project and the composition of existing pavement is known, the Engineer may approve material on the basis of the composition. When the composition of obtained RAP is not known, the following procedure will be used for approval:
1.Conduct a minimum of six extraction gradation analyses of the RAP material. Take samples at random locations in the stockpile. The average asphalt cement content of the six stockpile samples must be 4% or greater with no individual result below 3 -1/2%.
2.Request the Engineer to make a visual inspection of the stockpile of RAP material. Based on this visual inspection of the stockpiled material and the results of the Contractor ’s extraction gradation analyses, the Engineer will determine the suit ability of the materials.
3.The Engineer may require crushing of stockpiled material to meet the gradation criterion. Perform all crushing before the material is placed.
283-3 Spreading RAP Material.
283-3.1 Method of Spreading: Spread the RAP with a b lade or device which strikes off
the material uniformly to laying thickness and produces an even distribution of the RAP. The Contractor may also place the RAP material directly from the milling machine into the trench by a conveyor. When placing the RAP m aterial by conveyor directly from the milling machine, obtain the Engineer’s approval of the milling process.
283-3.2 Number of Courses: When the specified compacted thickness of the base is
greater than 6 inches, construct the base in two courses. Place the first course to a thickness of approximately one half the total thickness of the finished base, or sufficient additional thickness to bear the weight of construction equipment without disturbing the subgrade. Except as might be permitted by the Engin eer for special cases, conduct all RAP base construction operations for shoulders before placing the final pavement on the adjacent traveled roadway.
283-4 Compacting and Finishing Base.
283-4.1 General: Meet the requirements of 200 -6.1:
283-4.1 1 Singl e-Course Base: Construct as specified in 200 -6.1.1.
283-4.1 2 Multiple -Course Base: Construct as specified in 200 -6.1.2.
283-4.2 Moisture Content: Meet the requirements of 200 -6.2.
283-4.3 Density Requirements: Compact the material to a density of not less than
95% of maximum density as determined by FM 1-T180. Where the width of the base FY 2023-24 Return to Table of Contents construction is not sufficient to permit use of standard base compaction equipment, perform compaction using vibratory compactors, trench rollers, or other special equ ipment which will provide the density requirements specified herein.
283-4.4 Density Tests: Meet the requirements of 200 -7 with the exception of 200 -7.2.1.
Within the entire limits of the width and depth of the base, obtain a minimum density in any LOT of 95% of the maximum density as determined by FM 1-T180.
283-4.5 Thickness Requirements: Meets the thickness requirements of 285 -6.
283-5 Testing Surface.
Test the surface in accordance with the requirements of 200 -7-3.
283-6 Priming and Maintaining.
283-6.1 Priming: Apply the prime coat only when the base meets the specified density
requirements and the moisture content in the top half of the base is within 2% of optimum. At the time of priming, ensure that the base is firm, unyielding, and in such condition that no undue distortion will occur. The Engineer will not allow priming if the surface is dry, dusty, or sloughing.
283-6.2 Maintaining: Meet the requirements of 200 -8.2.
FY 2023-24 Return to Table of Contents SECTION 285 OPTIONAL BASE COURSE
285-1 Description.
Construct a base course composed of one of the optional materials shown on the typical sections.
285-2 Materials.
Meet the material requirements as specified in the Section covering the particular type of base to be constructed. Graded Aggregate ................................ ............... Section 204 Asphalt ................................ ................................ Section 234 Reclaimed Asphalt Pavement (RAP)* ................ Section 283 Limerock ................................ ............................. Section 911 Shell Base ................................ ............................ Section 911 Shell-Rock................................ ........................... Section 911 Cemented Coquina ................................ ..............Section 911 Recycled Concrete Aggregate (RCA)* * .............Section 911 *Only for use on non -limited access paved shoulders, shared use paths, or other non-traffic bearing applications. **Do not use on interstate roadways .
285-3 Selection of Base Option.
The Plans will include typical sections indicating the various types of base construction (material and thickness) allowable. When base options are specified in the Plans, use only those options. When base option s are not specified, select one base option as allowed for each typical section shown in the Plans. Only one base option is permitted for each typical section. See Tables 285 -1 and 285 -2 for optional base materials, thickness and additional restrictions. Notify the Engineer in writing of the base option selected for each typical section at least 45 calendar days prior to beginning placement of base material. FY 2023-24 Return to Table of Contents
Source: Florida Standard Specifications for Road and Bridge Construction, 2024 Edition. Pages 246–247 of 1,299.