SS317-002020-01.docx
DOCX document 31 KB Posted
- Attached to
- Construction, University Drive Bike Lanes
- Solicitation number
- IFB-114424
- Issued by
- Fairfax County, Virginia
About this file
This is a supplemental specification document issued by the Virginia Department of Transportation (VDOT) dated June 21, 2024, providing guidelines for Stone Matrix Asphalt (SMA) concrete placement on all projects. The specification amends Section 317.08 regarding compaction procedures and establishes technical requirements for contractors performing SMA paving work. Key requirements include the use of steel wheel rollers with a minimum weight of 10 tons, with at least three rollers available at all times. Contractors must exercise caution when using vibratory rollers, limiting them to no more than three passes on the highest frequency and lowest amplitude settings to minimize aggregate fracture. Contractors are required to monitor density continuously using nuclear density gages during compaction and must keep roller wheels properly moistened with water mixed with detergent or approved additives. Production lots are standardized at 5,000 linear feet with 1,000-foot sublots for courses 6 feet or greater in specified thickness, though lot sizes may be adjusted based on daily production volumes.
Acceptance testing and payment are contingent upon density performance measured through sawed specimens or cores extracted at single random test sites per sublot, with test locations marked sequentially and filled with paving mixture prior to daily completion. The Department will randomly select three plug or core locations during trial sections to determine in-place density according to VTM-22 standards. Payment schedules are graduated based on density achievement percentages: more than 98.0 percent receives 97 percent payment, 94.0 to 98.0 percent receives full payment, 92.0 to 93.9 percent receives 85 percent payment, 90.0 to 91.9 percent receives 65 percent payment, and any sublots below 90.0 percent must be removed and replaced at no additional cost to the Department. Sublots failing to achieve 90.0 percent of target maximum density (TMD) require complete removal and replacement at the Contractor's expense.
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Text version
Guidelines: Use on all projects.
SS317-002020-01 June 21, 2024
VIRGINIA DEPARTMENT OF TRANSPORTATION
2020 ROAD AND BRIDGE SUPPLEMENTAL SPECIFICATIONS
SECTION 317 – STONE MATRIX ASPHALT CONCRETE PLACEMENT
SECTION 317 – STONE MATRIX ASPHALT CONCRETE PLACEMENT of the Specifications is amended as follows:
Section 317.08– Compaction is replaced by the following:
Immediately after the mixture has been spread and struck off, it shall be thoroughly and uniformly compacted by rolling. Rolling shall be accomplished with steel wheel roller(s) with a minimum weight of 10 tons. A minimum of three rollers shall be available at all times for compaction and/or finish rolling.
The Contractor shall approach the use of vibratory rollers on SMA with caution to minimize coarse aggregate fracture/breakage in the aggregate skeleton of SMA mixes. If the Contractor elects to use a vibratory roller, the mat shall receive not more than three vibratory passes. The Contractor shall use the roller only on the highest frequency and lowest amplitude setting.
It shall be the Contractor’s responsibility to adjust the rolling procedures to provide the specified pavement density. Rollers shall move at a uniform speed. Rolling shall be continued until all roller marks are eliminated and the minimum density has been obtained. The Contractor shall monitor density during the compaction process by use of nuclear density gages to ensure that the minimum required compaction is being obtained. During the trial section, the Department will randomly select 3 plug or core locations to determine the in-place density according to VTM-22.
The Contractor shall keep the wheels of the rollers properly moistened with water that has been mixed with very small quantities of detergent or other approved additives to prevent adhesion of the mixture to the rollers.
For the purposes of evaluating and determining acceptance, each day’s production shall be considered a lot unless the paving length is less than 3,000 linear feet or greater than 7,500 linear feet. When paving is less than 3,000 feet, that day’s production amount shall be combined with the previous day’s production or added to the next day’s production to create a lot as described below.
The standard size of a lot shall be 5,000 linear feet, with 1,000 foot sublots, of any pass 6 feet or greater for the specified thickness of the course. The Engineer may approve an increase in the lot size to 7,500 linear foot lots with 1,500 foot sublots when the normal daily production is in excess of 7,000 feet. Pavers traveling in echelon will be considered as two passes. When a partial lot occurs at the end of a day’s production or upon completion of the project, the lot size shall be redefined as follows:
· If the partial lot contains one or two sublots, the sublots will be added to the previous lot.
· If the partial lot contains three or four sublots, the partial lot will be redefined to be an entire lot.
The Contractor shall perform acceptance testing for density for each sublot by obtaining one sawed 4 inch by 4 inch specimen, or one 4-inch-diameter cores, at a single random test site specified by the Engineer. Test sites shall not be located within 12 inches of the edge of any application width for surface and intermediate mixes.
· The sub-lot site shall be marked as described in VTM-76.
· The bulk specific gravity of the cores shall be determined in accordance with VTM-6.
· The density of the cores shall be determined in accordance with VTM-22.
The Contractor shall bulk the cores or plugs in the presence of the Engineer. The cores or plugs may be bulked on the project site. Sublot test sites shall be numbered sequentially per lot, marked on the pavement, filled with the paving mixture, and compacted prior to completion of each day’s production.
If any sublots are lower than 90.0% of TMD, those sublots shall be removed from the roadway and replaced at no additional cost to the Department.
The payment for lot density will be in accordance with the following schedule:
Payment Schedule
| % Density Achieved |
| % of Payment |
| More than 98.0 |
| 97 |
| 94.0 to 98.0 |
| 100 |
| 92.0 to 93.9 |
| 85 |
| 90.0 to 91.9 |
| 65 |
| Less than 90.0 |
| Remove and replace |
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