506 GAP-GRADED STONE MATRIX ASPHALT
From MDOT Policy Manual
- Place gap-graded stone matrix asphalt (GGSMA) surface as specified. GGSMA shall conform to Section 504, except as specified.
- 506.03.01 Demonstration. Demonstrate that a satisfactory mix can be produced, placed, and the compactive effort determined before proceeding with the actual work. Place a minimum of 100 tons of GGSMA outside the project limits for the demonstration. A new strip will be required if a project carries over to a new season. Paver and rollers shall conform to 504.03.01. A material transfer vehicle may be used as part of the demonstration strip.
- 506.03.02 Hauling Units. Use vehicles with tight, clean and smooth metal beds. Lightly coat the beds with an approved asphalt release agent, a combination of release agent/soap solution, or No. 10 dust coated with 1 percent asphalt or uncoated. Do not use petroleum derivatives or other coating materials that may contaminate the characteristics of the mix. Drain the bed before loading. Immediately after loading, cover each load with a full asphalt tarp, securely fastened along the sides and rear of the truck bed. The tarp shall contain no holes or rips.
- The time between plant mixing and shipment shall not exceed one hour. Storage time may vary depending upon gradation, type of binder and/or stabilizer. Stored material shall have results of no less quality than mixes discharged directly into hauling vehicles.
- 506.03.03 Weather Restrictions. Refer to 504.03.02. GGSMA placement will only be permitted when the ambient and surface temperatures are at least 50 F.
- 506.03.04 Material Transfer Vehicle (MTV). Use a material transfer vehicle to apply the final surface course. The MTV shall perform additional mixing of the GGSMA and then deposit the mix into the paver at a uniform temperature and consistency.
- 506.03.05 Asphalt Placement. Refer 504.03.06.
- 506.03.06 Pavement Thickness. The thickness of the pavement shall be as specified. 504.03.13 (Thin Lift) is not applicable to GGSMA.
- 506.03.07 Tack Coat. Refer to 504.03.04 or 504.03.05 except the resulting coating shall be asphalt applied at a rate of 0.04 to 0.08 gal/yd2 for Tack Coat. Apply Non-Tracking Tack Coat (NTTC) when specified at a rate of 0.05 to 0.10 gal/yd2.
- 506.03.08 Compaction. Compact the GGSMA using a minimum of three steel-wheeled rollers, each weighing 10 to 12 tons. The rollers shall be equipped with a plain or soapy watering system to prevent the material from sticking. The rollers shall follow the paver within 500 ft or roll per the approved Quality Control Plan. Rolling shall start immediately after placement. In-place density shall conform to 504.03.12, except density shall be in accordance with 506.04.01.
- 506.03.09 Control Strip. The construction of a control strip may be required at any time during of GGSMA placement, based on the evaluation of compaction results.
- The ContractorAny person having a Contract with a procurement agency. Contractor does not include an employee with an employment Contract, or an employee organization with a collective bargaining agreement. may opt to construct a control strip between 400 and 500 ft in length for guidance in determining roller patterns to achieve optimum density. Construct control strips on the first workday in which GGSMA is placed. Based on ContractorAny person having a Contract with a procurement agency. Contractor does not include an employee with an employment Contract, or an employee organization with a collective bargaining agreement. evaluation of the initial control strip, paving may continue at risk.
- A density pay adjustment will not be assessed for the amount of material required for the control strips. Removal of any control strip shall be at no additional cost.
- 506.03.10 Verification of Mix Design. Refer to 904.04.05
- 506.03.12 Pavement Profile. Refer to Section 535 in the Contract DocumentsThe written agreement executed between an Administration and the successful bidder, covering the performance of the work and furnishing of labor, equipment and materials, by which the Contractor is bound to perform the work and furnish the labor, equipment and materials, and by which the Administration is obligated to compensate him therefore at the mutually established and accepted rate or price. The Contract Documents shall include the Invitation for Bids, Notice to Contractors, Instructions to Bidders, Proposal, Contract Forms and Bonds, General Provisions, Specifications, Supplemental Specifications, all Special Provisions, all Technical Provisions, all Plans and Notices to Proceed, also any written Change Orders and Supplemental Agreements that are required to complete the construction of the work in an acceptable manner, including authorized extension thereof.
506.04 MEASUREMENT AND PAYMENT.
- GGSMA will be measured and paid for at the Contract unit price per ton, complete and in place. The payment will be full compensation for furnishing, hauling, placing all materials, material transfer vehicle, anti-stripping additive, tack coat, control strips, setting of lines and guides where specified, and for all material, labor, equipment, tools, and incidentals necessary to complete the work.
- Material produced for the demonstration will not be measured but the cost will be incidental to the GGSMA item.
- 506.04.01 Payment Adjustment for GGSMA and Pavement Density. Refer to 504.04 except as follows. Payment adjustments for pavement density will be based on individual sublot core test data for a given lot and the lot average density as specified in this section and the following.
TABLE 506 A GAP Graded Stone Matrix Asphalt Mixes - Percent of Maximum Density Lot Average % Minimum No Individual Sublot Below % Pay Factor (DF) 95.0 95.0 1.050 94.9 94.8 1.045 94.8 94.6 1.040 94.7 94.4 1.035 94.6 94.2 1.030 94.5 94.0 1.025 94.4 93.8 1.020 94.3 93.6 1.015 94.2 93.4 1.010 94.1 93.2 1.005 94.0 93.0 1.000 93.8 92.7 0.990 93.6 92.4 0.980 93.4 92.1 0.970 93.2 91.8 0.960 93.0 91.5 0.950 92.8 91.2 0.940 92.6 90.9 0.930 92.4 90.6 0.920 92.2 90.3 0.910 92.0 90.0 0.900 91.8 89.7 0.890 91.6 89.4 0.880 91.4 89.1 0.870 91.2 88.8 0.860 91.0 88.5 0.850 Less than 91.0 — 0.750 rejected per EngineerAny person designated by the Administrator or the procurement officer, acting directly or through his duly authorized representative, such representative acting within the scope of the particular duties assigned to him or of the authority given him.
- Note 1: When any test data is above 97.0, the lot may be rejected per the EngineerAny person designated by the Administrator or the procurement officer, acting directly or through his duly authorized representative, such representative acting within the scope of the particular duties assigned to him or of the authority given him.. When not rejected, the lot will receive a pay adjustment in accordance with the following:
- (a) When the density lot average is above 97.5, the pay factor = 75%.
- (b) When 3 sublot densities are above 97.0, the pay factor = 95%.
- (c) When 4 or more sublot densities are above 97.5, the pay factor = 75%.
- Note 2: When the ContractorAny person having a Contract with a procurement agency. Contractor does not include an employee with an employment Contract, or an employee organization with a collective bargaining agreement.'s core specific gravity data does not compare with the AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02.'s core specific gravity data, only the AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02.'s single sublot values and lot average value will be used in acceptance decision.
- Note 3: The average sublot values and the lot average will be used in acceptance decision.
- 506.04.02 Dispute Resolution. Refer to 915.02.03.