CATEGORY 500 PAVING SECTION 506 — GAP-GRADED STONE MATRIX ASPHALT
506.01 Description
Place gap-graded stone matrix asphalt (GGSMA) surface as specified. GGSMA shall conform to Section 504, except as specified.
506.02 Materials
Gap-Graded Stone Matrix Asphalt Mix 904.05 Production Plants Section 915
506.03 Construction
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 as specified in 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.
2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
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 gal/yd2 to 0.08 gal/yd2 for Tack Coat. Apply Non-Tracking Tack Coat (NTTC) when specified at a rate of 0.05 gal/yd2 to 0.10 gal/yd2.
506.03.08 Compaction. Compact the GGSMA using a minimum of 3 steel-wheeled rollers, each
weighing 10 tons 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 according to the approved Quality Control Plan. Rolling shall start immediately after placement. In-place density as specified in 504.03.12, except density shall be as specified in 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 Contractor may opt to construct a control strip between 400 ft 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 Contractor 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
506.03.11 Verification Evaluation. MSMT 735 and 904.04.06.
506.03.12 Pavement Profile. Refer to Section 535 in the Contract Documents. 506.03.13 Sampling and Testing for Mixture and Density. Refer to 504.03.11 and 504.03.12.
506.04 Measurement and Payment
Gap-Graded Stone Matrix Asphalt 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 Gap-Graded Stone Matrix Asphalt item.
506.04.01 Payment Adjustment for Gap-Graded Stone Matrix Asphalt and Pavement
Density. Refer to 504.04 except as follows. Payment adjustments for pavement density will be 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS 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 Engineer Note 1: When any test data is above 97.0, the lot may be rejected per the Engineer. 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 percent. (b) When 3 sublot densities are above 97.0, the pay factor = 95 percent. (c) When 4 or more sublot densities are above 97.5, the pay factor = 75 percent. Note 2: When the Contractor's core specific gravity data does not compare with the Administration's core specific gravity data, only the Administration's single sublot values and lot average value will be used in acceptance decision. Note 3: decision.
506.04.02 Dispute Resolution. Refer to 915.02.03.
2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS The average sublot values and the lot average will be used in acceptance 507 — SLURRY SEAL AND MICRO-SURFACING CATEGORY 500 PAVING SECTION 507 — SLURRY SEAL AND MICRO-SURFACING
507.01 Description
Construct an asphalt emulsion seal course using Slurry Seal (SS) or Micro-Surfacing (MS).
507.02 Materials
Slurry Seal and Micro-Surfacing Section 923
507.03 Construction
507.03.01 Certification. Furnish certified weigh tickets daily for the emulsion, residual asphalt
content, latex emulsion, aggregate, and mineral filler. The weigh tickets will be used to determine in-place application rates.
507.03.02 Sampling and Testing. Sample the asphalt emulsion seal mixture and the asphalt
emulsion at least once daily during paving. Provide samples for asphalt content from the completed mix produced by each mixing unit to be tested by the Administration. Asphalt content will be determined by Ignition Method. Engineer to witness and submit the samples and proper documentation/certification to the Asphalt Technology Division of the Office of Materials Technology (OMT). Residual asphalt content and gradation will be determined in accordance to T 30 and T 164, or T 308. The residual asphalt content shall be within +/- 1.5 percent of the Job Mix Formula (JMF). When successive tests for a mixing unit fail, or one test fails by more than 2 percent, that unit shall be removed from service until approved.
507.03.03 Weather Restrictions. Place asphalt emulsion seal when the air and surface
temperatures are at least 50 F. The morning minimum surface temperature may be 40 F provided the ambient temperature is expected to rise to or above 60 F and is not expected to fall below 32 F within 24 hours after placement. Cease placement when the surface or air temperature falls below the specified limits. Ensure surface is dry, with no standing water. Place asphalt emulsion seal when it is not raining or foggy.
507.03.04 Mixing Equipment. Use a self-propelled, front feed, continuous loading mixing
machine. The machine shall proportion and deliver the materials to a revolving, multi-blade, shafted mixer; and discharge it continuously and uniformly. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
Source: Maryland Standard Specifications for Construction and Materials, 2025 Edition. Pages 654–657 of 1,113.