PLANT MIX BITUMINOUS BASE AND PATB
327.01 Description.
The work under this Section shall consist of constructing a Plant Mix Bituminous Base layer composed of an aggregate and bituminous material hot mixed in a central plant and hot laid on a prepared surface in accordance with these specifications and in close conformity with the lines, grades, typical section, mix, and average weight per square yard shown on the plans or directed by the Engineer. The work under this Section shall also include the construction of a Permeable Asphalt Treated Base (PATB) layer to serve as a drainage layer in the pavement structure.
327.02 Materials.
a.Plant Mix Bituminous Base.
2.Mix Design. The type of required mix will be shown on the plans. The minimum allowable VMA shall be 13.0. The job mix shall be designed by the Marshall Method or a 60 gyration gyratory compactor design. The Marshall Method must produce a minimum of 1200 pounds {5.5 kN} stability at 50 blows or a minimum of 2,700 pounds {12 kN} stability at 60 gyrations, unless shown otherwise on the plans. The design air voids shall be 4.0%.
3.Aggregate. Fine aggregate shall meet the requirements given in Article 802.04. Coarse aggregate shall be gravel, processed reef shell, crushed slag, crushed stone, or a combination thereof meeting the requirements given in Section 801 unless noted otherwise by the requirements given in this Section. The coarse and fine aggregates shall be combined in a total blend that will produce an acceptable job mix within the gradation limits shown in the following table. The blend shall be made from at least two stockpiles of different gradations. At least 10% of the blend shall be taken from each of the stockpiles. The requirements for allowing the use of RAP and RAS are given in Article 410.02. AGGREGATE FOR PLANT MIX BITUMINOUS BASE AND PERMEABLE BASE SIEVE PERCENT PASSING BY WEIGHT {MASS} Plant Mix Bituminous Base Permeable Base (Square Mesh Type) Mix 1 Mix 2 * PATB 2 inch {50 mm} Sieve 100 1.5 inch {37.5 mm} Sieve 100 82 – 97 100 1 inch {25.0 mm} Sieve 95 - 100 95 - 100 3/4 inch {19.0 mm} Sieve 80 - 95 55 – 85 1/2 inch {12.5 mm} Sieve 64 - 84 25 - 60 3/8 inch {9.5 mm}Sieve 56 - 74 40 – 65 No. 4 {4.75 mm} Sieve 40 - 56 30 – 52 0 - 10 No. 8 {2.36 mm} Sieve 28 - 42 22 – 42 0 - 5 No. 16 {1.18 mm} Sieve 20 - 34 No. 30 {600 m}Sieve 13 - 26 No. 50 {300 m} Sieve 8 - 20 5 – 22 No. 100 {150 m} Sieve 4 - 14 1 – 18 No. 200 {75 m} Sieve 2 - 6 0 - 8 0 - 4 * Mix 2 is intended to be used as a narrow width buildup in widening projects. All design criteria on Mix 2 is waived due to the size of the coarse aggregate. The M & T Engineer will determine the liquid asphalt binder content and gradation within the general composition of the mix.
4.Liquid Asphalt Binder. If the grade of liquid asphalt binder is not shown on the plans the Contractor shall use PG 67- 22 liquid asphalt binder. The proportion of liquid asphalt binder to total sample by weight shall be 3.5 % to 7.0 % for Mix 1 and 3.0 % to 6.0 % for Mix 2. The exact proportion shall be fixed by the job mix formula. Additives or modifiers shall be used to prevent stripping of liquid asphalt binder if stripping is observed during design, production or laydown. These additives or modifiers shall be furnished and used at no additional cost to the State.
b.Permeable Asphalt Treated Base Mix (PATB).
2.Mix Design. PATB shall be open graded, hot laid, central plant mixed, asphalt base material with no requirement for density, air voids, VMA, or stability. The mix shall be designed with a target liquid asphalt binder content of 2.0 to 3.0 %.
3.Aggregate. PATB shall be made with crushed stone meeting the requirements given in Section 801 unless noted otherwise by the requirements given in this Section. The crushed stone shall meet the gradation requirements given in the table AGGREGATE FOR PLANT MIX BITUMINOUS BASE AND PERMEABLE BASE in this Section. The blend shall be made from at least two stockpiles of different gradations. At least 10% of the blend shall be taken from each of the stockpiles. The requirements for allowing the use of RAP and RAS are given in Article 410.02.
4.Liquid Asphalt Binder. If the grade of liquid asphalt binder is not shown on the plans the Contractor shall use PG 67- 22 liquid asphalt binder. The proportion of liquid asphalt binder to total sample by weight shall be 2.0 % to 3.0 %. During the drying process, the aggregate shall not be heated to a temperature greater than 280 °F {138 °C}. The liquid asphalt binder and the dried aggregate shall be mixed in such a manner that the finished mixture shall not exceed 275 °F {135 °C}. Additives or modifiers shall be used to prevent stripping of liquid asphalt binder If stripping is observed during design, production or laydown. These additives or modifiers shall be furnished and used at no additional cost to the State.
5.Geotextile Filter. The geotextile filter shall comply with the requirements given in Section 604, Geotextiles In Permeable Asphalt Treated Base Application.
c.Sampling and Testing Frequency. The sampling and testing requirements for Plant Mix Bituminous Base and Permeable Asphalt Treated Base are given in Article 106.09.
327.03 Construction Requirements.
a.Plant Mix Bituminous Base. The construction requirements for Plant Mix Bituminous Base shall be the requirements given in Section 410 unless noted otherwise by the requirements in this Section. The edges shall be trimmed immediately after final rolling, using an accurately aligned string or wire to a tolerance of 2 inches {50 mm} outside the theoretical edge of the layer and to a slope not flatter than 1:1. Any edge distorted by rolling shall be promptly corrected. The required density shall be determined by the pay factors located in Table IV in Section 410.08.(b) Permeable Asphalt Treated Base Mix (PATB). The construction requirements for Permeable Asphalt Treated Base shall be the requirements given in Section 410 unless noted otherwise by the requirements in this Section. A static steel wheel roller shall be used to compact the permeable base applying 0.5 to 1.0 tons per foot of roller width {1.5 to 3.0 metric tons per meter of roller width}. The roller shall make one to SECTION 401 BITUMINOUS SURFACE TREATMENTS three passes, as directed by the Engineer, when the temperature of the mixture reaches approximately 150 °F {66 °C}. No portion of the PATB layer shall be exposed to the elements between laydown and cover for more than five calendar days. When required, the geotextile filter shall be furnished and installed to comply with the requirements of Section 604 or as shown on the plans or directed by the Engineer. If rutting of PATB occurs when placing the next layer due to grade of roadway, temperature of the PATB, etc., the Engineer may require the use of a tracked paver. No traffic shall be allowed to operate or park on the travel lane or outside shoulder portion of the permeable base. Limited operation of equipment, e.g. delivery vehicles may be permitted on the inside edge.
327.04 Method of Measurement.
Measurement of the work included under this Section will be as provided in Article 410.08.
327.05 Basis of Payment.
a.Unit Price Coverage. Payment for the work included under this Section will be as provided in Article 410.09. For Pay Item 327-E, payment for furnishing and installing a required geotextile filter will not be included in this item of work. The payment for furnishing and installing a required geotextile filter will be included in Pay Item 604-A, Separative Geotextile.
b.Payment will be made under Item No.: 327-A Plant Mix Bituminous Base, Mix - per ton {metric ton} 327-B Plant Mix Bituminous Base, Patching, Mix - per ton {metric ton} 327-C Plant Mix Bituminous Base, Leveling, Mix - per ton {metric ton} 327-D Plant Mix Bituminous Base, Widening, Mix - per ton {metric ton} 327-E Permeable Asphalt Treated Base - per ton {metric ton}
Division 400
SURFACING AND PAVEMENTS SECTION 401 BITUMINOUS SURFACE TREATMENTS
401.01 Description.
a.General. The work covered by this Section consists of basic bituminous treatments such as prime coat, asphalt flush coats, liquid seals, and bituminous surface treatments. This Section also covers the work of applying a bituminous surface treatment containing a polymer additive. Each bituminous treatment shall consist of one or more hot applications of bituminous material and, except for prime coats, includes a specified cover aggregate which shall be spread after each bituminous application. The work also includes the cleaning of the existing surfaces as well as furnishing and applying all materials, and necessary incidental work thereto, all in accordance with plan details and these Specifications.
b.Bituminous Treatment Table. The following table shows the amount of bituminous material and the size and amount of cover aggregate required for the various types of bituminous treatments. The types are designated in the table by letters of the alphabet such as A, B, C, D, etc. The proposal will designate in the pay item description which of the various types are to be used. The kind of bitumen may also be specified or, if none is specified, the Contractor may select one of the kinds, if not in conflict with other provisions of these Specifications, permitted by the table. All other requirements of the tabular line opposite the type designation shall apply. SECTION 401 BITUMINOUS SURFACE TREATMENTS (Example: A bituminous treatment Type AKG, specifies a prime coat with the quantities specified online "A", covered by a single surface treatment with the quantities specified on line "K", covered in turn by a seal treatment with the quantities shown online "G".) Bituminous materials shall be placed within the tolerance specified by the table for the type treatment involved, unless otherwise ordered by the Engineer in writing. Any variation outside of the designated limits shall be cause for ordering the treatment to be removed and replaced or corrected as directed by the Engineer, all without additional cost to the Department. The rate of aggregate coverage shown by the table is the approximate rate found to produce an acceptable coverage when properly applied. Regardless of the rate shown, the Contractor shall provide aggregate in sufficient quantities and so spread the aggregate that the bitumen is uniformly and evenly covered. The Engineer will notify the Contractor in writing should it become advisable to change the amounts of any material from the limits specified in the table. In such event an adjustment in the contract unit price will be made as specified in Subarticle 401.06(a). BITUMINOUS TREATMENT TABLE SUBARTICLE 401.01(b) Designated Letter Type Treatment Aggregates **** Gallons {Liters} of Bituminous Material per square yard {m²} of Treatment ** Size cu. ft./ sq. yd. {m³/m²} Liquid Asphalt Binder Emulsified Petroleum Resin, Cutback or Emulsified Asphalt A Prime Coat 0.10 – 0.25* {0.45 - 1.13}* B Flush Coat "B" Sand 0.15 {0.0051} 0.16 – 0.19 {0.72 - 0.86} C Flush Coat "C" 9 0.20 {0.0068} 0.16 – 0.19 {0.72 - 0.86} D Liquid Seal "D" 78 or 89 0.25 {0.0085} 0.18 – 0.21 {0.81-0.95} 0.20 – 0.23 {0.90 - 1.04} E Liquid Seal "E" 78 0.25 {0.0085} 0.22 – 0.25 {1.00-1.13} 0.25 – 0.28 {1.13 - 1.27} F Liquid Seal "F" 78 0.27 {0.0091} 0.26 – 0.29 {1.18-1.31} 0.31 – 0.34 {1.40 - 1.54} G Liquid Seal "G" 7 or 78 0.27 {0.0091} 0.31 – 0.34 {1.40-1.54} 0.35 – 0.38 {1.58 - 1.72} H Liquid Seal "H" 6 0.40 {0.0135} 0.31 – 0.34 {1.40-1.54} 0.35 – 0.38 {1.58 - 1.72} J Surface Treatment "J" 6 0.42 {0.0142} 0.33 – 0.36 {1.49-1.63} 0.38 – 0.41 {1.72 - 1.86} K Surface Treatment "K" 5 0.50 {0.0169} 0.35 – 0.38 {1.58-1.72} 0.40 – 0.43 {1.81 - 1.95} L *** Surface Treatment "L" 1st Application 4 0.9 {0.0305} 0.35 – 0.38 {1.58-1.72} 0.40 – 0.43 {1.81 - 1.95} Dry Choke 78 0.20 {0.0068} 2nd Application 78 0.25 {0.0085} 0.55 – 0.58 {2.49-2.63} 0.62 – 0.65 {2.81 - 2.94} * Appropriate rate will be set by the Engineer within the maximum and minimum range. ** For shoulders, different amounts of aggregate and bitumen may be shown on plans or in the proposal. *** Aggregate for this treatment shall be crushed aggregate. **** Approximate rate of application for uniform coverage. Minor adjustments to these rates may be ordered by the Engineer to fit the physical properties of aggregates furnished for use. SECTION 401 BITUMINOUS SURFACE TREATMENTS Multipurpose and Cationic Emulsified Asphalts shall be in the same quantities as shown above for Emulsified Asphalt. Conversion of aggregate volume to weight {mass}, when required, shall be in accordance with AASHTO T 19. The application rates of Bituminous Materials shown above are based on the material being at 60 °F {16 °C}.
401.02 Materials.
All materials shall comply with the requirements of Division 800, Materials, except as noted herein. Special reference is made to the following:
a.Bituminous Materials, Section 804. The grade of bituminous material shall be within the following limits unless the kind and grade are specified on the plans or in the proposal.
1.Prime: Emulsified Asphalt AE-P, BC-1HT, CRS-1h, CMS-1hp, or NTSS-1HM Cutback Asphalt MC 3O or MC 7O for tight bases; MC 250, RC 7O or RC 250 for open bases Emulsified Petroleum Resin EPR * *This material shall not be used as a prime on processed reef shell base courses, crushed aggregate base courses, or rubblized concrete. This material shall not be left exposed for more than four days before placing a base layer of asphalt over it. This material shall also be supplied by the producer in the form in which it shall be placed. Material in a concentrated form that requires dilution after delivery will not be allowed.
2.Asphalt Flush Coat: Emulsified Asphalt AE-P, BC-1HT, CRS-1h, CMS-1hp, or NTSS-1HM Cutback Asphalt MC 3O or MC 7O for tight bases; MC 250, RC 7O or RC 250 for open bases Emulsified Petroleum Resin EPR * Emulsified Asphalt CRS 2
3.Liquid Seals and Surface Treatments without Polymer Additive: Liquid Asphalt Binder PG 58-22 Cutback Asphalt RC 250, RC 800, MC 800 Emulsified Asphalt CRS 2, CRS 2h
4.Liquid Seals and Surface Treatments with Polymer Additive: Liquid Asphalt Binder PG 64-22 * Emulsified Asphalt CRS 2p, CRS 2hp, CRS-2l * This liquid binder shall be manufactured from PG 58-22 with polymer additive to achieve the PG 64-22 grade. Where the plans require the placement of a bituminous plant mix overlay over a bituminous surface treatment or liquid seal, the overlying layer shall not be placed until the asphalt in the bituminous surface treatment or liquid seal has cured to the satisfaction of the Engineer. Curing time is dependent upon several factors including temperature, humidity, and wind velocity. When emulsified asphalt is used, curing begins with a distinct change in color, from brown to black, and proceeds until the asphalt satisfactorily retains the aggregate. Traffic stripe on each layer shall be provided and paid for in accordance with Section 701.
b.Aggregate. Coarse aggregates for bituminous surface treatments shall be crushed aggregate meeting the requirements of Section 801. The kind of aggregate materials used shall be at the Contractor's option within the following limits:
1.The use of carbonate stone such as limestone, dolomite, or aggregate tending to polish under traffic shall be restricted as follows, based on the average daily traffic (ADT) count in both directions:
a.500 vehicles or less per day - No restrictions apply.
b.More than 500 but less than or equal to 1,000 vehicles per day - Carbonate stone shall not be used in the final application. Aggregates for the final application (wearing layer) shall be limited to siliceous aggregates such as granite, quartzite, blast furnace SECTION 401 BITUMINOUS SURFACE TREATMENTS slag or lightweight aggregates (expanded clays or shales produced by the Rotary Kiln Method).
c.Over 1,000 vehicles per day - Carbonate stone shall not be used in any application. The above will not apply to shoulder surfacing or detours, or to bituminous surface treatments which are to be covered over with a bituminous plant mix layer.
2.Crushed gravel may be used for all applications which are to be covered with a bituminous plant mix layer, for all applications on roads having an average daily traffic count (ADT) of less than 1500 vehicles, and for all applications of shoulder surface treatment work.
c.Polymer Additive. The polymer additive shall meet the requirements of Section 811. The polymer additive shall be co-milled into the emulsified asphalt at the manufacturer's facility by pre-mixing the polymer into the liquid asphalt binder before the material is emulsified. This method of adding the polymer shall be at the rate of 3%, by volume, of the asphalt emulsion. Any change to the above must be approved in writing by the Engineer. The temperature of the emulsified asphalt shall be between 140 °F {60 °C} and 180 °F {85 °C} at the time of introduction of the polymer additive.
401.03 Construction Requirements.
a.Equipment. In general, it shall be the Contractor's responsibility to select the proper sizes and amount of equipment to provide the desired results, but the following basic items shall be provided. In addition, all equipment necessary for the proper prosecution of the work shall be assembled on the site and must be approved and in good working order before permission to start any treatment will be given. All equipment approved for use shall be on a trial basis and should after a short test section the equipment prove unsatisfactory, it shall be removed, replaced, or supplemented as deemed necessary to accomplish the desired results.
1.Cleaning Equipment. Cleaning equipment shall be capable of cleaning the surface thoroughly without cutting, tearing, or otherwise damaging the surface.
2.Pressure Distributor. A pressure distributor shall be required and shall be so designed and operated that it will distribute the contents in a uniform spray for the full width of the treatment area without atomization, at the rate and within the limits specified. Heating equipment shall be provided. Distributors shall be capable of circulating or agitating the bitumen throughout the heating process providing a uniform temperature, with the ranges specified herein, and suitable means shall be provided for determining such temperatures. Suitable measuring equipment for accurately measuring the volume of the contents shall be provided. The distributor shall be equipped with a spray bar of adjustable height, hand hose, and nozzle. Heating equipment will not be required for the application of Emulsified Petroleum Resin prime.
3.Aggregate Spreader. A self-propelled aggregate spreader with mechanically actuated spreading attachments and adjustable widths of satisfactory design and performance will be required; however, when the area to be processed is of such size or shape that to require the use of a mechanical spreader would be impractical, the Engineer may permit the aggregate to be spread manually.
4.Rollers. A self-propelled steel wheel roller having a weight {mass} between 5 tons {4 metric tons} and 8 tons {7 metric tons} shall be required immediately behind the aggregate spreader followed by a self-propelled pneumatic tired roller. Only one coverage shall be made with the steel wheel roller.
b.Temperature and Weather Limitations For Placement Of Surface Treatments. All bituminous treatments shall be applied in strict conformity with the following:
1.Weather. Bituminous surface treatments shall not be placed on a wet surface or when the Engineer will not allow the placement due to existing unfavorable weather conditions. They shall not be placed when the temperature is expected to fall below freezing during the night regardless SECTION 401 BITUMINOUS SURFACE TREATMENTS of daytime temperature, when the ground is frozen, or when the surface temperature is less than 32 °F {0 °C}. Bituminous Surface Treatment A (Prime Coat) shall not be placed when the air temperature is below 40 °F {4 °C}. All other bituminous surface treatments (B, C, D, etc.) shall not be placed when the air temperature is below 60 °F {15 °C}.
2.Moisture in Aggregate. Aggregates spread when the temperature is 70 °F {20 °C} and above may be surface damp but not wet. Aggregates spread when the temperature is below 70 °F {20 °C} shall be surface dry. Aggregates found by the Engineer to contain excessive moisture or free water at the time of use shall be rejected. The above limitations shall not be waived unless approved in writing by the Engineer.
c.Preparation of Existing Surface. Loose material, dust, dirt, caked clay, or any foreign material shall be removed. Cleaning shall be continued until the surface is clean or, in case of application on a soil or aggregate surface, all the loose dirt is removed and the surfaces of the larger size aggregate in the road surface are exposed but not dislodged. All cleaning of the area to be treated shall be completed before any bituminous material is applied.
d.Application of Bituminous Material.
1.General. No bituminous material or treatment shall be applied until the base or underlying surface has been approved.
2.Preparation of Bituminous Material. Bituminous materials used for each treatment shall be heated as previously noted. The material shall be maintained within the specific temperature range during application. Any material which has not been maintained within the specified range shall be rejected. The following temperature (°F {°C}) ranges shall apply: TYPE OF BITUMEN PRIME HOT APPLICATION Liquid Asphalt Binder 275 °F – 350 °F {135 °C - 175 °C} Cutback Asphalt RC-70, MC-30, MC-70, MC-250 100 °F – 150 °F {35 °C - 65 °C} RC-250 125 °F – 180 °F {50 °C - 80 °C} RC-800, MC-800 170 °F – 240 °F {75 °C - 115 °C} RC-3000, MC-3000 215 °F – 270 °F {100 °C - 130 °C} Emulsified Petroleum Resin Ambient Temperature Emulsified Asphalt 120 °F – 170 °F {50 °C - 75 °C} 120 °F – 170 °F {50 °C - 75 °C} Emulsified Asphalt With Polymer Additive - - - - - - 140 °F – 180 °F {60 °C - 80 °C} It is recommended that, in general, liquid asphalt binders be used June through September and either emulsified asphalt or cutback be used the remainder of the season. Emulsified Petroleum Resin prime will not be required to be heated and shall be applied at ambient temperature. No Emulsified Petroleum Resin prime shall be placed when the ambient temperature is below freezing.
3.Application of Bitumen. The bitumen shall be applied uniformly over the area to be treated. Where the treatment width is 26 feet {8 m} or less, the entire width shall be treated in one application, unless otherwise directed. Where only a partial width is treated in one application, extreme care shall be used to ensure a slight overlap of adjacent treatments, but not in excess of 4 inches {100 mm}.
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Source: 2026 Standard Specifications for Highway Construction, 2026 Edition. Pages 188–194 of 826. View official source ↗