202 SECTION 422
422.01 Description
This work consists of applying a material composed of emulsified asphalt, aggregate, water, and additives over a prepared surface.
422.02 Equipment
Equipment Section Aggregate Trucks 152.01 C Bituminous Tank Trucks 152.01 E Micro Surfacing and Slurry Seal Equipment 154.02 D Calibrate each mixing unit in the presence of the Engineer before starting work. Perform calibration according to ISSA-MA 1. The Engineer may accept previous calibration documentation if the calibration was done within the calendar year. Include the individual calibration of each material at various settings in the documentation.
422.03 Materials
Item Section Water 812 Aggregate for Slurry Seal 816.05 Bituminous Materials for Slurry Seal 818.04 Obtain samples of the bitumen under the observation of the Engineer. The Engineer will take immediate possession of the samples.
A.Aggregates. Screen the stockpile before delivery to the paving machine to prevent having oversize material in the mix.
B.Mineral Fillers. Use mineral filler to improve mixture consistency and to adjust mixture breaking and curing properties. Use material that meets the require ments of ASTM D 242. Use levels of mineral filler between 0.0 and 3.0 percent. Submit a certificate of compliance for the mineral filler.
C.Field Control Additives. If necessary, use additives to accelerate or retard the break/set of the slurry seal. Submit a certificate of compliance stating that the liquid field control additive is compatible with the mix design.
D.Emulsion. Obtain and submit a certificate of compliance from the emulsion manufacturer stating that the aggregate and emulsion are compatible. 203 422.04 CONSTRUCTION REQUIREMENTS
A.Mix Design. Submit a mix design prepared by a qualified testing laboratory. Submit the certified test reports with the mix design. Use the same materials in the mix design as on the project. The laboratory must approve the appropriate field control additives and their application use range as part of the mix design. Obtain a new mix design from a testing laboratory before changing any materials in the mix design. Submit a mix design conforming to Table 422-01. Table 422 -01 Slurry Seal Mix Design Test ISSA Test No. Specification Mix Time @77° F TB-113 Controllable to 180 Seconds Minimum Slurry Seal Consistency TB-106 2.0 - 3.0 cm Wet Cohesion @30 Minutes (Set) @60Minutes (traffic) TB-139 12 kg-cm Minimum 20 kg-cm or Near Spin Minimum Wet Stripping TB-114 Pass (90% Minimum) Wet-Track Abrasion Loss One-hour Soak TB-100 75 g/ft2 Maximum Excess Asphalt by LWT Sand Adhesion TB-109 50g/ft2 maximum Before use, allow the Engineer to review the design mix, all slurry sealing materials and methods. Use component materials that meet requirements in Table 422-02. 204 Table 422 -02 Slurry Seal Component Material Requirements Component Quantity Residual Asphalt Type II: 7.5 - 13.5% Type III: 6.5 - 12% (Based on dry weight of aggregate) Mineral Filler 0.0 - 3.0% (Based on dry weight of aggregate) Additives As needed Water As required to produce proper mix consistency
B.Test Strip. Construct a one lane, 1,000 foot test strip for each machine used on the project at an approved location within the project limits. Construct the test strip between 6:00 am and 9:00 am. Construct the test when the emulsion temperature is below 122°F. Open the test strip to traffic within 90 minutes. The Engineer will inspect the test strip for damage immediately after it begins carrying traffic. Begin full production only after the Engineer accepts the test strip. If the test strip is unable to carry traffic after 90 minutes, modify the material and placement and construct another test strip. In place of construction of a test strip, submit evidence of successful construction of a test strip on another Department project using the same mix designs. The project must have been constructed in the same construction season. The material, material source, and equipment used for the test strip must be identical to all parts of the proposed material, material source, and equipment. The Engineer may direct the cons truction of a new test strip during production application. Construct a new test strip if the material or equipment changes.
C.Weather Li mitations. Place material when the surface and ambient temperatures are at least 45°F and rising and the forecast is greater than 32°F for 24 hours after placement. Do not place the material if the pavement or ambient temperatures is below 50°F and falling. Do not place the material if it is raining.
D.Surface Preparation.
1.General. Remove deleterious material. Protect manholes, valve boxes and other service entrances from the surfacing material.
2.Tack Coat. If a tack coat is required, allow tack coat to cure before the applying the slurry seal. 205 E. Application. Fog the surface with water if necessary. Adjust the rate of application of the fog spray to suit the pavement surface and atmospheric conditions. Uniformly spread the material using the spreader. Ensure the material does not prematurely break in the spreader box and is homogeneous during mix ing and spreading. Use hand methods to spread the mixture in areas inaccessible by mechanical spreaders. Complete handwork at the time of the machine applied application. Finish hand-worked areas to resemble the mechanical spreader finish. Construct joints with no excessive buildup or uncovered areas. Place longitudinal joints on lane lines. Construct straight edges along curbs and shoulders and through intersections, with no runoff. Clean the spreader box to be free of material buildup at the start of each work day. Stop operations and clean the spreader box if material buildup begins to affect performance.
422.05 Method of Measurement
The Engineer will measure, completed and in place as specified in Section 109.01, “Measurement of Quantities” and as follows: The Engineer will measure the dry aggregate weight. The Engineer will subtract the weight of moisture determined from moisture tests. The Engineer will determine the moisture content by collecting 3 samples each day material is placed and averaging the moisture contents. The Engineer will measure traffic control as specified in Section 704.05, “Method of Measurement” .
422.06 Basis of Payment
Pay Item Pay Unit Aggregate for Slurry Seal - Type_ Ton Asphalt Emulsion for Slurry Seal Gallon Such payment is full compensation for furnishing all materials, equipment, labor, and incidentals to complete the work as specified. Section 430 206 SECTION 430 HOT MIX ASPHALT (HMA)
430.01 Description
This work consists of constructing bituminous pavement. Sample and test as outlined in the Field Sampling and Testing Manual.
430.02 Equipment
Equipment Section Self-Propelled Pneumatic -Tired Roller 151.01 C Smooth -Faced Steel -Wheel Roller: Tandem – Type A 151.03 A.2 Smooth -Faced Steel -Wheel Roller: Tandem – Type B 151.03 A.3 Vibratory Roller 151.03 B Combination Roller 151.04 Bituminous Trucks 152.01 D Bituminous Tank Trucks 152.01 E Bituminous Equipment 154 When air temperatures fall below 50˚ F at any place along the haul route of the mix, deploy the tarps installed on the bituminous trucks.
430.03 Materials
Item Section Bituminous Material s 818
A.Asphalt Cement. The Engineer will accept asphalt cement as outlined in the Combined State Binder Group agreement for North Dakota. The Contractor shall obtain samples of this material under the observation of the Engineer. The Engineer will take immediate possession of the samples.
B.Aggregate. Develop a mix design that contains an aggregate gradation that conforms to the requirements in Table 430 -01.
Source: North Dakota Standard Specifications for Road and Bridge Construction, 2022 Edition. Pages 237–240 of 550.