433.02 Materials.
430.05 Basis of Payment.
a.Unit Price Coverage . Surfacing material ordered and accepted, measured as noted above, will be paid for at the contract unit price bid which shall be full compensation for the material complete in place on the roadbed and includes all costs incident to furnishing and producing the material, all hauling, spreading, mixing, watering, compacting, shaping, and for all equipment, tools, labor, and incidentals ne cessary to complete the work. Additional material used in the maintenance will be measured and paid for under this item.
b.Payment will be made under Item No .: 430-A Soil Type Surfacing( Kind Material ) - per cubic yard {cubic meter} 430-B Aggregate Surf acing( ALDOT Size of Material ) - per ton {metric ton} SCRUB SEAL
433.01 Description.
This Section covers the placement of a polymer modified asphalt rejuvenating scrub seal.
433.02 Materials.
All materials shall comply with the requirements of Division 800, Materials, except as noted herein. Special reference is made to the following:
a.Emulsion. Sources for scrub seal shall meet the requirements given in Article 804.01. The emulsion shall be a CMS -1PC for rejuvenating scrub seal meeting the requirements in Table 1. Table 1 Property Method Specification CMS-1PC Test on Emulsion Viscosity @ 77°F (SFS) AASHTO T 59 50-350 Residue, w%, minimum AASHTO T 59 60 pH ASTM E70 2.0-5.0 Sieve, w%, max. AASHTO T 59 0.1 Oil distillate, w%, max. AASHTO T 59 0.5 Test on Residue(1) Penetration @ 39.2 °F, 200 g, 60 sec., minimum AASHTO T 49 30 MSCR, 52 °C, Jnr, 3.2/kPa, max. AASHTO T 350 4.0 MSCR, 52 °C, % Recovery, 0.1/kPa, minimum AASHTO T 350 30 Test on Polymer: Tensile strength, die C dumbbell, psi, minimum ASTM D412 (2) 800 Swelling in rejuvenating agent, % maximum; 48 hours exposure @ 104°F ASTM D471(3) Modified 40% Test on Rejuvenating Agent: Flash point, COC, °F AASHTO T 48 380 Min Viscosity, 140°F, CST AASHTO T 201 15-175 Saturate, % by wt. ASTM D2007 30 Max Asphaltenes ASTM D2007 1.0 Max. Test on Residue from RTFO Weight Change, % AASHTO T 240 6.5 Max. Viscosity Ratio AASHTO T 201 3 Max
433.02 Materials.
1.Exception to AASHTO T59: Bring the temperature on the lower thermometer slowly to 350o F plus or minus 10o F. Maintain at this temperature for 20 minutes. Complete total distillation in 60 plus or minus 5 minutes from first application of heat.
2.Tensile Strength Determination: Samples for testing for tensile strength in accordance with ASTM D412 shall be tested with the following test procedure modifications: Prepare the polymer film, dilute the waterborne polymer to 40% Total Solids Content and pour 57 g into a Teflon or silicone release mold of dimensions 7’’ X 7’’ X ¼’’. Allow to dry at 23°C (73 °F) and 50% RH (controlled conditions) for 7 – 10 days total time, during which time the film should be flipped around once, preferably after 3 or 4 days. The film should be transparent in the end. To drive out any residual water, place the film in an oven at 50°C for 30 min. Dried film thickness should be 25 mil +/- 5 mils. Discard films <20 mil. Cut out dumbbell -shaped test specimens of dimension 75 mm total le ngth, 25 mm mid -section (L) and 4 mm width of mid -section. Grip in Instron machine with gap size 1 inch, use 8 inch/min cross -head speed.
3.Polymer testing shall be prepared from polymer as follows: Resistance to Swelling: Using a syringe, place 0.8 g m of latex into an 18 mm diameter DSR mold. Allow the sample to dry at ambient lab conditions (air conditioned) on the bench for 72 hours. Sample should be easily removable from the mold. Take the “button” out of the mold and place the sample into a force d air oven at 4 0°C (104°F) for 48 hours (on release paper). If at the end of the ambient dry, the sample sticks to the mold, place it into the oven and check it after 1 -2 hours. After 48 hours cool and weigh the sample to the nearest 0.0001 gram and recor d the weight. Put ½ inch of Rejuvenating Agent into a 3 oz penetration tin. Place the “button” on the Rejuvenating Agent , and add another ½ inch of Rejuvenating Agent , so that the “button” is covered. Put the cap on the penetration tin and place it into the 40°C oven for 48 hours. . Remove the “button from the Rejuvenating Agent , blot surface of the “button” to remove excess Rejuvenating Agent , cool the “button” to room temperature and weigh it. Calculate weight gain of the “button”, express as a percent. The emulsion manufacturer shall submit certification that the emulsion meets the specification. The polymer manufacturer, through the emulsion supplier and the contractor, shall submit to the Department test results from an approved laboratory and certif ication that the polymer is cationic and meets the required specifications. The manufacturer of the recycling agent, through the emulsion supplier and the contractor, shall submit the test results on the recycling agent and certification that the recyclin g agent meets the required specifications. Polymer films required for testing shall be prepared by the same laboratory testing the polymer performance requirements as outlined in the specification. The manufacturer of the recycling agent shall submit to the laboratory testing the polymer a one- quart sample of the recycling agent for use in the swell test. For the polymer, certification shall be from a laboratory with an ISO 17025 certification and accredited by IAS. Laboratories must be accredited in the test procedures specified above for the polymer and the rejuvenating agent. Certifications and test results on the emulsion, the polymer and the recycling agent shall be submitted to the Materials and Tests Engineer and approved prior to starting the work.
b.Aggregate. The aggregate shall be an ALDOT Size No. 89 or No. 89 Modified in accordance with the material requirements for bituminous surface treatments given in Section 801 and the modified No. 89 gradation below: Sieve % Passing ½” 100 ⅜” 90-100 #4 20-55 #8 0-15 #16 0-10 #50 0-5
433.03 Construction Requirements.
433.03 Construction Requirements.
a.Placement Rates and Temperature. The placement rate for the emulsion shall be from 0.25 to 0.35 gallons per square yard. The Engineer will require that the placement rate be adjusted up or down as necessary to fill the cracks in the roadway. The placement rate for the aggregate shall be from 18 to 25 pounds per square yard. The Engineer will require that the placement rate be adjusted so that no bleed through occurs during rolli ng.
b.Weather. The scrub seal shall only be applied when the air temperature is above 45 °F with the forecast high temperature being less than 100 °F. The application of the scrub seal shall be sto pped a minimum 24 hours prior to expected rain.
c.Surface Preparation. The area to be covered shall be cleaned of dirt, vegetation, and dust and other deleterious materials prior to the application of the surfacing. On pavements where the scrub seal is to be the fina l layer, the Contractor sh ould remove all existing thermoplastic striping, markings, and legends within the scrub seal limits prior to the scrub seal operation. If a subsequent surface treatment or pavement layer will be placed over the scrub seal, removal of the existing thermoplastic may not be required. Prior to the scrub seal operation, the Contractor shall remove all raised pavement markers including any excessive adhesive left on the pavement caused from the removal of raised pavement markers. Prior t o the scrub seal operation, all drain inlet covers, monument covers, and all other utility covers shall be protected from the Contractor’s scrub seal operations by applying a sheet of plastic over the exposed facilities, or other methods approved by the En gineer.
d.Test Section. The Contractor shall demonstrate the capability of meeting the placement requirements. The materials used in the test section shall be those that are proposed for production use. The Engineer will identify the location and length of the test section. The test section shall be one lane, 12 feet in width and up 1000 feet long. The Contractor shall verify in the presence of the Engineer the asphalt distributor’s and aggregate spreader’s calibrated application rates. If the application to the test section is unsuccessful, the Contractor shall make the necessary corrections and apply a new test section without additional compensation. The placement rate and adhesion of the emulsion and aggregate will be evaluated.
e.Equipment.
1.Asphalt Distributor. An asphalt distributor shall be furnished for the application of the asphalt emulsion. The distributor shall have a full circulating spray bar that is adjustable to at least 16 feet wide in two feet increments and is ca pable of heating and circulating the emulsion simultaneously. It shall have computerized rate control for adjusting and controlling the application from the cab. The rate shall be is adjustable by .01 gallons per square yard increments. The distributor sha ll also be equipped with a volume measuring device and a thermometer for measuring the emulsion temperature in the tank.
2.Emulsion Broom. The emulsion broom frame shall be constructed of metal. The emulsion broom shall be attached to and pulled by the di stributor truck. The emulsion broom must be equipped with a means of raising and lowering the emulsion broom at desired points. It shall be towable in the elevated position. The broom assembly shall be such that it does not squeegee the emulsion off the ro adway surface. The main body of the emulsion broom shall have a minimum frame size of 6.5 feet wide and 10 feet long. The maximum transverse rigid frame width at any point shall not exceed 6.75 feet. The nearest and furthest members, paralleling the back of the spreader truck, and diagonal members shall be equipped with street brooms. The leading member and the trailing member shall have brooms heads angled at 10 to 15 degrees off the centerline of the supporting member. The diagonal members shall have bro om heads attached in line with the centerline of the supporting member. Each individual street broom attached to the emulsion broom assembly shall be 3.5 inches wide x 6.5 inches high x 16 inches long and have stiff nylon bristles. Bristle height is to be maintained at a minimum of five inches (5”). The emulsion broom shall be equipped with hinged wing assemblies attached to the main
433.04 Method of Measurement.
body not to exceed 4.5 feet per side, with diagonals and equipped with street brooms. The purpose of the maximum rigid frame width and the hinged wing extensions is not only for maximum width of 16 feet but to maintain the scrubbing process evenly as contours and cross -sections change across the existing road surface.
3.Aggregate Spreader. A self -propelled spreader with computerized rate control shall be used to spread the aggregate. The spreader shall have front discharge and shall be capable of evenly distributing the aggregate at the required placement rates.
4.Rollers. Two pneumatic tire rollers shall be used to seat the a ggregate into the emulsion. The rollers shall be self -propelled. The minimum total weight of each roller shall be 5 tons.
5.Aggregate Removal Equipment. A mechanically powered pick -broom shall be furnished with a vacuum for the removal of excess aggrega te.
f.Material Application. The emulsion broom shall be pulled behind the emulsion distributor immediately after the application of the emulsion. All cracks in the pavement shall be filled by emulsion by the movement of the weighted emulsion broom through the emulsion. The aggregate shall be dry during spreading. The aggregate shall be evenly spread over the scrubbed emulsion. The seal should be rolled immediately after the aggregate is applied. There shall be at leas t three passes made with a pneumatic roller. The scrub seal system shall be stiff enough to allow sweeping up excess aggregate without damage to the pavement surface. The excess aggregate shall be removed with the vacuum broom within two hours of rolling o r as directed by the Engineer. The roadway shall not be opened to traffic until at least two hours after the completion of the placement of the emulsion and aggregate. The Engineer may require a second power sweeping to remove any loose aggregate. Excess a ggregate shall be removed from the project unless otherwise approved by the Engineer. For inner layer applications the scrub seal shall be sufficiently cured prior to placing a bituminous overlay, micro -surfacing, or other asphalt surface treatments. The E ngineer will require a second power sweeping of the scrub seal surface at least two hours after completion of the placement of the emulsion and aggregate to determine the status of the scrub seal being cured. The ability to sweep all loose aggregate from t he surface without removing any aggregate adhered to the bituminous emulsion shall determine that the scrub seal is cured. Longitudinal joints shall not overlap. The longitudinal construction joint shall coincide with the painted lane line or at the outsi de edge of shoulder.
g.Sampling. A minimum of one daily sample of the aggregate will be taken from the application vehicle and tested for gradation. If the average test results vary from the gradation requirements, production shall stop. The Contractor s hall identify the cause and document in detail what corrective action was taken. Documentation of the corrective action shall be furnished to the Engineer before placement will be allowed.
h.Acceptance. The Contractor shall be responsible for the mainte nance of the surface treatment until the work is accepted by the Engineer. Damage or loss of aggregate in the surface exceeding 2 % of the surface area in any 500 -foot-long section shall be repaired by use of additional emulsion and aggregate. All bleeding (excess asphalt) surfaces shall be covered with additional concrete sand in such a manner that the asphaltic material will not adhere to or be picked up by the wheels of vehicles. If in the Engineer’s judgment, defective areas warrant removal, the Contrac tor shall remove and replace those areas at the Contractor’s expense with materials meeting specification requirements.
433.04 Method of Measurement.
Scrub seal will be measured in units of square yards.
450.02 Materials.
433.05 Basis of Payment.
a.Unit Price Coverage. The unit price of the scrub seal shall be full compensation for all materials, equipment, tools, and labor required for furnishing and placing the scr ub seal, for removing and disposing of raised pavement markers, and for post -sweeping. If removal of thermoplastic striping, markings, or legends is required, it will be paid for under Item 701D or Item 703C.
b.Payment will be made under Item No.: 433-A Scrub Seal - per square yard SECTION 450 PORTLAND CEMENT CONCRETE PAVEMENT
450.01 Description.
The work covered by this Section consists of constructing a pavement of Portland Cement Concrete.
450.02 Materials.
a.References for Material Requirements . All materials shall conform to the requirements given in Division 800, Materials. The requirements given in the following Sections are directly applicable to the materials furnished for the concrete pavement: • Section 801 Coarse Aggregate • Section 802 Fine Aggregates • Section 804 Bituminous Materials • Section 806 Mineral Admixtures • Section 807 Water • Section 808 Air Entraining Additives • Section 809 Chemical Admixtures for Concrete • Section 815 Cement • Section 830 Concret e Curing Material • Section 832 Concrete Joint Fillers, Sealers, and Waterstop Material • Section 835 Steel Reinforcement
b.Aggregates .
1.Fine Aggregate . Fine aggregate shall be ALDOT Size No. 100 Concrete Sand meeting the requirements of Section 802. Sand shall be natural sand except that it may include 20 percent crushed quartzite particles. A blend of two natural sands will be permitted if a written request is submitted to the Mate rials and Tests Engineer for approval .
2.Coarse Aggregate.
a.Gradation. Each component size shall be stockpiled separately at the batching plant.
b.Type of Coarse Aggregate. Coarse aggregate shall be granite, sandstone, quartzite, or gravel with a speci fic gravity greater than 2.550 (specific gravity requirement applies to gravel only). Gravel with a specific gravity less than or equal to 2.550 will not be allowed. Aggregates that tend to polish under traffic, such as limestone, dolomite, or marble, sha ll be permitted as noted in the following table.
Source: Alabama Standard Specifications for Highway Construction, 2022 Edition. Pages 248–251 of 934.