401.01 Description.
Division 400
SURFACING AND PAVEMENTS 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, a nd 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 pri me 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, al l 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. (Example: A bituminous treatment Type A KG, specifies a prime coat with the quantities specified on line "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 on line "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, th e 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).
401.02 Materials.
BITUMINOUS TREATMENT TABLE SUBARTICLE 401.01(b) Aggregates **** Gallons {Liters} of Bituminous Material per square yard {m²} of Treatment ** Designated Letter Type Treatment Size cu. ft./ sq. yd. {m³/m²} Liquid Asphalt Binder Emulsified Petroleum Resin, Cutback or Emulsified Asphalt A Prime Coat 0.22 – 0.25* {1.00 - 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} * On cement treated layer, reduce prime bituminous amounts 20 percent. ** 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 a pplication for uniform coverage. Minor adjustments to these rates may be ordered by the Engineer to fit the physical properties of aggregates furnished for use. 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 Materi als.
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, 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 *
401.03 Co nstruction Requirements.
* 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 from 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 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 a ccordance 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: • 500 vehicles or less per day - No restrict ions apply. • 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 slag or lightweight aggregates (expanded clays or shales p roduced by the Rotary Kiln Method). • 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 bit uminous 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 applica tions 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 in to 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 a nd amount of equipment to provide the desired results, but the following basic items shall be provided. In addition,
401.03 Construction Requirements.
all equipment necessary for the proper prosecution of the work shall be assembled on the site and must be approved and in good working orde r 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, at a pressure between 30 psi {200 kPa} to 75 psi {500 kPa}, 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 det ermining 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 re quired 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 h aving 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.Seasonal No Bituminous Surface Treatment, which will be exposed to traffic, including shoulder paving, shall be placed between the dates of October 1 and May 1 in North Alabama and between the dates of November 1 and April 1 in South Alabama regardless of weather conditions. For the purpose of identification, South Alabama shall be referred to for projects lying partly or wholly in the area of the State lying south of latitude 33°N and with North Alabama encompassing the remaining or northern portion of the State. This seasonal limitation will not apply to Prime Coat.
2.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 o f 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 treatm ents (B, C, D, etc.) shall not be placed when the air temperature is below 60 °F {15 °C}.
3.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 i s 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.Prepara tion 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.
401.03 Construction Requirements.
d.Application of Bituminous Material .
1.General . No bitumin ous 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 wit hin 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 prim e 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 ap plication, unless otherwise directed. Where only a partial width is treated in one application, extreme care shall be used to insure a slight overlap of adjacent treatments, but not in excess of 4 inches {100 mm}. The spray bar shall be adjusted to the pro per height for exact single or double overlap of spray area without partial overlap. Uniformity of discharge shall be checked before beginning application and at other times as directed. Streaked areas and any other areas lacking uniform distribution shall immediately be made uniform. In all cases the distributor shall be stopped before the application begins to run light (just before the distributor tank is completely empty). A method of making joints shall be used that will insure that in beginning and ending the distribution of each load, a proper junction is made with the preceding and succeeding work without excessive bituminous material at the joints. In applying bituminous materials, the Contractor shall use effective means to protect structures, walls, curbs, etc. from discoloration or spattering.
4.Special Details. Before applying a prime coat, the surface shall be prepared as provided in Subarticle 401.03(c) above and, if necessary, it shall be sprinkled with water. After the prime coat has been applied, the contractor shall keep all traffic off the road until, in the opinion of the Engineer, the prime coat is dry and cured. When directed, the Contractor shall, without extra compensation, spread the minimum necessary amount of approved clean, coarse sand over the bituminous prime to prevent its breaking up under traffic or to speed up curing. No overlying surface shall be placed until the prime coat has been approved by the Engineer. The Contractor shall, without extra compensation, maintain the pri me treatment and the surface of the base intact until it is covered by an application of a surfacing material. Maintenance shall
401.06 Basis of Payment.
include satisfactory repair to all holes, ravels, depressions, and areas deficient in prime so that the prime surface shall be smooth and of uniform texture before placing of an overlying surface.
e.Spreading and Embedding Aggregate . The size and amount of aggregate used shall be in accordance with provisions of Subarticle 401.01(b) for the type treatment required by the plans o r proposal. Spreading of aggregate shall follow application of bituminous material as closely as practicable using mechanical aggregate spreaders; inaccessible areas shall be covered as directed. Sufficient aggregate to cover each distributor load, in loaded trucks along with an adequate crew of workmen equipped with brooms standing by, shall be at the site before bituminous application begins. Spreading of the aggregate shall begin and continue immediately behind the application of the bituminous material. However, if excessive rolling of the aggregate occurs during spreading, the Engineer may allow the chip spreader to delay slightly in order to hold aggregate rolling to a minimum. Rolling shall begin immediately behind the spreading operation. Sufficient rollers shall be furnished to insure that the initial pass of the roller is made within five minutes of the spreading of the aggregate. Rolling shall be continuous, providing coverage of the entire area of treatment to insure thorough embedment of the aggr egate. Unless a sufficient number of rollers are in operation to complete the above requirement, the next load of bituminous material shall not be applied until the rolling of the previous application is completed. When the Engineer determines the aggregat e has been thoroughly embedded, rolling shall cease and the Contractor shall, without delay, remove all excess aggregate from the treatment area.
f.Special Construction Requirements for placing of Bituminous Treatment "L" . When placing surface treatment "L", special emphasis will be placed on not allowing either public or construction traffic over the work while placing of the treatment; if this cannot be avoided, it shall be well controlled and kept to a minimum. The sequence of placement of the material shall be as follows: 1st Step - Cleaning of surface and applying the first application of bitumen at the rate shown in Subarticle 401.01(b). 2nd Step - Placement of cover aggregate so as to have a uniform cover in contact with the asphalt. The surface should then be rolled with a light roller to key the aggregate with the asphalt. 3rd Step - Place dry choke aggregate and continue rolling and brooming until voids are filled. 4th Step - Apply 2nd application of hot bitumen at rate shown in Subarticle 401.01(b). 5th Step - Apply 2nd application of aggregate and continue brooming and rolling until the voids are filled and the aggregate is keyed to the asphalt.
401.04 Maintenance and Protection of Surface and Traffic.
Maintenance shall include immediate repair of any failures or defects that occur, repeated as often as is necessary to keep the surface continuously intact and acceptable. Maintenance shall be performed without direct compensation. Unless otherwise specified on the plans or in the proposal, the Contractor shall handle traffic through the work and over the surface except while bituminous material is actually being applied and covered with aggregate. It shall be his responsibility to take whatever steps are necessary or directed to protect both the work and the traveling public.
401.05 Method of Measurement.
Measurement will be made of the number of square yards {square meters} of accepted bituminous treatment, complete in place. The length shall be the actual length measured along the surface of the treatment. The width shall be the designated width of completed surface. Where the pay item specifies a prime coat plus an overlying treatment, the measurement will not include the additional width of the prime coat. Where the pay item spec ifies a prime coat only, the width will be the specified width of the prime coat.
401.06 Basis of Payment.
a.Unit Price Coverage . Payment for accepted bituminous surface treatment, or bituminous surface treatment with polymer additive, Pay Item No. 401- B, measured as provided above, will be paid for at the contract unit price per square yard {square meter} complete in place for the type of bituminous treatment specified in the proposal by the type designation letter or letters; except that adjustments in the
402.01 Description.
contract unit price shall be made as follows: When changes in amounts of treatment materials are ordered as provided in Article 401.01, the contract unit price will be adjusted upward or downward accordingly. Adjustment will be based on the increase or decrease in amounts per square yard {square meter}, at the verified cost, f.o.b. delivery point plus 2 cents per gallon {0.5 cent per liter} for the bitumen, and the verified cost per square yard {cubic meter} for the aggregate delivered to the spreader. The contract unit price or adjusted contract unit price for the accepted area complete in place shall be payment in full for furnishing all material, placement of materials, maintenance thereof and for all equipment, tools, labor, and incidentals necessary to complete the work.
b.Payment will be made under Item No .: 401-A Bituminous Treatment Type designation letter/letters, Type of bitumen, if specified - per square yard {square meter} 401-B Bituminous Treatment Type designation letter/letters, Type of bitumen, if specified (With Polymer Additive) – per square yard {square meter} SECTION 402 SLURRY SEAL COAT
402.01 Description.
This Section shall cover the work of constructing a surface course approxim ately 1/8 to 3/8 of an inch {3 to 10 mm} in thickness placed on existing paved surfaces in accordance with these specifications and within reasonably close conformity to the lines, grades, and widths shown on the drawings and as specified.
402.02 Materials .
a.Asphalt Emulsion . CQS-1h or CQS -1hp shall meet the requirements of Section 804.
b.Aggregate . Aggregate shall meet the appropriate requirements of Section 801 and 802 with lightweight aggregate and manufactured sand made from limestone added to the list of approved stones.
c.Filler . Filler, if required, shall meet the requirements of Section 805.
d.Water . The water shall be potable and free from harmful soluble salt.
e.Composition of Mixtures . The aggregate, asphalt emulsion, water and, if required, filler meeting the requirements herein specified, shall conform to the composition by weight {mass} percentages as specified by the Engineer, but within the limits of Table A of this Section. Type I. This aggregate blend is used to seal cracks an d fill voids. It should be used on areas where a minimum wearing surface and a maximum seal is desired. This fine gradation requires an application rate of 4 to 10 pounds {2 to 5 kg} of dry aggregate per square yard {square meter}. Type II. This aggregate blend is used to give crown corrections and a moderate wearing surface. This surface course shall be used in areas that require this size of aggregate to fill in voids and leave a substantial wearing surface. This gradation requires an application rate of 10 to 20 pounds {5 to 10 kg} of dry aggregate per square yard {square meter} resulting in a surface thickness of approximately 1/8 to 3/8 of an inch {3 to 10 mm}. The slurry seal shall meet the requirements of Subarticle 410.02(b) where applicable.
Source: Alabama Standard Specifications for Highway Construction, 2022 Edition. Pages 183–188 of 934.