00706.00 704 Section 00706 - Emulsified Asphalt Slurry Seal Surfacing Description
00706.00 Scope - This Work consists of applying one or more layers of slurry seal consisting of
Emulsified Asphalt , water, Aggregate, and additives on a prepared surface as shown or directed. Materials
00706.10 Emulsified Asphalt - Furnish CQS -1h Emulsified Asphalt meeting the following
requirements when tested according to AASHTO T 59: Saybolt Viscosity, seconds at 77 °F ..................... 15 - 50 Residue from Distillation, Weight % ..................... 57% minimum Sieve Test, % Retained on No. 20 Sieve ............. 0.1 maximum Particle Charge, Electroplate ................................ (informational) Settlement (Storage Stability), 24 hour ................. 1% maximum Cement Mixing Test ............................................. (informational) The residue shall meet the following requirements : Penetration at 77 °F, 3.5 ounces, 5 sec ............... 40 - 90 minimum Solubility in CS 2 or TCE ........................................ 97.5 minimum Ductility at 77 °F, inch ........................................... 15.7 minimum
00706.11 Polymer Modified Emulsion - Furnish CQS -1h polymer modified emulsion. The polymer
modifier shall be either a solid synthetic rubber or latex material. Combine the polymer modifier with the base asphalt or asphalt emulsi on, prior to loading at the manufacturing plant, at the minimum rate of 2.5 to 3 percent polymer solids by weight of asphalt. The polymer modified emulsion shall be compatible with the mix design developed for the conventional slurry seal. Each shipment of Emulsified Asphalt shall be accompanied by a certificate of analysis or certificate of compliance from the manufacturer.
00706.12 Aggregate - The Aggregate used shall be clean, angular, durable, well graded and
uniform. The Aggregate shall consist of broken stone, crushed G ravel, slag or a combination of them. To assure the Material is totally crushed, 100 percent of the parent Aggregate shall be larger than the largest stone in the gradation to be used. Aggregate gradation shall meet one of the following types: 00706.15 TYPE I - Parking Areas, Urban and Residential Streets, Airport Runways TYPE II - Urban and Residential Streets, Airport Runways TYPE III - Primary and Interstate Routes Sieve Size Percent Passing Percent Passing Percent Passing Stockpile Tolerance 3/8" 100 100 100 0 No. 4 100 90 - 100 70 - 90 ± 5% No. 8 90 - 100 65 - 90 45 - 70 ± 5% No. 16 65 - 90 45 - 70 28 - 50 ± 5% No. 30 40 - 65 30 - 50 19 - 34 ± 5% No. 50 25 - 42 18 - 30 12 - 25 ± 4% No. 100 15 - 30 10 - 21 7 - 18 ± 3% No. 200 10.0 - 20.0 5.0 - 15.0 5.0 - 15.0 ± 2.0% The job mix gradation shall be within the gradation band for the desired type. After the target gradation has been submitted then the percent passing each sieve shall not vary by more than the stockpile tolerance and still remain within the gradation band.
00706.13 Additives and Mineral Filler - Liquid retardant and mineral fillers may only be used when
their quantity can be metered. The use of additives in the slurry mix, (or individual Materials), shall comply initially with the quantities predetermined by the mix design, or with field adjustments if required, after approval by the Engineer . Portland cement, hydrated lime, limestone dust, fly ash or other approved filler required by the mix design shall meet the requirements of ASTM D242, and shall be considered as part of the dry Aggregate.
00706.14 Water - Water shall be potable, free of harmful salts and contaminants, and compatible
with the slurry mix. Water used in mixing or curing shall be reasonably clean and free of oil, sugar, organic matter or other substance injurious to the finished product.
00706.15 Job Mix Formula - Prior to the pre -construction conference, submit a signed slurry seal
mix design for the specific Materials to be used on the Project. Show the percentages of each individual Material required on the mix design report . The complete mix design shall be made with the same Aggregate gradation that will be used on the Project. After the mix design has been approved no substitution will be allowed unless approved. Water, not exc eeding 11 percent by weight to asphalt emulsion, shall be used to develop a good mix.
a.Laboratory Evaluation - Have the mix design prepared and tested by a laboratory which has experience in designing Emulsified Asphalt slurry seal Surfacing . Determine the proportions of component Materials and perform the tests described in 00706.15(b). The final mix design shall meet the limits described in 00706.15(b) and 00706.15(c). 00706.15 706 (b) Mix Design Tests: Test Description Specification ISSA TB -106 Slurry Seal Consistency ISSA TB -139 (For quick -traffic systems) Wet Cohesion, 30 minutes set 60 minutes set 0.10 lb. -in. min. 0.17 lb. -in. min. ISSA TB-109 (For heavy traffic areas only) Excess Asphalt by LWT and Sand Adhesion 1 lb./sq. yd. max. ISSA TB -114 Wet Stripping Pass (90% minimum) ISSA TB-100 Wet Track Abrasion Loss One hour soak 1.5 lb./sq. yd. max. ISSA TB-113 Mix Time * Controllable to 180 sec. minimum * The mixing test and set time test should be done at the highest temperatures expected during construction. The wet track abrasion test is used to determine the minimum asphalt content. The mixing test is used to predict how long the material can be mixed in the machine before it begins to break. The laboratory shall also report the quantitative effects of moisture content on the unit weight of the Aggregate (bulking effect). The report shall clearly show the proportions of Aggregate, the minimum and maximum proportions of mineral filler and water, additive usage, and asphalt emulsion based on the dry weight of the Aggregate. All the component materials used in the mix design shall be representative of the materi als proposed for use on the Project. Show the percentages of each individual material required in the laboratory report. Adjustments may be required during the construction, based on the field conditions. The Engineer will give final approval for all such adjustments.
c.Component Materials - The Engineer will approve the mix design, all slurry seal materials and methods prior to use. The component materials shall be within the following limits: • Residual Asphalt: • Type I - 10% - 16% • Type II - 7.5% - 13.5% • Type III - 6.5% - 12% • Based on dry weight of Aggregate • Mineral Filler: • 0.5% - 2.0% • Based on dry weight of Aggregate • Additives - As needed. • Water - As needed to achieve proper mix consistency. Total mix l iquids shall not exceed the loose Aggregate voids. Use ISSA T106 to check optimum liquids. 00706.21 707 00706.16 Tolerances and Limits - Tolerances for individual materials as well as the slurry seal mixture during production are as follows: • After the designed residual asphalt content is determined, a plus or minus one percentage point variation will be allowed. • The percentage of Aggreg ate passing each sieve shall be within the stockpile tolerance range as stated in 00706.12. • The percentage of Aggregate passing shall not go from the high end to the low end of the specified range of any two successive sieves. • The slurry consistency shall not vary more than plus or minus 0. 2 inch from the job mix formula after field adjustments. • The rate of application, on ce determined by the Engineer, shall not vary more than plus or minus 2 pound per square yard while remaining within the design application rate.
00706.17 Quality Control - Be responsible for qualit y control as required by Section 00165. Perform
quality control sampling and testing as follows:
a.QC/QA Slurry Seal Program - Test gradation, mixture, moisture, and asphalt according to Section 00165 .
b.Slurry Seal Production (Gradation): • Stockpile - Every 60,000 square yards. • Tanker - Every 60,000 square yards. • Mixture - To be taken directly out of pug mill every 60,000 square yards.
c.Verification Testing - If comparisons of test results are outside the allowable differences, the Contractor and Engineer will investigate the reason. The Engineer may stop production while the investigation is in progress if the potential for Pavement failure is present. The investigation may include review of calculation, testing of the remaining samples, review and observation of Contractor testing procedures and Equipment , and a comparison of sample test results. Equipment
00706.20 Equipment - Provide suitable surface preparation Equipment , traffic control Equipment ,
hand tools and any other support Equipment required as necessary to perform the Work .
00706.21 Mixing Equipment - The machines shall be specifically designed and manufactured to lay
slurry seal. Mix slurry seal in continuous pug mill mixers; a self -propelled machine specifically designed and manufactured to accurately deliver and proportion the Aggregate, Emulsifi ed Asphalt , mineral filler, control setting additive and water to a revolving blade mixer that discharges the thoroughly mixed product on a continuous flow basis. Concrete transit mixer trucks shall not be used. Minimum slurry seal machine size shall be 7 cubic yards. In the case of Equipment failure have a minimum of two machines on -site with another off site for immediate backup. The machine shall be capable of mixing materials at pre-set proportions regardless of the speed of the machine and without changing machine settings. The mixing machine shall be equipped with an approved fine feeder that provides an accurate metering device or method to introduce a predetermined proportion of mineral filler into the mixer at the same time and location that the Aggregate is fed. Use the fine feeder whenever added mineral filler is a part of the Aggregate blend. 00706.22 708 The mixing machine shall be equipped with a water pressure system and fog type spray bar adequate for complete fogging of the surface preceding spreading Equipment .
a.Proportioning Devices - Provide and properly mark individual volume or weight controls, such as revolution counters or similar devices, for proportioning each material to be added to the mix (for example; Aggregate, mineral filler, add itive, Emulsified Asphalt and water). Instruct the Engineer how to calculate the application rate per square yard utilizing the Contractor's proportioning devices.
b.Calibration - Calibrate, in the presence of the Engineer, each slurry mixing unit to be used on the Project prior to construction. Previous calibration documentation covering the exact materials to be used may be accepted by the Engineer provided they were made during the calendar year. The documentation shall include an individual calibration of each material at various settings, which can be related to the machines metering devices. No machine will be allowed to Work on the Project until the calibration has been completed and accepted.
00706.22 Spreading Equipment - Spreader Box - Attach to the mixer machine a mechanical type
squeegee distributor equipped with flexible material that is in contact with the Pavement surface to prevent the loss of slurry from the distributor. Adjust the distributor to prevent the loss of slurry on varying grades and crown and to assure uniform spread. There shall be a steering device and a flexible strike-off. The spreader box shall have an adjustable width. Keep the spreader box reasonably clean, and do not allow buildups of asphalt and Aggregate. Only one tail rubber will be allowed. Any type of drag used shall be subject to approval by the Engineer and kept in a completely flexible condition at all times.
00706.23 Rollers - If required by Special Provision, rollers shall be self-propelled, steel-wheeled or
pneumatic-tired type and be equipped with a water spray system. Steel-wheeled rollers shall be capable of providing a weight of not less than 2,400 pounds per foot width of the compression roll or rolls. Pneumatic-tired rollers shall be capable of exerting a ground pressure of not less than 80 pounds per square inch of tire contact area. Labor
00706.30 Quality Control Personnel - Provide a technician having a CAT-I technical certification.
Construction
00706.40 Weather Limitations - Do not apply the slurry seal if either the Pavement or air
temperature is below 50 °F and falling. The slurry seal may be applied when both the Pavement and air temperature are above 45 °F and rising. Do not apply if there is a danger that the finished product will freeze before 24 hours. Do not apply when weather conditions prolong opening to traffic beyond a reasonable time. Do not apply in the rain. Replace slurry damaged by rain after application according to the Specifications, and as determined by Engineer, at no additional cost to the Agency. Clean the street of all remaining slurry mix materials prior to re-application. Adjust the rate of application of the fog spray during the Day to suit temperatures, surface texture, humidity and dryness of Pavement surface. Do not spray additional water into the spreader box.
00706.41 Preparation of Surface - Submit details of the proposed street cleaning for approval by
the Engineer prior to the preconstruction conference. Remove any organic materials in cracks or joints not removed during crack sealing as part of the Pavement preparation. 00706.43 Pavement preparation shall consist of removal of all oil spills, flushing and sweeping. Complete flushing, as needed, prior to sweeping. Finish sweeping with a vacuum sweeper no more than 24 hours prior to application of the slurry seal. If there is a delay of more than 48 hours between sweeping and slurry sealing caused by weather conditions or other unforeseen circumstances, re-sweep as determined by the Engineer, at no additional cost to the Agency. Prepare the Pavement on which the slurry seal is to be placed as follows, as directed.
a.Base Repairs - Where determined by the Engineer, excavate and replace Surfacing materials according to Section 00748.
b.Surface Repairs - Where the Pavement is severely cracked, rutted, deformed or otherwise distressed, place a Leveling Course or patch using 3/4" or 1/2" ACP. The class of mix to be used shall conform to Sections 00744 and 00745, as applicable. Place the mixture according to Sections 00744 and 00745, as applicable.
c.Crack Sealing - Clean and fill cracks 1/8 inch and larger inside the proposed slurry seal area.
d.Tack Coat - On old, dry bituminous Pavements and on rigid Pavements, the Engineer may direct that tack coats be applied prior to placing the slurry seal. The tack coat shall be a diluted asphalt emulsion of the same type and grade specified for the slurry mix. The ratio of asphalt emulsion to water shall be 1:3. Apply the diluted material uniformly with a pressure distributor at a rate between 0.05 to 0.10 gallon per square yard, as determined by the Engineer. The tack coat shall be cured thoroughly prior to the application of the slurry seal.
e.Street Equipment and Procedure - Immediately prior to applying the slurry seal, clear the surface of all loose material, silt spots, vegetation, oil spots and other objectionable material. Any standard cleaning method will be acceptable. If water is used, allow cracks to dry thoroughly before slurry sealing. The Engineer will approve the surface preparation prior to sealing.
f.Utility Covers - Protect manholes, valve boxes, drop inlets and other service entrances from the slurry seal by a suitable method. Clean these covers as quickly as possible after the application of the slurry seal and definitely prior to the final set. If necessary, clean slurry residual from the interior of the utilities.
g.Pavement Markings - Cover, or remove, all reflector buttons before slurry seal is to be applied to any area, as determined by the Engineer. Cover all thermo-tape markings and do not slurry seal over, or remove and replace as directed. Remove all paint pavement markings to prevent bleeding through the slurry seal and to allow proper adhesion.
00706.42 General - The surface may be wetted by fogging ahead of the slurry box, if required by
local conditions. Apply water used in wetting the surface at such a rate that the entire surface is damp with no apparent flowing water in front of the slurry box. The slurry mixture shall be of the desired consistency upon leaving the mixer. Do not add additional elements. Carry a sufficient amount of slurry in all parts of the spreader at all times so that complete coverage is obtained. Do not allow lumping, balling or unmixed Aggregate in the spreader box. Do not allow segregation of the emulsion and Aggregate fines from the Coarse Aggregates. If the Coarse Aggregate settles to the bottom of the mix, remove the slurry from the Pavement. Do not allow excessive breaking of the emulsion in the spreader box. Do not leave streaks, such as caused by oversized Aggregate, in the finished Pavement. Maximum mixing time in the pug mill shall be 4 minutes.
00706.43 Application Rate - The minimum rate of application of dry Aggregate per square yard will
be determined by the Engineer. The depth of the slurry seal shall be sufficient to correct surface conditions, fill surface voids, and provide sealing and a minimum wearing surface. The maximum allowable vehicle speed for the rate of application shall be 180 feet per minute. Failure to demonstrate 00706.44 the proper rate of application will result in suspension of the Work until the Contractor can demonstrate otherwise, at no additional cost to the Agency. ISSA TB112 gives a method to determine expected application rates. The slurry seal mixture shall be of proper consistency at all times to provide the application rate required by the surface condition. The average application rate, as measured by the Engineer, shall be according to the following table: Recommended Use Application Rate TYPE I Parking Areas, Urban and Residential Streets, Airport Runways 6.7 - 10.0 lbs./sq. yd. TYPE II Urban and Residential Streets, Airport Runways 10.0 - 16.7 lbs./sq. yd. TYPE III Primary and Interstate Routes 15.0 - 25.0 lbs./sq. yd.
00706.44 Applying Slurry Seal Sample Strip - The strip shall consist of two Panels approximately
50 feet long, placed side by side to form a typical seam between them. The width of the Panels shall be the same as the Contractor plans to use on the streets. Place the strip at least 24 hours prior to the beginning of the actual Work. Use the strip to calculate and monitor the rate of application in relation to weight of material per area, and to define the speed of the Equipment related to the rate of application. If it is determined by the Engineer on the basis of this test strip that there are deficiencies in the mix design, method of application and rate of application, the Engineer may require the Contractor to revise the mix design, or repair or modify the Equipment or application. After all changes are made, lay a new sample strip.
00706.45 Joints - Construct a uniform line along the edge and a good seal at curb lines. Construct
the flow line at curbs to allow storm drainage flow to catch basins without bonding along the curb line. In the case of a concrete gutter, cover the gutter line joint with the slurry seal, but do not overlap onto the gutter. Remove any overlap, as determined by the Engineer, at no additional cost to the Agency. Streets that have been recently slurry sealed that cross this Project shall not be slurry sealed again. The slurry joints and Panels shall be straight, neat and uniform and follow the contour of the existing curb or concrete gutter. The width of the Panels shall be the same as demonstrated in the sample strip. Floating (adding additional water other than what is required for the approved mix design) of the emulsion or slurry mixture in the pug mill or spreader box to cover or overlap missed areas will be prohibited. Keep lines straight at intersections to provide a good appearance.
00706.46 Handwork - Use approved squeegees to spread slurry in areas not accessible to the slurry
mixer. Limit handwork at the beginning and end of the Panels to prevent segregation of the Rock from the emulsion and to minimize cosmetic drag mop marks or defects in the finished product. The same type finish as applied by the spreader box shall be required. Complete handwork prior to setting of the slurry.
00706.47 Curing - The rate of curing of the slurry seal shall be such that a street may be opened to
traffic after application without tracking or damage to the surface. Protect the area for the full curing period with suitable barricades or markers. The Agency will not be responsible for any damage to the slurry seal prior to opening the area. Repair all damage to the slurry, to the satisfaction of the Engineer, at no additional cost to the Agency. 00706.90
00706.48 Rolling - If required by Special Provision, apply a minimum of two full Coverage Passes to
the surfaced areas by the roller, or as directed.
00706.49 Cleanup - Remove all debris associated with the performance of the Work on a daily basis.
Temporary
00706.51 Provision for Traffic - Be responsible for notifying all abutting property owners along the
streets according to the approved schedule, or an approved revision of the schedule, 48 hours prior to the specific Work. Remove all traffic control promptly when it is determined that the street may be open to traffic. Do not seal any street that requires closing overnight without the approval of the Engineer. If the slurry seal does not cure in a timely manner and remains trackable overnight, apply a covering of 1/4 inch minus Material to prevent tracking and related property damage prior to permitting traffic on the street at no additional cost to the Agency. Be responsible for all damage to the uncured slurry or to private or public property due to tracking of the uncured Material. Measurement
00706.80 Measurement - Crack sealing will be measured on the length basis, of Material in place.
Slurry seal will be measured on the area basis. Asphalt concrete Pavement repair will be measured according to 00748.80. Payment
00706.90 Payment - The accepted quantities of Work performed under this Section will be paid for
at the Contract unit price, per unit of measurement, for the following items: Pay Item Unit of Measurement
a.Slurry Seal Crack Sealing ..................................................................... Foot
b.Slurry Seal ...................................................................................... Square Yard Payment will be payment in full for furnishing and placing all Materials, and for furnishing all Equipment, labor, and Incidentals necessary to complete the Work as specified. Asphalt concrete Pavement repair will be paid for according to 00748.90. When the Contract Schedule of Items does not indicate payment for Work under this Section, no separate or additional payment will be made. Payment will be included in payment made for the appropriate items under which this Work is required. 00710.00
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Source: Oregon Standard Specifications for Construction, 2024 Edition. Pages 770–777 of 1,268. View official source ↗