5-1 Division 5 – Hot Mix Asphalt Pavements
AND SURFACE TREATMENTS Section 501. Plant -Produced Hot Mix Asphalt ................................................... 5-3 Section 502. HMA Crack Treatment ................................................................ 5-26 Section 503. Paver -Placed Surface Seal ........................................................ 5-31 Section 504. Micro -Surfacing .......................................................................... 5-36 Section 505. Chip Seals .................................................................................. 5-47 Section 506. Slurry Seal .................................................................................. 5-56
5-2 Notes
5-3 Section 501. Plant -Produced Hot Mix Asphalt
501.01. Description This work consists of providing and placing h ot mix asphalt ( HMA ) mix using Superpave mixture design methods.
A.Definitions Binder Content. Percent by weight of asphalt cement in the total mixture. Broken Aggregate. Cracked aggregate caused by construction operations. Bulk Specific Gravity of Aggregate (G sb). Ratio of the oven dry weight in air of a unit volume of an aggregate at a stated temperature to the weight of an equal volume of water at a stated tem perature. Crack. Visible fissure of varying length and orientation in the HMA, partially or completely through at least one course. Effective Specific Gravity (G se). Ratio of the oven dry weight in air of a unit volume of an aggregate (excluding voids perm eable to asphalt) at a stated temperature to the weight of an equal volume of water at a stated temperature. Flushing. Shiny or reflective condition, tacky to the touch, appearing on the HMA surface when asphalt binder collects in the voids at high pavement temperatures. HMA Mix Design. Selection and proportioning of aggregates, mineral filler, reclaimed asphalt pavement (RAP), and asphalt binder to meet the required mix design criteria. HMA Segregation. Areas of HMA pavement exhibiting non- uniform distribu tion of coarse and fine aggregate particles, visually or otherwise identifiable. Job Mix Formula (JMF). HMA mix for a specific project, including adjustments to optimize the field application. Lot. A lot is made up of a discrete tonnage of one mixture. A lot typically has five sublots (see definition of “sublot”) . Maximum Specific Gravity of Mixture (G mm). Ratio of the weight in air of a unit volume of an uncompacted HMA at a stated temperature to the weight of an equal volume of water at a stated temperature. Pavement. Completed HMA placement, including layers on driving lanes and shoulders. Pavement Edge. Extremity boundaries of the pavement. MDOT Standard Specifications for Construction Section 501
5-4 Roller Cracking. High-density surface map-cracking that appears
immediately after rolling. Rutting. Depression or displacement of the HMA surface that occurs in a longitudinal direction or a localized area. Quality Assurance (QA). All activities dealing with acceptance of the product, including but not limited to materials sampling, testing, construction inspection, and review of Contractor quality control ( QC) documentation. The Engineer ’s HMA QA procedures are contained in MDOT’s HMA Production Manual and MDOT’s HMA QA Plan . Quality Control (QC). All activities dealing with process control to ensure quality, including but not limited to training, materials sampling, testing, project oversight , and documentation. For example, the Contractor ’s HMA QC procedures are contained in the Contractor’s HMA QC Plan . Sublot. Portion of a lot or an individual sample that is represented by a complete set of QA tests. Sublots are approximately equal in size at 1,000 tons. The Contractor and the Engineer may agree to reduce the typical 1, 000-ton sublots based on project staging or other project condi tions. Target Value. JMF parameter value that may be adjusted, if approved by the Engineer, to account for changes in the physical properties of the mixture. Temporary Pavement . Roadway and appurtenances constructed to help the movement of highway and pedestrian traffic around a construction operation that will be removed upon completion of the project. Unlimited Daily HMA Production . Unrestricted daily HMA production tonnage. Voids in Mineral Aggregate (VMA). Volume of void space between the aggregate part icles of a compacted paving mixture that includes the air voids and the asphalt binder not absorbed into the aggregate, expressed as a percent age of the total volume of mixture. MDOT Standard Specifications for Construction Section 501
5-5 501.02. Materials
Provide materials in accordance with the following sections : Superpave HMA Mixtures ..................................................................... 902 Superpave Aggregates ......................................................................... 902 Mineral Filler, 3MF ................................................................................ 902 Anti-Foaming Agent .............................................................................. 904 Asphalt Binders ..................................................................................... 904 Bond Coat , SS-1h, CSS -1h, LTBC -1, LTBC -2 ...................................... 904 Plant -produced HMA consists of asphalt binder, aggregates, mineral filler, and ot her additives. Provide release agents that do not harm the HMA mixture. Do not use fuel oil or other distillate derivatives. Provide the HMA mix type and the performance grade of asphalt binder as required by the contract. Provide blended aggregates for HM A top course mixtures, except top courses for shoulders, bike paths, temporary roads, and parking areas, meeting the required Aggregate Wear Index (AWI).
A.Composition of HMA Mixtures
1.Mix Design . Develop an HMA mix design in accordance with the HMA Production Manual and submit to the Department. The Department will evaluate the design in accordance with Section 1 of the HMA Production Manual , “Procedures for HMA Mix Design Processing.” Provide written certification that the materials in the mix design are from the same source and meet the material properties in the mix design or the Department -approved JMF. Make all JMF adjustments in accordance with the HMA Production Manual . Provide combined aggregate blends meeting the properties specified in section 902. Provide a mix design that meets the requirements in Table 501-1, Table 501-2, and Table 501-3. For mix design purposes, top and leveling courses are the mix layers within 4 inches of the surface. The base course consists of the layers below 4 inches from the surface. For mix layers within the 4 -inch threshold, if less than 25% of the mix layer is within 4 inches of the surface, the mix layer is a base course. MDOT Standard Specifications for Construction Section 501
5-6 Table 501- 1: Superpave Mix Design Criteria
Design Parameter Mix Number 5 4 3 2 Percent of maximum specific gravity (%G mm) at the design number of gyrations (N d) 96.0%(a) %G mm at the initial number of gyrations (N i) See Table 501- 3 %G mm at the maximum number of gyrations (N m) ≤98.0% Voids in mineral aggregate (VMA) min % at N d (based on aggregate bulk specific gravity (G sb)) 15.00 14.00 13.00 12.00 Voids filled with asphalt ( VFA) at N d See Table 501- 2(b) Fines to effective asphalt binder ratio (P No200/Pbe) 0.6–1.2 Tensile strength ratio (TSR) 80% min
a.Unless noted otherwise on the plans, design all mixtures to 96.0% of maximum specific gravity (%G mm) at the design number of gyrations (N d). During field production, increase percent of maximum specific gravity (%G mm) at the design number of gyrations (N d) to 97.0%. Use liquid asphalt cement for regression of mixes unless otherwise noted on plans.
b.For regressed mixtures t he maximum criteria limits do not apply. Table 501- 2: VFA Minimum and Maximum Criteria Estimated Traffic (million ESAL) Mix Type Top and Leveling Courses Base Course ≤0.3 EL 70–80% 70–80% >0.3 – ≤3.0 EML 65–78% 65–78% >3.0 – ≤30 EMH 65–78%(a) 65–75% >30 – ≤100 EH 65–78%(a) 65–75% ESAL = equivalent single -axle load
a.The specified VFA range for m ix Number 5 is 73 –76%. Table 501- 3: Superpave Gyratory Compactor Compaction Criteria Estimated Traffic (million ESAL) Mix Type %G mm at (N i) Number of Gyrations(a) Ni Nd Nm ≤0.3 EL ≤91.5% 7 50 75 >0.3 – ≤3.0 EML ≤90.5% 7 75 115 >3.0 – ≤30 EMH ≤89.0% 8 100 160 >30 – ≤100 EH ≤89.0% 9 125 205 ESAL = equivalent single -axle load
a.Compact mix specimens fabricated in the Superpave gyratory compactor (SGC ) to N d. Use height data provided by the SGC to calculate volumetric properties at N i. Compact mix specimens at optimum P b (percent asphalt binder content) to verify N m for mix design specimens only. If high-stress HMA is shown on the plans, provide the same mix designation (5EML, 5EMH, 4EML, 4EMH, etc.) as required for the MDOT Standard Specifications for Construction Section 501
5-7 mainline top and leveling courses, except change the
performance-graded (PG) binder as shown on the HMA application table.
2.Recycled Mixtures . Recycled asphalt pavement ( RAP) may be substituted for a portion of the new material required to produce the HMA mixture. Design and produce the mix to meet the criteria in this subsection and the contract.
a.Stockpile Requirements. Process RAP to the size required for the specified HMA mix. Ensure the stockpile contains enough material to produce the recycled mixtures the Engineer approves for the project. If the RAP stockpile is not sufficient to produce recycled mix quantities required for the project, provide an Engineer -approved mix design without RAP at the same unit price. Provide documentation of testing (one test per 1000 tons, minimum of three tests) and accumulated tonnage in the stockpile to the MDOT laboratory. The tonnage may be estimated. The Department will begin evaluating the mix design after receipt of the documentation.
b.Mix Design. Submit required documentation for recycled mix designs in accordance with Section 1 of the HMA Production Manual , “Procedures for HMA Mix Design Processing.”
B.HMA Plant Certification. Ensure HMA plants are certified by the Department at least 5 days before mix production begins. The Engineer will certify HMA facilities in accordance with Section 2 of MDOT’s HMA Production Manual , “Certification Procedure of HMA Plants.” Post a seal of certification in the plant control office.
C.HMA Production . Submit an approved mix design for the mix required to the Engineer at least 4 days before production begins. Provide even heating of the mass of asphalt binders and maintain heat control. Heat asphalt binders to the temperature required for the type of binder. Do not exceed the maximum temperature specified in Table 904- 8 for asphalt binder and HMA. The Department will reject asphalt binder and mix if the temperature exceeds the maximum specified in Table 904-8 . The Department will reject contaminated asphalt binder. Stockpile aggregates at the facility in a manner that prevents segregation. Dry aggregates to a moisture content that will ensure an appropriately coated HMA mix. For batch and continuous plants, the Department will reject aggregates in the hot bins that contain sufficient moisture to cause foaming or a water -saturated mixture. Remove rejected materials from the bins. MDOT Standard Specifications for Construction Section 501
5-8 Place uniform gradations of aggregates in the cold feed system. If
providing a blend of aggregates for the mix by combining aggregates from at least two cold feed bins, ensure that the blend meets the combined gradation (from JMF) QC tolerances. The use of at least one hot aggregate bin to proportion aggregates to meet the JMF tolerances is allowed if the cold feed requirements are m et. 501.03. Construction
A.Equipment. Provide equipment in accordance with section 107, capable of producing pavement that meets the requirements of this section.
1.Cold -Milling Machines. Provide equipment that consistently removes the HMA surface, in one or more pass es, to the required grade and cross section, and produces a uniformly textured surface. Provide machines equipped with the following:
a.Provide a cold- milling machine that has sufficient power, traction, and stability to maintain an accurate depth of cut. Maintain the propulsion and guidance system of the milling machine in such condition that the milling machine may be operated to straight and true lines ;
b.Provide a cold- milling machine capable of operati ng using minimum 30 -foot automatic grade controls (contact or non-contact) averaging system or other approved grade control systems and capable of transverse slope control. Describe the use of such controls in the Contractor ’s Cold-Milling Quality Control Pla n; and
c.Provide a cold- milling machine capable of picking up the removed material in a single operation. A self -loading conveyor will be an integral part of the milling machine. Windrows are not allowed.
2.Hauling Equipment . Ensure that transport trucks are equipped to protect the mix from the weather and retard the loss of heat. Equip transport trucks and trailers with a working backup alarm.
3.Pressure Distributor . Provide a pressure distributor in accordance with subsection 505.03.A.1.
4.Pavers. Equip each p aver with a full -width vibratory or tamper bar screed capable of spreading and finishing HMA to the required cross section and grade. Use a paver that produces a uniformly finished surface, free of tears, other blemishes, and measurable segregation. Equip the paver to provide a uniform head of material ahead of the screed. Install reverse pitch augers or paddles inside the ends of the auger shafts to force the mix to the center of the main screed. MDOT Standard Specifications for Construction Section 501
5-9 Ensure that extensions added to the main screed provide the same
vibrating or tamping action and heating capabilities as the main screed. Adjust extensions to the main screed so, after breakdown rolling, no longitudinal marks remain on the surface. Equip in-line screed extensions with a continuation of the automati cally controlled spreading augers to within 12 inches of the outside edge. Follow the manufacturer ’s recommendations for other screed extensions. Except for the paving operations listed in subsection 501.03.F.1.a through subsection 501.03.F.1.d, equip pavers with an automatically controlled and activated screed with grade reference and transverse slope control. Use an Engineer -approved grade referencing attachment, at least 30 feet long for lower courses and the first pass of the top course. Ensure that the Engineer approves alternate grade referencing attachments before use. After placing the first pass of the top course, the Contractor may, with prior approval from the Engineer, substitute a joint matcher, a grade referencing attachment at least 10 feet long, or other grade referencing equipment for constructing adjacent passes of the top course.
5.Rollers
a.Steel -Wheeled Rollers . Provide self -propelled vibratory steel -wheeled rollers, static tandem rollers, or self -propelled static three -wheeled rollers. Provide a steering device that allows the roller to follow the established alignment. Equip rollers with wheel sprinklers and scrapers. Provide smooth roller wheels, free of openings or projections that will mar the pavement surface. Provide vibratory rollers with an automatic shutoff to deactivate the vibrators if the roller speed decreases below ½ mph. Provide rollers that operate in accordance with the manufacturer ’s recommended speed, impacts per foot, and vibration amplitude for the thickness of HMA mix.
b.Pneumatic-Tired Rollers . Provide self -propelled pneumatic -tired rollers. Equip rollers with at least seven wheels spaced on two axles so the rear group of tires does not follow in the tracks of the forward group, providing at least ½-inch tire path overlap. Provide smooth tires capable of being inflated to the pressure recommended by the roller or tire manufacturer. Equip the rollers MDOT Standard Specifications for Construction Section 501
5-10 with a mechanism that can smoothly reverse the motion of the
roller. Equip the rollers with wheel sc rapers and skirting to enclose the wheels to within 3 inches of the pavement surface. Use a release agent to prevent material from sticking to the tires and being deposited on the top course pavement during rolling.
c.Combination Rollers . The Contractor may use combination pneumatic -tired and steel -wheeled rollers manufactured specifically for HMA compaction, if equipped with the required sprinklers and scrapers.
6.Spreaders. Use self -propelled spreaders capable of pushing the hauling units. Ensure that spreaders can maintain the required width, depth, and slope, without causing segregation.
7.Material Transfer Device. When a material transfer device (MTD) is required, it must be capable of delivering HMA mix from the truck transport to the paver hopper to ensure constant paver speed, remixing HMA material using manufacturer ’s developed technology, and depositing material in the paver hopper. Provide a paver hopper insert with at least a 10-ton capacity in the paver and keep at least two-thirds full of mix d uring paving. A windrow pickup machine does not satisfy the requirements for an MTD.
8.Compressed Air System . If a compressed air system is required for cleaning pavement, equip the air compressor with a moisture separator to remove oil and water from the ai r supply. Provide a compressor capable of producing at least 100 psi and continuous 150 cfm airflow.
9.Miscellaneous Equipment . Provide a straightedge, at least 10 feet long, and other tools to finish the work.
10.Lights on Equipment . If maintaining traffic on HMA construction, equip equipment within the project, including cold-milling machines, distributors, and rollers, with at least one Department -approved flashing, rotating, or oscillating amber light. Equip pavers with at least one light on each side. Mount the lights so the warning signal is visible to traffic in every direction. Operate the lights while work is in progress. Ensure that hauling units activate four -way flashers on the project.
B.Preparation of Base. Provide subgrade, subbase, aggregate base course, crushed and shaped base, or rubblized base in accordance with the relevant sections of Division 2 and Division 3, before HMA placement. MDOT Standard Specifications for Construction Section 501
5-11 C. Preparation of Existing Pavement. Prepare the existing surface as
required to construct HMA pavements, shoulders, and approaches.
1.Drainage Structures, Monument Boxes, and Water Shutoffs. Adjust, temporarily lower, or both, catch basins, manhole covers, monument boxes, and water shutoffs in accordance with subsection 403.03.A. Meet the smoothness requirements required in subsection 501.03.H .
2.Cleaning Pavement . Using methods approved by the Engineer, clean dirt and debris from the pavement surface and paved shoulders before placing HMA. Remove loose material from joints and crack s using compressed air. If the Engineer determines the compressed air system will not remove deleterious material, remove loose material by a hand or mechanical method, as approved by the Engineer. The Department will pay for removal of material by hand or mechanical methods in accordance with subsection 501.04.E. Do not place HMA until the Engineer inspects and approves the condition of the existing pavement.
3.Removing Existing Pavement for Butt Joints . If a butt joint is required, remove the existing surface to the thickness of the proposed overlay for the full width of the joint. Uniformly taper the removal to the original surface over at least 35 feet.
4.Edge Trimming . For required removal of HMA shoulder material or no greater than 1 foot width of HMA pavement, cut the HMA material full depth along the pavement edge or removal line to prevent tearing the pavement surface. Cut joints, where the completed surface will be exposed, with a saw, cold-milling machine, or other methods approved by the Engineer. Cut joints, where the completed surface will be covered by HMA mix, with a coulter wheel, saw, cold-milling machine, or other method approved by the Engineer.
5.Cold -Milling HMA Surfaces . Before milling existing pavement, obtain a Department -approved mix design in accordance with subsection 501.02.A, and ensure the availability of HMA mix quantities to cover milled surfaces. Do not maintain traffic on the milled surface unless specified in the contract or approved by the Engineer. Cold -Milling QC Plan and Cold -Milling Operations Plan. Prior to beginning milling operations, submit a Cold -Milling QC Plan and a Cold-Milling Operations Plan to the Engineer for approval. MDOT Standard Specifications for Construction Section 501
5-12 a. Include, as a minimum, the following items in the Cold-Milling QC
Plan: The schedule for replacing the cutting teeth; The daily preventive maintenance schedule and checklist ; Proposed use of automatic grade controls ; The surface testing schedule for smoothness ; The process for filling distressed areas ; The schedule for testing macrotexture of the milled surface; Corrective procedures if the milled surface does not meet the minimum macrotexture specification; Corrective procedures if the milled surface does not meet the minimum transverse or longitudinal surface finish when measured with a 10-foot straightedge; The methods for l ongitudinal control guidance (painted string line or measure offs) ; and Contact information for on-site contractor personnel responsible for the work and authorized to adjust the QC plan.
b.Include, as a minimum, the following specific items in the Cold-Milling Operations Plan: Number, types , and sizes of mill machines to be used; Width and location of each mill machine pass ; Number and types of brooms and or vacuum trucks to be used a nd their locations with respect to the mill machine; Proposed method for mill machine and wedging around existing structures such as manholes, valve boxes, and inlets ; Longitudinal and transverse typical sections for tie-ins at the end of the day ; If requested by the Engineer, a plan sheet showing the milling passes ; and Names of macro -texture testing personnel and sequencing of testing (minimum of three tests daily that are representative of the day ’s milling). Remove the HMA surface to the depth, width, grade, and cross section shown on the plans. Backfill and compact depressions MDOT Standard Specifications for Construction Section 501
5-13 resulting from removal of material below the specified grade, in
accordance with subsection 501.03.C.9. If the milling machine discovers buried structures within the specified gra de, such as valve boxes, manholes, or railroad tracks that are not identified on the plans, the Department will pay for all associated costs, as extra work, in accordance with subsection 103.02. Immediately after cold-milling, clean the surface. Dispose of removed material in accordance with subsection 104.07.D and subsection 204.03. Mill the existing pavement to the cross slope shown on the plans. Supply a 10-foot straightedge. Ensure that the finished surface does not vary longitudinally or transversely more than ¼ inch from a 10-foot straightedge. Ensure that the milled area is free from gouges, continuous grooves, and ridges and has a uniform texture. Ensure that the horizontal gouge in the vertical edge created from the milling operation i s limited to a maximum width of 1.0 inch. Adjust speed, drum speed, and/or teeth as necessary to meet the requirements of this specification. Ensure that the milling operation provides an acceptable surface texture by achieving a maximum mean texture depth of 0.108-inch thickness according to ASTM E965. Perform three random QA macro texture tests daily that are representative of the day ’s milling to maintain texture and verify conformance with the 0.108-inch thickness mean texture depth requirement. For projects with less than 3, 000 square yards, a minimum of one random QA macro texture test per day is required. Perform tests as soon as practical behind the milling operations.
6.Removing HMA Surface. Except as specified in subsection 501.03.C.4, removing an HMA surface applies to removing HMA overlying a material designated for removal or that is required to remain in place. Cut joints, exposed in the completed surface, with a saw or cold-milling machine. Cut joints, covered by HMA mix, with a coulter wheel, saw, or cold-milling machine. Obtain the Engineer ’s approval of alternate methods for cutting joints. When removing HMA overlying a base course that is to remain in place, cut the edges of the surface requiring removal along straight lines for the full depth of the HMA surface. MDOT Standard Specifications for Construction Section 501
5-14 When removing HMA by cold- milling, the Engineer may direct removal
to be less than the full depth of HMA surface.
7.Removing HMA Patches. Remove patches that may compromise the performance of the overlay.
8.Joint and Crack Clean out. If the plans show joint and crack cleanout, use mechanical or hand methods to remove joint sealants to at least 1 inch deep. Remove vegetation, dirt, and debris that cannot be removed using the methods specified in subsection 501.03.C.2 from transverse and longitudinal joints and cracks. Use hand patching to fill cleaned joints and cracks at least 1 inch wide.
9.Hand Patching . If the contract requires hand patching, fill holes, depressions, joints, and cracks in the existing pavement and replace existing patches . Compact the hand patching material in no greater than 3-inch layers to the adjacent pavement surface grade using a machine vibrator or Department -approved roller. Use top course or other Engineer -approved mix for hand patching material.
10.Repairing Pavemen t Joints and Cracks. Repair joints and cracks as required.
D.Bond Coat . Uniformly apply the bond coat and provide complete coverage to a clean, dry, surface with a pressure distributor. Obtain the approval of the Engineer for the application rate after work begins. Application rate must be within a range of 0.05 to 0.15 gallons per square yard. Apply the bond coat ahead of the paving operation to allow the bond coat to cure before placing HMA. Do not leave pools of bond coat on the surface and do not spr ay the bond coat on adjacent pavement surfaces. Apply the bond coat to each HMA layer and to the vertical edge of the adjacent pavement before placing subsequent layers.
E.Transportation of Mixtures . Weigh each load of HMA, accepted by the Department, to the nearest 20 pounds on an approved scale with an automatic printout system. Provide a scale and printout system for platform and suspended scales in accordance with subsection 109.01.B.6. Provide a ticket to the Engineer with each load. Apply a release agent, in accordance with subsection 501.02, to hauling units. Loads with excessive amounts of release agent will be rejected. Do not place crusted HMA in the paver. The Department will reject loads, immediately prior to placement, with a temperature either below 250°F (225°F when using a warm mix chemical MDOT Standard Specifications for Construction Section 501
5-15 additive) or greater than 20°F from the recommended maximum mixing
temperature specified by the binder producer.
F.Placing HMA
1.General Place HMA on a cured bond coat using pavers in accordance with subsection 501.03.A.4 unless placing mixtures for the following:
a.Variable width sections ;
b.The first course of a base course mix on a subgrade or sand subbase;
c.Base course mi xtures for shoulders and widening less than 10½ feet wide; or
d.Top and leveling course mixes for shoulders and widening less than 8 feet wide. Place HMA mix in layers, and do not exceed the application rate. If the application rate for an HMA pavement exceeds the maximum rates specified in Table 501-4 and the edges are not confined, construct the pavement in at least two layers. Table 501- 4: HMA Application Rates Mix Number(a) Course Application Application Rate (lb/yd²) , minimum – maximum(b) 2 Base 435–550 3 Base, l eveling 330–410 4 Leveling, top 220–275 5 Top 165–220
a.See Table 501-1 for the mix number design parameters.
b.Minimum application rates do not apply to wedging courses. Wedge with HMA to remove irregularities in the existing road surface. Place and compact HMA wedging to correct the foundation. Allow the wedging to cool enough to support construction equipment without causing visible distortion of the mat before placing subsequent wedging, base, leveling, or top cours e mixtures. Place HMA mix to the slope and width shown on the plans. Place subsequent HMA course to align the vertical edge with the previous courses, without constructing a ledge. Correct ledges that result from placing material in excess of the width shown on the plans at no additional cost to the Department. MDOT Standard Specifications for Construction Section 501
5-16 Place shoulder aggregate and compact flush after placement of each
layer of HMA at the end of the paving day or place traffic control devices in accordance with subsection 812.03, at no additional cost to the Department. Complete final shaping and compaction of the shoulders after placing the top course of HMA. If delays slow paving operations and the temperature of the mat immediately behind the screed falls below 200°F, stop paving and place a trans verse construction joint. If the temperature of the mat falls below 190°F before initial breakdown rolling, remove and replace the mat at no additional cost to the Department. If placing the uppermost leveling and top course, place the longitudinal joint t o coincide with the planned painted lane lines. If the temperature of the mat falls below 170°F before placing the adjacent mat, apply bond coat to the vertical edge of the mat. If constructing the lanes with at least two pavers in echelon, match the depth of loose HMA from each paver at the longitudinal joints.
2.Joints in HMA Pavement
a.Transverse Construction Joint . If constructing a transverse construction joint, stop the paver and lift the screed before material falls below the auger shaft. Remove the paver and roll through the planned joint location. Cut a transverse vertical joint and remove excess HMA. Place burlap, canvas, or paper as a bond breaker ahead of and against the vertical face. Place HMA against the bond breaker and taper from the new mat to the existing surface. Extend the temporary taper 5 feet for each inch of mat thickness, or as directed by the Engineer. Compact and cool the temporary taper before allowing traffic on the new surface. Remove the temporary taper before resuming paving.
b.Feather Joint . Transition the new mat to existing surfaces at the beginning and end of resurfacing sections and at intersections unless using butt joints. Transition the new mat to existing surfaces at a rate of 1 inch over 35 feet. Construct trans itions on a cured bond coat applied at a rate of 0.10 gallon per square yard. After compaction, spray with bond coat, sand, and roll the first 3 feet of the joint and 1 foot of the existing surface.
c.Vertical Longitudinal Joint . When opening to traffic, plan the work to resurface adjacent lanes to within one load of the same MDOT Standard Specifications for Construction Section 501
5-17 ending point at the completion of paving operations each day.
Construct a vertical joint to conform to the pavement cross section. When compacting an unsupported (unconfined) edge of the mat, keep the roller from 3 to 6 inches inside the unsupported edge on the first pass; ensure that the roller overhangs the unsupported edge by 3 to 6 inches on the second pass. When placing HMA in a lane adjoining a previously placed lane, place the mixt ure so that the strike-off shoe will produce an edge that is adjacent to or minimally overlaps the adjoining course. Compact the longitudinal joint by rolling from the hot side, keeping the edge of the roller approximately 6 inches to 8 inches inside the cold joint for the first pass. For the second pass of the roller, compact the joint from the hot side while overlapping the cold side by 6 to 8 inches.
d.Tapered Overlapping Longitudinal Joint . A tapered overlapping longitudinal joint may be used instead of a longitudinal vertical joint. If using tapered overlapping longitudinal joints, resurfacing lanes within one load of the same point -of-ending at the completion of paving operations each day is not required. Pave adjacent lanes within 24 hours unless delayed by inclement weather or approved by the Engineer. Construct the tapered overlapping longitudinal joint by tapering the HMA mat at a slope no greater than 1: 12. Extend the tapered portion beyond the normal lane width. Place a ½ -inch to 1-inch notch at the top of the taper on paving courses. Provide a uniform slope by constructing the tapered portion of the mat using a Department -approved strike- off device that will not restrict the main screed. Apply bond coat to the surface of the taper before placing the adjacent lane.
3.Placing HMA Shoulders . Use a self -propelled mechanical paver or spreader to place HMA shoulders. If placing the top course on new shoulders, or placing leveling, or top course on existing HMA shoulders at least 8 feet wide, plac e the mix using a paver with an automatically controlled and activated screed and strike- off assembly and corresponding grade referencing MDOT Standard Specifications for Construction Section 501
5-18 equipment. Use grade-referencing equipment as directed by the
Engineer. Stop shoulder paving at crossroad approaches, auxiliary lanes, commercial driveways, and ramps. Do not pave through these areas.
4.Placing HMA Approaches . Place HMA on driveway or crossroad approach foundations, as approved by the Engineer. Place approaches in layers no greater than the application rate. Do not stop mainline paving of lanes adjacent to the approach to pave the HMA approach.
5.Safety Edge . Construct the safety edge on the shoulders at locations shows on the plans. The finished shape of the safety edge will be in accordance with MDOT Standar d Plan R -110 series. Ensure that the safety edge is constructed monolithically with the shoulder and is of the same material type. Prior to placing HMA shoulder overlays, prepare the existing shoulder material to provide a smooth and uniform paving surface. Excavate, trench, and/or shape the existing shoulder material so that the safety edge may be placed as required on the plans. Ensure that the existing material does not impede the paving equipment and placement of HMA. For new or reconstructed shoulders , prepare base materials in accordance with the plans. Use an approved longitudinal safety edge system to create a sloped edge profile onto the roadway shoulder. Use an approved safety edge system that compacts the HMA and provides a finished sloped wedge in accordance with the contract. Do not use a single plate strike off. Use a system that is adjustable to accommodate varying pavement thicknesses. Prior to commencing any shoulder work, provide a test section to demonstrate the safety edge finished shape and compaction of the proposed safety edge system. The Engineer may waive the test section if satisfactory evidence is provided that the proposed system has been successfully used on other MDOT or MDOT local agency projects. Ensure that all safety edge systems have been approved by the Engineer.
G.Rolling. Compact each layer of HMA in accordance with the contract and free of roller marks. Keep the surface of the steel roller wheels moist during rolling. Use a pneumatic tire roller on HMA ov erlay projects in the intermediate rolling position to knead HMA over existing pavement. MDOT Standard Specifications for Construction Section 501
5-19 H. Smoothness Requirements. After final rolling, the Engineer may test the
surface longitudinally and transversely using a 10-foot straightedge at selected locations in accordance with Michigan Test Method ( MTM) 722. Construct the surface and correct variations, at no additional cost to the Department, to the tolerances specified in this subsection.
1.Base Course. Construct lower layers of base courses to a tolerance of ¾ inch and final layers of base courses to a tolerance of ⅜ inch.
2.Leveling and Top Course . For multiple course construction, construct lower courses to a tolerance of ¼ inch and top courses to a tolerance of ⅛ inch.
3.Single Course Overlays. Construct single courses to a tolerance of ¼ inch.
4.Longitudinal Joints . Construct adjacent lanes to a tolerance of ¼ inch for base and leveling courses and a tolerance of ⅛ inch for top course s.
5.Drainage Structures, Monument Boxes, and Water Shutoffs. Construct to a tolerance of ¼ inch.
I.Weather Limitations
1.HMA Weather Limitations. Place HMA in accordance with the following restrictions:
a.Do not place HMA or apply bond coat when moisture on the existing surface prevents curing;
b.Do not place HMA unless the temperature of the surface being paved is at least 35°F and there is no frost on or in the grade or on the surface being paved, unless ot herwise approved by the Engineer in writing;
c.Place only HMA courses that are greater than 200 pounds per square yard if the temperature of the surface being paved is greater than 35°F ;
d.Place only HMA courses that are greater than 120 pounds per square yard if the temperature of the surface being paved is at least 40°F ; and
e.Place any HMA course if the temperature of the surface being paved is at least 50°F .
J.Protection of Structures. Protect bridges, curbs, gutters, driveways, sidewalks, barriers, and other appurtenances to prevent surfaces from becoming discolored during application of bond coat or HMA to the road MDOT Standard Specifications for Construction Section 501
5-20 surface. Remove material from appurtenances, as directed by the
Engineer, at no additional cost to the Department.
K.Aggregate Shoulders . On resurfac ing projects, scarify existing aggregate shoulder surfaces before placing new aggregate material. Maintain the shoulder for vehicles to pass the construction equipment. If Contractor operations or traffic disturbs the area between the pavement and the right -of-way line, restore the area to a condition approved by the Engineer at no additional cost to the Department.
L.Monument Boxes. Place or adjust monument boxes in accordance with section 821.
M.Quality Control Plan . Prepare and implement a QC plan for HMA in accordance with MDOT’s HMA Production Manual . Make adjustments in process controls to prevent production of non-conforming material instead of accepting payment at a reduced price. The Department will not allow continual production of non-conforming mater ial at a reduced price instead of making adjustments. The Engineer will not perform sampling or testing for QC or assist in controlling the HMA production and placement operations.
N.HMA Mix Acceptance. The Engineer will inspect field- placed material, perform QA sampling and testing, and monitor Contractor adherence to the Contractor’s HMA QC Plan .
1.HMA Field-Placed Inspection . The Engineer will perform a visual inspection of HMA to identify areas requirin g corrective action. The Engineer will inspect the base and leveling courses within 18 hours and the top course within 36 hours of placement. If the Engineer determines that corrective action is required, do not pave overlying courses until after corrective action is completed and the Engineer determines that the pavement is in conformance with the contract. The Engineer will determine the need for corrective action based on the factors specified in Table 501- 5. Corrective action may include remedial treatm ent, including crack or surface sealing, or replacement. Submit an action plan to the Engineer that addresses all factors that resulted in the need for corrective action. Complete all corrective action required to repair or replace unacceptable work at no additional cost to the Department. If the Engineer and the Contractor agree, the Department may make a contract adjustment of no greater than 100% of the bid price for corrective action. MDOT Standard Specifications for Construction Section 501
5-21 Table 501- 5:
HMA Criteria f or Corrective Action Criteri on(a) Length Extent(b) Severity Corrective Action(c) Segregation — >215 ft²/ 328-foot LL Heavy(d) Replace Rutting — >32 feet >¼ in ch average depth over the length of occurrence Replace Flushing — >108 ft²/ 328-foot LL High(e) Replace Edge of paved shoulder >33 feet Visible ledges >3 in ches Trim Crack(g) Any Any All Seal(f) LL = lane length
a.Criteria apply to all courses except flushing, which applies to the top course only.
b.Extent is calculated by summing locations within the required length.
c.The appropriate corrective action depend s on the extent and severity of the criteria and on the intended service life of the pavement.
d.Segregation severity will be determined in accordance with MTM 326. If segregation thresholds are met twice on a paving course, the use of a n MTD for the remaining paving for that course may be required at no additional cost to the Department.
e.Flushing severe enough to significantly affect sur face friction (Friction Number <35).
f.Other corrective action may be required as crack frequency increases.
g.A reflective crack determined by the Engineer to be caused by an underlying condition does not require corrective action. The Department wi ll not grant extensions of time for repair work to meet the inspection acceptance requirements specified in subsection 501.03.N.1. The Engineer will determine the area subject to corrective action, for removal and replacement of top courses, as the longitu dinal extent of corrective action multiplied by the width of the paving course affected. The Department will accept HMA subject to corrective action as follows:
a.HMA placed for corrective action involving full removal and replacement will be accepted in acc ordance with the contract.
b.The area requiring corrective action other than full removal and replacement will not be measured for incentive payment.
c.If more than 10 % of the area of a sublot requires corrective action, the sublot will not be measured for inc entive payment.
2.HMA Testing Acceptance. The Engineer will accept HMA based on visual inspection, small tonnage, or QA sampling and testing MDOT Standard Specifications for Construction Section 501
5-22 acceptance criteria The Engineer will notify the Contractor before
conducting QA sampling to allow the Contractor to witness the sampling, but not in a manner that will allow alteration of production in anticipation of sampling. The Engineer will conduct QA sampling in accordance with MTM 313 or MTM 324.
a.Visual Inspection Acceptance Criteria. The Engineer may accept quantities less than 500 tons, of any individual mixture, in accordance with MDOT’s Materials Quality Assurance Procedures (MQAP) Manual .
b.Temporary Pavement Acceptance Criteria. The basis for measuring the mixture quality is QC testing and the Q C processes specified in the applicable contract specifications for Superpave or Marshall mixes. Provide a copy of QC result to the Department within 24 hours upon request. The Department is not required to perform QA testing for the t emporary HMA but reserves the right to perform verification testing. All materials and HMA mixture requirements apply. The initial production lots will be waived upon request. There are no pay factor or price adjustments based on mixture volumetrics for the t emporary HMA. Perform all maintenance with the exception of snow and ice removal during the seasonal shutdown period. Maintain temporary pavement until the completion of the contract or the opening to traffic of the new pavement. Correct all deficiencies with the t emporary pavement. The Engineer will make a negative adjustment for deficiencies requiring repairs or renewals, not corrected within the time frames stated in section 812 and for each occurrence that maintenance is required on the t emporary HMA. Contract price adjustments will be made, according to Table 501-6, for each occurrence that repairs or renewals are required on the temporary roadway that are not attributable to normal wear and tear of traffic, weather , or an inadequate base condition not addressed in the contract.
O.Asphalt Binder Acceptance. The Department will accept asphalt binder in accordance with Department procedures. MDOT Standard Specifications for Construction Section 501
5-23 Table 501- 6:
Contract Adjustments for Maintenance of Temporary Pavement ADT(a) Per Maintenance Occurrence 0–10,000 $2,000(b) 10,000–40,000 $4,000(b) ≥40,000 $8,000(b)
a.Based on average daily traffic ( ADT) shown on Title Sheet
b.The contract adjustment will be doubled if the Contractor ’s HMA -QC Plan is not adhered to. 501.04. Measurement and Payment Pay Item Pay Unit HMA, 5 E __ ........................................................................................ Ton HMA, 4 E __ ........................................................................................ Ton HMA, 3 E __ ........................................................................................ Ton HMA, 2 E __ ........................................................................................ Ton HMA, (type), High Stress .................................................................... Ton HMA Approach .................................................................................... Ton HMA Approach, High Stress ................................................................ Ton HMA, Temp Pavt (mix type) ................................................................. Ton Pavt for Butt Joints, Rem ...................................................... Square Yard Edge Trimming .................................................................................. Foot Cold Milling HMA Surface ............................................. Square Yard, Ton HMA Surface, Rem ............................................................... Square Yard HMA Patch, Rem ................................................................... Square Yard Joint and Crack, Cleanout ................................................................. Foot Hand Patching ..................................................................................... Ton Pavt, Cleaning ......................................................................... Lump Sum Pavt Joint and Crack Repr, Det __ .................................................... Foot
A.HMA, (type), High Stress . The Department may pay for HMA, (type), High Stress for up to 150 feet outside the limits shown on the plans to allow time to transition to the high-stress HMA. The Department will pay for high-stress HMA placed outside the 150-foot limit as other HMA mix pay items.
B.Pavement for Butt Joints, Removal. The unit price for Pavt for Butt Joints, Rem includes the cost of removing and disposing of concrete or HMA materials. MDOT Standard Specifications for Construction Section 501
5-24 C. Edge Trimming. The Engineer will measure Edge Trimming along the
cut edge. The unit price for Edge Trimming includes the cost of cutting, removing, and disposing of excess HMA material.
D.Cold Milling HMA Surface . The unit price for Cold Milling HMA Surface includes the cost of removing, loading, hauling, weighing, and disposing of the cold-milled material, and cleaning the cold-milled pavem ent. If paid by the ton for cold-milled HMA, deposit the cold-milled material directly from the cold milling machine into the hauling units and weigh on a scale meeting the requirements of subsection 109.01.B before placement in a stockpile or a disposal area. Material picked up by cleaning after cold milling is not weighed or paid for. Macrotexture testing, macrotexture corrective actions, cleaning, and all other work related to mean texture depth requirements will not be measured and paid for separately but must be included in the work. Separate payment will not be made for providing and maintaining an effective Cold-Milling QC Plan , nor for providing and maintaining an effective Cold-Milling Operations Plan.
E.Pavement, Cleaning . The Engineer will measure Pavt, Cleaning as a unit, including paved shoulders, approaches, and widened areas. The unit price for Pavt, Cleaning includes the cost of cleaning the foundation, joints, and cracks, and sweeping shoulders, base courses, and leveling courses. If the Engineer directs additional hand or mechanical methods to clean the pavement, the Department will pay for this work as Joint and Crack, Cleanout if the contract includes the pay item. If the contract does not include a pay item for joi nt and crack cleanout, the Department will pay for additional hand or mechanical work as extra work, in accordance with subsection 109.05 .
F.Joint and Crack, Cleanout. The Engineer will measure Joint and Crack, Cleanout along the cleaned joint and crack.
G.Hand Patching. The unit price for Hand Patching includes the cost of placing HMA, by hand or other methods, and compacting the material.
H.Removing HMA Surface. The Engineer will measure, and the Department will pay for removing HMA surface, no greater than 12 inches thick, overlying a material designated for removal or that is required to remain in place, as HMA Surface, Rem . The unit price for HMA Surface, Rem includes the cost of edge cutting to establish a neat line, as required, and removal and disposal of the HMA material. MDOT Standard Specifications for Construction Section 501
5-25 For removal of HMA surfaces from structures, the unit price for HMA
Surface, Rem includes the cost of removing old membrane. The Engineer will measure, and the Department will pay for removing HMA surface, greater than 12 inches thick, overlying a material designated for removal or that is required to remain in place, as Pavt, Rem in accordance with subsection 204.04.
I.Pavement Joint and Crack Repair. The Engineer will measure Pavt Joint and Crack Repr , of the detail required, along the joint and crack. If the pavement joint and crack repair exceeds 30 inches in width, the Engineer will measure each 30-inch wide segment, or portion thereof, separately for payment. The Department will pay for the HMA material used to fill the joints after removal of objectionable material, as Hand Patching .
J.Safety Edge. Separate payment will not be made for constructing a safety edge. All costs associated with providing a safety edge, including base preparation and additional equipment or modification to existing equipment , will be included in the applicable unit prices for the related HMA mixtures.
K.HMA. The Engineer will measure, and the Department will pay for, HMA and HMA, Temp Pavt (mix type) of the mix specified based on the weight placed, as supported by wei gh tickets. The Engineer will adjust the unit price for HMA of the mix specified, in accordance with the contract.
Source: Michigan Standard Specifications for Construction, 2020 Edition. Pages 260–284 of 1,146.