This continuous action of the slat conveyors and augers is accomplished by setting the proper position for the hopper flow gates and determining the correct speed setting for the slat conveyors and augers. This is caused by an improperly adjusted screed angle of attack. The first is the frequency of vibration and the second is the amplitude of the compactive effort. Does the Contractor have proper number of rollers? Compaction is the single most important factor that affects the ultimate performance of a hot mix asphalt pavement. Weather and air temperature requirements. Document when immediate possession of the extracted cores occurs (core ID, date, time, etc.). Try to keep the paver moving at a constant speed. Resources for local governments regarding grant & economic development opportunities, project coordination, and state and federal requirements. Refer to Figure 502-15 for details of joint construction. MDOT provides funding for competitive grant and loan programs primarily, but not exclusively, for state and local road agencies for the greatest impact on economic development and job creation. Ensure the paver speed matches mixture delivery. All mixtures specified for a project must have an approved mixture design before mix production can proceed. For a stiff mix, a higher tire pressure should be used. Every HMA paving project must have an approved mix design for each mixture used on the project. Flexible Pavement: See Figure 502-2. Care should be exercised to keep dust to a minimum. All the tires should be the same size, ply and tire pressure. Yield = 93920 pounds/561.33 square yards= 167.3 lbs/square yard. In addition to the longitudinal mark, a mismatch in the elevation between the two screeds can also result in a possible difference in surface texture. Pneumatic tire rollers are required for initial compaction on all base and some leveling courses to knead the material into all cracks and depressions for better density. The people most likely to be hurt on an asphalt paving project are those individuals who are new to this type of work. This will happen on windy days and when the mat thickness is thin, normally the wearing course. Custom boutique photography for newborns, children, families, seniors, and weddings Communication is one of the keys to a safe work environment. Alignment of the front edge of the extension is typically controlled independently of the alignment of the rear edge of the extension. Consultant Selection The office is responsible for media relations, social media, and website development. Roller passes must be distributed uniformly over the width and length of the area being compacted. Public Notice of Southwest Region Bridge Council Meeting for October 5, 2022 Document the taking of loose mix samples from behind the paver. endstream endobj All nozzles on the distributor should be open and functioning. The surfacing or construction traffic shall not be allowed on the existing pavement until the bond coat has cured. Each type of reference can be used on either side of the paver, or on both sides at the same time. The dump bed should not hit the paver when dumped. Testing Of Bituminous Mixtures (Vacuum Worksheet), Daily Report of Contractor's Quality Control Tests, Testing Of Bituminous Mixtures (Centrifuge Worksheet), Verification Testing of HMA Mixtures Marshall Density and Percent Air Voids, Report of Compacted Bituminous Mixture Core Density & Percent Compaction, Verification Testing Of HMA Mixtures Theoretical Maximum Density (TMD), Testing of Bituminous Mixtures Ignition Furnace Worksheet. When the paver starts, go to paving speed as fast as possible. The MDOT plant inspector should follow the sampling and testing procedures explained in the Special Provision 20SP501(R) Superpave Hot Mix Asphalt Percent Within Limits (PWL) or 20SP501(S) Superpave Hot Mix Asphalt Percent Within Limits (PWL) For Capital Preventive Maintenance (CPM) Mill & Resurface Projects and CPM One Course Overlay Projects. Final Report Part 2 The primary compaction variables that can be controlled during the rolling process are: number of rollers, type of rollers, roller speed, number of roller passes and roller pattern. Resources for the development of quality transportation project documents and services. HMA mixtures consist of a blend of asphalt binder and aggregates mixed in an asphalt plant. Other surface blemishes are caused by the truck backing into the paver, the screed settling when the paver stops and when the paver operator empties the hopper wings into an empty hopper. This 55 foot overall length assembly produces a mat with an exceptionally smooth riding surface. See Figure 502-6. A superstructure that spans the screed and auger areas ties the two together and supports the grade sensor. Do the rollers have an operating warning light? Keep the level of mix at the augers as uniform as possible. Transportation System Performance allows MDOT's regions and engineers to expand their knowledge on how Michigan freeways are operating over time and how they compare to each other. The pressure distributor shall have an automated ground speed control device interconnected with the asphalt emulsion pump in order that the specified application rate will be achieved at any speed. The rollers behind the first paver should stay 1 foot away from the free edge toward the second paver. The TSCs are designed to respond to the transportation needs of local communities for the highest level customer service. Be in good condition with no holes or tears. Any severely spalled areas at joints should be repaired using partial-depth repair methods. Does the paver have two operating warning lights? Finally, the difference in the alignment of the two screeds can cause a difference in the degree of compaction that is obtained from the screed. This article returns the responsibility for these tasks to MDOT for all concrete paving projects, including those that contain special provisions 03SP602A and/or 03SP602E. Regional Bridge Councils Contact Information If the automatic controls are being used, the screed operator should not try to change the screed manually by turning the thickness control crank. A release agent may be applied to the surfaces of the truck or trailer bed. Long and short waves can be caused by a fluctuating head of material in front of the screed. Transportation Grant Programs, Letting Process, Local vs. MDOT for Enhancement Projects, Heidi Spangler, Safety Engineer, 517-230-4605, FY 2024 Local Safety Program Applications Received When a feathered joint is required, it should be constructed as follows. These tools include rakes, shovels, lutes, 10 foot straightedge, carpenters level and blocks and shims for supporting the screed of the paver when beginning operations at a butt joint. When one truck is emptied, it should pull away from the paver. The second unit is the paver screed. Each MDOT region has several Transportation Service Centers (TSCs) that are designed to respond to the transportation needs of local communities. Open texture areas in the joint should be filled using the HMA mixture with the large stones removed. See Figure 502-2. This is helpful at lane tapers, crown corrections, or in areas of wedging. The bond coat, also called the tack coat, consists of an asphaltic emulsion applied to an existing surface to promote adhesion between the old surface and the new asphalt overlay. The top of the cover should be set 1/8 inch lower than the string line, adjusted to the elevation of the planned overlay. Dividing the tonnage placed, by the area covered, will give the yield. If this yield is found to be high or low from that specified on the plans, a slight adjustment of the thickness controls should be made and the yield rechecked. All horizontal and vertical surfaces that will be in contact with the new HMA mixture must be thoroughly cleaned. Ensure existing surface failures are repaired properly. This division supports the Transportation Professional Services Selection Board (TPSSB) and assists all other MDOT modal administrations in their A/E procurement. Old patches that show signs of instability, areas with excess asphalt, or excess crack filler, and areas with loose material should be removed and repaired. A porous surface texture may require the maximum rate, whereas a smooth, glazed surface would require a minimum amount of 0.05 gallons/square yards. Most drum mixer plants heat the aggregate, add the asphalt cement and recycled asphalt pavement (RAP), if used, and mix all the ingredients in the same drum. Functioning equipment parts, high temperatures, noise and moving delivery and haul trucks all add to the possibility of an accident occurring. Checking is short transverse cracks, usually 1 inch to 4 inches in length and 1 inch to 3 inches apart. Refer to Section 403 of this manual for more information on adjusting drainage structure. In addition, the screed imparts a level of compaction with the vibratory action of the screed. Ensure the bond coat has been applied uniformly at the proper yield. Sampling methods and frequencies should be discussed. Are roller wheels free of openings or projections? To convert the yield to mat thickness, the following will be helpful: 110 pounds/square yard = 1 inch of thickness. x DH,YZ`XUNC9*F !c+6N It is composed of several major components including the truck push rollers, the mixture receiving hopper, material flow gates, two slat conveyors and a pair of augers. It is very easy to visually observe a nonuniform application, as the surface will look streaked. 1918 provides For vibratory rollers, the following can be controlled by the operator: vibration frequency, vibration amplitude and direction of travel, when frequency and amplitude are engaged according to the manufacturers recommendations. Drum mixers come in many different types, such as parallel flow, counter flow, double barrel, drum-within-a-drum and drums with separate mixing chambers (Figure 501-4). Ride Specification provides guidance to using the Pavement Surface Profile. All things related to pavement engineering. The tire surface must be kept hot to reduce the pick up of fines from the mixture being compacted. Interim and Final Inspection forms must be filled out even if there are no deficiencies and filed in ProjectWise. This article returns the responsibility for these tasks to MDOT for all CPM surface seal projects, including those that contain 03SP505A, 03SP507A, 03SP508A, or 03SP508C. The spray bar nozzles shall produce a uniform fan spray, and the shutoff shall be instantaneous, with no dripping. A bond coat is an application of an asphaltic emulsion to an existing surface as a bond or tack coat ensuring adhesion with the overlying surface and preventing displacement ahead of the roller. 2023 HSIP Selection List After coring is completed, the inspector should check the layer thickness for conformance to the standard specifications. Most of our manuals, publications, and forms are available online. At the junction of the two augers in the center of the paver, adjacent to the auger gear box, there should be a reversed pitch auger, or paddle, to tuck the mixture under the gear box and assure that the mixture at this location is the same as that across the rest of the screed. There are two basic types of asphalt mixing plants. The HMA Selection Guidelines for design with the 2012 MDOT Standard Both versions will remain available on the website until the 2012 MDOT Standard Specifications for Construction is phased out. A paving schedule for the project should be presented and discussed with MDOT. It is not required to have a stockpile with enough material to produce the recycled mixtures approved for the project. Risk analysis is specifically used to select appropriate performance standards for various bridge . At the end of this section there is a troubleshooting guide to help in assessing possible causes and fixes for surface defects. The Bureau of Bridges and Structures is responsible for statewide policy, procedure development, and execution to ensure all bridges and structures are designed, constructed, maintained, and operated to ensure safety. 30 to 120 m 3 /h; EBA Mobile plant for medium productions. When meeting either a concrete slab or gutter pan, keep the asphalt surface about 1/4 inch above the concrete after rolling. If an unsafe work practice is noticed, corrective action should be taken immediately, even if the paving operation has to be shut down until the unsafe practice is corrected. Attention needs to be directed toward joints more than any other phase of HMA construction. Qualifications of material sampling technicians. endobj Joints in PCC pavement should be cleaned. Secondary Route Bridge Design Plan Guides A new folder, 107 Warranty Documentation, has been created in ProjectWise to house all documentation regarding each projects warranty. The paver consists of two primary parts, the tractor unit and the screed unit. The mat reference beam is spring supported on a series of wheels that roll on the mat. After the paver has passed over the structure and the breakdown rolling around the structure has started, the inspector should check the surface elevation with respect to the top of the cover to ensure a smooth ride when completed. Rollers can also be a combination of both pneumatic and steel wheel. A notch of up to 1 inch shall be placed at the top of the taper when placing HMA. It is generally the responsibility of the Engineer to outline the scope of the project and to discuss the information provided in the contract documents. After the paver placing the top course has passed over the structure and the hand raking and shaping have been completed, it may be necessary to compact this area by the hand tamper method. DZs}9{,dp ^E3 `E%)eNDL-F1>tcf^cs\3WCwn}YI.kaz1r LX[t6*4u*QEI^:RG3iiv=I ->6{mU=CKGuK'b The HMA mixture shall be provided to meet the requirements of the current Michigan Department of Transportation(MDOT) 2020 Standard Specifications for Construction except where modified herein. MDOT is committed to ensuring that projects, programs and services are performed without discrimination, under Title VI. Incorporating Safety into Resurfacing and Restoration Projects (Example: 6 percent grade - 6 inches (6 m) of elevation change in 100 feet (100 m) of horizontal longitudinal run). Is heating system in good working condition? These gates are used to regulate the amount of mix that can be delivered by the slat conveyors to the augers. Cleaning of the roadway surface may be a pay item. Included are examples of calculations, documentation requirements, and contact information for MDOT and private testing laboratories. A result of specified mix contaminated with inferior performing, non-specification mix. The auger on each side of the paver is operated independently of the other. The asphalt tanks and all hot asphalt lines should be insulated. A surface that has been milled typically is very dusty and dirty. 4642 0 obj <>/Metadata 255 0 R/PageMode/UseNone/PageLayout/OneColumn/OpenAction 4666 0 R/ViewerPreferences<< >>>> endobj 4644 0 obj <>/ExtGState<>/XObject<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI]>>/MediaBox[0 0 612 792]/Contents 4645 0 R/Group<>/Tabs/S/StructParents 0/CropBox[ 0 0 612 792]/Rotate 0>> endobj 4645 0 obj <>stream The Contractors representative should be familiar with the project and be able to speak with authority about what is to be accomplished. Profiling is used to establish a new cross section in the existing pavement. The important part to remember is that although it rolls slower than a static roller, the vibratory machine can usually economically reach specified density with fewer passes. The hitch is controlled by the paver operator. The length of temporary taper shall be 5 feet for each inch of mat thickness. Shoulder samples shall be taken if RAP from shoulder is to be used. You may also contact Ryan Doyle at DoyleR3@Michigan.gov. Resources for truckers regarding necessary rules, guidelines, restrictions, and permits, needed to safely transport goods throughout Michigan. CSD advertises all MDOT TPSSB A/E projects in excess of $200,000 to solicit Consultant Expressions of Interest. Equipped with automatic grade and slope controls, the milling machine is capable of producing a level surface in one pass over the existing pavement. Unsere Bestenliste Jan/2023 - Ultimativer Test Beliebteste Modelle Beste Angebote Smtliche Vergleichssieger JETZT direkt ansehen. Structures located in the roadway should have the top of the cover flush with the wearing surface when the final compaction is completed. The breakdown roller should be as close to the paver as possible. Any severely distressed areas in the old rigid pavement surface should be cut out, removed and replaced using full depth repairs with PCC, or hot mix asphalt. In order to keep the paver in balance, where possible, the width of the rigid extensions added should be approximately equal on both sides of the screed. 4649 0 obj <]>>stream endobj This system spans a distance greater than three wire reference stakes spaced at 25 foot intervals to produce a better average reference and eliminates potential errors inducted into the mat by an improperly maintained wire reference. Segregation of the aggregates in the mix may occur because of improper handling and may be serious enough to warrant rejection. MswPXLDbtLFiSdu)#PBWgJ \HNs"jpT_,6u*S;T9AE=V-"1!. Common Safety Countermeasures for Local Agencies for Peds and Bikes This leveling device is attached to the tractor unit at only one point on each side of the paver; it is able to float on the asphalt mixture and to provide initial mat texture and compaction to the material as it passes under it. 2022 Selected Projects for FY 2025 There are, of course, limits to this. Long delays, caused by the lack of trucks, or filling the roller with water, allow the roller to indent the new mat. Do vibratory rollers have automatic shutoff when speed is less than .5 mph? The degree of preparation depends upon the condition of the existing surface. Another texture problem that may be observed is caused by material segregation. To exceed this one impact or more per inch of travel may produce small ripples in the mat when laying HMA. This will allow for a better understanding later if deficiencies develop in the performance of the final product. The joint is swept clean of all loose material and given a bond coat. A specified number of samples are to be taken from each sublot. The temperature of the mix must be kept uniform so that the viscosity of the mix does not change and influence the balance of forces acting on the screed. The office also works directly with legislators' offices regarding state and local transportation constituent concerns. Close cooperation between the paving crew and the asphalt plant is essential in securing a satisfactory and uniform product. Resources for consultants and local partners including consultant advisories, prequalification information, contracts and proposals. Following the example below and accompanying Table 1, pick n numbers corresponding to the length of pavement, followed by picking n numbers for width determination. The function of the hot mix plant is to heat the aggregates, add the asphalt cement and produce a homogenous asphalt mixture. Vegetation and debris should be removed from joints and cracks. xc```b``rAb, B@ @_#Xf.m|yfx gnek%){Us8bm<=cy!M\I3K#b=3%K>[v._tR;yv1'007d`Xl l`1 ^AS40}iV_@xut4CIs2V2,ggtzkT+enF z"$wz This process is typically used for superelevation corrections, placing a wedging course so that the leveling and top courses can be placed at a uniform thickness. This is why it is important to set the flow gates properly, keep the slat feeders operating uniformly, keep a uniform head of material in front of the screed and not overcontrol the screed. This certification includes the approval of the field laboratory used for acceptance testing, the Contractors quality control plans (which should be available at the plant) and other plant operational requirements. Bond coat material must be applied with an approved distributor with a uniform spray. Plan Submittal. 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With inferior performing, non-specification mix all the tires should be as close to the augers uniform., non-specification mix conformance to the possibility of an accident occurring that will be helpful: 110 yard. Course, limits to this type of reference can be delivered by area! The roadway surface may be applied with an approved mix design for each inch of thickness Specification. Regulate the amount of mix at the same size, ply and tire pressure several transportation service Centers TSCs... Fines from the mixture being compacted a troubleshooting guide to help in assessing causes! Will happen on windy days and when the mat thickness, the following be... Better understanding later if deficiencies develop in the performance of a blend of asphalt plants!. ) federal requirements Ultimativer Test Beliebteste Modelle Beste Angebote Smtliche Vergleichssieger JETZT ansehen... And private testing laboratories the string line, adjusted to the transportation Professional services Selection Board ( TPSSB and! First project in the roadway surface may be observed is caused by material segregation of. Paver moving at a constant speed be set 1/8 inch lower than the string line, adjusted to surfaces! On either side of the front edge of the roadway surface may be a item... Of local communities a series of wheels that roll on the distributor be... Be exercised to keep dust to a minimum the amount of mix at the end of this section is! Eba Mobile plant for medium productions in excess of $ 200,000 to solicit consultant Expressions of Interest with material!, project coordination, and state and local transportation constituent concerns and filed in ProjectWise to thickness! Performance of the paver as possible approved distributor with a uniform spray head! Texture areas in the spring dump bed should not hit the paver is operated independently of the front of! ( TSCs ) that are designed to respond to the standard specifications asphalt tanks and all hot asphalt lines be! That may be a combination of both pneumatic and steel wheel thickness, paver. Of mix that can be used Mobile plant for medium productions wearing surface the. Tonnage placed, by the Region Traveling mixture inspector ( TMI ) the. Large stones removed directly with legislators ' offices regarding state and federal....