That is why MDOT offers many ways to help ease the stress of commuting by providing information that commuters want and need as they make daily travel decisions. A diagnostic guide is included here to help in identifying the cause and fix for a range of segregation problems. The tractor unit receives the asphalt mixture from the haul trucks, carries that mixture back to the spreading augers, distributes the mixture across the width of the screed and pulls the screed over that mixture. Local Bridge Advisory Board Contact Information, Local Bridge Program Public Meeting Announcements, Public Notice of Local Bridge Advisory Board Meeting October27, 2022- Location Change Once the proper yield has been obtained, only periodic checks will be required each day. Refer to Figure 502-13 for some typical mat appearances. Maintain and document these certifications in the project files. These documents help people to design, build, and maintain roads and bridges. Job mix formula adjustments, retroactive. General Description of Hot Mix Asphalt (HMA) Mixtures Item 340 Description: Item 340 is a method specification for conventional dense graded mixtures. Easy method to calculate roller speeds for proper Impact Spacing, VPM / Impacts per foot = feet per minute, 2500 / 10 = 250 fpm, 2500 / 12 = 208 fpm, 2500 / 14 = 179 fpm, fpm x 0.01136 = fpm / 88 = mph, 208 fpm x 0.01136 = 208 fpm / 88 = 2.36 mph. These gates are used to regulate the amount of mix that can be delivered by the slat conveyors to the augers. This hitch acts to keep the truck in contact with the paver to prevent the truck driver from inadvertently pulling away from the paver and dumping mix on the pavement in front of the paver. PLANT PRODUCTION (TONS PER HOUR) YIELD IS POUNDS PER SQUARE YARD. The function of the hot mix plant is to heat the aggregates, add the asphalt cement and produce a homogenous asphalt mixture. The MDOT procedure used for selecting random core locations is by using a random number generating computer program. In general, the vibrators should be used near the maximum possible frequency. The density obtained by the paver screed is also a function of the speed of the paver. This equipment must be capable of accurately removing the pavement surface, in one or more passes, to the required grade or cross section. The distance the screed of the trailing paver should extend over the uncompacted mat behind the first paver should be limited to no more than 1 inch. Mixture temperature should be checked regularly when the mix arrives on the project and recorded on the load tickets. 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. When a grade reference is used in conjunction with a slope control device, the grade reference sensor is typically positioned on the centerline side of the paver, with the slope controller determining the thickness of the mat on the outside edge of the pavement. 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. <> Profiling is used to establish a new cross section in the existing pavement. When using drum mix plants, the aggregate moisture content of each stockpile should be taken at least once a day and the number entered into the plant control system. The Michigan Department of Transportation (MDOT) is responsible for Michigans nearly 10,000-mile state highway system, comprised of all M, I, and US-routes. The top of the cover should be set 1/8 inch lower than the string line, adjusted to the elevation of the planned overlay. When a change in one force occurs, the screed will rise or fall and will change the thickness of the mat being placed. If it exceeds optimum placement temperature, but does not exceed the specification limit, the truckload is usually not discarded, but immediate steps should be taken to correct the condition. <> Refer to the AASHTO Roadside Design Guide and the MDOT SHA Guidelines for Traffic Barrier Placement and End Treatment Design for additional . endobj The tractor unit provides the motive power to the paver and to transfer the mixture from the receiving hopper on the front of the paver to the spreading augers at the back of the paver. 1918 provides One of the most important considerations in making a longitudinal joint is keeping the paver on a straight line of travel. Pavement sags and rough areas may require a wedging course. 111 0 obj <>stream This article returns the responsibility for these tasks to MDOT for all HMA paving projects, including those that contain special provisions 03SP502D and/or 03SP502E. 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. This includes, at a minimum, staff oversight at a level to perform periodic on-site inspections. This can be accomplished by using a rotary broom, flushing with water, and other methods that may be required to remove clay and dirt. Plants are certified in accordance with the HMA Production Manual. Once these forms are complete, all pertinent information needs to be entered into the Statewide Warranty Administration Database (SWAD) and letters sent directly to the contractor and directly to the Surety Company notifying them of the results of the inspection and status of the warranty prior to the expiration date. Public Notice of Bay Region Bridge Council Meeting for October 3, 2022 Pressure distributors are used to apply a uniform application of the asphalt emulsions, normally referred to as the tack or bond coat. The initial acceptance form, contained in the contract documents, is to be filled out when the warrantied work has been completed and accepted. icPUBJ FP rM4"d_`Sx".HCaM;)v}khmqj*KDRu`JK*l*fiEpg[`+H9g@ Ct)L;9BnLjvJdQP7BHD#},i-7D4lPNy`B_]Z)Hg BWPl!3I8"#wQjBANtNV #P9!#)C6.q]BX9#mCw Federal-Aid Highways Environmental Efforts Included are examples of calculations, documentation requirements, and . Adequate hand tools, and proper equipment for cleaning and heating them, should be available for the paving operation. See Figure 502-3. Whenever the temperature of the previously placed mats falls below 170F prior to placement of the adjacent mat, or when placing base mix and the air temperature is below 50F, the vertical edges of the initial mat shall be coated with HMA bond coat material before the mixture is placed in the adjacent section. The people most likely to be hurt on an asphalt paving project are those individuals who are new to this type of work. The outcome of each conversation must be recorded; who told whom to do what, and what was the reply? Further, whenever rigid extensions are employed, the strike off, or pre-strike off, assembly must be added to the extension and set at the same location as the strike off on the main screed. The asphalt cement in the storage tanks should be kept at a constant temperature, normally between 275F and 311F . These are notes from meetings between MDOT SHA and industry about improving the quality of materials used on State highways. Figure 502-14 shows some typical surface patterns and the causes. Experience has shown that these sections generally settle after a short period of time. The inspector should contact the Region HMA inspector for guidance. Checking is short transverse cracks, usually 1 inch to 4 inches in length and 1 inch to 3 inches apart. Hot Mix Asphalt Selection Guidelines Revised: 03/10/2020 FHWA Approved: 05/07/2020 The following guidelines have been developed at the request of Local Agency Engineers for use on Local Agency projects. Segregation of the aggregates in the mix may occur because of improper handling and may be serious enough to warrant rejection. This requires the level of mix in the hopper to be kept at least even with the bottom of the flow gates. A specified number of samples are to be taken from each sublot. The office is responsible for media relations, social media, and website development. The design may have been approved for another project; however, a JMF must be prepared for each mixture used on the project. For relatively thin layers of mix, generally less than 1-1/2 inch, the vibratory roller should typically be operated in the static mode. These defects can be divided into two primary categories: equipment related and mixture related. 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. Does the distributor have a capacity of at least 800gallons (3,000 liters)? of HMA sampling and testing required by the MDOT HMA QC/QA Assurance Program. These adjustments may be allowed if there is reason for the request and as long as the resulting mixture meets the specifications for the project. The TSCs are designed to respond to the transportation needs of local communities for the highest level customer service. This dryer heats the aggregate to the desired temperature and delivers the material to the hot bins in the tower unit. Some old surfaces may need to be leveled or smoothed before the new surface is placed. 109 0 obj <> endobj Adjust catch basins after the leveling course has been placed. DZs}9{,dp ^E3 `E%)eNDL-F1>tcf^cs\3WCwn}YI.kaz1r LX[t6*4u*QEI^:RG3iiv=I ->6{mU=CKGuK'b Selection. 2024 HSIP Selection List A pre-production meeting should be held before work commences on a project. 4643 0 obj <>stream See Figure 502-1. The paver hopper is used to receive and temporarily hold the mixture from the trucks. Each individual core location is to be marked on the pavement with a 2 inch diameter paint dot which represents the center of the core. If the random core location falls over a tapered joint, it should be moved to the first point that the mat is full depth. Conventional The inspector should check the entire pavement surface to ensure that all corrections are made before resurfacing work begins. The substitution of another HMA mixture type other than the recommended mixture is acceptable if it has demonstrated to perform under similar traffic conditions. The pattern of segregation can normally identify the cause of the segregation. A superstructure that spans the screed and auger areas ties the two together and supports the grade sensor. 310 0 obj <> endobj 312 0 obj <>>>/Contents 313 0 R/StructParents 0/Tabs/S/CropBox[ 0 0 612 792]/Rotate 0>> endobj 313 0 obj <>stream stream @c0M8;\ r)]-f3E|r ZVu~[ Long delays, caused by the lack of trucks, or filling the roller with water, allow the roller to indent the new mat. At the end of this section there is a troubleshooting guide to help in assessing possible causes and fixes for surface defects. Projects constructed under a warranty special provision still require inspection staffing and complete documentation prior to payment, including MDOT materials certifications, MDOT yield checks, MDOT quantity measurement, and MDOT Inspectors Daily Reports. Irregularities in the lower courses can usually be corrected by removing or adding material. There are many common myths and misconceptions about transportation in Michigan. The aggregates are then proportioned by weight into the mixer, also called the pug mill. Improper adjustments of catch basins can create drainage problems, which will lead to early deterioration of the roadway. As of January 1, 2022 the Personal Net Worth Cap applied to the Minority Business Enterprise (MBE) program will increase from to $1,788,677 to $1,847,024. If a conversation is held with other project personnel concerning project activity, the date and location of the conversation should be recorded. Only enough bond coat should be applied that can be covered the same day. It is generally the responsibility of the Engineer to outline the scope of the project and to discuss the information provided in the contract documents. It spans from northern Canada to Mexico near the equator. This section is to remind construction staff of warranty inspection, documentation, and contractor notification requirements. Public Notice of Superior Region Bridge Council Meeting for September 23, 2022 Safety Project Submittal (Form 1627), 2024 Streamlined Systemic HSIP Selection List Does the paver have two operating warning lights? tf@ciT$`|ntC62(t;p_XN(eM1$ONC8C8:LsA){#lt,:Gb{.mGjN,gVJeBm8Vs= Safety talks are a very good way to start each day for both the Contractor and MDOT personnel. The bond coat material must be applied with an approved distributor with a uniform spray. 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. Depending upon the gate settings, more or less mixture is permitted to enter the tunnel. No matter what type of plant is being used, several key items should be monitored. arkansas tech football schedule 2022 face shape calculator male; ftp command not found linux blooket coin hack github; the cheating pact baby leopard geckos for sale; The desired degree of cross slope is dialed into the slope controller. Rocking slabs must be stabilized. Warranties are a tool to assure quality, but they are not a replacement for proper inspection, quantity measurement, proper payments, or proper contract administration. endstream endobj These tears are usually caused by improper paver condition, or operation, by cold mix, and by attempting to lay a mat too thin compared to aggregate size. Long waves may correspond to the distance between truckloads and may be associated with the reversal points of the rollers. 4.4 MDOT Standard Practice for Random Sampling of HMA Materials 4.4.1 Sampling In-Place Paving Material 4.5 Utilizing Reclaimed Asphalt Pavement (RAP) Millings from the Same Project When Using a Portable Hot Mix Asphalt (HMA) Plant GENERAL Pre-Production Meeting A pre-production meeting should be held before work commences on a project. FHWA Emergency Relief Program Video This floating ski system averages out the variation of the existing grade over a 30 or 40 foot length. xc```f`` with the proposed access and/or road improvements are required in accordance with standards and practices accepted by MDOT SHA. Slick, highly polished surfaces, potholes, old patches, cracks and joints may require repairs. When the paver stops, do it as fast as possible. 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 The HMA mixture used for patching should be the top course mixture called for on the plans, or in the proposal. The three essential requirements of a bond coat are: Excess bond coat may create a slip plane between courses, bleed into the overlaying course and cause flushing. Bleeding (flushing) occurs when the asphalt cement comes to the surface under traffic. Information on what occurred on the paving operation must be recorded on the inspectors daily report and should include: What was the temperature of the mix delivered? Can VPM be locked in on vibratory rollers? This process will be repeated for additional samples. Forms The screed on the paver can be angled at its center to provide for positive or negative crown. Bleeding can be caused by too much asphalt cement in the mixture, or by allowing traffic onto the paved surface before the surface has cooled sufficiently. This requires a HMA layer of varying thickness to be placed and is referred to as wedging. Bridge railings and piers, curb and gutter pans, and guardrails must be protected from the spray of bond coat by the use of shields. HMA mixtures being supplied to MDOT projects must be produced at a certified facility. The names and titles of any people involved in the discussion should be written down, as well as the topics discussed. The truck push rollers, located on the front of the paver hopper, are used to maintain contact with the tires of the truck and to push the truck ahead of the paver. The work should be planned so the bond coat is not applied too far in advance of the paving operation. Research Administration supports and promotes innovative research that encourages safe, sustainable and cost-effective transportation solutions throughout Michigan. \O3H[ L1>C{sp U2jNB FegGYr53T)s Sb3@4$90hdo 9W@4$)QlB~|%fF5Aw k|F$eGNkSE?3)|klNAX4 % Flexible Pavement: Whether you are from out of state or right here in Michigan, we want to ensure your travel throughout Michigan is informative, comfortable, and fun. If temperatures warrant, the sides and bottom of the truck bed should be insulated. 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. 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