&[a);8fUcK@=fCW ?Qdo 1 0 obj Mixture temperature should be checked regularly when the mix arrives on the project and recorded on the load tickets. Care must be taken to adjust the top of the cover to the slope of the planned finished roadway. 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. When the inspector sees an improper bond coat application, the operation should be stopped. 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. Select all. Copies of the letters sent should also be filed in the ProjectWise folder for future reference. If the wedging course is 3 inches or less, the inspector should string line the area to be wedged to determine the limits of wedging. Resources for general work zone mobility guidelines for engineering and technical staff. When a feathered joint is required, it should be constructed as follows. The paint dot is to be visible on the core during handling and testing. See Figure 502-1. What number and type of rollers were used? This equipment should be thoroughly checked before using it on the project. This material can be neat, unmodified or modified with polymers, rubber, latex, etc. The elevation of the string line must be set by a survey crew and the set line must be very taut. The stockpiles shall be large enough to supply a project continuously and consistently. 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. 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. There should be enough trucks to provide a continuous flow of mix to the paver. 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. Do vibratory rollers have automatic shutoff when speed is less than .5 mph? The rollers must be clean and free to rotate to allow smooth forward travel of the paver. The surface can have two types of waves: long waves and short waves. Is spray bar capable of having its height adjusted for uniform height, both sides? If trucks backing into the paver pick up emulsion, thus leaving the pavement clean, the bond coat is not cured. 2024 HRRR Selection List Does the distributor have a capacity of at least 800gallons (3,000 liters)? The Veteran Internship Program assists honorably discharged veterans of the United States Armed Forces as they transition into the civilian workforce. Density is required across the full pavement width. If it falls at the free edge of the pavement, the core location should be moved 2 inches in from the edge. It is important for the screed extension to be attached securely to the main screed. Further, the extension must be set at the same elevation and angle as the basic screed to prevent the presence of a transition line, or ridge, at the intersection of the main screed and the extension. Adequate hand tools, and proper equipment for cleaning and heating them, should be available for the paving operation. This floating screed principle is employed on all modern pavers in use today. Pavement sags and rough areas may require a wedging course. Depending on the material and job conditions, this can be quite dramatic. As the department strives to monitor warranties more closely and ensure that inspections are completed timely prior to the warranty expiration, staff should ensure canned reports are being utilized from SWAD and monthly reminder emails are being sent to the correct people in each Transportation Service Center (TSC) to ensure inspections are occurring timely. The rolling zone should be kept as short as possible. Rigid extensions come in several widths, usually 6 inch, 12 inch, 2, 3, and 5 foot sections. The purpose of the shoes is to allow one or more of them to pass over a high or low point in the existing surface without altering the slope of the whole beam. t6h ($Y+q Keep the level of mix in the hopper above the flow gates. Before the automatic screed controls are engaged, the screed must be nulled before paving starts and the proper angle of attack must be set. The rollers behind the first paver should stay 1 foot away from the free edge toward the second paver. When slope control is used, the thickness of the mat on the side of the paver that is controlled by the slope sensor could be variable, depending upon the condition of the existing surface. of seven wheels? 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. 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. 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. This unit is responsible for the development of statewide processes for the implementation of all required state and federal regulations as it relates to local agencies. If it is below the specification limit, 250F, it should be discarded. At MDOT, safety is paramount. Did the paver have to stop and wait for trucks? b. Profiling is used to establish a new cross section in the existing pavement. 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. Refer to the AASHTO Roadside Design Guide and the MDOT SHA Guidelines for Traffic Barrier Placement and End Treatment Design for additional . 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. 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 mat reference beam is spring supported on a series of wheels that roll on the mat. Plants are certified in accordance with the HMA Production Manual. The TRAC Internship is an extension of the TRAC Program and is designed to provide opportunities for 12th grade students interested in transportation and engineering careers. . The materials used in the HMA mixtures will be shown on Form 1931 HMA Mix Design (Figure 501-1), and those materials will meet the requirements as specified in Tables 501-1, 501-2 and 904-2 of the Standard Specifications for Construction. The paver should be started slowly, pick up the truck, and brought back to the preselected paving speed as quickly and as smoothly as possible. Because of its short length, the joint matching shoe will not remove any major variations that occur in the existing surface, or adjacent paved lane. These asphalt cements may also contain anti-strip agents. When constructing the first lane, a string line should be employed to guide the paver operator to establish a uniform edge. TRAC engages high school and middle school students in solving real-world problems, such as designing bridges or analyzing the environmental effects of building a highway. The certification is normally completed by the Region Traveling Mixture Inspector (TMI) before the Contractor starts his first project in the spring. 2023 HRRR Selection List, Highway Safety Manual (HSM) Process FY 2024 Webinar Recording The adjacent pavement, curb, or curb and gutter, shall be replaced to the original elevation, condition and type of construction, unless otherwise provided. The Contractors representative should be familiar with the project and be able to speak with authority about what is to be accomplished. The top course will then be placed at a uniform rate. On two-course projects, the first course should be reduced gradually at a rate of 1 inch in 33 feet and end at a point 33 feet or more from the butt joint. It may be necessary for the Contractor to make adjustments of the screed, vibrators, hopper flow gates, or the screed augers, to ensure a uniform surface texture. 2P3G(30120&gp9@. Segregation of the aggregates in the mix may occur because of improper handling and may be serious enough to warrant rejection. 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. endstream endobj This device consists of a short 12 inch shoe or ski that is used to reference the grade of an adjacent piece of pavement or curb. 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. Agreement is needed on the methods to be employed to complete the project on schedule, within specification and with minimum delays. Trying to reconstruct events at a later time without written notes and complete test data is usually frustrating and often results in conflicting opinions as to exactly what happened. Laying out core locations, discuss how it will be done. Secondary Route Bridge Design Plan Guides 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. ?,E_Bs>B~Ke?Ltqv`K?7GT=?e{T.gJu08!RmK?>\TG>X*zsK>C/>RXKG9>DOcpbcc?~JvGp_dfXq1]=K57:To dr>I7|IT3E?K8C.C i>Jspv0phJvpv@!C],U)BZ9**#"52pODGJ)E2A@oq )N-?Ihr>jcvM2}czL=NwX]QD;vu;djZkSLpX\w]>4t7~~}>kzr}^a{~cW/juWQ1fwH0?c:@ ^ ^ thI9#~wLH0]=.DEe4k;kR/_w\W]6xLK} 1Gp=azK%Ad/?t-[3)3x!Kyho6pkF1?Q!+]P#6Nt|ioF7K{O^j5[5U=uFh=tq-17|~%{knFic7'Fz]T^Ukkk}g[ L o.yhyKRr+a'oE. Before placing any HMA patch, the area to be patched must be cleaned and a bond coat applied. Field experience and test data have shown that a vibratory compactor will produce required density in fewer passes than a static roller, while moving at a slower speed. The degree of preparation depends upon the condition of the existing surface. This minimum rate should also be used between courses as a tack coat. Incorporating Safety into Resurfacing and Restoration Projects If the push rollers are not cleaned periodically and do not rotate freely, the truck tires will slide on the rollers and increase the load on the paver. 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. Things that can cause a nonuniform application are, improper temperature, improper pump speed, sprayer bar height improperly set, spray nozzles clogged, or the nozzle overlap pattern is improperly adjusted. Any questions about the information in the contract documents should be raised and clarification requested, if necessary. Communication is one of the keys to a safe work environment. documented in the HMA-QC Plan and discussed at the pre-production meeting. In this instance, the two numbers chosen were: 0.376 and 0.529, for length and transverse offset. 1918 provides %PDF-1.7 % Stop the paver at this point, remove it from the roadway and remove any excess HMA material from the roadway. String line allows for the smoothest possible asphalt mat behind the paver screed. Care should be taken to neatly construct the joint at a right angle to the centerline of the roadway. of HMA sampling and testing required by the MDOT HMA QC/QA Assurance Program. Once the truck bed has been emptied of mix, the truck hitch is withdrawn and the truck is able to pull away from the paver. This mark can easily be eliminated by adjusting the elevation of the extendable screed in relation to the main screed. Trucks should stop short of the paver and be picked up by the paver. After production begins, the Contractor may ask for JMF adjustments. Generally speaking, this means that vibratory rollers normally operate in the 2 to 3 mph range. A superstructure that spans the screed and auger areas ties the two together and supports the grade sensor. FY 2022 LAP Bridge Scoping Cost Estimate Worksheet Consultant Selection Bond coat, also referred to as tack coat, is an asphalt emulsion. All existing pavements, including newly-constructed HMA widening, which are to be surfaced, should receive a bond coat application. Contract Plans Specify 165 pounds/square yard. The office is responsible for media relations, social media, and website development. The use of a tapered, overlapping longitudinal joint eliminates the requirement that all lanes be resurfaced to within one truckload of the same point of ending. The web Browser you are currently using is unsupported, and some features of this site may not work as intended. 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 rollers vibratory frequency should match its travel speed. The tiers identified below apply to Superpave 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. The method for determining the binder grade in HMA mixtures incorporating RAP and/or RAS is divided into three categories designated Tier 1, Tier 2 and Tier 3. FY 2026 Local Bridge Program - Call for Applications Submission Sheet, Secondary Route Bridge Design Plan Guides, Final Report Part 1 Communication cannot stop once the pre-production meeting is concluded. This page was last edited on 13 January 2022, at 11:41. 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Modified with polymers, rubber, latex, etc for uniform height, both sides having its height adjusted uniform! 3 mph range and be able to speak with authority about what is to be mdot hma selection guidelines! Cover to the main screed, should receive a bond coat application string line allows for the possible... Relations, social media, and some features of this site may not as... Be familiar with the HMA Production Manual height, both sides at a right angle to centerline... Paver should stay 1 foot away from the edge future reference in accordance with the project this be... The specification limit, 250F, it should be kept as short as possible taken to adjust the top will... Screed extension to be visible on the material and job conditions, this means that vibratory rollers operate. Length and transverse offset and wait for trucks flow gates instance, the two numbers chosen were: and. Will then be placed at a right angle to the main screed away from the edge backing!
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