The good looking surface texture can lull the operator into a false sense of security. ~zWRGO#wnpOs1`(yvM>.D>N^-E*na71K7L.E5! Before the application of bond coat, the surface must be dry and free of sand, gravel and dust. This equipment must be capable of accurately removing the pavement surface, in one or more passes, to the required grade or cross section. Is heating system in good working condition? MDOT Microstation Workspace Instructions, Asset Management Guide for Local Agency Bridges in Michigan Asphalt paving projects, like many construction projects, are not always built as originally scheduled. The second unit is the paver screed. 4649 0 obj
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Whenever a rigid screed extension is employed on the basic screed, auger extensions and the accompanying auger tunnel extensions should also be added. Plants are certified in accordance with the HMA Production Manual. 2022 Selected Projects for FY 2025 FY 2024 Webinar Recording 4642 0 obj
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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. Public Notice of University Region Bridge Council Meeting for October 12, 2022, FY 2025 Local Bridge Applications Received This type rollers compactive effort is a function of the wheel load, the tire pressure, the tire design and the depth of penetration of the tires into the mix. The inspector should check the placement yield occasionally. Does paver have properly working screed heaters? This should be checked using a straightedge or string line. Proper subsurface drainage should be installed as necessary. The street inspector can easily get hurt if they are not aware of the number of vehicles operating on the paving site. When the paver stops, do it as fast as possible. Roller passes must be distributed uniformly over the width and length of the area being compacted. When butt joints are called for on the plans or in the proposal, construction should be as follows. In the past, special provisions 03SP502D and 03SP502E delegated certain aspects of project oversight to the contractor. The surfacing or construction traffic shall not be allowed on the existing pavement until the bond coat has cured. U@A#8TEtAr]wWxazj+%=[,dM,MAg/z{F }G=lNPjeG&Pku,T]cXQo
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K65 MDOT has seven region offices and several geographically located Transportation Service Centers (TSCs) in each region that handle transportation-related construction and maintenance programs. 4643 0 obj
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It is also used in Mexico. To convert the yield to mat thickness, the following will be helpful: 110 pounds/square yard = 1 inch of thickness. This floating screed principle is employed on all modern pavers in use today. The names and titles of any people involved in the discussion should be written down, as well as the topics discussed. Bond coat shall be applied to the taper before the adjacent lane is placed. 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 The aggregate used to make the mix can be a single aggregate, but it is generally different sizes blended together through the cold feed bins to produce proper gradation. At the end of this section there is a troubleshooting guide to help in assessing possible causes and fixes for surface defects. The mix that is carried to the back of the tractor unit by the slat conveyors is deposited in front of the augers. These checklists do not replace or supersede the referenced MDOT, American . This type of reference device is used only when the grade being sensed is relatively smooth. The uniform application of the emulsion is a function of the asphalt distributor and the skill of the operator. Three types of self-propelled rollers are currently being used: static steel wheel, pneumatic tire rollers and vibratory rollers. Document when immediate possession of the extracted cores occurs (core ID, date, time, etc.). Ensure the bond coat has been applied uniformly at the proper yield. A release agent may be applied to the surfaces of the truck or trailer bed. In this instance, the two numbers chosen were: 0.376 and 0.529, for length and transverse offset. HMA types will be as specified on the plans or in the proposal. 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. Rocking slabs must be stabilized. Refer to Section 403 of this manual for more information on adjusting drainage structure. Most paver manufacturers have developed hydraulically extendable screeds that trail the main screed on the paver. Yield = 93920 pounds/561.33 square yards= 167.3 lbs/square yard. Rollers are used to compact the mixture to the required density. If the end of the lane is to be left open overnight, a ramp joint should be used. Long waves may correspond to the distance between truckloads and may be associated with the reversal points of the rollers. This will allow for a better understanding later if deficiencies develop in the performance of the final product. The Contractor would then correct the problem and show that a uniform application can be made before being allowed to continue paving on the project. Open texture areas in the joint should be filled using the HMA mixture with the large stones removed. The dump bed should not hit the paver when dumped. In addition, the screed imparts a level of compaction with the vibratory action of the screed. Communication cannot stop once the pre-production meeting is concluded. PLANT PRODUCTION (TONS PER HOUR) YIELD IS POUNDS PER SQUARE YARD. The asphalt cement delivery system must be calibrated. of seven wheels? Once it is determined how many passes are needed to achieve compaction at any point, the roller pattern for an area will be calculated by multiplying the number of roller passes needed for compaction by the number of rollers needed to cover the width being paved. ?,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. If the mix is tender, a lower tire pressure will displace the mix less than a higher pressure. Each tier has a range of percentages that represent the contribution of the RAP and/or RAS binder toward the total binder, by weight. An end gate is attached to the end of the screed to restrict the outward movement of the mix around the end of the screed. For each roller employed on a project, the mat width should be divided by the width of the compaction roller to determine the number of passes needed to cover the entire width being paved. From 30 to 100 m 3 /h; MODULMIX Plant for large productions and special concretes. A sufficient amount of millings or cores shall be taken at each test location to ensure an adequate amount of RAP is obtained to perform a full mix design. This type of roller must be equipped with a skirt around the bottom of the roller and within 3 inches of the new surface. The design may have been approved for another project; however, a JMF must be prepared for each mixture used on the project. The completed centerline joint should be uniform, closed and flush with adjacent lanes. Flexible Pavement: See Figure 502-1. Every individual should know what is expected and know how to perform the assigned tasks. Contract Administration and Oversight Guidelines for Projects Containing Warranty Work Email this Page Contents 1 All Projects 2 Hot Mix Asphalt (HMA) Paving Projects 3 Concrete Paving Projects 4 Capital Preventive Maintenance (CPM) Surface Seal Projects 5 Documentation and Notifications All Projects Two factors within the screed itself can contribute to the degree of compaction. All nozzles on the distributor should be open and functioning. Nonuniform mat texture can appear in the mat both transversely and longitudinally. 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. Plan the width of application to ensure having bond coat under the matching longitudinal joint. 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. These documents help people to design, build, and maintain roads and bridges. Unsere Bestenliste Jan/2023 Ultimativer Produktratgeber Die besten Produkte Bester Preis Testsieger Jetzt direkt lesen. 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. Be extremely careful when an asphalt surface is being placed on an aggregate base adjoining a slab or curb. Density is required across the full pavement width. It is good practice to keep the speed of the paver as constant as possible during the paving operations. The Office of Governmental Affairs represents MDOT's interests as new or amendatory legislation is developed or moving through the legislative process. Of sufficient weight and strength to resist tearing. Are the king bolts in good condition on steel wheeled rollers? The screed on the paver can be angled at its center to provide for positive or negative crown. Steam rising from the mix as it is dumped into the hopper of the spreader indicates moisture in the mix. 2024 HSIP Selection List The Internship Program offers undergraduate and graduate students interested in civil engineering and construction management careers, valuable experience by working with professional field staff. 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. The top course mixture can be used for wedging when the thickness is less than 2 inches. The aggregate stockpiles should be built on a clean, dry and stable foundation, with positive drainage. These asphalt cements may also contain anti-strip agents. If a good bond is not formed between the existing surface and the new overlay, a slippage, or sliding-type, failure can easily occur. The inspector may use the following checklist to record the condition of equipment. The Office of Procurement and Contract Management (OPCM) Consultant Services Division (CSD) procures all Maryland Department of Transportation State Highway Administration (MDOT SHA) A/E contracts using Qualifications-Based Selection (QBS), as defined in Code of Maryland Regulations (COMAR) Title 21, Subtitle 12, "Procurement of Architectural Services and Engineering Services" and 23 CFR . Functioning equipment parts, high temperatures, noise and moving delivery and haul trucks all add to the possibility of an accident occurring. It is the MDOT inspectors responsibility to ensure that the Contractor is providing a specification product. Fuel oil is not permitted for use on tapered joint rollers and mobile mat reference wheels. 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. USDOT Navigator Website. This is helpful at lane tapers, crown corrections, or in areas of wedging. Care must be taken to adjust the top of the cover to the slope of the planned finished roadway. See Figure 502-6. The Bureau of Transportation Planning develops and implements a comprehensive transportation planning process which results in investments that are consistent with the policies of the State Transportation Commission. Contract Plans Specify 165 pounds/square yard. This will help ensure that sampling technicians for the project are formally qualified by the department. Communication is one of the keys to a safe work environment. This page was last edited on 13 January 2022, at 11:41. All horizontal and vertical surfaces that will be in contact with the new HMA mixture must be thoroughly cleaned. You may also contact Ryan Doyle at DoyleR3@Michigan.gov. 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. Risk analysis is specifically used to select appropriate performance standards for various bridge . This arrangement can sense and correct any change in screed elevation. If distortion of the base course occurs during the paving operation, the mixture placement should be stopped until the condition of the base course is corrected. FY 2023 Project Planning Guide I3 Q[LSP'@Df]]nt .Q1-^zAi"AN|.Tc 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 consultants and local partners including consultant advisories, prequalification information, contracts and proposals. The mobile reference system, illustrated in Figure 502-8, combines the front mounted 30 foot floating beam with a 20 foot mat reference beam. MDOT Highway Safety When the inspector sees an improper bond coat application, the operation should be stopped. The surface can have two types of waves: long waves and short waves. The grade sensor usually rides directly on the beam at its midpoint. x\YoF~A4 M!"Gcy-3_}TA(z #*v}Ow>~_c~y}On}]mvy}Rc*UQ]n/?]v./8:~o?Q`Sv;WE]f_MAuOF}@,c?uQUYcmEEPuB',~WMQsE$XF-,V-g6mMa%[+ndv6>%T&G/fQx&[0{Rm z5WB3^sha!QBk`LB#D1V'iuZtDW}} . The certification is normally completed by the Region Traveling Mixture Inspector (TMI) before the Contractor starts his first project in the spring. If it is below the specification limit, 250F, it should be discarded. To make a proper adjustment, the inspector should string line along the roadway after the leveling course has been placed, 15 feet either side of the structure in a longitudinal direction and in a transverse direction from the centerline to the edge of pavement, or curb line. It spans from northern Canada to Mexico near the equator. The hauling unit must be capable of completely protecting the mixture from the weather and ensuring that the mixture temperature is maintained during the hauling time. `qr`@UtT! u#$$mB3B2(&qiB[g%R(ck7H,D"-Vg#Y If aggregates larger than what is required for mix design still exist after processing, the contractor must demonstrate that additional screens are installed on the RAP feed system to ensure that the RAP being introduced into the HMA mixture contains no aggregate larger than the top size aggregate allowed in the mix design. The field application of the applied mix design is called the Job Mix Formula (JMF), (Figure 501-2). 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. Are circulating systems working properly? However, the amount of overlap between the first and second lanes is very important. If a hydraulically extendable screed is to be used at a fixed width for a period of time, the paver should be equipped with auger extensions to within 12 inches of the end gate. Stop-and-go paving operations must be avoided; every time the paver stops more than momentarily, the screed settles, producing roughness. A slight change in direction, or curl, is beneficial at each reversal spot to further reduce the tendency of the mix to shove under the compactor and to eliminate the possibility of a bump at the point where the roller reversal occurs. Adjust catch basins after the leveling course has been placed. These gates are used to regulate the amount of mix that can be delivered by the slat conveyors to the augers. Avoid spraying adjacent completed surfaces that will remain exposed. endobj
The sides, or wings, of the hopper are movable. Any dust and dirt left on the milled surface will greatly affect the bond between that course and the new overlay. 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. The faster a roller passes over a point on the asphalt surface, the less time the weight of the roller has to work on that point; this means that less compactive effort is applied to the mixture. 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. A multi-unit culvert is considered a bridge if the total length, as measured along the centerline of the roadway, is greater than 20 feet and the distance between the culvert units is less than half the diameter of the smallest unit.
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