Are the water sprinklers in good operating condition? Therefore, the first sample should be taken 1985 feet from the beginning of the pavement and 6.3 feet from the designated (right or left) edge of the pavement. 111 0 obj <>stream Selection of appropriate pavement marking materials (paint, thermoplastic . 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. 2022 Selected Projects for FY 2025 Once the mix from the second paver is placed against the uncompacted edge, the rollers behind the second paver will densify the joint area. The subject of joints includes longitudinal joints and transverse joints, as well as the matched joint between an asphalt surface and a concrete pavement, or gutter pan. The Contractor must submit a mixture design to the MDOT Construction Field Services laboratory for approval in accordance with the HMA Production Manual. This should be checked using a straightedge or string line. 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. Document the extraction of the cores from the locations marked (random numbers, date, time, etc.). FY 2024 HSIP Streamlined Systemic Application Since there are 5280 feet in the sublot, pick two numbers using the random number generating calculator, which are then multiplied by 5280. Resources regarding MDOT's contracting processes, including contractor prequalification, bid letting, contract awards, and contractor payments. After a short mixing process, the asphalt cement is added and the entire mixture is mixed for 30 to 45 seconds. Adjustments to the JMF will not be allowed outside the mixture limits shown in Tables 501-1 and 501-2 of the Standard Specifications for Construction. An asphalt mix that has all the desirable mix design characteristics will perform poorly, if not compacted to the proper density. Paver speed is a large contributor to the smoothness of the ride on a finished pavement. ?,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. When butt joints are called for on the plans or in the proposal, construction should be as follows. Is the automation ski of proper length 30 feet +/- for all courses except last pass top course? Before the application of bond coat, the surface must be dry and free of sand, gravel and dust. 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. 81R ?+iKEsNAn#w The guidelines illustrate how to collect appropriate data, estimate risk of failure from an estimated failure probability and associated economic losses, and use risk in a structured approach to select an appropriate management plan. A notch of up to 1 inch shall be placed at the top of the taper when placing HMA. When cold-milling by the ton is a pay item, a weigh person will be needed. Does the paver have reverse pitch augers or paddles at center of paver? 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. 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. The initial acceptance form, contained in the contract documents, is to be filled out when the warrantied work has been completed and accepted. At MDOT, safety is paramount. Deviations in the pavement surface are averaged out over the length of the grade reference device. This will allow for a better understanding later if deficiencies develop in the performance of the final product. For the floating screed principle to work properly, it is important that the pull points on both sides of the tractor be at the same level above the ground. Is heating system in good working condition? Slick, highly polished surfaces, potholes, old patches, cracks and joints may require repairs. A list of equipment that will be used on the project should be supplied to MDOT. Moreover, if one roller rotates freely and the other does not, the paver may tend to change direction. The Contractor must provide all equipment required to prepare the base and place the HMA in accordance with the plans and specifications. It is important for the screed extension to be attached securely to the main screed. It is necessary for the screed to be the same temperature as the mixture being placed in order to assure that the mix does not stick to the screed plate and tear the mat, causing a rough texture to the surface. This minimum rate should also be used between courses as a tack coat. A vibratory compactor should never exceed a rolling speed that will provide less than one impact of the drum per inch of travel. The first yield check should be made as soon as the Contractor has completed all paver adjustments. The uniformity of the roller passes is just as important as the number of passes. 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. Once the Contractor has finished the rolling operation, the inspector will identify the locations where the density cores will be taken; these locations are randomly selected both longitudinally and transversely. Too Cold: A generally stiff appearance, or improper coating of the larger aggregate particles, indicates a cold mixture. Does the Contractor have proper number of rollers? Material from the existing surface is milled out to a depth as shown on the plans, or equal to the top course, across the entire width of the joint and to a length of 35 feet minimum. %PDF-1.5 % Attach copies of the qualification documentation for the sampling technician to the preproduction meeting minutes for each HMA paving project where HMA sampling is required. It is good practice to keep the speed of the paver as constant as possible during the paving operations. This special provision applies to all Hot Mix Asphalt (HMA) acceptance testing for all Road Commission for Oakland County (RCOC) roads. 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. Enough tie-down points to secure properly and prevent flapping. Hand tools, level, straightedge and boards. The screed is continually attempting to keep in balance all the forces acting on it. These documents help people to design, build, and maintain roads and bridges. This will help ensure that sampling technicians for the project are formally qualified by the department. MDOT's commissions, councils, task forces, and partnerships are responsible for establishing policies, supervising programs, overseeing state and federal funds, providing recommendations and advisement, and acting as a resource. A surface that has been milled typically is very dusty and dirty. This section serves to provide guidance for utilizing Reclaimed Asphalt Pavement (RAP) millings from the same project when using a portable Hot Mix Asphalt (HMA) plant. Risk analysis is specifically used to select appropriate performance standards for various bridge . Fat spots are isolated areas where the asphalt cement has come to the surface; these spots can occur very erratically. Screed plates first wear out about four to six inches from the trailing edge. 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. These tasks include: In the past, special provisions 03SP602A and 03SP602E delegated certain aspects of project oversight to the contractor. The OAG audit found the lack of documentation regarding the initial acceptance of the warrantied work, interim and final inspections, and notification to the contractor and Surety Company after the final inspection was completed. Cutoff shoes can be used, if necessary, to reduce the width of mixture being placed to a width that is less than the basic main screed width. Another texture problem that may be observed is caused by material segregation. If the wedging is greater than 3 inches, two courses of HMA mixture may be required. While the paver is operating, laborers may work, or rework, a portion of the mix to fit the paving around objects and to fill in areas that the paver does not pave adequately, or cannot reach. One side of the paver is controlled by the grade referencing sensor and the other side is controlled by the slope controller. The Contractor will use several types of rollers and each type is used for different purposes. These guidelines have been reviewed and approved by the County Road Association of Michigan (CRA) Engineering Committee, and concurred with by Federal Highway Administration (FHWA) Michigan Section, and MDOT. 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. The importance of staying within the surface tolerance for smoothness cannot be overemphasized. At the time of the periodic on-site inspection, complete the following tasks: In addition, do not make payment until the measured quantities are checked for correlation to the contractors submitted material certifications/tickets and yield calculations. If the required smoothness is obtained in the first course, the subsequent courses can usually be placed uniformly by simply setting the paver for the thickness desired. Forms The trucks should not be loaded by slowly driving forward while the mix is being delivered from the silo. Care should be exercised to keep dust to a minimum. Care must be taken to adjust the top of the cover to the slope of the planned finished roadway. The other type adds the asphalt cement and RAP in a separate mixing chamber out of direct contact with the burner flame. The aggregates are then proportioned by weight into the mixer, also called the pug mill. This type of roller must be equipped with a skirt around the bottom of the roller and within 3 inches of the new surface. When specified, special additives may be required. This can be accomplished by using a rotary broom, flushing with water, and other methods that may be required to remove clay and dirt. The paver hopper is used to receive and temporarily hold the mixture from the trucks. Paver speed for various production and application rates can be calculated using the following equations or selected from Figure 502-5. One of the most important considerations in making a longitudinal joint is keeping the paver on a straight line of travel. The next truck should then be backed toward the paver, stopping short of the paver. Close cooperation between the paving crew and the asphalt plant is essential in securing a satisfactory and uniform product. However, if the project does not call for HMA mixtures, or the patching is in advance of the paving operation, any mixture readily available and approved by the Engineer can be used. Depending on the material and job conditions, this can be quite dramatic. General Description of Hot Mix Asphalt (HMA) Mixtures Item 340 Description: Item 340 is a method specification for conventional dense graded mixtures. Short waves can be caused by a screed in poor mechanical condition, such as too much play in the screed control connections. The paver consists of two primary parts, the tractor unit and the screed unit. The patch shall be compacted so that the patch is smooth with adjacent 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. 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. The old saying Safety is Everyones Business is certainly true on an HMA paving project. The aggregate base course must meet all the requirements for moisture content, density and smoothness. This mark can easily be eliminated by adjusting the elevation of the extendable screed in relation to the main screed. 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. The wedging is greater than 3 inches, two courses of HMA may... Cooperation between the paving operations numbers, date, time, etc )... 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