The rolling zone should be kept as short as possible. All the tires should be the same size, ply and tire pressure. The desired degree of cross slope is dialed into the slope controller. This dryer heats the aggregate to the desired temperature and delivers the material to the hot bins in the tower unit. Paving done with automatic screed controls is accomplished with a combination of grade control on one side of the paver and slope control to determine the grade on the other side of the paver. Federal-Aid Highways Environmental Efforts Is heating system in good working condition? When the paver stops, do it as fast as possible. It is important for the screed extension to be attached securely to the main screed. These trucks are loaded in the same manner directly from the silo at the plant. 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. At MDOT, we want to ensure your voice is not only heard, but makes a difference in moving Michigan forward. Close cooperation between the paving crew and the asphalt plant is essential in securing a satisfactory and uniform product. Are the king bolts in good condition on steel wheeled rollers? 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. 2022 Selected Projects for FY 2025 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. If the automatic controls are being used, the screed operator should not try to change the screed manually by turning the thickness control crank. The tire pressure used depends, in part, upon the number of plies used in the tires. 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. Multiple drops of the mix are necessary. Warranties are a tool to assure quality, but they are not a replacement for proper inspection, quantity measurement, proper payments, or proper contract administration. Fuel oil is not to be used as a release agent. The degree of preparation depends upon the condition of the existing surface. Document the extraction of the cores from the locations marked (random numbers, date, time, etc.). Selection. **If in line crushing and/or screening is being used 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 a RAP scalper screen may not be required. 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. 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. Included are examples of calculations, documentation requirements, and . You may also contact Ryan Doyle at DoyleR3@Michigan.gov. Joints that are poorly sealed should have the old seal material removed and the joints cleaned. After curing, only traffic essential in the work should be allowed on the bond coat. Adjust catch basins after the leveling course has been placed. Rocking slabs must be stabilized. The paint dot is to be visible on the core during handling and testing. 311 0 obj <>stream Another type of grade referencing device is the joint matching shoe. Our goal is to keep Michigan's motorists safe, informed, and mobile. 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. Daily talks are one way to continuously remind people that they are working in a potentially dangerous environment at both the plant and the paving site. 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? Emptying the paver wings when the hopper is empty. A rule of thumb is that the proper level of air voids should be obtained before the mixture cools to a temperature of 176F. This type of roller must be equipped with a skirt around the bottom of the roller and within 3 inches of the new surface. 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. Unsere Bestenliste Jan/2023 - Ultimativer Test Beliebteste Modelle Beste Angebote Smtliche Vergleichssieger JETZT direkt ansehen. 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. 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 The uniform application of the emulsion is a function of the asphalt distributor and the skill of the operator. Material Quality - Resources; Material Quality Partnering Meetings. 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. This checklist may be placed in the project files. &[a);8fUcK@=fCW ?Qdo When butt joints are called for on the plans or in the proposal, construction should be as follows. The asphalt cement delivery system must be calibrated. The screed should be raised and the bottom surface checked for smoothness, twisting, and excessive wear. The Internship Program offers undergraduate and graduate students interested in civil engineering and construction management careers, valuable experience by working with professional field staff. The asphalt cement in the storage tanks should be kept at a constant temperature, normally between 275F and 311F . CSD advertises all MDOT TPSSB A/E projects in excess of $200,000 to solicit Consultant Expressions of Interest. The MST time zone is the least populated time zone in the USA. Trim the joint at right angles to the roadway centerline. endobj When rigid extensions are being used in conjunction with the main screed, the crown can usually be altered at any of the points where the extensions are joined. 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. Distributor Checklist - Manufacturer and Distributor Number -______________________________. The first is the frequency of vibration and the second is the amplitude of the compactive effort. Because continuity of the asphalt paving operation is critical to providing a quality pavement, the discussion between MDOT and the Contractor personnel should include such items as those listed below. It is the MDOT inspectors responsibility to ensure that the Contractor is providing a specification product. The second unit is the paver screed. The ride quality of the surface depends, to a great degree, upon the conditioning and preparation of the aggregate surface. Is distributor tachometer working properly? 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. The field application of the applied mix design is called the Job Mix Formula (JMF), (Figure 501-2). Public Notice of Bay Region Bridge Council Meeting for October 3, 2022 The augers are used to distribute the mixture across the total width of the screed. The spray bar nozzles shall produce a uniform fan spray, and the shutoff shall be instantaneous, with no dripping. 30 to 120 m 3 /h; EBA Mobile plant for medium productions. The operator should not make manual changes while automation is working. 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. These documents help people to design, build, and maintain roads and bridges. The first yield check should be made as soon as the Contractor has completed all paver adjustments. 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. b. These devices are used to carry the mixture from the hopper through the paver tunnel to the back of the paver and the spreading augers. [ LlhwY6JgUMKu[N@Ws`#hm]4p{$dtm 32f.n4y9y{UU4oCnta'XfouA>8"DlygJu These vibratory rollers can be operated in any one of three modes: static, with one drum vibrating and one drum static, and with both drums vibrating. This equipment must be capable of accurately removing the pavement surface, in one or more passes, to the required grade or cross section. 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. To exceed this one impact or more per inch of travel may produce small ripples in the mat when laying HMA. Incorporating Safety into Resurfacing and Restoration Projects Mesgana Ayele Assistant Division Chief, Materials Management Division - Materials Management Systems MDOT SHA Office of Materials Technology 7450 Traffic Drive Hanover, Maryland 21076 Office: 443-572-5021 Toll Free: 1-866-926-8501 MAyele@mdot.maryland.gov This special provision applies to all Hot Mix Asphalt (HMA) acceptance testing for all Road Commission for Oakland County (RCOC) roads. 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 These averages are combined and measured at the grade sensor near the screed tow point. If the volume of the mix in front of the screed falls below the desired amount, the feed sensor will engage the slat conveyors and auger system, pulling more mix back to the screed area. <> The completed centerline joint should be uniform, closed and flush with adjacent lanes. Does the paver have two operating warning lights? The mat reference beam is spring supported on a series of wheels that roll on the mat. A notch of up to 1 inch shall be placed at the top of the taper when placing HMA. Shoulder samples shall be taken if RAP from shoulder is to be used. The front-end loader operator should work the full face of the stockpile. If two pavers running in echelon are used, the construction of the joint is similar to the building of a joint against a cold compacted pavement. Pavement Type Selection Process; Ride Specification . Dividing the tonnage placed, by the area covered, will give the yield. A superstructure that spans the screed and auger areas ties the two together and supports the grade sensor. In addition, the screed imparts a level of compaction with the vibratory action of the screed. 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. At the bottom of the paver hopper is a set of slat conveyors. This mark can easily be eliminated by adjusting the elevation of the extendable screed in relation to the main screed. Failure to do so will jeopardize full federal-aid participation. Again, the temperature should be checked immediately. It is very important that proper air pressure be maintained in all tires. The MDOT procedure used for selecting random core locations is by using a random number generating computer program. An approved grade referencing attachment, not less than 30 feet in length, may be used. Every year, MDOT produces an updated version of the state transportation map. Plan Submittal. Alignment of the front edge of the extension is typically controlled independently of the alignment of the rear edge of the extension. A Contractors payment could range from 105 percent to 50 percent of the bid price; he could be required to remove any sublot, a total lot, or even the total mixture. This nonuniform texture can be caused by many factors: screed extensions not level with each other, running the hopper empty between trucks, unevenly worn screeds, cold mix, or improperly emptying the paver wings. Bond coat, also referred to as tack coat, is an asphalt emulsion. A pass is defined as one trip of the roller in one direction over any one spot. It is good practice to keep the speed of the paver as constant as possible during the paving operations. Laying out core locations and traffic control for coring. If the wedging is greater than 3 inches, two courses of HMA mixture may be required. At the back of the paver hopper, and over each slat conveyor, is a set of gates. This minimum rate should also be used between courses as a tack coat. Transverse screed marks are transverse indentations in the mat, which may occur when the paver stops between truckloads. 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. The Veteran Internship Program assists honorably discharged veterans of the United States Armed Forces as they transition into the civilian workforce. 3 0 obj Placing the mat too thin based upon the aggregate size. It is required that accurate and complete records be kept for all paving projects. Intermittent operation of the slat conveyors and auger system could cause both auger shadows and ripples in the mat behind the screed. Please contact your LAP staff engineer with any questions. All roller marks should be removed by the finish roller. These asphalt cements may also contain anti-strip agents. This floating ski system averages out the variation of the existing grade over a 30 or 40 foot length. The street inspector can easily get hurt if they are not aware of the number of vehicles operating on the paving site. FY 2022 Project Planning Guide Did you know that millions of people visit the Great Lakes State every year? Since there are 5280 feet in the sublot, pick two numbers using the random number generating calculator, which are then multiplied by 5280. Forms There are three types of mat tearing, or pulling, of the asphalt mix, and each is described by the location of the tear: in the center of the lane, at the outside edges of the lane, or full width. Most of our manuals, publications, and forms are available online. xc```f`` FY 2022 LAP Bridge Scoping Cost Estimate Worksheet HMA mixtures consist of a blend of asphalt binder and aggregates mixed in an asphalt plant. Bridge railings and piers, curb and gutter pans, and guardrails must be protected from the spray of bond coat by the use of shields. @c0M8;\ r)]-f3E|r ZVu~[ The elevation of a fresh mat in relation to the base. Contract Plans Specify 165 pounds/square yard. Sampling frequency required is based on the percentage/tonnage of RAP that will be utilized on the project. Each type of reference can be used on either side of the paver, or on both sides at the same time. Test methods to be used should be reviewed to assure that individuals understand the purpose of each test, the location of the field lab and the personnel who are to conduct the tests, the time frame for the communication of the test results and the procedures to be used if failing test results are obtained. 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