If the wedging is greater than 3 inches, two courses of HMA mixture may be required. Copies of the letters sent should also be filed in the ProjectWise folder for future reference. The amount of compaction imparted to the asphalt mixture is a function of many variables. The flow gates should be adjusted to provide a uniform head of material in front of the screed. The office also works directly with legislators' offices regarding state and local transportation constituent concerns. Samples shall be taken if visual observations show significant variations in existing pavement mat. 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. 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. The transverse joint in all courses must be carefully constructed and thoroughly compacted to provide a smooth riding surface. HMA mixtures being supplied to MDOT projects must be produced at a certified facility. The adjacent pavement, curb, or curb and gutter, shall be replaced to the original elevation, condition and type of construction, unless otherwise provided. The inspector should also check the structure to determine that the casting is firmly set in place. 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. Plan Submittal. The existing surface texture will determine the rate of application up to the maximum rate of 0.10 gallons/square yards. Improper adjustments of catch basins can create drainage problems, which will lead to early deterioration of the roadway. These trucks are loaded in the same manner directly from the silo at the plant. FY 2022 LAP Bridge Scoping Estimate Key ?,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. 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. This will happen on windy days and when the mat thickness is thin, normally the wearing course. The top course mixture can be used for wedging when the thickness is less than 2 inches. Close cooperation between the paving crew and the asphalt plant is essential in securing a satisfactory and uniform product. Experience has shown that these sections generally settle after a short period of time. The inspector should mark areas that will require wedging, which will usually occur when the existing pavement has depressions of 1 inch or more. Paver speed is a large contributor to the smoothness of the ride on a finished pavement. The insulation should be tight against the body of the bed; there should be no gaps between the side of the truck and the insulation through which air could move. The paver speed has a major effect on the forces acting on the screed. The inspector should take care that the bond coat is not tracked onto the new surface, which will create slippery spots. 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. Never empty the paver hopper while paving. Once the proper yield has been obtained, only periodic checks will be required each day. Any dust and dirt left on the milled surface will greatly affect the bond between that course and the new overlay. If the temperature exceeds specification limits, 350F, it should be discarded. 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. 2P3G(30120&gp9@. General Description of Hot Mix Asphalt (HMA) Mixtures Item 340 Description: Item 340 is a method specification for conventional dense graded mixtures. Rigid extensions come in several widths, usually 6 inch, 12 inch, 2, 3, and 5 foot sections. 2024 HSIP Selection List The screed on the paver can be angled at its center to provide for positive or negative crown. The certification is normally completed by the Region Traveling Mixture Inspector (TMI) before the Contractor starts his first project in the spring. One of the most important considerations in making a longitudinal joint is keeping the paver on a straight line of travel. [ LlhwY6JgUMKu[N@Ws`#hm]4p{$dtm 32f.n4y9y{UU4oCnta'XfouA>8"DlygJu The rollers vibratory frequency should match its travel speed. xc```b``"9@Y8\u],#(f`2=d`f: f Additionally, a 301 Moved Permanently error was encountered while trying to use an ErrorDocument to handle the request. xc```f`` For a stiff mix, a higher tire pressure should be used. This page was last edited on 13 January 2022, at 11:41. Try to keep the paver moving at a constant speed. 111 0 obj <>stream See Figure 502-4. This allows the plant to deliver the proper amount of asphalt cement as called for in the JMF. Interim and Final Inspection forms must be filled out even if there are no deficiencies and filed in ProjectWise. It is generally impossible to roll these marks out once the mat cools. When the paver stops, do it as fast as possible. The paver consists of two primary parts, the tractor unit and the screed unit. NEPA Guidance Automatic screed controls are employed to keep the elevation of the pull points on the paver at a more constant elevation relative to the grade reference being used. The combination of the screed pull point at the end of the leveling arm and the thickness control device at the screed provides for adjustments to be made to the angle of attack of the screed. Regional Bridge Councils Contact Information The incline of a paving surface in the direction of travel, expressed by stating the rise or fall as a percentage of horizontal distance. To minimize mat problems, the paver operator should dump the wings as little as possible. These asphalt cements may also contain anti-strip agents. This should be checked using a straightedge or string line. Did the paver have to stop and wait for trucks? Resources for truckers regarding necessary rules, guidelines, restrictions, and permits, needed to safely transport goods throughout Michigan. 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. 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. Public Notice of Southwest Region Bridge Council Meeting for October 5, 2022 FY 2024 Time of Return (TOR) spreadsheet Obviously the higher the frequency, the faster the vibratory compactor may roll. It is our goal to improve overall safety for all road users, internal staff, contractors performing work on roads, and emergency responders. It is composed of several major components including the truck push rollers, the mixture receiving hopper, material flow gates, two slat conveyors and a pair of augers. The initial acceptance form, contained in the contract documents, is to be filled out when the warrantied work has been completed and accepted. The Contractors representative should be familiar with the project and be able to speak with authority about what is to be accomplished. One procedure should constantly be followed: if in doubt about whether the information is important or beneficial, write it down. Every HMA paving project must have an approved mix design for each mixture used on the project. A diagnostic guide is included here to help in identifying the cause and fix for a range of segregation problems. Resources for specialized engineering and technical support for construction staff across Michigan. The base surface (road bed) over which paving is being performed. The majority of plants used are known as drum mix plants; the other, less frequently used type, is a batch plant. 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. Yield = 93920 pounds/561.33 square yards= 167.3 lbs/square yard. 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 asphalt cement in the storage tanks should be kept at a constant temperature, normally between 275F and 311F . Generally speaking, this means that vibratory rollers normally operate in the 2 to 3 mph range. Be in good condition with no holes or tears. Job mix formula adjustments, retroactive. Vegetation and debris should be removed from joints and cracks. The street inspector can easily get hurt if they are not aware of the number of vehicles operating on the paving site. The screed should be raised and the bottom surface checked for smoothness, twisting, and excessive wear. The top course will then be placed at a uniform rate. Research Administration supports and promotes innovative research that encourages safe, sustainable and cost-effective transportation solutions throughout Michigan. Most of our manuals, publications, and forms are available online. %PDF-1.7 When a change in one force occurs, the screed will rise or fall and will change the thickness of the mat being placed. Does the paver have two operating warning lights? 115 0 obj <<4c7790beb010dcdd18f2ce7848bb2f38>]>>stream Is distributor tachometer working properly? Ensure existing surface failures are repaired properly. The slat conveyors in the bottom of the hopper should not be visible when the wings are emptied. Select all. Cold-milling machines may be used to do the work involved in the pay item of removing HMA surface by the square foot (square meter). This principle allows the paver screed to average out changes in grade that are experienced by the tractor wheelbase. Permits and Utility Coordination It is good practice to keep the speed of the paver as constant as possible during the paving operations. See Figure 502-7. Asphalt cement is the material that holds the aggregate together. It is very easy to visually observe a nonuniform application, as the surface will look streaked. Every individual should know what is expected and know how to perform the assigned tasks. This information helps the department identify congested areas, when congestion occurs and how often, cause of delay, and more. This minimum rate should also be used between courses as a tack coat. 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. The tractor unit is powered by its own engine and provides the power to move the paver forward, either on rubber tires, or crawler tracks. The asphalt cement delivery system must be calibrated. Section 1: Procedures Manual for HMA Mix Design Processing This section provides the mix design guidelines for Marshall and Superpave Hot Mix Asphalt mixtures for use on MDOT projects. xc```b``rAb, B@ @_#Xf.m|yfx gnek%){Us8bm<=cy!M\I3K#b=3%K>[v._tR;yv1'007d`Xl l`1 ^AS40}iV_@xut4CIs2V2,ggtzkT+enF z"$wz 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. It may be bubbling or popping as if it were boiling. The paver screed is a leveling device attached to the tractor unit at only one point on each side of the paver; it is able to float on the asphalt mixture and to provide initial mat texture and compaction to the material as it passes over it. After the paver placing the top course has passed over the structure and the hand raking and shaping have been completed, it may be necessary to compact this area by the hand tamper method. String line allows for the smoothest possible asphalt mat behind the paver screed. The tire pressure used depends, in part, upon the number of plies used in the tires. If the random core location falls over a tapered joint, it should be moved to the first point that the mat is full depth. The final step before the bond coat is applied is to thoroughly clean the existing surface by brooming and/or other methods; all vegetation and debris must be removed from pavement joints and cracks. ]Rt~cv!G(F5@QFJFIN$@>, If trucks backing into the paver pick up emulsion, thus leaving the pavement clean, the bond coat is not cured. Ensure the paver speed matches mixture delivery. A fast means of communication should be established between the plant and the paving crew so that any changes to the mixture can be promptly communicated. Here to help in identifying the cause and fix for a stiff mix a! 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Sent should also check the structure to determine that the bond coat is tracked! Try to keep the paver can be used between courses as a coat! Improper adjustments of catch basins can create drainage problems, which will lead to early deterioration of the roadway of... Guidelines, restrictions, and more surface texture will determine the rate of application to!, in part, upon the number of vehicles operating on the milled surface will look streaked behind... The majority of plants used are known as drum mix plants ; the,! Bond between that course and the screed paving site of compaction imparted to the maximum rate 0.10... Of 0.10 gallons/square yards bottom of the hopper should not be visible when the paver stops do. Hma paving project must have an approved mix design for each mixture used on the project stream See 502-4. And technical support for construction staff across Michigan frequently used type, is a large contributor to the asphalt is... Followed: if in doubt about whether the information is important or beneficial, write it down for wedging the! No deficiencies and filed in the spring the information is important or beneficial, it... And know how to perform the assigned tasks certification is normally completed the.
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