Section 300 Base Courses

Transcription

1 Table of Contents 1. Importance of Base Courses Types of Bases A. Cement Treated Permeable Base Course B. Bituminous Concrete Base Courses C. Superpave Asphalt HMA Base Course D. Aggregate Bituminous Base Course E. Aggregate-Cement Base Course F. Cold Recycled Bituminous Base Course, Cold-in-Place G. Cold Recycled Bituminous Base Course, Central Plant H. Asphalt Treated Permeable Base Course PennDOT Publication i

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3 1. Importance of Base Courses When a pavement section is constructed with a strong base course placed on a good subbase and subgrade, it will carry any normal traffic load and be serviceable for many years. Many of the older roads in Pennsylvania were built in this way and still provide good service under heavy traffic. To obtain good results, the base course (or base) should be well constructed and have uniform strength. If there are weak areas in the base, due to improper thickness, poor material quality, improper drainage, segregation, or lack of adequate compaction, the extended forces of traffic will prematurely deteriorate the pavement. Ultimately, these failures necessitate repairs that cost the Department money that could be used for other projects. Types of Bases Many types of bases provide good service. The base should be constructed so that the pressure of a vehicle tire applied to a small area on the road surface will be spread over a much larger area of the subbase or subgrade, supporting the vehicle without failure. To illustrate this concept, consider the following analogy: If a man steps directly on soft mud, his foot will sink into the mud. However, if he lays a wide board on the mud and steps on it, the board will not sink as deeply because it spreads the man s weight. A base course acts in much the same way as the board in spreading the weight of a vehicle. Bases are of three general types: rigid, crushed aggregate, or one in which soil particles and/or aggregates are held together by a cementing material. A rigid base spreads the load by slab action. A base of Portland cement concrete is an example. The rigid base is the strongest type of base course; however, a rigid base of Portland cement concrete is costly. Therefore, this type of base is used typically on higherclass highways and roadways with large volumes of heavy vehicles. A crushed aggregate base (CAB) spreads the load because the edges and corners of the individual aggregate lock the base together. This particular base was widely used in the past; however, because of increasing labor costs and decreasing skilled labor, the unit price of this type of base course has risen sharply. It is specified mostly for township or other local roads. PennDOT Publication

4 Most contracts that specify a CAB are changed in the field by the inspector in charge and replaced with a flexible base of higher quality. A third type of base is one in which soil particles and/or aggregates are held tightly together by some cementing material, such as Portland cement, lime-pozzolan, asphalt, or tar. This type of base is the most popular because of the ease in handling and placing it, which also makes it more economical. Also, this type of base can be more readily patched or reconstructed if a failure occurs to the subgrade. These types of bases include the following: Cement Treated Permeable Base Course A cement treated permeable base course (CTPBC) is composed of aggregate and cement uniformly blended and mixed with water. The mixed material is spread with a mechanical spreader or asphalt paver and compacted with steel-wheeled rollers. The work is cured with white membrane concrete curing compound immediately after completion. No traffic is permitted on the base for three days. All work is performed in accordance with Publication 408, Section 303. Bituminous Concrete Base Course A bituminous concrete base course consists of a layer or layers of hot-mixed, hot-laid bituminous concrete. The base course is comprised of bituminous material and aggregates. The construction requirements for a bituminous concrete base course are similar to those for placing plant mix pavements as described in Section 400, Chapter 3 of this manual. Superpave Asphalt Mixture Design, Standard Construction, HMA Base Course A superpave asphalt mixture design, standard construction, HMA base course consists of a layer or layers of hot-mixed, hot-laid bituminous base course. This pavement course is comprised of a plant-mixed HMA base course prepared using a volumetric mixture design developed with the superpave gyratory compactor. The construction requirement for the base course are similar to those for placing a bituminous concrete base course, with specific requirements described in Section 400, Chapter 3 of this manual. PennDOT Publication

5 2. Types of Bases A. Cement Treated Permeable Base Course References This subchapter addresses cement treated permeable base courses (CTPBC) on a prepared surface. If the course is placed on subgrade, the work includes the preparation of the subgrade. Publication 212 (Traffic Control) Publication 408, Section 106 (Control of Material) Publication 408, Section 108 (Performance and Progress) Publication 408, Section 303 (Cement Treated Permeable Base Course) Publication 408, Section 711 Concrete Curing Material PTM 1, Method of Test for Probability Sampling Approved Traffic Control Plans Approved Concrete Paving Quality Control Plan Approved Cement Treated Permeable Base Mix Designs Material & Equipment Materials for the work include an approved cement treated aggregate mixture and white membrane curing compound or white polyethylene sheeting material, used for curing. The cement treated permeable base consists of Type 1 or Type 2 cement, Type A or Type B coarse aggregate, and water. These materials must meet the requirements outlined in Publication 408, Section 303. The cement treated permeable base must be supplied by an approved cement concrete batch plant listed on the contractor s approved material source of supply and mixed according to an approved mix design. The contractor uses an asphalt paver or mechanical spreader, equipped with a screed, tracklines that operate outside of the freshly placed CTPBC, plate vibrator, and fully automated sensors to control profile and transverse grades. Steel-wheel rollers that meet the requirements of Publication 408, Section 303 are also used in constructing the permeable base course. Construction Methods Well in advance of placing the cement treated permeable base course, the contractor thoroughly sprinkles the subbase (including rubblized pavement) with water to ensure that the surface will absorb water and is moist. Using a paver or mechanical spreader meeting the requirements outlined in Publication 408, Section 303, the contractor places the CTPBC in lifts of 100 mm (4 inches) compacted depth. The base course is then compacted with a steel wheel power roller as specified in Publication 408, Section 303. PennDOT Publication

6 Immediately after compaction, the base course is covered with white membrane curing compound or polyethylene sheeting for curing as specified in Publication 408, Section 303. The CTPBC is cured as specified for a minimum of three days before placing the subsequent lifts. Traffic is not permitted on the base course, with the exception of equipment required to place the next CTPBC lifts or pavement course. The inspector in charge checks surface tolerance and determines depth check locations using PTM 1 as specified in Publication 408, Section 303. For depth checks, the contractor drills a 150 mm (6 inches) diameter test hole at each location and the inspector measures the depth of the material. If the base is defective in depth, surface tolerance or other defects, the inspector and the contractor follow the remediation procedures outlined in Publication 408, Section 303. All work must be completed in strict accordance to the approved quality control plans. Measuring & Payment Methods Cement treated permeable base courses are paid by the square meter (square yard). The area of the work is field measured, with computations and payment shown on a PSA. The measured width for payment should not exceed plan width unless authorized by a department representative. Documentation On the PSA, document: That traffic control, if required, was set up per traffic control plans or Publication 212 An item description and location Details of the paving operation, including materials used, tests performed, and equipment used Reference that information on placement is in the Concrete Inspector s Diary (CID) Any of the statements in the Key Elements Checklist that can be included to provide details as to what occurred during the paving Payment. If applicable, indicate partial payments, as agreed to by the contractor, and reference any documentation that may have a schedule of payments Key Elements Checklist All outside agencies have been notified about the paving, as well as the time and date it is to occur. A PennDOT approved copy of the approved mix design and approved quality control plan is on site. All safety devices, such as flaggers, cones, lights, and warning signs, are in place as required. PennDOT Publication

7 Traffic patterns for maintenance and protection of traffic are in place per the approved project traffic control plan. The subbase is moist before base course is placed. Only steel-wheeled rollers are used for compaction. Finished surfaces are tested using a 3 m (10 feet) straight edge. Irregularities of more than 12.5 mm (½ inch) are corrected. Immediately after compaction, the base course is covered with white polyethylene sheeting for curing as specified in Publication 408, Section 303. No traffic or additional courses are allowed on the course for three days after placement. Surface is protected from rain prior to the initial set. Depth is checked every 2,500 m 2 (3,000 square yards). Material certification (Form CS-4171) is obtained for all material incorporated into the work prior to payment. Delivery tickets are obtained for materials. Water timing is performed according to the specifications. At the conclusion of the paving activities, both daily and at job completion, all traffic patterns are removed and traffic is restored to normal flow, if applicable. PennDOT Publication

8 B. Bituminous Concrete Base Courses This subchapter addresses bituminous concrete base courses. A bituminous concrete base course consists of a layer or layers of hot-mixed, hot-laid bituminous concrete. The base course is comprised of bituminous material and aggregates. The construction of a bituminous concrete base course is similar to placing plant mix pavements as described in Section 400, Chapter 3 of this manual. References Publication 212 (Traffic Control) Publication 408, Section 106 (Control of Work) Publication 408, Section 108 (Performance and Progress) Publication 408, Section 305 (Bituminous Concrete Base Course) Publication 408, Section 401 (Flexible Pavements) Publication 408, Section 702 (Bituminous Material) Approved Bituminous Paving Quality Control Plan PTM 402 (Determining in Place Density of Construction Materials by use of Nuclear Gauges) PTM 403 (Determining In-Place Density of Bituminous Cocnrete Using Electrical Impedance Measurement Methods) Approved Bituminous Mix Design Approved Traffic Control Plans Material & Equipment The materials required to produce the bituminous concrete base course must meet the requirements outlined in Publication 408, Section 305. The bituminous concrete base course must also be supplied by an approved bituminous batch plant listed on the contractor s approved material source of supply and mixed using an approved mix design. The approved mix design must be supplied to the project inspector in charge and must be signed and dated by the district materials engineer each year. The contractor must also provide an approved asphalt paving quality control plan. The contractor must supply a material certification (Form CS-4171) as specified in Publication 408, Section 106, a bill of lading, and a certificate of analysis for the bituminous material on the first day of paving and each time there is a five day or longer break in paving. The bituminous material vendor s bill of lading should list all the information required as outlined in Publication 408, Section 702. For reference, a copy of the approved mix design, asphalt paving quality control plan, and bill of lading must be kept with the paving inspector during paving operations. PennDOT Publication

9 Usually the contractor will paint guide marks showing alignment, direction and changes in cross slope of the lift of base course being placed. These marks aid the paving crew in placing the base course material at the proper location and depth. The bituminous concrete base course must be delivered in tightly sealed vehicles. When the air temperature is below 10 C (50F), the truck body should be insulated on all sides, double walled, or heated. The contractor uses pavers that are self-contained and power propelled, with activated screeds or activated strike off assemblies and automatic screed controls. Steel wheel, pneumatic tire, or vibratory rollers as specified in Publication 408, Section 108 are used to compact the bituminous concrete base course. The contractor also uses an asphalt paver equipped with a screed plate vibrator and fully automated sensors to control grade. The contractor and the inspector need a thermometer or infrared temperature gun to check the temperature of the bituminous material when it arrives on the project to ensure it is within minimum and maximum heating temperatures specified in Publication 408, Section 401 for the type of asphalt cement used (such as PG 58-28). Typically, the temperature is checked for each of the first five loads and then on every third load. The contractor typically uses a nuclear gauge to check the density of the compacted base course. An electrical impedance gauge may also be used to check the density. Construction Methods The bituminous concrete base course arrives on the project in hauling equipment meeting the requirements of Publication 408, Section 401 and is end dumped into the paver hopper. At this time, the inspector checks the material temperature to ensure it is within limits specified in Publication 408, Section 401. Paver screeds should be checked with a srtingline prior to paving to insure proper adjustment. A crown of 1/16 th to 1/8 th of an inch is typical. Augers should be within 18 of extension to insure minimal segregation of base course material. The contractor must use a paver meeting the requirements of Publication 408, Section 401 to place the base course to the required elevation, cross slope, and width. Material placement depth is controlled as specified in Publication 408, Section 305. The base course is compacted behind the paver using rollers that meet the requirements of Publication 408, Section 108. Compaction density of the material is determined by one of the methods outlined in Publication 408, Section 401. If the compaction of the base course is to be accepted by the Optimum-Rolling Pattern, the contractor s technician must establish an optimum rolling pattern as specified in PTM 402 or PTM 403. The contractor s paving technician may determine an optimum rolling pattern when the density of the paving is accepted under Non-Movement or Pavmement Cores, but it is not required by Publication 408. The inspector in charge determines depth check locations using PTM 1 as specified in Publication 408, Section 305. For depth checks, the contractor drills a 150 mm (6 inches) diameter test hole at each location and the inspector measures the depth of the material. If the PennDOT Publication

10 base is defective in depth, the inspector and the contractor follow the remediation procedures outlined in Publication 408, Section 305. All testing of the base course must be performed according to the approved quality control plan and Publication 408, Section 305 specifications. Measuring & Payment Methods Bituminous concrete base course are paid by the square meter (square yard). The area is field measured, with computations and payment shown on a PSA. The measurement for payment of the width should not exceed plan width unless authorized by a department representative. Occasionally, base course materials are used as build-up material and paid by the tonne (ton). See Section 400 Chapter 10 of this manual for details on asphalt build-up courses. Documentation On the PSA, document: That traffic control, if required, was set up per traffic control plan or Publication 212 An item description and location Details of the paving operation, including materials used, tests performed, and equipment used Any of the statements in the Key Elements Checklist that can be included to provide details as to what occurred during the paving Payment. If applicable, indicate partial payments, as agreed to by the contractor, and reference any documentation that may have a schedule of payments References to or calculations showing test locations Key Elements Checklist All outside agencies have been notified about the paving, as well as the time and date it is to occur. A PennDOT approved copy of the approved mix design and approved quality control plan is on site. All safety devices, such as flaggers, cones, lights, and warning signs, are in place as required. Traffic patterns for maintenance and protection of traffic are in place per the approved project traffic control plan. Delivery tickets are obtained for all materials. The base course is not placed on a wet surface or if the air or surface temperature is 2 C (35F) or lower. PennDOT Publication

11 If a depth of 130 mm (5 inches) or more is needed, construction is done with two lifts of equal compacted depth, with no layer less than 65 mm (2½ inches) or more than 103 mm (5 inches). If the temperature is below 5 C (40 F), only base courses greater than 200 mm (8 inches) are constructed in two equal lifts of not less than 100 mm (4 inches). Care is taken to avoid paving in the rain. If rain begins during paving operations, the contractor immediately calls the plant and halts production. The IIC or district materials engineer is consulted for further instructions. The contractor uses a material transfer unit as often as practical to avoid material segregation. Care is also taken to keep the paver moving at a constant speed. The paving machine operator should keep the screws in the rear of the paver adequately covered. Material temperature is taken as it is dumped out of the truck and immediately behind the paver to ensure that the temperature is in the range specified in Publication 408, Section 305. One test location, using PTM 1, is marked in each of three sublots for the day s paving All traffic, including construction vehicles, are kept off of the newly constructed asphalt mat until the temperature is below 140F Lifts do not exceed the compacted depth indicated in Publication 408. Uncompacted depth is periodically checked to ensure proper compacted depth. Material certification (Form CS-4171 or Form TR-465) is obtained for all material incorporated into the work. At the conclusion of the paving activities, both daily and at job completion, all traffic patterns are removed and traffic is restored to normal flow, if applicable. PennDOT Publication

12 C. Superpave Asphalt HMA Base Course References This subchapter addresses superpave asphalt mixture design, standard construction, HMA base courses. This base course consists of a layer or layers of hot-mixed, hot-laid bituminous material. This pavement course is a plant-mix HMA base course prepared using a volumetric mixture design developed with the superpave gyratory compactor. The construction of a superpave asphalt HMA base course is similar to that of a bituminous concrete base course as described in Section 400, Chapter 3 of this manual. Publication 212 (Traffic Control) Publication 408, Section 106 (Control of Material) Publication 408, Section 108 (Performance and Progress) Publication 408, Section 309 (Superpave Asphalt Mixture Design, Standard Construction, HMA Base Course) Publication 408, Section 409 (Superpave Mixture Design, Standard and RPS Construction of Plant Mixed HMA Courses) Publication 408, Section 702 (Bituminous Material) PTM 402 (Determining In-Place Density of Construction Materials by Use of a Nuclear Gauge) PTM 403 (Determining In-Place Density of Bituminous Concrete Using Electrical Impedance Measurement Methods) Approved Bituminous Mix Design Approved Bituminous Paving Operation Quality Control Plan Approved Traffic Control Plans Material & Equipment The material required to produce the superpave HMA base course must meet the requirements of Publication 408, Section 409, be supplied by an approved bituminous batch plant as listed on the contractor s approved source of supply, and mixed using an approved bituminous mix design. The contractor must supply the inspector in charge with a copy of the bituminous material vender s bill of lading. The bill of lading should contain all of the required information outlined in Publication 408, Section 702. The contractor must also supply a certificate of analysis and a certification of compliance (Form CS-4171), as specified in Publication 408, Section 106. The contractor will submit their QC Plan for Department approval. This plan must be approved prior to beginning paving operations. The vehicles used to deliver the superpave HMA base course to the project must be tightly sealed with covers sized to protect the entire load. When the air temperature is below 10 C (50F), all sides of the truck body should be insulated, double walled or heated. PennDOT Publication

13 In constructing the base course, the contractor uses an asphalt paver equipped with screed plate vibrator and fully automated sensors to control grade. Steel-wheel rollers are also used. The contractor uses a bituminous paver that is self contained and power propelled, with activated screeds or strike off assemblies and automatic screed controls, meeting all other requirements of Publication 408, Section 409. Rollers used to compact the base course must meet the requirements of Publication 408, Section 108. The contractor and the inspector need a calibrated thermometer or an infrared temperature gun used to check the temperature of the material when it arrives on the project to ensure it is within specifications. The contractor also needs a nuclear gauge used to check the density of the compacted base course. Construction Methods The superpave HMA base course material is delivered in vehicles meeting the requirements of Publication 408, Section 409 and is then end dumped in to the paver hopper or material transfer unit. At this time, the inspector checks the material temperature to ensure it meets the requirements specified in Publication 408, Section 409. The paver places the bituminous material to the plan grade and cross slope, in lifts as specified in Publication 408, Section 309. The material is then compacted to the required density, using rollers meeting the requirements of Publication 408, Section 108. Using a nuclear gauge or electrical impedance gauage, the contractor s technician establishes an optimum rolling pattern, following the procedures outlined in PTM 402 or PTM 403. The inspector in charge determines depth check locations using PTM 1 as specified in Publication 408, Section 309. For depth checks, the contractor drills a 150 mm (6 inches) diameter test hole at each location and the inspector measures the depth of the material. If the base is defective in depth, the inspector and the contractor follow the remediation procedures outlined in Publication 408, Section 309. All required tests on the superpave HMA base, as outlined in Publication 408, Sections 309 and 409, must be performed and all work must be completed in strict accordance to the contractor s approved quality control plans. Measuring & Payment Methods Superpave HMA base courses are paid by the square meter (square yard) or tonne (ton). The area of the work is field measured, with computations and payment shown on a PSA. The measured width for payment would not exceed plan width unless authorized by a department representative. Documentation On the PSA, document: Traffic control, if required, was set up per traffic control plans or Publication 213 An item description and location PennDOT Publication

14 Details of the paving operation, including materials used, tests performed, and equipment used Any of the statements in the Key Elements Checklist that can be included to provide details as to what occurred during the paving Payment. If applicable, indicate partial payments, as agreed to by the contractor, and reference any documentation that may have a schedule of payments Key Elements Checklist All outside agencies have been notified about the paving, as well as the time and date it is to occur. The contractor s paving crew includes an HMA field technician to control the placement of the bituminous mixture. A PennDOT approved copy of the approved mix design and approved quality control plan is on site. All safety devices, such as flaggers, cones, lights, and warning signs, are in place as required. Traffic patterns for maintenance and protection of traffic are in place per the approved project traffic control plan. The base course is not placed on a wet surface or if the air or surface temperature is 2 C (35F) or lower. If the indicated depth of a Superpave 25.0 mm HMA base course is more than 150 mm (6 inches), place the HMA base course in two or more layers of equally compacted depth, with no layer less than 80 mm (3 inches) or no more than 150 mm (6 inches). If the indicated depth of a Superpave 37.5 mm HMA base course is more than 200 mm (8 inches), place the HMA base course in two or more layers of equally compacted depth, with no layer less than 100 mm (4 inches) or no more than 200 mm (8 inches). Delivery tickets are obtained for materials. Appropriate paperwork is obtained for the tack coat. An approved bituminous paving quality control plan is on file. Care is taken to avoid paving in the rain. If rain begins during paving operations, the contractor immediately calls the plant and halts production. The IIC or district materials engineer is consulted for further instructions. The contractor uses a material transfer unit as often as practical to avoid material segregation. Care is also taken to keep the paver moving at a constant speed. The paving machine operator should keep the augers in the rear of the pave adequately covered. Material temperature is taken as it is dumped out of the truck and immediately prior to placement to ensure that the temperature is in the range specified in Publication 408, Section 409. For depth tests, use PTM 1 to determine test location as specified in Section 309. PennDOT Publication

15 For density tests, see Publication 408, Section 409 for test methods and lot/ sublot information. Uncompacted depth is periodically checked to ensure proper compacted depth. Material certification (Form CS-4171 or TR-465) is obtained for all material incorporated into the work. At the conclusion of the paving activities, both daily and at job completion, all traffic patterns are removed and traffic is restored to normal flow, if applicable. PennDOT Publication

16 D. Aggregate Bituminous Base Course References This subchapter addresses the construction of a bituminous-treated, aggregate base course. If the course is placed on subgrade, the work includes the preparation of the subgrade. Publication 212 (Traffic Control) Publication 408, Section 106 (Control of Material) Publication 408, Section 108 (Performance and Progress) Publication 408, Section 320 (Aggregate Bituminous Base Course) Publication 408, Section 460 (Bituminous Tack Coat) Publication 408, Section 702 (Bituminous Material) Approved Mix Designs Approved Bituminous Paving Quality Control Plans Approved Traffic Control Plans Material & Equipment Material for the work includes a class PG or emulsified asphalt. The materials used to produce aggregate bituminous base course, such as bituminous material and coarse aggregate, must meet the requirements of Publication 408, Section 320. All material must be from approved suppliers listed on the contractor s approved material source of supply. The contractor must supply a copy of the bituminous material vendor s bill of lading. The bill of lading should contain the information required by Publication 408, Section 702. The contractor must also supply a copy of the material certification (Form CS-4171) as specified in Publication 408, Section 106. The material is hauled from the mix plant to the project, using vehicles that are tight, clean and have protective covers that are not torn nor have holes. In placing the base, the contractor uses a spreader, bituminous distributor, and compaction equipment. The spreader used is adjustable, self-propelled, and capable of placing and screeding the base material without segregation. Rollers meeting the requirements of Publication 408, Section 108 are used to compact the base material to the required density. If in-place mixing and spreading is done, the contractor needs a travel plant to place the material as outlined in Publication 408, Section 320. If the travel plant is not equipped to meter the liquid bituminous material, the contractor needs a bituminous distributor meeting the requirements of Publication 408, Section 460 to apply the bituminous material as specified in Publication 408, Section 320. The inspector and the contractor need a thermometer or infrared temperature gun to check the temperature of the base material to ensure it is within specifications. The contractor may also PennDOT Publication

17 need a nuclear gauge to check the compaction density of the base to ensure it meets the requirements specified in Publication 408, Section 320. Construction Methods If batched at a mixing plant, the base material arrives on the project in hauling equipment meeting the requirements of Publication 408, Section 320, then end dumped into a spreader that meets the requirements of Publication 408, Section 320. All mixing and spreading of the base materials must also meet the requirements outlined in Publication 408, Section 320. Using rollers that meet the requirements of Publication 408, Section 108, the contractor compacts the base material to the specifications outlined in Publication 408, Section 320. If in-place mixing and spreading is done, the contractor needs a travel plant as specified in Publication 408, Section 320 to spread the base material. If the travel plant is not equipped to meter the liquid bituminous material, the contractor must use a distributor truck that meets the requirements of Publication 408, Section 460 to apply the bituminous material. The base material is mixed, compacted, and finished in a continuous operation, with finishing completed in daylight hours. The base material is then tested for density, surface tolerance, and depth as specified in Publication 408, Section 320. The inspector in charge determines depth check locations using PTM 1 as specified in Publication 408, Section 320. For depth checks, the contractor drills a 150 mm (6 inches) diameter test hole at each location and the inspector measures the depth of the material. If the base is defective in depth, the inspector and the contractor follow the remediation procedures outlined in Publication 408, Section 320. All work must be completed in strict accordance to the approved quality control plans. Measuring & Payment Methods Aggregate bituminous base courses paid by the square meter (square yard). The area is field measured, with computations and payment shown on a PSA. The payment width should not exceed plan width unless authorized by a department representative. Documentation On the PSA, document: Traffic control, if required, was set up per traffic control plans and Publication 213 An item description and location Details of the paving operation, including materials used, tests performed, and equipment used Any of the statements in the Key Elements Checklist that can be included to provide details as to what occurred during the paving Payment. If applicable, indicate partial payments, as agreed to by the contractor, and reference any documentation that may have a schedule of payments PennDOT Publication

18 Key Elements Checklist All outside agencies have been notified about the paving, as well as the time and date it is to occur. A PennDOT approved copy of the approved mix design and approved paving quality control plan is on site. All safety devices, such as flaggers, cones, lights, and warning signs, are in place as required. Traffic patterns for maintenance and protection of traffic are in place per the approved project traffic control plan. Water is sprayed uniformly through the aggregate prior to application of the emulsified pavement to ensure moisture content of 2% to 8% when tested with PTM 106. Paperwork is on file for all bituminous material. The temperature of the bituminous material is maintained when added to the mixture. Distributors are calibrated. Base courses of 150 mm (6 inches) or less are constructed in one layer. If a depth of 150 mm (6 inches) or more is needed, construction is done with two lifts of equal compacted depth, with no layer less than 75 mm (3 inches) or more than 150 mm (6 inches) in depth. Only necessary shaping and processing equipment is allowed to travel over the spread mixture. Mixture that is contaminated or displaced is removed and replaced. Base course is compacted to 100% of design density. If using asphalt cement, compact to at least 90% of the design density. Tack coat is applied between layers. Base course is mixed, compacted, and finished in a continuous operation during daylight hours. One field density test is taken for each 2,500 m 2 (3,000 square yards). Depth is tested every 2,500 m 2 (3,000 square yards). Only necessary traffic is allowed on the base course. Material certification (Form CS-4171) is obtained for all material incorporated into the work prior to payment. Delivery tickets are obtained for all materials. At the conclusion of the paving activities, both daily and at job completion, all traffic patterns are removed and traffic is restored to normal flow, if applicable. PennDOT Publication

19 E. Aggregate-Cement Base Course References This subchapter addresses the construction of a cement-treated aggregate base course. If placed on subgrade, construction includes preparing the subgrade as specified. Publication 212 (Traffic Control) Publication 408, Section 106 (Control of Material) Publication 408, Section 108 (Performance and Progress) Publication 408, Section 320 (Aggregate Bituminous Base Course) Publication 408, Section 321 (Aggregate Cement Base Course) Publication 408, Section 460 (Tack Coat) AASHTO T-134 (Moisture Density Relations of Soil Cement Mixtures) Approved Mix Designs Approved Concrete Paving Quality Control Plans Approved Traffic Control Plans Material & Equipment Material for the work includes Type C or better coarse aggregate and Class RS-1 of CRS-1 emulsified asphalt. The materials required to produce and to place the aggregate cement base course must meet the requirements outlined in Publication 408, Section 321. The cement and coarse aggregate are mixed either by a central mix plant or mixed in-place as specified in Publication 408, Section 321. Regardless, the materials must be mixed per the approved mix design. All materials are provided by a supplier listed on the contractor s approved source of supply. All material used must be certified (Form CS-4171), as specified in Publication 408, Section 106. Material mixed at a central mix plant must be transported to the project in vehicles meeting the requirement specified in Publication 408, Section 320. The contractor needs a mechanical spreader that is adjustable, self-propelled, and capable of placing and screeding the base material without segregation. Rollers meeting the requirements of Publication 408, Section 108 are used to compact the base course as specified in Publication 408, Section 321. The contractor also needs a distributor truck meeting the requirements of Publication 408, Section 460, to apply the bituminous cure as specified in Publication 408, Section 321. Construction Methods For aggregate cement base course mixed at a central mix plant, the base course is delivered to the project site in hauling vehicles that meet the requirements of Publication 408, Section 320, then end dumped into the mechanical spreader. The contractor spreads the material to PennDOT Publication

20 grade following the lift placement depth requirements specified in Publication 408, Section 321. If the base course material is mixed in-place, the contractor spreads materials uniformly on the prepared area as specified in Publication 408, Section 321. Using a roller, the base is compacted to the required density specified in Publication 408, Section 321. The inspector determines optimum moisture content and maximum dry weight density in the field according to AASHTO T-134. The contractor must mix, compact, and finish the base course in a continuous operation and complete the finishing in daylight hours. Compaction must be completed 3 hours after adding the water. After compaction and finishing, the contractor prepares the base and, using a distributor truck, applies the bituminous cure as specified in Publication 408, Section 321. The aggregate cement base course is tested for density, surface tolerance, and depth as specified in Publication 408, Section 321. The inspector in charge determines depth check locations using PTM 1 as specified in Publication 408, Section 321. For depth checks, the contractor drills a 150 mm (6 inches) diameter test hole at each location and the inspector measures the depth of the material. If the base is defective in depth, the inspector and the contractor follow the remediation procedures outlined in Publication 408, Section 321. All work must be completed in strict accordance to the approved quality control plans. Measuring & Payment Methods Aggregate cement base courses are paid by the square meter (square yard). The area is field measured, with computations and payments shown on a PSA. The payment width should not exceed the plan width unless authorized by a Department Representative. Documentation On the PSA, document: Traffic control, if required, was set up per traffic control plans and Publication 213 An item description and location Details of paving operation, including material used, tests performed, and equipment used Any of the statements in the Key Elements Checklist that can be included to provide details as to what occurred during the paving Payment. If applicable, indicate partial payments, as agreed to by the contractor, and reference any documentation that may have a schedule of payments Key Elements Checklist All outside agencies have been notified about the paving, as well as the time and date it is to occur. PennDOT Publication

21 A PennDOT approved copy of the approved mix design and approved paving quality control plan is on site. All safety devices, such as flaggers, cones, lights, and warning signs, are in place as required. Traffic patterns for maintenance and protection of traffic are in place per the approved project traffic control plan. Delivery tickets are obtained for all materials. Distributors are calibrated. Aggregate and cement is mixed to prevent formation of cement balls when water is added. Mixture is not spread or placed if the base area is excessively wet or frozen. Work is performed only if the temperature is 5 C (40F) or above. Base courses of more than 200 mm (8 inches) are constructed in two equal lifts, with each no less than 100 mm (4 inches) and no more than 200 mm (8 inches). A maximum compacted depth of 200 mm (8 inches) is allowed if the required compaction density can be attained for the full depth of each layer. The loose base course mixture is compacted to at least 100% of the maximum dry mass density. Base course mixing, compacting and finishing are done in a continuous operation during daylight hours. If directed, surface scarifying and recompacting are done during the shaping operation to eliminate imprints left by equipment. After completion, material is swept free of foreign material and moistening and rolling is done to integrate loose and dry surface material. Bituminous material is applied at a rate of 0.45 liters/m 2 to 0.68 liters/m 2 (0.10 gallon per square yard to 0.15 gallon per square yard). Sufficient moisture is maintained in the surface of the base course to prevent penetration of the bituminous material. If necessary, water is immediately applied to fill voids before applying bituminous materials. The entire surface is covered to protect the base course. Fine aggregate is spread if traffic is to be maintained before bituminous course is placed. The base course is kept from freezing. Density determinations are made as specified in Publication 408, Section 320. Sections that are below five pounds per cubic foot density are replaced. Areas that are deficient in depth are surface scarified and additional material is placed. PennDOT Publication

22 Material certification (Form CS-4171) is obtained for all material incorporated into the work. At the conclusion of the paving activities, both daily and at the job completion, all traffic patterns are removed and traffic is restored to normal flow, if applicable. PennDOT Publication

23 F. Cold Recycled Bituminous Base Course, Cold-in-Place References This subchapter addresses the on-grade construction and material processing of a cold recycled bituminous base course that uses bituminous material combined with RAP, RAM, or virgin aggregates. Construction typically includes milling to an indicated depth, adding and mixing emulsified asphalt, placing, compacting, and testing. Publication 212 (Traffic Control) Publication 242, Chapter 5 Publication 408, Section 106 (Control of Material) Publication 408, Section 108 (Performance and Progress) Publication 408, Section 341 (Cold Recycled Bituminous Base Course Cold In-Place) Publication 408, Section 703 (Aggregate) Approved Mix Designs Approved Bituminous Paving Quality Control Plans Approved Traffic Control Plans Material & Equipment The materials used to produce the cold recycled base course must meet the requirements outlined in Publication 408, Section 341. The bituminous material would be one of the types listed in Publication 408, Section 341 and added to the reclaimed material per the approved mix design. All materials must be from the suppliers listed on the contractor s approved material source of supply. The contractor must supply a copy of the material certification (Form CS-4171) as specified in Publication 408, Section 106. The contractor uses equipment capable of milling the existing pavement, mixing and placing the material, and automatically metering liquids with a variation of not more than plus or minus 2% by weight of liquids. The contractor needs rollers meeting the requirements of Publication 408, Section 108 to compact the base material to the requirements of Publication 408, Section 341. The contractor also needs to construct a test strip and check the density of the compacted base course as specified in Publication 408, Section 341. Construction Methods The contractor takes samples of the reclaimed material and performs testing to establish the mix design. At least three weeks prior to the planned start of the mixture production, the mix design is submitted to the district materials engineer for review. Refer to Bulletin 27, Chapter 2 for procedures. PennDOT Publication

24 The contractor uses equipment capable of processing the asphalt pavement material on grade, including the mixing and placing operations. The contractor uses a single train or multiple unit train of equipment to construct the cold recycled bituminous base course. The inspector measures the milled depth and records at least one measurement on a PSA in each 2,500 m 2 (3,000 square yards) to ensure that the pavement is milled to the depth indicated. Using a nuclear gauge, the contractor s technician sets up a density control strip of approximately 500 m 2 (600 square yards). Using the control strip, the technician determines the density required to compact the base course as specified in Publication 408, Section 341. If directed, the contractor checks the surface tolerance using a 3 m (10 feet) straight edge as specified in Publication 408, Section 341. The inspector in charge determines depth check locations using PTM 1 as specified in Publication 408, Section 341. For depth checks, the contractor drills a 150 mm (6 inches) diameter test hole at each location and the inspector measures the depth of the material. If the base is defective in depth, the inspector and the contractor follow the remediation procedures outlined in Publication 408, Section 341. The base course is cured and protected as specified in Publication 408, Section 341. Measuring & Payment Methods Payment for cold in-place recycled bituminous base courses is in three parts. The recycled bituminous base course is paid by the square meter (square yard). This area is field measured, with computations and payment shown on a PSA. The payment width would not exceed the plan width unless authorized by a department representative. Coarse aggregate is paid by the tonne (ton), for the total incorporated into the work and shown on the material delivery tickets. Bituminous material is paid in liter (gallon) for the total incorporated into the work, measured by an acceptable method Documentation On the PSA, document: Traffic control, if required, was set up per traffic control plans and Publication 213 An item description and location Details of paving operation, including material used, tests performed, and equipment used Any of the statements in the Key Elements Checklist that can be included to provide details as to what occurred during the paving Payment. If applicable, indicate partial payments, as agreed to by the contractor, and reference any documentation that may have a schedule of payments Key Elements Checklist All outside agencies have been notified about the paving, as well as the time and date it is to occur. PennDOT Publication

25 A PennDOT approved copy of the approved mix design and approved quality control plan is on site. All safety devices, such as flaggers, cones, lights, and warning signs, are in place as required. Traffic patterns for maintenance and protection of traffic are in place per the approved project traffic control plan. Delivery tickets are obtained for all materials. Distributors are calibrated. Appropriate documentation is received for the asphalt material. Reclaimed material, aggregates, and bitumen are combined according to mix design. Base courses are not placed from September 1 to April 30 in Districts 1-0, 2-0, 3-0, 4-0, 9-0, 10-0; and from October 1 to April 30 in all other districts, unless directed by the Department. An adequate quantity of the mixture is maintained. Compacted layers between 80 mm and 130 mm (3 inches and 5 inches) in depth are provided. A test strip of 500 m 2 (600 square yards) is constructed, under the guidance of a nuclear gauge operator, for the purpose of determining the maximum density. The base course is compacted to a minimum density of 96% of average control strip density. The base course is completed during daylight hours. The base course is protected from marring, distortion, and other damage. The smoothness and accuracy of grade is tested both transversely and longitudinally, using a 3 m (10 feet) straight edge or template. A 2,500 m 2 (3,000 square yard) area is tested at three locations. Where the average of the minimum space exceeds 13 mm (½ inch), the area is corrected. Base courses are cured for one week before placing additional asphalt courses. Additional courses are not placed if the moisture content exceeds 2%. Milling depth is checked for a 2,500 m 2 (3,000 square yard) area at three locations. Where depth is deficient by more than 13 mm (½ inch), corrections are made. Mixture is not spread or placed if base area is excessively wet or frozen. Work is performed only if the temperature is 7 C (45F) or above. Material certification (Form CS-4171) is obtained for all material incorporated into the work At the conclusion of the paving activities, both daily and at the job completion, all traffic patterns are removed and traffic is restored to normal flow, if applicable. PennDOT Publication

26 G. Cold Recycled Bituminous Base Course, Central Plant References This subchapter addresses the construction of a cold recycled bituminous base course, central plant mix, using a combination of RAP, RAM, or virgin aggregates, mixed with bituminous material in a continuous or batch type mixer. Publication 212 (Traffic Control) Publication 242, Chapter 5 Publication 408, Section 106 (Control of Work) Publication 408, Section 108 (Performance and Progress) Publication 408, Section 341 (Cold Recycled Bituminous Base Course, Cold in Place) Publication 408, Section 342 (Cold Recycled Bituminous Base Course, Central Plant Mix) Bulletin 27, Chapter 2 Approved Quality Control Plans Approved Traffic Control Plans Approved Mix Design Material & Equipment The materials used to produce the cold recycled base course must meet the requirements outlined in Publication 408, Section 341. The bituminous material would be one of the types listed in Publication 408, Section 341 and added to the reclaimed material per the approved mix design. All materials must be from the suppliers listed on the contractor s approved material source of supply. The contractor must supply a copy of the material certification (Form CS-4171) as specified in Publication 408, Section 106. To haul the material from the central mix plant, the contractor must use vehicles that are clean, tight, and if required, have protective covers. The contractor needs mixing equipment that conforms to Publication 242, Chapter 5 and is capable of mixing the pulverized reclaimed material and additive into a homogeneous mixture. A mechanical spreader is used to place the material on a prepared surface to a uniform depth conforming to Publication 242, Chapter 5. Rollers meeting the requirements of Publication 408, Section 108 are used to compact the base course to the required density. The contractor also needs a nuclear gauge to establish and check the density of the compacted base course as specified in Publication 408, Section 341. Construction Methods The contractor takes samples of the reclaimed material and performs testing to establish the mix design as specified in Publication 408, Section 341. At least three weeks before the planned start of mixture production, the mix design must be submitted to the district materials engineer for review. PennDOT Publication