State Study 111 - Polymer Modified Hot Mix Asphalt Field Trial.pdf

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CHAPTER 1: INTRODUCTION This project was awarded in May 1994 to Lehman-Roberts Company to rehabilitate some existing pavement with hot mix asphalt (HMA) combined with polymer modifiers. Construction of the modified HMA sections did not occur until the 1996 construction season because of the milling and substantial HMA tonnage to be placed prior to placement of the polymer modified HMA. BACKGROUND Rehabilitation of existing asphalt and concrete pavements is most often accomplished with HMA overlays. A problem plaguing HMA pavements is rutting, which develops because of the high summer temperatures and heavy trucks. A rut, as defined by Webster, is the formation of a recessed track, channel, or furrow, worn by the habitual passage of a wheel on the surface of pavement. This channeling effect, depending on its severity, causes drainage, safety, and ride quality problems that must be resolved in some manner. For rutting up to approximately 1 inch, the typical rehabilitation procedure in the past has been to either overlay with HMA or combine milling of the rutted pavement with an overlay. Many different polymer modifiers for asphalt cement have been developed to help improve both the rutting and thermal cracking problems of HMA by altering the properties of the asphalt cement binder. Manufacturers of polymer modifiers claim the incorporation of their product with the asphalt cement binder in the manufacture of HMA can significantly extend the service life of HMA pavements. These polymer modified pavements are reputed to resist rutting, improve overall stability, and increase useful life. If additional service life can be achieved, then life cycle costs can be lowered, thereby allowing overall savings to the cost of maintaining pavements. OBJECTIVES The primary objective of this research was to evaluate the engineering properties and performance, especially rut resistance, of dense graded HMA containing specific polymer modifiers in comparison to the other polymer modified HMA mixes as well as to a control section containing no modifiers. The polymer modifiers were used in the HMA for the top two pavement layers (total thickness of 3 inches) of an HMA overlay of a flexible pavement. This project was located on I-55 in the Grenada area, an area that had experienced unacceptably high rutting in recent years. This research also incorporated data for other polymer modified HMA mixes used on projects that the Mississippi Department of Transportation (MDOT) had constructed from 1993 through the date of construction for this polymer modifier field trial. v
SCOPE The experimental design called for the use of nine different modifiers, each to be used in sections approximately 0.5 mi. long in the 1.5 inch top binder and 1.5 inch surface courses. Transition sections, also approximately 0.5 mi. long, separated the test sections. All test sections as well as the control section were in the northbound lanes of I-55 and had essentially the same type and amount of traffic loading. The control section with no modifier comprised the remainder of the northbound lanes outside the test sections and transitions and contained at least 2 miles having the same general topography as that in the test sections. Other than the modified binder, all other HMA material parameters were the same throughout the test and control sections. Asphalt cement grade AC-20 was the base asphalt for all the modified asphalt cement binders. The control section utilized an AC-30 asphalt cement, which is the standard asphalt cement used by MDOT. The nine different modifiers were specified by brand name and manufacturer. A special effort was made to select modifiers from the different chemical groups that are in widespread use for modifying HMA. Polymer loading for each different polymer was determined on the basis of its manufacturer’s recommendation along with documented previous usage of the polymer for traffic and environmental conditions similar to those to be encountered on this project. The following is a list of the modifiers used in this research: TRADENAME MANUFACTURER TYPE KRATON Shell Chemical Company SBS Block Copolymer ULTRAPAVE Textile Rubber & Chemical SB Latex NOVOPHALT Advanced Asphalt Tech. LDPE (Recycled) STYRELF Koch Materials SB Block Copolymer GF-80 RUBBER Rouse Rubber Industries -80 Mesh Tire Rubber SEAL-O-FLEX Ergon SBS VESTOPLAST-S VP-S Company Ethylene, Butylene, Terpolymer MULTI-GRADE Asphalt Materials Gelled Asphalt CRYO-80 MESH Cryopolymer Cryogenic Ground Rubber The nine modifiers included two crumb rubbers and one gelled asphalt. OTHER MDOT POLYMER PROJECTS Immediately joining this project to the south is another project that experienced unacceptable rutting before the rehabilitation project was completed. This project, Project Number 54-0055- 03-067-11, 12, 13, consisted of rubblization of 8 inches of CRCP in the northbound lanes, installation of edge drains at each edge, and an overlay with 6.5 inches of HMA. The 2
Page 1 and 2: FINAL REPORT STATE STUDY NO. 111 PO
Page 3 and 4: NOTICE The contents of this report
Page 5 and 6: TABLE OF CONTENTS Section Page CHAP
Page 7: 22. FWD deflections for Styrelf 37
Page 11 and 12: This policy was not in effect when
Page 13 and 14: TRAFFIC VOLUMES Traffic for this se
Page 15 and 16: CHAPTER 3: DESIGN AND CONSTRUCTION
Page 17: was then repeated for the surface c
Page 25 and 26: Table 1. Material Types for Polymer
Page 27 and 28: Table 4. Actual stationing for test
Page 29 and 30: Modifier Course Station-to-Station
Page 31 and 32: CHAPTER 4: TESTING PROCEDURES AND R
Page 33 and 34: CONTROL Section Both the binder and
Page 35 and 36: as would be expected for new paveme
Page 37 and 38: BINDER AIR VOIDS AIR VOIDS, % 9 8 7
Page 39 and 40: VISCOSITY CHART FOR BINDER COURSES
Page 42 and 43: AVERAGE SHEAR STRENGTH COMPUTED FRO
Page 44 and 45: FWD DATA FOR KRATON (Sensor locatio
Page 46 and 47: FWD DATA FOR NOVOPHALT (Sensor loca
Page 48 and 49: FWD DATA FOR ULTRAPAVE (Sensor loca
Page 50 and 51: FWD DATA FOR CRYOPOLYMER RUBBER (Se
Page 52 and 53: FWD DATA FOR CONTROL SECTION (Senso
Page 54 and 55: AVERAGE RUT DEPTH (INCHES) 0.40 0.3
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Table 8. Relative ranking of the di
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areas of high equivalent single axl
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APPENDIX A ROLLING PATTERNS 56
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POLYMER MODIFIED HMA FIELD TRIAL RO
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ASPHALT INSPECTORS DAILY REPORT Lot
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Lot No. 180 Date 08/07/1996 Project
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APPENDIX C MANUAL RUT MEASUREMENTS
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State Study 111 - Polymer Modified Hot Mix Asphalt Field Trial.pdf

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