Final Report FHW A/IN/JTRP-2000/28 DEVELOPMENT OF A PROCEDURE TO IDENTIFY AGGREGATES FOR BITUMINOUS SURFACES IN INDIANA Terry R. West Professor Principal Investigator and Kyu H. Cho Research Assistant Department of Earth and Atmospheric Sciences Purdue University Joint Transportation Research Program Project No. C-36-6RR File No. 2-4-44 SPR-2206 Prepared in cooperation with the Indiana Department of Transportation and the U.S. Department of Transportation Federal Highway Administration The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the data herein. The contents do not necessarily reflect the official views or policies of the Indiana Department of Transportation or the Federal Highway Administration at the time of publication. This report does not constitute a standard, specificationor regulation. Purdue University West Lafayette, Indiana September 2001 TECHNICAL REPORT STANDARD TITLE PAGE 1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. FHW A/IN/JTRP-2000/28 4. Title and Snbtllle S. Report Date September 2001 Development of a Procedure to Identify Aggregate for Bituminous Surfaces in Indiana 6. Performing Organization Code 7. Author(s) 8, Performing Organization Report No. Terry R. West and Kyu H. Cho FHWA/IN/JTRP-2000/28 9. Performing Organization Name and Address 10. Work Unit No. Joint Transportation Research Program 1284 Civil Engineering Building Purdue University West Lafayette, Indiana 47907-1284 11. Contract or Grant No. SPR-2206 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered Indiana Department of Transportation State Office Building Final Report 100 North Senate Avenue Indianaoolis. IN 46204 14. Sponsoring Agency Code 15. Supplementary Notes Prepared in cooperation with the Indiana Department of Transportation and Federal Highway Administration. 16. Abstract Adequate friction resistance is needed to prevent pavement slipperiness allowing vehicles to stop in a reasonable distance. For stone mastic asphalt surfaces, friction resistance is mainly a function of the interaction between the aggregates exposed at the road surface and vehicle tires. Aggregate performance is reduced with time by wear and polishing as a consequence of vehicular traffic. In this research a method to investigate performance based on physical, chemical and petrographic factors has been evaluated. The objective was to develop a laboratory method to test Indiana dolomite, limestone, sandstone, and gravel aggregates to predict friction resistance in the field and determine causes for the range of values among these aggregates. Assessment of gravel sources was based on individual rock types and their proportions comprising the gravel. Initial friction Values (IFV) and Polished Values (PV) were determined in the laboratory with the British Wheel and Pendulum test and field values obtained from the towed friction trailer. For two laboratories involved a significant difference in IFV and PV was obtained so that further verification is required. Correlations between parameters were established which provide predictions of friction resistance based on laboratory specimens. A database of physical and chemical properties should be collected on aggregates used or considered for bituminous wearing courses. This includes the testing required for Class A aggregates plus elemental Mg and elemental Ca content. 17, Key Words 18. Distribution Statement bituminous surfaces, friction resistance, dolomite, limestone. No restrictions. This document is available to the public through the National Technical Information Service, Springfield, VA 22161 19. Security Classlf. (of this report) 20. Security Clnsslf. (of this page) 21. No. of Pages 22. Price Unclassified Unclassified 115 Form DOT F 1700.7 (8-69) TECHNICAL Summary INDOT Research Technology Transfer and Project Implementation Information TRB Subject Code: 35-1 Mineral Aggregate Characteristics and Tests September 2001 Publication No.: FHWA/IN/JTRP-2000/28, SPR-2206 Final Report Development of a Procedure to Identify Aggregates for Bituminous Surfaces in Indiana Introduction Adequate friction resistance is needed to prevent was based on individual rock types and their pavement slipperiness allowing vehicles to stop proportions comprising the gravel. Initial friction in a reasonable distance. For stone mastic asphalt Values (IFV) and Polished Values (PV) were surfaces, friction resistance is mainly a function determined in the laboratory with the British of the interaction between the aggregates Wheel and Pendulum test and field values exposed at the road surface and vehicle tires. obtained from the towed friction trailer. For two Aggregate performance is reduced with time by laboratories involved a significant difference in wear and polishing as a consequence of IFV and PV was obtained so that further vehicular traffic. In this research a method to verification is required. Correlations between investigate performance based on physical, parameters were established which provide chemical and petrographic factors has been predictions of friction resistance based on evaluated. The objective was to develop a laboratory specimens. A data base of physical laboratory method to test Indiana dolomite, and chemical properties should be collected on limestone, sandstone, and gravel aggregates to aggregates used or considered for bituminous predict friction resistance in the field and wearing courses. This includes the testing determine causes for the range of values among required for Class A aggregates plus elemental these aggregates. Assessment of gravel sources Mg and elemental Ca content. Findings This study was a continuation of previous work Following aggregate collection, by Bruner, Choi and West, 1995, FHWA/IN/JHRP megascopic and microscopic evaluation of the 95/11, which focused primarily on dolomite aggregate samples was accomplished. Twenty- aggregates (19 sources). In the current study, 21 four additional rock thin sections were examined limestone sources, three sandstones and six to extend those from the first study. Laboratory gravel sources were added. Data from both tests included acid insoluble residue (ASTM, studies were evaluated to provide an overall D3042), size distribution of acid insoluble residue, conclusion. Frictional performance is determined elemental Mg content (ASTM, C602), Los by polishing aggregate coupons with the British Angeles abrasion (ASTM, C131), sulfate Wheel machine and measuring friction values soundness (ASTM, C88), freeze-thaw loss in with the British Pendulum tester. This provides water and in brine solution (AASHTO, T103, the IFV (initial friction value), PV (polished value Procedure A), absorption and specific gravity or BPN at 10 hours) and the difference between (ASTM, C127). These were conducted at INDOT, IFV and PV, WI, wear index. Division of Materials and Tests, and at Purdue University. 35-1 9/01 JTRP-2000/28 INDOT Division of Research West Lafayette, IN 47906 Aggregate coupons of limestones, Mississinewa Member are impure carbonates sandstones and gravels were made for the British with higher friction values. The Huntington Wheel test and British Pendulum test (ASTM, Dolomite and Brassfield Limestone possessing D3319, E303). The coarest portion of the No. 11 high carbonate purity, showed lower friction INDOT gradation, 12.5 mm to 9.5 mm in size, was values. used. To construct the coupons, aggregates were Factors greatly affecting PV for dolomite embedded in epoxy resin and a hardener aggregates are IFV, absorption, specific gravity, component added. The epoxy was different from sodium sulfate loss, elemental Mg content, and that used in the 1995 study (Bruner, Choi and percentage of insoluble residue, minus #200 sieve West). Coupons were polished using the British size. The most influential independent variables Wheel machine and measured with the British for dolomite are absorption and elemental Mg Pendulum tester after zero hours (IFV), 1 hour, 3 content. hours, 6 hours and 10 hours (Polished value, PV The important factors affecting PV for or BPN10). These data were added to the existing limestone aggregates are total insoluble residue information from the previous dolomite study and percent insoluble residue, minus #200 sieve (Bruner, Choi and West, 1995, FHWA/IN/JHRP size. In all, the most influential independent 95/11). variable is the total insoluble residue content. Finally, analysis of all data from the Considering dolomite and limestone current and the 1995 study were combined and a aggregates collectively, the most important statistical evaluation performed. Results were variables are absorption, elemental Mg content compared to those from other states. Based on and total insoluble residue. this, PV of dolomites and limestones required for Multiple linear regression equations bituminous surface courses can be were developed which can be used to predict PV. recommended. Results can be used to develop These are provided in the report. specifications to evaluate additional sources for As a starting point for further research medium and high vehicular traffic pavements using the British Polishing Wheel and Pendulum having bituminous overlays in Indiana. test the following is proposed: Gravels consisted primarily of limestones and dolomites. The weighted PV Minimum Frictional Resistance ranged from 22.6 to 26.3 and PV correlates best Polish Value of Bituminous Surface with freeze-thaw loss. Other important factors are 24 or less Poor absorption,