Technical Report Documentation Page 1. Report No. FHWA/TX-13/0-6444-1 2. Government Accession No. 3. Recipient's Catalog No. 4. Title and Subtitle TREATMENTS FOR CLAYS IN AGGREGATES USED TO PRODUCE CEMENT CONCRETE, BITUMINOUS MATERIALS, AND CHIP SEALS: TECHNICAL REPORT 5. Report Date Published: July 2013 6. Performing Organization Code 7. Author(s) Anal K. Mukhopadhyay, Brandon Pitre, Andrew Russell, Edith Arambula, Cindy Estakhri, and Youjun Deng 8. Performing Organization Report No. Report 0-6444-1 9. Performing Organization Name and Address Texas A&M Transportation Institute College Station, Texas 77843-3135 10. Work Unit No. (TRAIS) 11. Contract or Grant No. Project 0-6444 12. Sponsoring Agency Name and Address Texas Department of Transportation Research and Technology Implementation Office P. O. Box 5080 Austin, Texas 78763-5080 13. Type of Report and Period Covered Technical Report: September 2009–August 2012 14. Sponsoring Agency Code 15. Supplementary Notes Project performed in cooperation with the Texas Department of Transportation and the Federal Highway Administration. Project Title: Treatments for Clays in Aggregates Used to Produce Cement Concrete, Bituminous Materials, and Chip Seals URL:http://tti.tamu.edu/documents/0-6444-1.pdf 16. Abstract The clay contamination of coarse and fine aggregates and its effects on pavement performance of portland cement concrete, bituminous mixes and chip seals is a major concern for Texas Department of Transportation. We proposed (i) to determine what type and concentration of clay mineral will result in poor pavement performance, (ii) to identify a quick field test method to detect the presence of deleterious clay minerals in the stockpile, and (iii) suggest remedial techniques to make the clay contaminated aggregates acceptable for use. The modified methylene blue (MMB) and X-Ray Diffraction (XRD) tests were identified as the most promising methods to identify and quantify clay mineral in aggregate fines. Nearly thirty aggregate sources have been tested using the MMB test. XRD was used to determine the content of different clay minerals present in these samples. A strong positive correlation between expansive clay content and methylene blue value (MBV) was evident which clearly indicates that the MMB test is the most reliable and rapid test method to detect clay minerals in aggregate fines. XRD is an advance research tool which was used to validate the MMB test. The correlation between MBV and concrete performance testing (both PPC and HMA) became the basis to assign a threshold MBV (corresponds to the maximum permissible clay content within the aggregate fines) and categorize aggregates fines with different ranges of MBV. A high MBV indicate increased potential for diminished aggregate performance in asphalt, concrete, and other construction applications. The Methylene Blue Test is sensitive to clays which contribute to stripping in HMA and could be used to eliminate problematic field sand sources. It appears that HMA is more robust and can tolerate higher amounts of clay contamination than PCC, mainly because water is not present in HMA. Although the bar linear shrinkage and sand equivalent tests give good repeatability in the results, these tests fail to provide consistent and accurate indications of clay minerals present in aggregate fines. Based on MMB test, materials that are failed by the current specifications (e.g., aggregate fines with clay size non-clay mineral particles) can be allowed, which promotes sustainability and save money. Therefore, type and concentration of clay minerals present in aggregate fines are very important aspects in relation to pavement performance. The guidelines for controlled use of aggregate fines with varying level of clay contamination have been developed and further research / implementation plan has been proposed. 17. Key Words Clay Minerals, Aggregate Fines, Quantification, Methylene Blue, XRD, Concrete, Shrinkage, Strength, HMA, Hamburg, DMA, Remedial Techniques, Surfactants 18. Distribution Statement No Restrictions. This document is available to the public through NTIS: National Technical Information Services Alexandria, Virginia 22312 http://www.ntis.gov 19. Security Classif.(of this report) Unclassified 20. Security Classif.(of this page) Unclassified 21. No. of Pages 190 22. Price Form DOT F 1700.7 (8-72) Reproduction of completed page authorized
TREATMENTS FOR CLAYS IN AGGREGATES USED TO PRODUCE CEMENT CONCRETE, BITUMINOUS MATERIALS, AND CHIP SEALS: TECHNICAL REPORT
Jun 29, 2023
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Related Documents
