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Evaluation of the Polish Resistance of Fine Aggregates in PCC Pavements DAVID W. FOWLER University of Texas at Austin, Department of Civil, Environmental and Architectural Engineering 10100 Burnet Road/Building 18B, Austin, TX, 78758 PH (512) 232-2575; FAX (512) 471-3191; email: dwf@mail.utexas.edu MARC M. RACHED University of Texas at Austin, Department of Civil, Environmental and Architectural Engineering 10100 Burnet Road/Building 18B, Austin, TX, 78758 PH (512) 471-1630; FAX (512) 471-4555; email: marc_rached@yahoo.com Submission Date: August 1, 2011 Word Count: 7,344 word equiv. = 4,344 words + 12 Tables and Figures @ 250 word equiv./ea. ABSTRACT Many state agencies have limited the use of some sources of fine aggregates in portland cement concrete (PCC) pavements because of possible skid issues related to the incorporation of such sands. TxDOT for example, has adopted the acid insoluble residue test (AIR) as a method to identify polish resistant aggregates. Since calcium carbonate is soluble in acid, no carbonate sand passes the AIR test which has a minimum limit of 60% acid insoluble residue in Texas. This paper describes research that was done to evaluate the polish resistance of aggregates using a laboratory concrete performance test. Concrete slabs made with different fine aggregates were evaluated for skid using a circular track meter (CTM), a dynamic friction tester (DFT), and a three-wheel-polishing device (TWPD). For each concrete slab tested, the change in texture and friction was monitored for a total of 160,000 polishing cycles. To ensure that the values obtained at the laboratory related to field performance, test sections constructed with 100% limestone sand and blended sands were also evaluated. Results show that some of the aggregates that failed the AIR test performed as well as some of the siliceous fine aggregates that passed the AIR test. Other aggregate tests such as the fine aggregates micro-Deval have shown to relate more closely to the concrete performance tests performed under laboratory conditions. Results obtained from laboratory and field testing also show that blending a small quantity of siliceous sand with limestone sands considerably increased the skid resistance of concrete. KEYWORDS Fine Aggregate, skid resistance, polish resistance, friction, texture, PCC pavements, acid insoluble residue, micro-Deval, manufactured fine aggregate, carbonate aggregates, abrasion. TRB 2012 Annual Meeting Paper revised from original submittal.
