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Porous Asphalt The Specs Tim Horton, Skillings Connolly Jessica Knickerbocker, City of Tacoma Mark A. Palmer, P.E., LEED AP, City Engineer, City of Puyallup WAPA October 28, 2014

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Porous Asphalt: The Specs Why? Who? Site Design Materials and Specifications Construction Sequencing Whats Next? October 28, 2014 Porous Asphalt -The Specs Washington Asphalt Paving Association 2 Icon Paving Cheney Stadium

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Why do we need a standard spec? $66 Million Grants Failing Roadways Stormwater Regulations Puget Sound Contractor Complaints No Industry Standards October 28, 20143 Porous Asphalt -The Specs Washington Asphalt Paving Association

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Partners 4 Porous Asphalt -The Specs Washington Asphalt Paving Association October 28, 2014

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Site Design October 28, 2014 Porous Asphalt -The Specs Washington Asphalt Paving Association 5

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Mix Design October 28, 2014 Porous Asphalt -The Specs Washington Asphalt Paving Association 6 WSDOT specifications for Class HMA PG 70-22 (Polymer modified) with the following modifications: Binder content shall be between 6.0% and 7.0% by weight of total (dry aggregate) mix, and will be the highest percentage that meets 0.3% maximum drain down test (ASTM D6390-05) Void ratio of 16% to 25% (ASTM D3203) requirements tests at 75 gyrations (Ndesign = 75) or higher. The contractor shall adjust the aggregate to meet the maximum drain down test requirements within the ranges provided in section 9-03.8.

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Drain Down Drain Down-ASTM D6390-05, 0.3% maximum @ 15 above design mix temperature ODOT has alternate ODOT TM 318 Drain Down Test-subjective Consider adding fiber to mix design if draindown is excessive Still working on a good test Porous Asphalt -The Specs Washington Asphalt Paving Association 7 October 28, 2014 Tucci Paving Clay Huntington Way

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Gradation SievePercent Passing 100 90-100 3/855-85 No. 410-25 No. 80-13 No. 2000-5 The aggregate should consist of crushed stone Other aggregates can be acceptable, both larger and smaller. Percent of two face fracture shall be greater than 90%. Fines can be increased to meet Drain Down Test and make porous mix more manageable at the production plant. Porous Asphalt -The Specs Washington Asphalt Paving Association October 28, 2014

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Construction Prior to Paving Porous Asphalt Treated Based Instead of choker course Maintain access on permeable ballast Watch materials and placement: Look for aggregate to be porous, no sheen or sealed off areas Porous Asphalt -The Specs Washington Asphalt Paving Association 9October 28, 2014 Permeable Ballast

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Watch for asphalt in the beds of delivery trucks-indicates drain down issue. Porous mix producers can often utilize warm mix technology if necessary. Rollers are on the asphalt in the correct temperature range (by mix design). Usually about 25 o F below dense graded mixes. Rollers are using vibratory compaction correctly (assuming test were passed during mix design) Establish firm/ unyielding roller pattern - Guard against over compaction. September 24, 2014 WSU Puyallup Technical Workshop Series- Permeable Pavement Design 10 Construction Paving Day

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Construction Acceptance Infiltration rate modified ASTM test (C1701) Initial tests should average over 200/hour City of Puyallup and Tacoma testing existing densities of porous asphalt to see if density range can be established for porous asphalt. If range can be established, will help inspectors with controlling compaction to desire range Look for sealed of areas in pavement. Porous Asphalt -The Specs Washington Asphalt Paving Association 11October 28, 2014

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Goals Improve Pavement Durability Develop a Standard Spec for Western Washington Move to a performance specification. Evaluating Batching and Lay Down Temperatures Looking at alternative tests used throughout the country that better reflect the final product. October 28, 2014 Porous Asphalt -The Specs Washington Asphalt Paving Association 12

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Mark A. Palmer, P.E., LEED AP City Engineer City of Puyallup (253) 435-3606 mpalmer@ci.puyallup.wa.us mpalmer@ci.puyallup.wa.us 13 Porous Asphalt -The Specs Washington Asphalt Paving Association October 28, 2014 Contact Information Jessica Knickerbocker Project Manager City of Tacoma (253) 502-2119 JKnicker@ci.tacoma.wa.us JKnicker@ci.tacoma.wa.us Tim Horton, P.E. Project Engineer Skillings Connolly (253) 435-3606 mpalmer@ci.puyallup.wa.us mpalmer@ci.puyallup.wa.us