Smoothseal is the industry name for ODOT Specification Item 424, Fine Graded Polymer Modified Asphalt Concrete, type A or B. Any asphalt concrete producer can produce Smoothseal to ODOT specification.

Smoothseal is blended of high-quality aggregates with polymer modified asphalt to produce one of the most durable, dense-graded paving mixtures available. These materials are especially well suited for thin, preventive maintenance overlays. Smoothseal is unique among paving materials in Ohio in that the ODOT spec requires sand having at least 50% silicon dioxide, SiO2 (quartz) to insure high skid resistance. No other ODOT specification material has this requirement. Because not all sands found in southwestern Ohio have the necessary percentage of SiO2, Flexible Pavements of Ohio issued an advisory letter to users and producers in southwestern Ohio. Read ourSmoothseal Advisory.

For more information on how to use " Smoothseal" to best advantage refer to the following technical documents and specification:

FPO Technical Bulletin: Smoothseal

Find the latest revision of the specification for Item 424 in the 2013 ODOT Construction and Material Specifications 

book and at http://www.dot.state.oh.us/Divisions/ConstructionMgt/OnlineDocs/Specifications/2013CMS/400/424.htm

June, 2001 - ODOT Issues Preventive Maintenance Guidelines

September, 2001 – Smoothseal - Gaining Acceptance

June, 2002 – Smoothseal – Gaining Acceptance, Part 2

October, 2002 – Smoothseal Rolls Over Microsurfacing in Alternate Bid Project

April, 2003 – Preventive Maintenance, A Good Idea Whose Time Has Come

Also, see the following related articles from Ohio Asphalt magazine on the

Winter, 2004 – Smoothseal Trickles Down

Fall, 2005 - A Report on Early Skid Findings for Smoothseal 

Fall, 2006 - Recycled Asphalt Pavement Now Permitted in Smoothseal

For information on the cost effectiveness of Smoothseal see the article on ODOT's study:

Winter 2006 - Analysis looks at Cost-Effectiveness of Preventive Maintenance Treatments