Pavement Preservation Techniques Used in Virginia Mike C. Dudley Director of Technical Services Virginia Asphalt Association

What Is Pavement Preservation? “a program employing a network level, long-term strategy that enhances pavement performance by using an integrated, cost-effective set of practices that extend pavement life, improve safety and meet motorist expectations."  Source: FHWA Pavement Preservation Expert Task Group Pavement Preservation offers different techniques that provide several benefits for the roadway, It must be understood that these treatments do not provide any real structural contribution for the pavement but they can improve surface friction, decrease the pavement permeability, and extend the pavement surface life in a cost effective manner.

Components of Pavement Preservation? Proactive Minor Rehabilitation Preventative Maintenance Routine Maintenance

What Techniques Are Used? Traditional Approaches Emerging Approaches Chip Seals Slurry Seal Microsurfacing Crack Sealing Cape Seals Fiber Modified Microsurfacing Fibermat THMACO SM-4.75

Chip Seals Types In VDOT Specs Surface Seal Modified Single Seal Modified Double Seal Commonly used on low- volume secondary roads and sub-divisions Surface Seal – Is one application of asphalt material or emulsion and one application of cover aggregate. Modified Single Seal – Is two applications of asphalt emulsion with one application of cover aggregate and one application of blot fine aggregate Modified Double Seal – Is three applications of asphalt material or emulsion with two applications of cover aggregate and one application of blot fine aggregate

Slurry Seals Types in VDOT Specs Type A Type B Type C Predominately used on lower volume primary and secondary routes Type used is function of traffic levels Type A: Has a very fine gradation of crushed aggregate which has a relativity smooth finish. Type B: Has a more versatile gradation and is sometimes used in double lift applications. Type C: Has the most aggressive or coarse gradation, high skid numbers, and thicker lift.

Latex Modified Emulsion Treatment or Mircosurfacing Types in VDOT Specs Type B Type C Predominately used on higher volume routes including interstates Latex modifier and emulsifiers are milled into the asphalt emulsion. Typically additives are used to control the set time which is much quicker than a typical Slurry Seal Type C has a coarser gradation and can be used for rut-filling.

Crack Sealing Types in VDOT Specs Used alone or with overlay Type A Type B Type C Used alone or with overlay Type A – combination of asphalt binder and up to 25% crumb rubber Type B – made from PG 64H-22 and up to 5% polyester fibers Type C – material same as Type B except installation requires routing

Cape Seals Combination of a Chip Seal foundation and Slurry Seal surface Normally used on higher volume primary and secondary routes Provides a better riding surface and a more aesthetic appearance. This treatment have grown in popularity in VA in the last few years.

Fiber Modified Microsurfacing Similar process as traditional micro- surfacing Combines polyester fibers in the micro- surfacing process Used on selected routes to combat cracking

Fibermat Similar to Chip Seal process Introduces a fiber material interlayer between tack coat and chips Normally overlaid like a Cape Seal with another asphalt-based material Fiber is applied with the distributor by blowing the fiber into the fresh emulsion prior to applying the chip. The fiber adds a layer of reinforcement that standard chip seals don’t have.

THMACO Asphalt concrete material Similar to fine SMA, but with smaller percentage of fines Laid at 1” or less Used on existing concrete and asphalt surfaces Typically on higher volume routes and interstates A lot of times THMACO is applied to a concrete pavement prior to adding a asphalt overlay to help reduce reflective cracking.

SM-4.75 Asphalt concrete material Laid at 0.75” – 1.25” Been used on sub-division streets, secondary and primary routes Installed with traditional paving equipment and provides and excellent riding surface and the traveling public loves the aesthetics.

Why Do We Care About Preservation? VDOT spending increasing amounts on pavement preservation Important to be good stewards of our transportation system Preservation system is part of VDOT’s pavement management plan State and federal dollars are used to fund many projects Different Pavement Preservation options provide more tools and alternatives for the industry to improve our pavements.

VDOT Spending Over Time Year Chips Seals Slurry/Micro 2012 $21,400,000 $32,400,000 2013 $37,000,000 $38,000,000 2014 $28,000,000 $37,800,000 2015 $37,700,000 $44,700,000 2016 $28,700,000 $28,400,000

What Are The Inspection Points and Reminders? Turn it over to Todd Rorrer from VDOT.

Questions