New references for three topics relevant to Hawaii roads were recently made available. This month we share those references for porous asphalt, stone matrix asphalt, and thin overlays. Click here to go to the feature article.
There is still time for students to submit their application for the first annual Hawaii Asphalt Paving Industry Scholarship.
Award: 2 - $1,000 scholarships to 4-year university students
2 - $500 scholarships to community college students
Click here for additional information and application form. Applications are due by the extended deadline of October 31, 2018.
On September 20th, HAPI conducted our Understanding a Job Mix Formula Submittal workshop at the HAPI office. Attendees learned the basics of asphalt pavement mixes, the production of asphalt pavements, and how the JMF submittal relates to the project specification. The next workshop is scheduled for March 2019.
The first ever Construction Career Day (CCD) on Kauai was conducted on September 21 at the Kauai Community College campus. The event attracted hundreds of students from middle and high schools on the island. Click here to learn more about CCD.
HAPI participated as an exhibitor. HAPI developed three new products and activities at our table as follows:
- A new 4-page brochure gives 3 reasons why the asphalt industry is an awesome career choice.
- An interactive activity lets students explore different career paths in our industry.
- A “Paving Train” activity shows the procedure and equipment needed to turn a road in disrepair into a newly paved smooth riding pavement.
About 100 students visited our table; click here for a complete report.
Closing out the year will be our PaveXpress/PaveInstruct workshop (click here for additional details and to register) on November 15th. PaveXpress is a free web-based pavement design tool available for use by local agencies, engineers and architects who need a reliable way to quickly determine the necessary pavement thickness for a given section of roadway or project.
The Kansas Department of Transportation conducted a verification exercise that confirmed PaveXpress calculates pavement designs that are consistent with the methodologies in AASHTO ’93 and ’98. Click here for the letter report.
Congratulations to Audrey Copeland, Ph.D., P.E., who has been named the next President & CEO of the National Asphalt Pavement Association. She will assume the new role at the NAPA 2019 Annual Meeting in January. Copeland succeeds Mike Acott, who has served as NAPA’s President since 1992. Click here for more about Copeland.
The Pavement Preservation and Recycling Alliance (PPRA), comprised of leaders at industry associations AEMA (Asphalt Emulsion Manufacturers Association), ISSA (International Slurry Surfacing Association), and ARRA (Asphalt Recycling & Reclaiming Association), has just launched RoadResource.org. This website is a compilation of relevant information with a standardized technical menu on 18 pavement preservation, recycling, and emulsion treatments, alongside useful network comparison calculators. Visit RoadResources.org to explore this new resource.
We foresee that the use of porous asphalt, stone matrix asphalt (SMA), and thin overlays will become much more commonplace in the future. Please consider the following references.
Permeable pavements are one of the low impact development (LID) improvements approved for use in the City's recently implemented Water Quality Rules. In our November 2017 issue of our newsletter (click here) we featured the use of porous asphalt, a type of permeable pavement, for a residential development in Wahiawa.
Often the design of porous asphalt pavements is focused on how well the pavement will handle water, not traffic. For most parking lots and light-duty surfaces this may be a reasonable approach, but as public agencies look to use full-depth porous asphalt pavements on roadways a traditional structural design methodology is needed.
The National Asphalt Pavement Association (NAPA) recently published a guide titled "Structural Design Guidelines for Porous Asphalt Pavements (Information Series 140)”. Written by Charles W. Schwartz, Ph.D., and Kevin D. Hall, Ph.D., P.E., the guide discusses the structural design procedure for porous asphalt and the required inputs using the AASHTO 93 design method. Information Series 140 is available as a PDF download through the NAPA store (click here).
Thinlays are a suite of thin-asphalt overlays designed specifically for pavement preservation. Dr. Archilla, Associate Professor of Civil and Environmental Engineering at the University of Hawaii, believes they can work in Hawaii and HAPI concurs.
With Thinlays, agencies can extend the life of pavements that are in good to fair condition, decreasing life-cycle costs, improving ride, and decreasing roadway noise. The guide, Thinlays for Pavement Preservation (Information Series 141) is available at the National Asphalt Pavement Association’s online store (click here).
Authored by Mike Heitzman and Ray Brown at the National Center for Asphalt Technology (NCAT) and John Hickey at the Asphalt Pavement Association of Oregon, Thinlays for Pavement Preservation provides comprehensive guidance on the proper use of Thinlays, how they fit within pavement management systems, when and how they should be used based on existing pavement condition, how the mixes should be developed and specified, and best practices for construction. This guide also helps users compare the cost and performance of common pavement preservation techniques.
Stone Matrix Asphalt (SMA) is an excellent wearing course for our roads We understand that the Hawaii Department of Transportation (HDOT) is considering specifying SMA for upcoming projects.
SMA has been used on two high volume road projects in Hawaii. The material was first tested on a section of the Moanalua Freeway on the town side of Red Hill in 2004. That section remains in good condition today, 14 years after laydown, confirming the extended life of a heavily used pavement built with this material.
More recently, the resurfacing of the H-1 Freeway between Middle Street and Ward Avenue was completed using SMA in 2014. This project was featured in the November 2014 issue of our newsletter (click here to go to the article).
The mix design goal of SMA is to create stone-on-stone contact within the mixture. It results in a material that’s stronger than typical asphalt and is designed to last 10-15 years, instead of 7 to 10 years, as explained in 2013 by Jadine Urasaki, then HDOT deputy director for capital projects.
NCAT Report 18-03 quantifies and compares the performance and life-cycle cost benefits of SMA and polymer-modified Superpave dense-graded mixtures used on similar trafficked highways. A market analysis and performance analysis were conducted and used as inputs to compare the life-cycle cost between the two mixtures. The report also includes a literature review summarizing the engineering properties and field performance of SMA. Results obtained from this study provide highway agencies with additional guidance regarding the use of SMA as a premium asphalt mixture. Click here to download a free copy of this report.
We encourage you to obtain a copy of the above references if you’re involved with the design or construction of a porous asphalt pavement, thin overlay, or an SMA pavement.
✤ AASHTO TSP2 Certification Exams, November 14, 2018; Honolulu, Hawaii
✤ PaveXpress/PaveInstruct Workshop, November 15, 2018; Honolulu, Hawaii
Other training opportunities!
✤ 1st International Conference on Stone Matrix Asphalt (SMA), November 5 to 7, 2018; Atlanta, Georgia
NAPA FREE Webinars - click here for additional information and to sign-up:
Asphalt Institute (all FREE):
✤ Asphalt Emulsion FREE Webinar Series Recordings
✤ Pavement Preservation Treatments FREE Webinar Series Recordings
✤ Advanced Pavement Preservation FREE Webinar Series Recordings
✤ Tack Coat Best Practices FREE Webinar
✤ Thin Lift Asphalt Overlays FREE Webinar
National Highways Institute: Full Depth Reclamation, or FDR, is a rehabilitation technique in which the full thickness of the asphalt pavement and a predetermined portion of the underlying materials (that is, the base, the subbase, and/or subgrade) is uniformly pulverized and blended to provide an upgraded, homogeneous material.