Danny Gierhart

Director of Engineering and Training
P.E.
Education | Engineering
Time at Asphalt Institute: 17 years

Danny Gierhart is the Asphalt Institute’s Director of Engineering and Training. Since joining the Asphalt Institute in 2009, he has served as the institute’s Southeastern Regional Engineer and as Deputy Director of Engineering. He earned his Civil Engineering degree from the University of Oklahoma in 1985 and has been a registered professional engineer since 1990. He has had a diverse career, working in industry, agency, and academia. He worked for 20 years with the Oklahoma DOT, primarily as an ODOT Bituminous Engineer. He spent 4 years in the industry as a Materials Engineer for Broce Construction Company. He also served at the College of Engineering at the University of Oklahoma for 11 years as an adjunct instructor.

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Danny's Articles

Danny Gierhart, P.E. Archives - Asphalt magazine The Magazine of the Asphalt Institute

  • %RAP is a percentage of what, exactly?
    by Danny Gierhart, P.E. on December 30, 2025 at 4:48 pm

    Three steps to properly calculate batch weights for asphalt specimens using RAP We see it every day in the industry: asphalt mixtures with 25% RAP, 15% RAP, etc. But if I see 23% RAP on a mix design, what exactly is it a percentage of? Many people would say either that it’s a percentage by The post %RAP is a percentage of what, exactly? appeared first on Asphalt magazine.

  • Balanced mix design, recycled binder availability and how they fit
    by Dr. Mark Buncher, Ph.D., P.E. on January 9, 2025 at 7:11 pm

    Collective critical thinking from Asphalt Institute engineers By Dr. Mark Buncher, Ph.D., P.E. and Danny Gierhart, P.E. Going back to 1956 with the first “MS-2 Mix Design Manual”, the Asphalt Institute (AI) has published established, well-proven mix design techniques that promote the long-term quality performance of asphalt pavement. Given that more than $25 billion is The post Balanced mix design, recycled binder availability and how they fit appeared first on Asphalt magazine.

  • Five handy rules of thumb for successful asphalt pavement construction
    by Danny Gierhart, P.E. on September 11, 2023 at 3:55 pm

    Planning is imperative for any type of successful asphalt paving project. When it comes to defining a successful asphalt project, success can be measured not only by the feasibility and execution of the project but also by the long-term performance of the pavement constructed. Pavement performance often is measured based on smoothness and overall condition. The post Five handy rules of thumb for successful asphalt pavement construction appeared first on Asphalt magazine.

  • Five handy rules of thumb for asphalt mix design
    by Danny Gierhart, P.E. on January 3, 2023 at 3:20 pm

    For as long as people have worked at things, they have been coming up with rules of thumb to make their work easier. We offer these five handy rules of thumb for asphalt mix designers. 1 For every 0.3% binder, the air voids change about 1% During the mix design process, trial batches often result The post Five handy rules of thumb for asphalt mix design appeared first on Asphalt magazine.

  • Solution for training pavement inspectors
    by Danny Gierhart, P.E. on January 11, 2022 at 10:00 pm

    I vividly recall my first day as an inspector for the Oklahoma Department of Transportation (ODOT) back in 1985, just days after being hired fresh out of college. I was given a vehicle and a spec book and told the location of the project on which I would serve as the ODOT inspector. I didn’t The post Solution for training pavement inspectors appeared first on Asphalt magazine.

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