▶▶Monismith: Pavements are complicated, they’re not the easiest thing in the world to build, believe or not. It may look simple but really is an engineered structure. It’s complex work, we test thousands of they may look the same but have subtle differences. Pavement is actually very layered. You don’t see it, but there’s big chunks of rock in there. You can see the top layer, which looks like any road, then all
Carl Monismith:
Green Technology and Policy on
Pavement Engineering
장 면과 같지만 그 아래에는 여러 다른 층들이 다
the layers underneath, which are filled with different kinds rocks. Ignoring pavement is a big mistake.
We spend about $100 billion a year on pavement in the U.S. $100 billion. You have to have people in the field that are going to build these pavements properly, because if they’re not built properly they’re not going to last.
▶Kim: Why do the roads have so many potholes?
▶▶Monismith: Heavy vehicles like trucks and buses do all the damage on pavement. Passenger cars do next to nothing.
▶Kim: So, does one pothole spawn another?
▶▶ Monismith: They sure do. There is more places, more spaces for water to enter. Consequently larger areas of pavement get wet, get softer, and as the pavement cracks they want to spread. So sure.
In a nutshell.
▶Kim: Why doesn’t the agency fix all those potholes immediately?
▶▶Monismith: If you try to fix the worst pavements first, you won’t have enough money. The trick is to try and maintain your network at a high level. Once a pavement the end its life, letting it go a little longer isn’t going to make a difference. Try and improve while you can. Prioritization of maintenance of pavement in network level is also important.
▶Kim: One more quick general question, we have earthquakes in California. Does that mean you use different kinds of pavement?
▶▶Monismith: No, not really.
▶Kim: I see. Shall we now move forward to our main topic, green pavement? I heard your institute researches about environmentally friendly pavement technology reducing green house gas. Would you explain your research approach about it?
▶▶Monismith: Pavement is everywhere, the U.S. has four million miles of paved roads, close to 10 percent of them are in California. It’s something that affects each and every one our lives. In pavement’s life-cycle, there exist roughly five different stages to produce greenhouse gas, material production, construction, operation, maintenance and rehabilitation, and end-of-life. We use life-cycle assessment
를 민감도 분석과정을 거쳐 캘리포니아 전체 도로 고 있습니다. EMFAC(The EMission Factors)는 캘리포니아 도로에서 주행 중인 모든 차량의 배기
approach to address in estimate GHG on each stage and develop technologies to reduce GHG. First, we divide network into categories based on the factorials and apply results from the categorical case studies to the network with additional sensitivity analyses like material’s types, production method, traffic level and congestion, construction method, materials’ recycling. We plan to develop a network-level application including GHG emission modeling. We also investigate and utilize the existing models developed by the U.S. and California state. EMFAC is the database model for California’s on-road vehicles emission inventory and Off-Road is the California’s off-road equipment emission inventory. CA4PRS software functions construction schedule analysis and road user (traffic) delay estimate. We extract and use data from them.
▶Kim: You mentioned there are different approach by different stage in pavement’s life-cycle. Would you mind to give me some examples in detail, each stage?
▶▶Monismith: Absolutely. Let me give you simple examples for stage by stage. First, in production of pavement materials, there are different level of energy consumption and GHG emission by different materials, asphalt or cement concrete. Also, size of aggregates and location of aggregate extraction make difference as well. Second, in construction technology, when they build asphalt concrete pavement, carbon level is different by the temperature of asphalt mix, like hot-mix asphalt or warm-mix asphalt. Third, we have hypothesis that the pavement’s smoothness makes difference on vehicles’
fuel efficience. We expect the higher level of pavement smoothness in network level contributes reducing GHG.
▶Kim: How much GHG emission can be reduced by maintaining high level of smoothness in network level?
▶▶Monismith: Our preliminary study result indicates that two to five percent of GHG can be reduced in long term. That’s gonna be a huge contribution in our environment.
▶Kim: How about pavement recycling? Does it help in reducing GHG? How much does California recycle the end-life pavement in new pavement?
▶▶Monismith: Transportation and energy consumption are required to get rid of the end-life pavement materials. Recycling them help to less produce new pavement materials and save the procedure for treating themselves. California now uses up to 10 percent of the end-life pavement as aggregate in new
변화를 강조하고 있습니다. 캘리포니아 정부기관 들도 Assemble Bills 32와 같은 정책과 법규 등 을 제정하면서 기후변화에 대응하는 솔루션을 찾 고 있습니다. 저는 교통 분야에서 기후변화에 대응 하는 해법들을 찾을 수 있다고 믿고 있습니다. 도 로포장 분야는 그 목적을 성취할 가능성이 높은 연 구대상이라고 믿습니다. 40~50년이라는 도로포 장의 수명을 고려할 때 혁신적인 포장 재료, 장기 수명 포장 기술, 시기적절한 도로유지·보수, 포장 재료의 재활용 등이 모두 녹색 환경을 만들어가는 데 기여할 것입니다.
▶ 김: 답변에 진심으로 감사드리며, 교수님과 도 로포장연구소가 녹색 도로포장 기술에 있어서 지 속적으로 크게 기여하기를 바랍니다. 대단히 감사 합니다.
▶▶모니스미스: 네, 방문해주셔서 감사합니다.
칼 모니스미스의 주요 저서
Creegan, Patrick J. and Monismith, Carl L. 1996. Asphalt-Concrete Water Barriers for Embankment Dams. New York : American Society of Civil Engineers Press.
Finn, Fred N. and Monismith, Carl. 1985. Asphalt Overlay Design Procedures (Synthesis of Highway Practices). New York : Transportation Research Board.
Monismith, Carl L. 1998. Asphalt Concrete: An Extraordinary Material for Engineering Applications. Pennsylvania : Diane Pub Co.
. 1992. Analytically-based Asphalt Pavement Design and Rehabilitation: Theory to Practice (1962-1992). New York : Transportation Research Board, National Research Council.
. 1992. TRB Distinguished Lecture, Part 1: Part 2: Developments in Flexible Pavement Design. New York : Transportation Research Record, National Research Council.
. 1984. New Directions in Construction: Rehabilitation and Reconstruction.
California : Institute of Transportation and Traffic Engineering, University of California.
. 1976. Rutting Prediction in Asphalt Concrete Pavement: A State-of-the-art. California : Institute of Transportation and Traffic Engineering, University of California.
. 1969. Fatigue of Asphalt Paving Mixtures. California : Institute of Transportation and Traffic Engineering, University of California.
. 1961. Asphalt Paving Mixtures Properties. California : Design and Performance, University of California, Berkeley.
Monismith, Carl L., Leahy, Rita B., Epps, John A. and Hongach, Andrew.
2001. Asphalt Paving Technology. Texas : Mcgraw-Hill.
pavement. Many researchers including ourselves are doing research on recycling pavement materials.
▶Kim: As the last question, would you like to share your perspective about green pavement in both engineering and policy?
▶▶ Monismith: The. U.S. Department of Transportation emphasizes Climate Change in Transportation.
California agencies are also establishing policies and rules, like Assemble Bill 32, to find solutions against Climate Change in many aspects. I believe many effective solutions can be found in Transportation fields. Pavement is a very good one to study in this goal. Considering 40 years, 50 years of life-cycle of pavement, innovative pavement materials, long-life pavement technology, timely maintenance scheduling, and pavement recycling, all of them contribute to making green environment.
▶ Kim: I truly appreciate your response and I hope you and your institute keep making great contribution in green pavement technology. Thank you very much!
▶▶Monismith: It’s my pleasure. Thank you for visiting us.
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