Research finds thicker pavement is more cost effective down the road

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As the summer months heat up, so will the asphalt and other materials used to make roads. Pavements, which are vulnerable to increased temperatures and excessive flooding due to sea level rise, can crack and crumble. Climate change can be a major contributor and as greenhouse gas emissions continue, which scientists say have caused an increase in global temperatures since the mid-20th century, these issues are projected to accelerate. Researchers at the University of New Hampshire say because of this one of the best ways to extend the life cycle of roads, and keep future costs down, is to increase the thickness of asphalt on certain roads.

"It's all about being strategic with the maintenance of our highways and byways," says Jo Sias, professor of civil and . "Just like a regular oil change can help extend the life of a car, our research shows regular maintenance, like increasing the asphalt-layer thickness of some roads, can help protect them from further damage related to ."

In their study, recently published in the journal Transportation Research Record, the researchers looked at the seasonal and long-term effects on pavement life, like climate-change-induced and higher groundwater levels due to and heavy rains. They looked at the changes in season length, increased flooding, average temperatures, projected temperatures and resilience based on those temperatures. As continue to rise, conditions will shift. The winter pavement season is projected to end by mid-century, replaced by a longer fall season. Pavement damage, now seen mostly in the spring and summer, is projected to be more distributed throughout the entire year. Based on their analysis that looked at the wear and tear of roads, the researchers determined that a 7% to 32% increase in the asphalt-layer thickness might be the best way to maintain the service ability of some roads.

"For agencies and towns, it is a balancing act to repair roads so we're trying to find some reasonable action that can be taken now to help manage their infrastructure," said Sias. "If global warming continues then we know temperatures will rise and pavement doesn't respond well to increased temperatures. The hope is to find some answers now so cities and towns can plan for the future."

The researchers recognize that increasing the asphalt thickness to certain roads can be an added expense for cities and towns but they point to considerable future savings of between 40% and 50% if done now rather than later. Along with the rise in cost of materials, there could also be other expense increases down the road like project planning, design, and construction. Environmental impacts could also be costly with rough pavements adding to increased greenhouse gas production, which has the potential to accelerate climate change.

While the study looked specifically at the impact of the changing pavement seasons and the increase in temperatures and flooding at a site in coastal New Hampshire, the researchers say the approach has the potential to be applied to most roads and highways both nationally and globally. The adaptation approach, of calculating the pavement layer thickness required to maintain a safe road reliability level, could provide the guidance to address the effects of rising temperatures and changing seasons on those byways.

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More information: Jayne F. Knott et al. Seasonal and Long-Term Changes to Pavement Life Caused by Rising Temperatures from Climate Change, Transportation Research Record: Journal of the Transportation Research Board (2019). DOI: 10.1177/0361198119844249
Citation: Research finds thicker pavement is more cost effective down the road (2019, July 10) retrieved 21 July 2019 from
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Jul 11, 2019
Basically a demonstration of the validity of an old rule.
Don't skimp on doing things the right way.
Just as study after study indicates what can be called the correctness of rules such as such things as eating are best done in moderation.
It could be recalled that, for example, too, Eastern European women used to carry out a rudimentary but effective form of inoculation.
"Science" says so many things but so often is proved wrong or results in proving that what was ridiculed for being traditional, but worked, was legitimate.
Another old rule, that what has worked so far can be said likely to be right.

Jul 11, 2019
The problem with making the asphalt thicker in the city is that water, sewer, electrical, and telephone/communications are often laid under the roads, so repairing or upgrading them will require more effort.

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