Monday, October 2, 2017

Project offers rare look at what lies beneath a highway surface

By Peter Corbett / ADOT Communications

36353349373_c1f6c95798_zA project underway on Interstate 40 just west of Williams offers a rare opportunity to see what lies beneath at least some of the seemingly endless miles of roadway in the state highway system.

Rather than milling off the top layer of pavement and installing a new surface, work occurring in eastbound lanes between mileposts 156 and 161 is rebuilding the roadway from the ground up.

This stretch, at an elevation of about 6,700 feet, has taken a beating from truck traffic and frequent freezing and thawing in winter. That led to cracking, potholes and, now, a $33.9 million improvement project.

So what lies under that road surface other than the ground?

36977928966_33d53c3f33_zIn this case, it begins with bits of what’s being replaced. A rock crusher breaks concrete that was part of the old roadway into small pieces that serve as a base layer of aggregate 8 inches deep.

Next up is a 4-inch base of asphalt the full width of the roadway, topped by 14 inches of grooved concrete for the travel lanes. Asphalt 18 inches deep goes down for the shoulders.

The video above has much more information on the work and its benefits, as does our news release on this project and others improving I-40 west of Flagstaff.

To accommodate construction in the eastbound lanes, both directions of travel are using the westbound lanes, separated by a concrete barrier.

With the eastbound work scheduled to end by winter, crews will return in the spring to rebuild westbound lanes. While a portion of the westbound stretch will be rebuilt from the ground up, the majority will be topped with 14 inches of concrete in the travel lanes and 14 inches of asphalt on the shoulders.

“ADOT is making a huge investment to improve the roadways to make sure travel is safe and efficient, to maintain the commerce corridors and get people where they need to be,” said Brenden Foley, ADOT’s senior resident engineer in charge of the project.

What makes up a particular stretch of highway depends on local conditions. In this case, the clay soil and remote location have a lot to do with the aggregate base topped by asphalt topped in turn by concrete.

I-40 Devil Dog to Williams
Posted by Steve Elliott   |  Labels:  I-40-paving, interstate-40, Paving


The Arizona Ombudsman – Citizens Aide helps you resolve ongoing issues with State Agencies.

Civil Rights

Pursuant to Title VI of the Civil Rights Act of 1964, the Americans with Disabilities Act (ADA) and other nondiscrimination laws and authorities, ADOT does not discriminate on the basis of race, color, national origin, sex, age, or disability. Persons that require a reasonable accommodation based on language or disability should contact ADOT’s Civil Rights Office at Requests should be made as early as possible to ensure the State has an opportunity to address the accommodation.

De acuerdo con el Título VI de la Ley de Derechos Civiles de 1964, la Ley de Estadounidenses con Discapacidades (ADA por sus siglas en inglés) y otras normas y leyes antidiscriminatorias, el Departamento de Transporte de Arizona (ADOT) no discrimina por motivos de raza, color, origen nacional, sexo, edad o discapacidad. Las personas que requieran asistencia (dentro de lo razonable) ya sea por el idioma o discapacidad deben ponerse en contacto con la Oficina de Derechos Civiles de ADOT en Las solicitudes deben hacerse lo más antes posible para asegurar que el Estado tenga la oportunidad de hacer los arreglos necesarios.