Jan. 25, 2000 Blacksburg, VA -- For three months this year, a Virginia Tech engineering faculty member, Imad Al-Qadi, was on the job by 6 a.m., at least six and sometimes seven days a week. The intensity of his work kept him each evening until about 8 or 8:30, and once in awhile, midnight. He went for almost an entire month without eating a meal with his wife and three children.
But for Al-Qadi, his labor was for a dream come true. He was involved in a once in a lifetime event, and the sometimes sacrifice, sometimes best time of his life was well worth the exhaustion.
A member of the civil and environmental engineering department, Al-Qadi is an expert on pavements. However, his normal workday as a university professor does not include the outdoor life of a construction contractor. In fact, not many contractors keep these hours.
Al-Qadi had the first opportunity of any researcher in the country to install instrumentation in a "smart road," the first highway of its kind to be built from the ground up. He knew the chance was not to be missed.
Identified simply as the Smart Road by Virginia's Department of Transportation, it is a full-scale research facility for pavement research and evaluation of Intelligent Transportation Systems (ITS) concepts, technologies, and products. ITS technologies are all about improving communications between drivers, vehicles, and the highways by using |sophisticated computers, electronics, and satellites.
In order to instrument the road with sensors and monitoring equipment, Al-Qadi had to stay several steps ahead of the contractor and not delay the job. "(The contractor) never waited even a day for us," the professor says. All of the instruments were buried inside the pavement as the road was being built.
Nine graduate students, one female undergraduate, and Geraldo Flintsch, also a faculty member in civil engineering, shared the time on the project with Al-Qadi. A timetable was developed to accommodate each student's class schedule, as well as Al-Qadi's classes.
The infrastructure that "we built with the Smart Road is unique," according to Al-Qadi. A Control Center, allowing remote monitoring and control of the instruments that are embedded in the road, is currently under construction. Also, an underground conduit network, accessible via a manhole cover, provides for the installation of a power and fiber optics data network without creating a safety hazard to vehicles that may leave the normal roadway. The road is also equipped to generate or simulate different types of weather conditions including rain and snow.
In creating these testing areas as the road was under construction, Al-Qadi says the true challenge was working without electricity except what he could manufacture from four generators. "It was a nightmare, especially when working after dusk," he adds simply.
He has divided his road test portion into 12 different flexible pavement designs. Each section is approximately 100 meters long. Seven of the 12 sections are located on a fill area, while the remaining five sections are in a cut through the existing terrain. All 12 sections have a complex array of sensors embedded beneath the road's surface.
"Each section was designed differently to obtain the desired experimental surface and structural capacity, and the pavement drainage is also different. Special sections included a newly developed geocomposite to prevent cracking and penetration by moisture. One surface design has an open graded friction course that will improve vehicular traction and reduce splashes, especially from trucks," Al-Qadi says.
Al-Qadi is using a pavement material called SuperPave™ for testing purposes. "Virginia is moving to the use of SuperPave™ by the beginning of the new century in most of our roads. We are one of the leading states in using SuperPave™ in our roads as trial sections. The expected benefit is that it will be a better pavement with greater service life and less pot holes will occur," Al-Qadi says. "Different binders in the asphalt surface mixes are used including polymerized binder and binders reinforced with fibers," he adds.
"With the Smart Road, each layer of material can be tested for its structural capacity as it is built, and again periodically after the construction of the whole pavement system, using a Falling Weight Deflectometer," he adds. A copper plate is buried between each two layers of pavement to be able to measure the dielectric properties of the materials which will be used to accurately measure the thickness of the pavement layers using ground penetration radar.
As Al-Qadi evaluates the different types of pavement materials and designs and the response of the various materials to different weight loads and to the environment through his array of sensors, his task will be made somewhat easier since the traffic will be controlled. Vehicles traveling on the test section will have prerecorded information such as tire pressure, axle loads, speed, and mismatch of dual tire pressures. Conventional traffic will be prevented from using the test bed area of the Smart Road for the present time.
Another benefit of the sensors is that they are placed so that they are directly under the wandering area of a vehicle's wheel path. If a driver of a vehicle was to start weaving in and out of the wheel path, the pavement response would still be captured. The environmental instrumentation was placed in the middle of the road.
Al-Qadi is looking forward to the next stage of his work. "Professionally for me, this work is truly exciting. We have a lot to prove in the testing and design of pavements and in introducing new technologies to increase their service life at the lowest possible cost with the least amount of downtime for maintenance. This is always a challenge," he says.
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