Heritage Group used innovative engineering and premium materials to pave the parking lot at its new Innovation Center and Research Laboratory in Indianapolis.
Building parking lots to last Heritage Group applies pavement design expertise at its new
Improper drainage — Parking lots have significant surface area and can collect water quickly. Proper drainage is critical to the long-term performance of the parking areas. Cracking — Parking areas can show premature cracking, often at lon- gitudinal joints or between concrete curbs at the interface with the as- phalt. Cracks can also be caused by thermal expansion and contraction. Once water enters the pavement, expedited damage can occur from weakened subgrade, which then leads to fatigue cracking — some- times described as alligator cracking. Premature aging — Asphalt placement in parking lots typically re- quires significant hand work around structures. Besides the asphalt mix being more prone to segregation in these hand-placed areas, the compaction effort is often done with smaller rollers and is inconsistent. This results in pavements having high localized air voids, leading to high permeability of air and water due to interconnected voids. Structural design — Commercial parking facilities tend to be struc- turally under-designed because of costs and underestimation of truck traffic. Local standards for thickness designs of parking areas typically vary based on subgrade strength and assumed truck traffic. It’s often assumed these parking lots will see no truck traffic, yet certain areas of the pavement such as delivery lanes see regular truck traffic and thus are under-designed. Lack of fatigue resistance — Most parking lots never utilize premium materials such as modified asphalt binders that have polymers that can add flexibility and strength to the pavement. Modified asphalt binders can enhance performance, especially in high strain conditions, which are often the case in thinner pavement systems.
Innovation Center and Research Laboratory. By Mark Buncher, Ph.D., P.E., and Tony Kriech
The Heritage Group opened its new Innovation Center and Research Laboratory in Indianapolis in August 2017. While the building and lab is a state-of-the-art facility, the associated roads and parking lots were also designed and built with state-of-the-practice innovation, features, and engineering prowess to ensure optimal performance. Too often, commercial development focuses on the facility itself with less emphasis on the pavement infrastructure. Pavement designs are often based on being the least initial cost with little concern for long- term performance. Construction can be rushed, with little oversight and inspection. Too often, the rush to get the facility open for business leads to the asphalt being placed in adverse weather conditions that should be avoided. The Heritage Group has extensive experience designing and building pavement systems all over the world for a wide range of applications. They applied this experience in the design, material selection, testing, and construction of the pavements around their new center and lab. Typical parking lot distresses The team’s first task was to identify the failure mechanisms most often occurring on commercial asphalt parking pavements. They came up with the following:
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may 2018
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