Nondestructive testing (NDT) is useful for evaluating variability in pavement. It can locate areas of weakness and determine the adequate load-bearing capacity of the pavement. While some structural properties may require laboratory testing, NDT can be used in the field during pavement evaluation without tearing up the pavement. SME is one of the only firms in the Midwest that owns and operates its own heavy falling weight deflectometer (FWD), which simulates moving vehicle loads on the pavement.

We use the FWD to:

• Evaluate variability of overall pavement and subgrade strength
• Select “strategic” core and boring locations
• Estimate subgrade soil strength
• Evaluate the pavement’s structural adequacy and remaining life
• Provide parameters for overlay design
• Evaluate potential void locations (concrete pavements)
• Estimate joint load transfer (concrete pavements)

 Other pavement evaluation techniques used by SME include Ground Penetrating Radar (GPR) to evaluate the pavement layer thickness, areas of entrapped moisture and deteriorated pavement layers.

According to numerous federal surveys, road users listed smooth pavement as a top road and highway characteristic. Rough or uneven pavement adversely affects driver safety, fuel efficiency, ride quality, vehicle wear and tear, and pavement durability. As part of SME’s pavement evaluation services, our engineers have found that those pavements built with better ride quality take longer to reach unacceptable levels of ride quality and, subsequently, longer times before rehabilitation is required. Our clients include federal, state, county and local entities and test tracks for major automotive companies.

Data Collection

SME engineers work with our clients to evaluate ride quality data collection. We define the methods, standards, and protocols to be used in collecting pavement ride quality data. SME owns and operates a Mark IV road profiler to collect pavement profile data to assess ride quality and compute International Roughness Index (IRI).

Quality Control

Our engineers and technicians measure and assess the profile characteristics of pavements throughout appropriate stages of construction to determine whether they meet the ride quality requirements set forth by the project specifications. By proactively monitoring pavement ride characteristics during construction, contractors can correct problems rapidly and avoid costly remedial actions and/or construction penalties.

Research

SME is nationally recognized as a leading researcher on ride quality issues. We have participated in numerous ride quality research studies with the Federal Highway Administration (FHWA), National Cooperative Highway Research Program (NCHRP) and other organizations. We have assisted several state highway departments in implementing new AASHTO Protocols to improve ride quality on roads and bridges.

Maintaining highways, runways and commercial parking lots is costly. SME’s pavement experts have a thorough understanding of pavement technology and evaluation to help you develop effective maintenance and rehabilitation strategies. Through a detailed evaluation program, we characterize existing pavement conditions and forecast future performance. This performance data can then be used to determine strategies that will correct deficiencies, mitigate pavement deterioration and reduce maintenance costs.

Preventive Maintenance

SME works with our clients to develop preventive maintenance programs using lower-cost treatments to reduce pavement deterioration, maintain or improve the functional condition, and extend the pavement's service life. Applied when the pavements are mostly in good condition, preventive maintenance can significantly improve the pavement condition and service life at a lower cost than repair.

Rehabilitation Strategies

SME develops pavement rehabilitation strategies that extend the pavement life, improve service levels and reduce future maintenance expenditures.

Detailed information is important for selection of the preferred rehabilitation strategy. Our process generally includes review of available historical data, current and projected traffic conditions, distress observed on the surface, age of the pavement, and surface type to establish a snapshot of the current pavement conditions. This information is typically supplemented with additional data obtained from nondestructive testing and pavement sampling to provide a full assessment of the pavement condition. SME’s experts work with our clients to understand their desired life expectancy, service levels and available funds to improve the overall conditions of their pavement assets. Based on our discussions, we tailor our recommendations to our client’s needs and available resources.

Deteriorating pavement is a constant problem for roads, parking lots and airports. To help our clients, SME’s pavement experts turn to a process called full-depth reclamation (FDR).

FDR rebuilds worn out asphalt pavements with a new and stronger foundation, and saves money by recycling the existing materials. FDR eliminates excavation and replacement with new materials to expedite construction time and reduce costs. The old asphalt and base materials are pulverized, mixed with cement and water or/or other chemical agents, and compacted to produce a strong, durable base for either an asphalt or concrete surface.

Sampling

Sampling and laboratory pre-testing is critical to provide a satisfactory mix design that will provide a stable and functioning newly developed subbase course as expected.

Quality Control

The success of an FDR project depends upon the careful attention to the quality control factors including adequate pulverization, proper cement content, proper moisture content, adequate density and adequate curing.

Mix Design

Material samples from the site should be pulverized in the lab to create an aggregate-soil mix that will be similar to that expected from the FDR process. The mix design procedure is the same as that performed for soil-cement.