Accelerated pavement testing is an effective and efficient way to evaluate the performance of roads. Controlled testing allows our clients to assess the performance of various pavement designs and materials, including geosynthetics quickly and accurately.
Accelerated pavement testing is used to evaluate products, design methods, and construction techniques used in road construction. Accelerated traffic loading is able to simulate years of real-world traffic in a short time. Several methods are employed for accelerated pavement testing, each with its own advantages and limitations. Two common approaches include:
TRI owns and operates a controlled laboratory to construct and test full-scale road simulations trafficked using a large accelerated pavement tester (APT). This laboratory features a concrete pit that is 36 ft. (11 m) long, 11 ft. (3.3 m) wide, and 4 ft. (1.2 m) deep. TRI’s APT is able to apply up to 22 kips (100 kN) on a half-axle, dual-wheel assembly. Full-scale testing offers the most realistic representation of actual road conditions, allowing researchers to observe pavement behavior under various environmental factors and loading scenarios.
TRI also owns and operates a CPL test device that is 7.5 ft (2.3 m) square by 6 ft. (1.8 m) deep to construct road simulations in a controlled manner and load them via a stationary cyclic plate, according to ASTM D1. This method is an alternative to full-scale testing using the APT. These smaller simulations are an efficient way to evaluate performance and behaviors of roads and geosynthetics.
Geosynthetics are polymeric materials used to enhance the performance and longevity of pavement structures. Geosynthetics offer a cost-effective and efficient way to improve pavements through increased strength, longer life, reduced maintenance, better durability, and improved drainage. These versatile materials come in various forms and offer a wide range of benefits in roadway applications. Common types of geosynthetics used in road construction, include:
Geotextiles
Geogrids
Geocells
Geonets
Geomembranes
Geocomposites
TRI is able to quantify the benefit of geosynthetics in pavement systems using the APT and CPL test methods described above. Three key performance indicators (KPIs) for geosynthetics are derived from these tests.
TBR compares the performance of a reinforced pavement section to an unreinforced section under accelerated traffic loading. It is calculated by dividing the number of traffic passes required to reach a specified level of distress (e.g., rut depth) in the geosynthetic-stabilized test section by the number of passes required to reach the same level of distress in the unstabilized (control) test section. A higher TBR indicates a greater improvement in pavement performance.
BCR quantifies the reduction in base course thickness that can be achieved by using a geosynthetic while maintaining the same pavement performance. A higher BCR indicates a greater potential for cost savings from reduced material usage.
LCR represents the improvement in the structural contribution of the base course layer due to the presence of a geosynthetic. It is used in the AASHTO ’93 pavement design equation to adjust the thickness of the base or subbase layers based on the improved performance provided by the geosynthetic.
The AASHTO pavement design guide incorporates the LCR into its structural number (SN) equation, which is used to determine pavement thickness requirements. By considering the LCR, engineers can optimize pavement designs to achieve target performance levels while potentially reducing material costs by utilizing geosynthetics.
TRI Environmental operates a state-of-the-art accelerated pavement testing laboratory equipped to conduct a comprehensive range of pavement performance evaluations.
TRI provides a full suite of geosynthetic testing and analysis services. Knowing the mechanical and performance properties of geosynthetic materials in specific applications allows us to fully characterize their potential when used in roads.