Concrete Slab Length and Thickness Optimization for Long-Term Concrete Pavement in Ohio

Transverse cracking of concrete pavement in Ohio has been a major issue in interstate routes that reduces its service life to approximately ten to fifteen years, costing Ohio department of transportation great deal of maintenance funds. Major factors that aggravate slab failure are slab length, axle spacing and permanent built-in curl which are not directly incorporated in the AASHTO 1993 design procedure. The procedure implies an increasing thickness of concrete will be needed as traffic increases. However, fatigue testing of concrete beams has shown concrete can endure an unlimited number of loads if the stress ratio (SR) is kept below a critical value. Therefore, field and experimental data from Ohio concrete pavements were employed to validate a 3D finite element (FE) model with which critical slab stresses were calculated for several slab geometries. Results from stresses and fatigue damage analyses showed slab thickness of 12 in (305 mm) and slab length of 13 ft (3.9 m) were optimum for concrete pavement in Ohio. Long term pavement performance analysis showed the 12 in (305 mm) thick by 13 ft (3.9 m) long slab exhibited superior performance in terms of IRI, faulting, cracking, and cost over a 50-year design life.