Redefining the Failure Mode for Thin and Ultrathin Whitetopping with 1.8- × 1.8-m Joint Spacing

Abstract

Bonded whitetopping is a thin concrete overlay on a distressed asphalt pavement. The existing design procedures for bonded whitetopping assume the failure mode is a function of the overlay thickness. It has been traditionally assumed that the failure mode for thin whitetopping [overlay thickness greater than 102 mm (4 in.) but less than 152 mm (6 in.)] is transverse cracking, and the failure mode for ultrathin white-topping [overlay thickness between 51 mm (2 in.) and 102 mm (4 in.)] is corner cracking. However, the performance of in-service whitetopping overlays indicates that the actual failure mode is dictated more by slab size than by overlay thickness. For both thin and ultrathin whitetopping with 1.8-m (6-ft) joint spacing, cracks initiate at the bottom of the overlay at the intersection of the transverse joint and the wheelpath and propagate longitudinally. At times, these cracks will continue to propagate in the longitudinal direction and intersect the adjacent transverse joint; at other times, they will turn on a diagonal and propagate toward the lane–shoulder joint. To verify this failure mechanism observed in the field further, a three-dimensional finite element model subjected to environmental and wheel loads was developed. The results support the proposed failure mode, showing that the critical tensile stress is indeed in the wheelpath and at the bottom of the portland cement concrete overlay. This type of failure results in a longitudinal crack.

Implementation of the Thin Bonded Concrete Overlay of Existing Asphalt Pavement Design Procedure in the AASHTOWare Pavement ME Design Software

“…The terminology used to describe these bonded concrete overlays of existing asphalt pavement varies. This type of pavement is referred to as a bonded concrete overlay of asphalt pavement mechanisticempirical (that is, BCOA-ME) by the developers at the University of Pittsburgh (2)(3)(4)(5). The term SJPCP overlay is used in Pavement ME (i.e., SJPCP-AC).…”

Mechanical Connectors to Enhance the Interfacial Debonding of Concrete Overlays

“…Nevertheless, in service situations, debonding is a very common problem that arises even when appropriate design and construction methods are used [18]. This tends to cause a premature failure before reaching the design life because the increment on stresses in the pavement layers.…”

“…On the other hand, thermal exchange, drying shrinkage, and autogenous shrinkage generate length changes that are translated into both normal and shear stresses [18][19][20][21][22][23]. In general, length Horizontal traffic loads (braking, acceleration, and centrifugal forces of vehicles) are applied by the wheel on the surface of the pavement.…”

“…The size of slabs may govern the failure mode of bonded whitetoppings on asphalt pavements [18,25,26]. Smaller slabs make it difficult to keep wheel paths away from joints, thereby incrementing the risk of flexural debonding due to vertical traffic loads [27].…”

Three‐dimensional FEM loading stress analysis on a new airport concrete pavement ultra‐thin whitetopping overlay structure

“…Afterwards, Mu and Zhao studied the interface between the asphalt and concrete overlays, and came up with a superimposed cohesive zone model to investigate the interface debonding. Li and Vandenbossche redefined the failure mode for thin and ultra‐thin whitetopping overlay with short joint spacing. Nam et al established equations to predict lifespan of full‐scale concrete pavement overlay over flexible pavement based on fatigue theories.…”