The choice of the most appropriate functional and structural rehabilitation technique for damaged road pavements obviously mainly depends on the type of surface degradation. The most common rehabilitation technique for flexible pavements deals with the resurfacing of the degraded wearing course by means of a bituminous layer, when it can't be completely replaced by similar mixtures. Nevertheless, maintenance of degraded flexible pavements can be carried out resorting to a different procedure, which is rarely used in Italy, although it is quite popular abroad: Ultra-Thin Whitetopping (UTW). It involves the damaged pavement being resurfaced with small thin cement concrete slabs. The interaction between the existing bituminous pavement and concrete layer generates a monolithic system, the performance of which is conditioned by various parameters: the volume of vehicular traffic, environmental conditions, the thickness of cement and bituminous concrete layers, the distance between joints, the adhesion between layers and maintenance technique. The paper describes the results of an Italian application of this technique. The experiments regarded the identification and characterization of the existing bituminous pavements (through cores and bearing capacity tests), the design of the UTW, the cement concrete mix design (PP and SB fibres were added to the mixture to enhance compressive strength and elasticity), the mechanical characterization of the new layer (by means of compressive strength and dynamic modulus), the construction of joints, the execution of loading tests on the slabs and measurement of longitudinal, transversal and vertical deflections by strain gauges and LVDTs. The study emphasizes the effectiveness of the maintenance technique. The UTW ensures a good bearing capacity to the pavement, thanks to high values of compressive strength and elastic modulus of the concrete, according to future traffic needs. Moreover, deflections are rather limited. Adequate functional properties (evenness, skid resistance) are also guaranteed.

Use of Ultra-Thin Whitetopping in the rehabilitation of degraded flexible pavements

PASETTO, MARCO;
2005

Abstract

The choice of the most appropriate functional and structural rehabilitation technique for damaged road pavements obviously mainly depends on the type of surface degradation. The most common rehabilitation technique for flexible pavements deals with the resurfacing of the degraded wearing course by means of a bituminous layer, when it can't be completely replaced by similar mixtures. Nevertheless, maintenance of degraded flexible pavements can be carried out resorting to a different procedure, which is rarely used in Italy, although it is quite popular abroad: Ultra-Thin Whitetopping (UTW). It involves the damaged pavement being resurfaced with small thin cement concrete slabs. The interaction between the existing bituminous pavement and concrete layer generates a monolithic system, the performance of which is conditioned by various parameters: the volume of vehicular traffic, environmental conditions, the thickness of cement and bituminous concrete layers, the distance between joints, the adhesion between layers and maintenance technique. The paper describes the results of an Italian application of this technique. The experiments regarded the identification and characterization of the existing bituminous pavements (through cores and bearing capacity tests), the design of the UTW, the cement concrete mix design (PP and SB fibres were added to the mixture to enhance compressive strength and elasticity), the mechanical characterization of the new layer (by means of compressive strength and dynamic modulus), the construction of joints, the execution of loading tests on the slabs and measurement of longitudinal, transversal and vertical deflections by strain gauges and LVDTs. The study emphasizes the effectiveness of the maintenance technique. The UTW ensures a good bearing capacity to the pavement, thanks to high values of compressive strength and elastic modulus of the concrete, according to future traffic needs. Moreover, deflections are rather limited. Adequate functional properties (evenness, skid resistance) are also guaranteed.
2005
Proceedings
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/1426329
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