Challenges confronting road freight transport and the use of vehicle-pavement interaction analysis in addressing these challenges

Traditional arguments for maintaining riding quality of pavement are expanded in this paper to examine the effects of deteriorating riding quality on vehicle operating costs, freight damage and logistics. The objectives of this paper are to analyse the effects of different levels of riding quality on a truck and its freight, and to discuss potential applications of the analysis in terms of effectiveness of the freight transport system. The paper discusses needs and drivers influencing freight transport costs, vehicle-pavement interaction concepts, and the potential physical effects and costs from roads with deteriorating riding quality. A case study is presented analysing vehicle-pavement interaction for selected roadways in California. It is concluded that investments in pavement and freight transport industry improvements can be investigated by applying vehicle-pavement interaction analysis to evaluate damage to pavement, vehicle and freight that would result from alternative levels of pavement riding quality. The paper recommends that existing concepts, tools and resources such as dedicated truck lanes and vehicle-pavement interaction analysis can help to improve the freight transport system. A framework is proposed to better understand the scale of potential impacts of riding quality from localised effects to larger-scale influences, including costs to customers and global competitiveness.Caltranshttp://www.journals.co.za/ej/ejour_civileng.htm

Time dependent viscoelastic rheological response of pure, modified and synthetic bituminous binders

Bitumen is a viscoelastic material that exhibits both elastic and viscous components of response and displays both a temperature and time dependent relationship between applied stresses and resultant strains. In addition, as bitumen is responsible for the viscoelastic behaviour of all bituminous materials, it plays a dominant role in defining many of the aspects of asphalt road performance, such as strength and stiffness, permanent deformation and cracking. Although conventional bituminous materials perform satisfactorily in most highway pavement applications, there are situations that require the modification of the binder to enhance the properties of existing asphalt material. The best known form of modification is by means of polymer modification, traditionally used to improve the temperature and time susceptibility of bitumen. Tyre rubber modification is another form using recycled crumb tyre rubber to alter the properties of conventional bitumen. In addition, alternative binders (synthetic polymeric binders as well as renewable, environmental-friendly bio-binders) have entered the bitumen market over the last few years due to concerns over the continued availability of bitumen from current crudes and refinery processes. This paper provides a detailed rheological assessment, under both temperature and time regimes, of a range of conventional, modified and alternative binders in terms of the materials dynamic (oscillatory) viscoelastic response. The rheological results show the improved viscoelastic properties of polymer- and rubber-modified binders in terms of increased complex shear modulus and elastic response, particularly at high temperatures and low frequencies. The synthetic binders were found to demonstrate complex rheological behaviour relative to that seen for conventional bituminous binders

Mechanistic model for transition probabilities

Journal of Transportation Engineering1201144-159JTPE

Performance-Based Pay Factors for Asphalt Concrete Construction: Comparison with a Currently Used Experience-Based Approach

Document summarizes a procedure to establish pay factors for asphalt concrete pavement construction using performance models for fatigue and rutting based on the analysis of accelerated pavement tests from the Caltrans Heavy Vehicle Simulator (HVS) and the WesTrack accelerated pavement performance test program. Results of the performance-based approach are compared with pay factors determined by the current Caltrans procedure using percent defective and experience-based weighting factors

Dynamic decision model for pavement management using mechanistic pavement performance submodel

Transportation Research Record139715-24TRRE

Stochastic model for pavement design

Journal of Transportation Engineering1186769-786JTPE

Truck Pavement Interactions: Requisite Research

A framework for consideration of the effects of dynamic loads on pavement performance is presented. The paper discusses requisite research which will permit both the pavement engineer and the truck designer to effectively utilize such a framework to arrive at optimal solutions which will result in overall savings to the agencies responsible for design, construction, maintenance, and rehabilitation of pavement facilities and to the users of the facilities as well.Included is a discussion of needed research to evaluate: the dynamic response of jointed portland cement concrete pavements to load, the influence of dynamic loads on the development of rutting in asphalt concrete pavements, and the development of new suspension concepts to reduce dynamic load variations with pavement roughness.Also included are recommendations for field measurement procedures to truly identify dynamic load spectra, methods to identify pavement profiles to reflect the effects of such profiles on truck suspension performance, and measurements to evaluate the methodology developed within the proposed framework

Truck Pavement Interactions: Requisite Research

A framework for consideration of the effects of dynamic loads on pavement performance is presented. The paper discusses requisite research which will permit both the pavement engineer and the truck designer to effectively utilize such a framework to arrive at optimal solutions which will result in overall savings to the agencies responsible for design, construction, maintenance, and rehabilitation of pavement facilities and to the users of the facilities as well.Included is a discussion of needed research to evaluate: the dynamic response of jointed portland cement concrete pavements to load, the influence of dynamic loads on the development of rutting in asphalt concrete pavements, and the development of new suspension concepts to reduce dynamic load variations with pavement roughness.Also included are recommendations for field measurement procedures to truly identify dynamic load spectra, methods to identify pavement profiles to reflect the effects of such profiles on truck suspension performance, and measurements to evaluate the methodology developed within the proposed framework