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Hartman, Anton M.
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Hartman, Anton M.
Official Name
Hartman, Anton M.
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Now showing 1 - 6 of 6
- PublicationFull scale accelerated testing of bituminous road pavement mixturesThe in-service behaviour of a standard Irish Dense Base Coarse Macadam mixture (DBC) was evaluated by using the material to overlay a road section, which was based upon a weak pavement structure. The response of the layer under a fully laden dual axle truck was examined using a series of pressure cells and asphalt strain gauges that were embedded in the test section. The section was traversed repeatedly until a network of fatigue cracks was observed on the road surface. The transverse horizontal tensile strain was found to be the most critical parameter in initiating pavement damage
450 - PublicationIn-situ Accelerated Testing of Bituminous Mixtures(Informa UK (Taylor & Francis), 2001-12-15)
; ; ; The in-service behaviour of a standard Irish Dense Base Coarse Macadam mixture (DBC) was evaluated by using the material to overlay a road section, which was based upon a weak pavement structure. The response of the layer under a fully laden dual axle truck was examined using a series of pressure cells and asphalt strain gauges that were embedded in the test section. The section was traversed repeatedly until a network of fatigue cracks was observed on the road surface. The transverse horizontal tensile strain was found to be the most critical parameter with respect to crack initiation. When based on in-situ measured strain data, the analytical model that was developed to predict pavement performance on the basis of fundamental laboratory test data, was found to underestimate the in-service fatigue life of the DBC mixture by a factor of 13.5. The underestimation may be attributed to factors that are not accounted for in the analytical models such as material healing, traffic wander and in-situ environmental , which possibly lead to lower fatigue estimates.499 - PublicationMechanical Test Procedures for Bituminous MixturesIn recent years the increasing traffic volumes on the world’s highways have indicated shortcomings in the existing empirical procedures that are used to assess road building materials. As a result, new fundamental performance based test procedures have been developed that are currently being considered for acceptance in defining material specification codes of practise. In Ireland, to date, it has only been possible to observe and monitor these developments. The procedures will shortly be introduced by the Central European Standards Organisation (CEN) and will affect Irish material suppliers, design engineers in local authorities and consulting engineers.
160 - PublicationMinimizing Distress on Flexible Pavements Using Variable Tire Pressure(American Society of Civil Engineers, 2001-06)
; ; ; The potential of variable tire pressure technology to minimize distress on flexible pavements with thin asphalt surfacing layers and peat soil subgrade was evaluated using in-situ stress-strain data. Pavement interfacial strains and corresponding subgrade stresses imposed by a three-axle truck were measured and used to estimate the fatigue life of the surfacing layer. Three levels of truck wheel loads in combination with four tire inflation pressures (350, 490, 630, and 770 kPa) were used to evaluate the potential distress by the single steering wheel and rear dual wheels in tandem. Results suggest that lateral strain due to the single steering wheel is the most critical to fatigue failure, which is influenced by the viscoelastic nature of asphalt, and therefore truck speed and axle configuration are important. Lower tire pressures increased the fatigue life of the surfacing layer with respect to the rear dual wheels and the steering wheel by up to 200 and 300%, respectively. Haulage trucks with systems for managing variable tire pressure such as the central tire inflation systems may therefore enhance the serviceability of pavements overlying peat or other soft soil foundations.884Scopus© Citations 51 - PublicationExperimental Facility for Simulating the Initiation and Propagation of Fatigue Damage in Bituminous Road Paving MaterialsAn exoerimental simulation facility was designed and constructed for the purpose of investigating the initiation and development of fatigue damage in bituminour road paving material. The design of the test facility was based upon a cicular wheel track which incorporated four pavement monitoring stations. Hot Rollede Asphalt specimens were manufactured and prepared for testing in order to verify the operation of this experimental facility. The variation of strains, deformations, and the distribution of pavement damage, in the form of cracking, were monitored digitally with increasing cycles of fatigue loading. Failure of pavement specimen due to local tensile strains, propogated through the complete thickness of the specimen and became apparent on the top surface.
320 - PublicationEvaluating Four-Point Bend Fatigue of Asphalt Mix Using Image AnalysisOne of the primary structural distress modes found in bituminous pavement layers is fatigue cracking, resulting from repeated application of traffic-induced stresses. The development of a four-point bending test arrangement to determine the dynamic mechanical properties of rectangular beam specimens (305×45×50mm dimensions) of bituminous mixtures is discussed. This novel system allows the crack-damaged surfaces of beam specimens to be inspected and monitored digitally in situ during fatigue tests. The test fixture, which was integrated with a closed-loop servo hydraulic feedback system, incorporates a constant clamping mechanism and uses a combined displacement and loading mode of control. A series of four-point bending fatigue tests were performed on specimens of two standard Irish mixtures: a hot rolled asphalt and dense base course macadam. The digitally imaged information on fatigue cracking was used to measure the extent of damage and to characterize a linear elastic fracture mechanics model.
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