COST 334

Chapter 44.5.9.2 Numerical modelTable 4.32 shows the load characteristics (tyre contact area and contact pressure) that wereused in CREEPN.Table 4.32 – Load characteristics for LNEC calculations (based on Penant 1999)Tyre code Axle load(tonne)Inflationpressure(bar)Width(mm)Length(mm)Contactstress(kPa)Ratiocontact/inflation(%)295/60R22.5 9.0 8 259 170 501.1 63.9295/60R22.5 11.5 10 259 174 625.6 63.8295/80R22.5 9.0 7 244 194 466.1 67.9315/80R22.5 9.0 6.5 255 185 467.7 73.4315/80R22.5 11.5 8 255 193 572.9 73.0385/65R22.5 9.0 10 283 201 775.8 79.1495/45R22.5 9.0 8 428 176 585.8 74.7495/45R22.5 11.5 10 428 180 731.9 74.6Four pavement structures were modelled, as shown in Figure 4.52. Thicknesses andmaterial characteristics conform to Table 4.6. A Poisson ratio of 0.35 was used for thegranular layers and the foundation, and a viscosity of 3000 MPas for the Burgers’ serialdamper in the characterisation of the asphaltic layers. Each simulation (combination ofload and structure) was done for one pass of the load at a speed of 13.89 m/s (50 km/h).Structure 1Structure 2Structure 3Structure 4100300Asphalt layerGranular layerFoundation200250Asphalt layerGranular layerFoundation330200Asphalt layerGranular layerFoundation280200Asphalt layerCement bound baseFoundationFigure 4.52 - Pavement structures modelled in CREEPNFigure 4.53 – Finite element mesh used in CREEPNversion 29 November 200195