CHAPTER 5 CONCRETE PAVEMENTS - TU Delft

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Figure 5.13: Flow diagram of the VNC design procedure for plain concrete pavements (2). 179
Axle load group (kN) Wheel load group (kN) Frequency distribution (%) Light traffic Medium traffic Heavy traffic 0-20 0-10 7.60 5.40 4.00 20-40 10-20 25.00 22.00 15.00 40-60 20-30 30.00 29.00 26.00 60-80 30-40 18.00 20.00 27.00 80-100 40-50 11.00 12.00 14.00 100-120 50-60 6.10 7.70 8.40 120-140 60-70 1.80 3.00 4.40 140-160 70-80 0.41 0.75 1.00 160-180 80-90 0.07 0.10 0.12 >180 >90 0.02 0.05 0.08 Table 5.4: Representative axle/wheel-load distributions of trucks on Dutch motorways (3). 5.4.3 Temperature gradients: The VNC design method includes a standard frequency distribution for the (positive) temperature gradients within the concrete pavement. This distribution (table 5.5) can be used in the design of plain concrete pavements for roads, bus bays etc. On heavily loaded airports and industrial yards the temperature gradients will be somewhat smaller because of the thicker concrete slabs. Temperature gradient ∆t (°C/mm) 0.00 0.01 0.02 0.03 0.04 0.05 ≥ 0.06 Frequency distribution (%) 71 17 6 3 2 1 0 Table 5.5: Standard temperature gradient frequency distribution according to the VNC method (2). 5.4.4 Strength criterion: In the two possibly critical locations of the concrete slab (VR and ZR, see figure 5.12) the temperature gradient stress σti has to be calculated for every positive temperature gradient ∆ti according to the procedure described in paragraph 5.3.3. Also in the locations VR and ZR the traffic load stress σvi has to be calculated for every wheel load Pi by means of the appropriate Westergaard equation (eq. 5.5 or 5.6), taking into account the load transfer (if any) at the slab edge under consideration (joint efficiency W ’ , eq. 5.11). 180
Page 1 and 2: CHAPTER 5 CONCRETE PAVEMENTS 160
Page 3 and 4: esistance to erosion) is applied to
Page 5 and 6: 2. Not preventing the adhesion betw
Page 7 and 8: (‘wild’) cracking, due to the c
Page 9 and 10: 5.3 Stresses and displacements in p
Page 11 and 12: Example Sand subgrade: ko = 0.045 N
Page 13 and 14: 1. positive temperature gradients m
Page 15 and 16: where: σ = flexural tensile stress
Page 17 and 18: The equations 5.5 and 5.6 and figur
Page 19: Figure 5.12: Design model for plain
Page 23 and 24: where: wl = deflection (mm) of the

CHAPTER 5 CONCRETE PAVEMENTS - TU Delft

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