CHAPTER 6 SMALL ELEMENT PAVEMENTS - TU Delft

It should be realised that the design graphs, shown in figure 6.16 and figure 6.17, donot take into account the frost penetration depth criterion. In the case of a frostsusceptiblesubgrade the total thickness of the pavement structure (concrete blocktoplayer + bedding sand layer + unbound base (if any) + sand sub-base) should be atleast about 0.7 m (western parts of The Netherlands) and about 1.0 m (northern andeastern parts of The Netherlands) respectively to prevent frost- and thaw-damage.6.4.5.3 Design examples:To illustrate the use of the design graphs, presented in the proceeding paragraph, intable 6.6 some design examples are given, i.e. for N=4*10 4 (lightly loaded pavement,for instance a residential street) and for N= 2.5*10 6 (heavily loaded pavement, forinstance road in industrial area). In the examples it is assumed that the total thicknessof the unbound base and the sand sub-base should be minimal (to limit theconstruction costs).Subgrade modulus E 0 (N/mm 2 ) 40Design traffic loading N 4*10 4 2.5*10 6Pavement structure S CCS CBS S 2) CCS CBS 2)Concrete paving blocks (m) 0.08 0.08 0.08 - 0.08 -Bedding layer, crushed sand (m) 0.05 0.05 - 0.05 -Base, concrete granulate (m) - 0.10 4) - 0.30 -Base, mix granulate (m) - - - - -Sand sub-base 0.90 0.40 5) - 1.10 -Subgrade modulus E 0 (N/mm 2 ) 140Design traffic loading N 4*10 4 2.5*10 6Pavement structure S CCS CBS S 3) CCS CBSConcrete paving blocks (m) 0.08 0.08 0.08 - 0.08 0.08Bedding layer, crushed sand (m) 0.05 0.05 0.05 - 0.05 0.05Base, concrete granulate (m) - 0.10 4) - - 0.13 -Base, mix granulate (m) - - 0.10 - - 0.15 4)Sand sub-base 0 0 0 0 0 01)S = sand sub-base onlyCCS = concrete granulate base and sand sub-baseCBS = mix granulate base and sand sub-base2)This pavement structure is not possible for the combination of E 0 = 40 N/mm 2 and N = 2.5*10 63)This pavement structure is not possible for the combination of E 0 = 140 N/mm 2 and N = 2.5*10 64)This base thickness is a theoretical thickness; in practice the thickness of the unbound basematerial, mostly having a grading 0/40 mm, normally is 250 or 300 mm, which results in an overdesignedpavement structure5)The sand sub-base thickness should be greater than 0.40 m tot prevent frost- and thaw-damageTable 6.6: Design examples for concrete block road pavements on a subgrade with adynamic modulus of elasticity E 0 = 40 N/mm 2 and E 0 = 140 N/mm 2respectivily.205