CT4860 STRUCTURAL DESIGN OF PAVEMENTS

Concrete quality
Property C28/35 C35/45 C45/55
(B35) (B45) (B55)
Characteristic* cube compressive strength
after 28 days for loading of short duration,
fcc,k,o (N/mm 2 )
35 45 55
Mean cube compressive strength after 28 days
for loading of short duration,
fcc,m,o (N/mm 2 )
43 53 63
Mean tensile strength after 28 days for loading
of short duration
fct,d,o (N/mm 2 )
Mean flexural tensile strength after 28 days for
loading of short duration, fct,fl,o (N/mm
3.47 4.01 4.55
2 ):
concrete thickness h = 180 mm
4.92 5.69 6.46
h = 210 mm
4.82 5.57 6.32
h = 240 mm
4.71 5.45 6.19
h = 270 mm
4.61 5.33 6.05
Young’s modulus of elasticity, Ec (N/mm 2 ) 31000 33500 36000
Density (kg/m 3 ) 2300 - 2400
Poisson’s ratio ν 0.15 – 0.20
Coefficient of linear thermal expansion α (°C -1 ) 1·10 -5 – 1.2·10 -5
* 95% probability of exceeding
Table 3. Mechanical properties of (Dutch) cement concrete for concrete
pavement structures.
2.5.2 Reinforced concrete
Just after construction the reinforced concrete pavement is a long continuous
strip in the longitudinal direction of the road (in the transverse direction the
dimension of the pavement is limited to maximum 5 m through the
construction of longitudinal joints). As a result of shrinkage of the concrete,
during the hardening process and due to temperature decreases during or
after the hardening process, longitudinal tensile forces develop in the concrete
layer because of the friction with the underlying base layer. The primary goal
of the (longitudinal) reinforcement in continuously reinforced concrete
pavements is to control the crack pattern that develops due to the tensile
forces. The longitudinal reinforcement should lead to a crack pattern of fine
transverse cracks at mutual distances of 1.5 to 3 m.
The reinforcement is located in, or just above, the middle of the concrete
layer. It thus is not a structural reinforcement but only a shrinkage
reinforcement. In an indirect way the reinforcement however contributes to the
strength of the pavement as the fine cracks result in a high load transfer (see
3.4.3).
The design of the reinforcement is explained in chapter 5 (i.e. section 5.4.10)
where the current Dutch design method for concrete pavements (5) is
discussed.
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