Page 228 - RoadCem Manual - PCT BV
P. 228

1. Introduction
This appendix gives a relative comparison of pavement structure designed using a traditional pavement structure design approach with a pavement structure designed using the RoadCem pavement structure design. The given pavement structures are intended to have equivalent performance with the RoadCem based structure typically requiring less maintenance than the traditionally designed pavement structure.
The examples given are for different soil types and different traffic loads and traffic intensity conditions.
Section 2 of the appendix summariswes the basic design criteria used for all the cases. Section 3 refers to a comparison for unbound (crushed concrete) and bound (BRAC) material and a RoadCem based solution for the case of clay soil, with a bearing capacity of 50 MPa. Section 4 refers to a comparison cases where sandy soils are present. Section 5 refers for heavy duty situations such as exist in harbour terminals.
2. Design Criteria
Before the comparison is made between a traditional construction and a PowerCem method it is necessary to determine the design criteria. The design criteria used for the examples given in this appendix are summarised below:
• Bearing strength of the sub-base- the dynamic elasticity modulus, for pavement structures on clay soils the design bearing capacity is 50 MPa, and pavement structures on sandy soils the design bearing capacity is 100 MPa.
• Groundwater level is more than 1 meter below the surface of the pavement.
• Soil structure is homogenous
• Capillarity of the soil and settling behaviour is taken into account for the clay soils.
• Behaviour of the frost/thaw cycle – the examples given assume no frost heave action occurs. In cases where this is not the case additional analysis is needed.
• Maximum load expected on the pavement is the axle load of 100 kN for the roads and for the heavy duty pavement( port terminals) the maximum axle load is 275 kN.
• Axle load configuration(s) of the different vehicles -For the roads and heavy duty pavements four standard wheels are assumed. For the roads it is assumed that the vehicles are double single wheel configurations and for the heavy duty pavements a reach stacker configuration is used.
• Number of axle load repetitions per load are given in the relevant tables.
• Structural lifespan of the pavement is 20 years.
• Tire pressure of the vehicles is 1000 kPa.
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