Pavements

• Description of the existing ground conditions (soils, rock, etc.)
 
• Comments about site preparation
 
• Modulus of sub-grade reaction and/CBR
 
• Long and short term design parameters
 
• Comments on reactivity - especially relevant for clayey soils
 
• Recommendations for controlling short (during construction) and long term (in service) moisture content
 
• Recommendations for fill control

Geotechnical engineering services during construction should include:

• Compaction testing for each layer of fill. Usually minimum one test per 2000m²
 
• Final report including test results confirming the sub-grade meets the design parameters

• Familiar analytical tools are used:
 
• Traditional elastic methods, for example, Meyerhof, Westergaard, etc.
 
• There are several design aids (computer programs) provided by suppliers of steel fibre
 
• Finite element elastic/plastic modelling has provided consistent and reliable results for internal forces
 
• Design tools should recognise the pavement and underlying ground work together to provide a working surface
 
• Designers should provide careful guidance for the pavement construction. A good understanding of construction methodology, concrete technology and geotechnical engineering is necessary.
 
• Contractors should actively seek to understand the system being implemented and work closely with the designer
 
• Soft areas are to be removed and reworked or replaced
 
• The sub-base should be minimum 30 mm thick. A thicker sub-base is needed on poor ground, possibly with cement added or made from recycled concrete
 
• Sub-base should match the slab profile to within 10 mm
 
• A pavement perimeter cut-off wall, 600 mm to 1500 mm deep mass concrete, is sometimes needed to control moisture content in reactive soils

Projects