Construction methods for external paving
Traditional construction methods for external paving can lead to slower rates of progress and as a result the construction of the paving may be on the ‘critical path’ of the construction programme. There is thus a need to significantly improve the construction productivity of external concrete paving, by developing simple uncomplicated and ‘buildable’ designs and by carefully rethinking the construction process.
In the past, external paving was often the last major item to be constructed. However, it is now usually necessary to start the construction of the paving early in the construction programme. This has distinct advantages; the completed paving provides a good running surface for construction traffic, and for cranes and access equipment working on the adjacent structure. The paving can also be used as a platform for storing construction materials under relatively clean conditions and with easy access. However, the loading should be monitored to make sure that it does not exceed the design capacity of the slab. The paving should not be constructed until all of the service runs beneath the pavement are in place. Alternatively, service corridors could be left for later infill.
Currently relatively few areas of industrial paving at warehouse and retail developments are constructed using mechanised methods, and generally manual construction methods are used, although the use of mechanised methods of construction is increasing. This is different from the situation of concrete pavements for highways and airports, where mechanised construction is very common. An increase in the use of mechanised construction is required to increase production rates and productivity. When mechanised methods are being used, best economy results if the whole area is made available at one time. There are additional advantages if the drainage and service manholes lie outside the paved area.
Laser Screed techniques, which have been successfully used for internal industrial ground floors for many years, are being used for external paving. More compact equipment is now available which makes its use feasible for smaller projects than was previously the case. As a general guide, Laser Screed construction becomes economic for pour areas above 1,000 to 1,500m2.
Roller-compacted concrete (RCC) can be used for industrial paving. RCC is a zero slump concrete, placed by a modified asphalt paving machine, and compacted using conventional vibrating rollers. The method becomes economic for areas greater than about 5,000m2.