Pavements are serviceable and durable surfaces designed specifically to stand up to the load of traffic passing over them. When developing land for occupancy, you need to create pavements for vehicles and pedestrians as well. The right type of pavement will last several years with little need for recurrent maintenance. Getting the right one means that you should only lay a pavement after you have carried out a geological survey on your site. The aim of the geological survey is to assess the various strata on your site and determine the type of pavements that you should go for. Important considerations taken into account include soil drainage and compaction requirements. The following discussion will help you understand the implications of geological surveys for rigid and flexible pavements:
Flexible pavements reflect the deformation of the underlying subgrade and other layers beneath it. In most cases, the pavements are made using asphalt laid irregularly. The asphalt can be reinforced using a special fabric to limit the flow or repositioning of the asphalt grains. The focus of this design is to take advantage of the load distributing ability of the layers that make up the pavement. Ideally, flexible pavements transmit compressive vertical force or stress to the lower layers of the pavement through the component asphalt grains. This means that they are ideal for sites where the subgrade and the layers beneath it are strong enough to stand up to the compression force transmitted from the top layers.
To add on that, they are only suitable for sites where the survey tests show that all layers (from the subgrade downwards) have good porosity because water clogged layers interfere with the transfer of the compressive force. This makes sandy soils the ideal choice for flexible pavements.
The most significant attribute of rigid pavements is their slab action or flexural strength in where the compressive force of the load is distributed over a large area of the surface and the subgrade. The soil layers beneath the subgrade are primarily meant for providing support to the top layer and the subgrade. This is unlike flexible pavements where the compressive force of the load is transmitted directly to the lower layers.
For optimal support, rigid pavements are ideal for sites with clay and loamy soil that require minimum compaction. However, the natural water retention capacity of these soils means that you have to provide alternative drainage alternatives such as stormwater pits.