Lime Stabilisation
The site compound was due to be located in an area at the bottom of a farmer’s field which was prone to lying wet and the designer had allowed for 400mm of crushed concrete and MOT Type 1 to be used to build up the area.
Having had previous experience of using lime stabilisation techniques, we proposed this process to replace the need for imported granular sub-base. We were able to offer significant benefits using this method, such as:
- Reduce the environmental impact due to fewer lorry movements
- Programme improvements
- Reduction in waste generation.
- Reduce costs in terms of aggregate and landfill taxes
A simplistic description of the operation and its environmental benefits is as follows:
When lime is rotovated into most subsoils, the effect can be compared with that of cement when mixed with aggregate to form concrete. The hardness and durability of both is controlled by the amount of lime/cement added and the amount of water present or added.
Unlike concrete, when areas of lime stabilised soils are required to be returned to agricultural use this can be achieved by rotovation using suitable equipment, and occasionally the addition of specific fertilisers to achieve the original pH value of the soil, where necessary.
The process requires special plant and equipment in addition to conventional earthmoving plant, but the overriding benefit is the saving in vehicular movements to achieve the same result as conventional granular sub-base construction.
By incorporating this process we were able not just to save the Client money, but also to reduce the environmental impact of the project by eliminating over 200 lorry movements.
Crushing Concrete on Site
The redundant sludge beds on site and the concrete access road were scheduled to be broken out and the surplus material hauled off site.
We proposed that by re-programming our work to focus our own resource in other areas of the site, we could crush the concrete on site and re-use it as engineering fill and sub base the road reconstruction. Once again we were able to make savings in terms of vehicle movements (100+ HGV deliveries / disposal of surplus materials), programme improvements, reductions in waste generation and of course procurement of virgin materials.
