A range of demolition methods are fully described in the Proceedings of the Second International RILEM Symposium Volume 1: Demolition Methods and Practice, 1988. However, for the purposes of waste minimisation, recycling and reuse it is only necessary to discuss the two extreme cases, namely wholesale demolition by various methods, and dismantling, since these represent the "worst" and "best" scenarios respectively, with regard to beneficial reuse and recycling of the materials.
Commercial pressures often demand the adoption of demolition methods and plant and equipment which effect the removal in the minimum time. Demolition methods which suit this imperative include:
Although these methods are not conducive to the reuse of materials, they are relevant to recycling. Figures 5.1 to 5.3 show the demolition of Poole Power Station, Dorset, using explosives.
Figure 5.1 The demolition of Poole Power Station, Dorset using explosives Dismantling
Where these methods are used architectural salvage of materials in building structures is possible and is widely practised throughout the UK. Figure 5.4 outlines the various scenarios for demolition waste management, which from the outset, clearly depend upon whether the demolition method has been selective or non-selective. It excludes the dismantling option.
Many of the same issues relating to demolition apply equally to refurbishment, in that for buildings it is largely a process of partial dismantling and demolition followed by new construction and fitting out within the structure. In roads and civil engineering the equivalent would be periodic maintenance and perhaps upgrading where the essential features of the scheme were retained but new surfacing, strengthening and maybe widening introduced.
There are two opportunities in refurbishment which are not available in demolition. First the reuse of materials and elements in the same structure or piece of infrastructure can minimise the quantities of new materials required. This relates closely to the process of design of refurbishment. It can be simpler to remove more rather than less from a building to achieve the same end result.
Figure 5.2 Demolition debris to be recovered and sorted at Poole Power Station after the explosions
Indeed demolition and new construction may be chosen as opposed refurbishment to avoid the uncertainties of the latter and the compromises associated with the plan arrangement of an existing building.
The second opportunity is to minimise the amount of material which is demolished or dismantled and removed from site. Through such processes as relocating and in-situ treatment it may be possible to minimise the amount of material generated as waste.
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