Bulk filling materials
The term ‘fill’ refers to material used to artificially raise existing ground levels. Bulk filling materials typically include soil, rocks and aggregates and coal ash.
Soil is used for example, for the formation of embankments and other areas of landscape that require fill. It is common to 'cut' soil from the high points of a site and place it in layers in lower areas, in a process known as 'cut and fill'. For more information see Cut and fill.
The soil used for bulk filling must be suitable to remain stable in the long-term. Examples of unsuitable soil material for filling includes:
- Soil from swamps, bogs and marshes.
- Perishable material such as peat, logs and stumps.
- Frozen materials.
- Materials having a liquid limit exceeding 80 and/or a plasticity index exceeding 50.
See also: Types of soil.
Rock fill consists of hard material of a suitable size for compaction and may include crushed stone, hard brick, concrete or other hard inert material. For more information, see Aggregate.
Coal ash is a material obtained from coal-fired power stations. For more information, see Coal ash.
Cellular Concrete (Foamed Concrete) has the advantages that it does not require compaction, does settle over time and it can be re-excavated at a later date if necessary. Large amounts can be placed quickly through small openings, so it is often used for emergency void filling, for example, following the appearance of sink holes or an underground tunnel collapse.
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