GAP65 aggregate can be placed in layers from 160 mm to 300 mm thickness. Aggregate layers should be placed in a thickness that is not less than 2.5 times the maximum size of the aggregate, but generally not greater than 300 mm thickness in a single layer. Volume = Length x Width x Thickness x Compaction factor (typically 1.3 to 1.5) – About 12 m3
Shallow foundations must be designed for the load combinations given in AS/NZS 1170 Structural design actions, as amended by Verification Method B1/VM1. Continuous perimeter foundation.
Load – 17-20Kg/m2 of wall and 12Kg/m2 of roof (Distributed load).
Nib wall/Ring beam 225mm above ground level (NZS 3604) (Interior – 20mm Kopine floor, 35mm Expol, 10mm sand, 100mm basecourse. 65mm x 450mm wide Expol for perimeter (See diagram).
250 micron (0.25mm) thick polyethylene sheet, taped joints
500 micron (0.50mm) thick polyethylene sheet, taped joints
Use Ditra membrane under wet / tiled areas (Waterproof layer on Kopine then Ditra).
What are Roadbases?
Roadbases are quarry materials which are used in the construction of road pavements. They are made up of a combination of coarse and fine crushed materials which, when placed and compacted at the correct moisture, form a rigid layer.
Why Supply Roadbase Materials Moist?
By adding water at the quarry, the moisture penetrates throughout the roadbase material producing a cohesive product when in transit to a site. This reduces the risk of the roadbase material segregating, ie the finer material separating from
the coarse particles.
Roadbase Density/Moisture Relationship
It is the interaction of the coarse and fine particles which determines how efficiently the roadbase materials bind together after placement and compaction. Roadbase materials bind together by a combination of aggregate interlock and the plasticity of the fine materials. This binding behaviour is crucial to the roadbase performance and this occurs more readily at what is called the Optimum Moisture Content (OMC) of the roadbase material. The OMC for a roadbase is the quantity of moisture within the material which, under the application of a standard compactive effort, provides the maximum dry density that the material can achieve.
If water is added beyond the optimum moisture content, the water will occupy the extra space since there is no air volume and dry density will reduce.
