the stabilization process
The stabilization process requires the intimate mixing of the soil, cement/additive, and water to ensure a homogeneous mix. This is then compacted, and cured. Specialized machines (with pointed teeth/bits) are required for this job. Alternative mixing equipment such as motorgraders, farm-type rotavators, disc-harrows are not allowed as these do not provide intimate mixing. Poorly mixed soil cement will result in hard spots and weak spots which easily deteriorate with load applications.
our full service "rapid roads" process
soil analysis and determination of appropriate cement/cement blend
Soil samples from the site is analyzed as there are different soil types which need to be considered. The appropriate additive is then selected for the soil+cement mix blend. Various cement percentages are then tested in the laboratory to determine the optimum cement dosage for the design of the road. Optimum water content and compaction tests are also done to determine requirements for the project.
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Roads with stones/rocks bigger than 2" diameter will be difficult to stabilize. As such, preparatory crushing work is done prior to stabilization. As in most gravel roads, larger stones/rocks are not visible from the surface. Thus, it will be pointless to stabilize these roads without ensuring that the underlying material is fairly homogeneous. A stabilized road with large stones will be prone to early deterioration. Crushing/Stabilizing depth is usually 10cm - 30cm deep depending on design.
The process of road stabilization includes:
1. Spreading/Proportioning of Cement/Cement Blend.
2. Watering the area until near OMC (Optimum Moisture Content) is reached.
(Powdered additives are mixed with the cement. Liquid additives are mixed with water)
3. Dry Mixing and Wet Mixing of the soil, cement, additive and water using specialized equipment
4. Grading the road to ensure proper camber (to aid in water drainage)
5. Compacting the stabilized area typically to 98%.
Notice that there is no need to import gravel/aggregates. As such, there are no dump trucks and loaders operating. The associated costs (gravel and hauling), commuter traffic, construction time are significantly reduced. Generally, the cost of having a road stabilized is similar to that of a gravel road rehabilitation. Upkeep and maintenance costs are much, much lower for stabilized roads.
soil WATERPROOFING (oPTIONAL)
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anti-crack additives (optional)
For extra heavy duty stabilized roads, this specialist chemical additive is used to allow higher cement contents (up to 8%) to be incorporated without the cement stabilized road being susceptible to reflective cracking. This is particularly important since cement shrinks whilst curing. Small cracks occur if higher cement contents are required and permeate through the pavement structure specially if thinner pavement seals (such as chip seals) will be used as wearing surface.
CHIP SEALing (as a wearing course)
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Chip seals are the most economical road pavement available. It consists of a thin film of bitumen emulsion topped by small aggregates. Chip seals are widely used in western countries and is best applied when the underlying structure is fundamentally strong (e.g. stabilized roads). In New Zealand, of their 92,000 kms. of roads, 60,000 kms. are chipsealed. In Australia, of their 800,000 kms. of roads, 270,000 kms. are chip sealed. In the USA and in Europe, chip sealing is also by far, the most popular surface dressing used for roads. Chip seals provide surface protection, waterproofing, skid resistance and motorists driving comfort/protection.