The Consolid System
The products developed for use in pavement construction are Consolid 444 and Solidry. They are normally used in combination (The Consolid System) by applying Consolid 444 to the total layer thickness (150 to 300 mm) and Solidry only additionally in the top 50 to 100mm. The Consolid System is a dual one, where both additives have their special jobs. Consolid controlling the capillary rise of water and Solidry controlling the influence of surface water.
The Consolid System was developed in the late 60's and Solidry completed the System in the early 1980's. Since then the Consolid System has been used and tested with time and traffic world wide and many products have been on the market and disappeared again. The Consolid System solves stability problems permanently in an environmentally friendly way due to the very small quantities of the additive required and the way it reacts with the soil, locking into the soil particles. It also allows the use of otherwise useless soils and quarry waste as construction material.
Consolid444 is a chemical product which reduces the interfacial tension of the water around the soil particles so that the barrier film surrounding the particles is dispersed in order for the surfaces of the particles to associate to each other. This causes an irreversible agglomeration of the fines. C444 is not a binding compound, but improves certain soil characteristics through the permanent change towards petrification. Consolid 444 is moderately acidic (ph = 6) has an ammonia odour. The process is permanent and irreversible once dried. The material (soil) treated with Consolid 444 has the following properties compared to untreated material:
- Reduced resistance to compaction due to loss of pore water
- Reduced rising capillary water
- Reduced permeability
- The optimum moisture content is lower and the density is higher for treated material. In such cases where density and optimum moisture content are the same as in the untreated material it has shown that the voids in the treated material have increased density due to the agglomerating effect of Consolid 444.
- Continued process of the agglomeration of fines with time
- Reduced water sensitivity (higher water resistance)
- Larger increase in dry density by after-compaction, even if compacted at a high moisture content.
- Lower penetration (better waterproofing)
- Reduced plasticity and swell.
Consolid 444 is mixed with water (To create the required Optimum moisture content and applied at a rate of 0.4 to 0.8 litres/m 3 (1-2% by weight). The pavement layer is normally mixed to a depth of 150 to 300mm. Larger quantities of Consolid 444 are not harmful. The mechanism of stabilisation is basically the formation of a tight, highly dense packing of the treated soil. Higher strengths are achieved by keeping the soil dry.
Solidry has similar active ingredients as Consolid 444. The ingredients have a synergetic effect. Solidry is applied to the top 50-100mm of the road or pavement that has been pre-treated with Consolid 444. Solidry is a dry powder product and is applied at a rate of 1 - 2% by weight of soil.
The cost of the Consolid System depends on the application rates (which depends on the soil type and missing fractions). In respect of cost comparison it is mis-leading to compare the costs of the Consolid System with treatments of cement/lime or bitumen, since the later treatments do not permanently change the soil and therefore comparisons are not the same.
Our findings state that the costs of a treated soil with Consolid additives provides substantial savings (as opposed to conventional construction of the same road) due to the fact that a much higher portion of in-situ soil can be used and that the wearing course can be reduced, contributing to major overall savings. These savings using the Consolid Road System have shown cost savings of 20% plus. The construction costs are similar to those of conventional treatments (e.g. cement, bitumen) except that curing is normally not required.
Environmentally Ground Stabilisation Ltd