The application of lime to improve soils can deliver significant benefits to ground engineering aspects of civil engineering and building projects alike. Lhoist has developed Proviacal® products for this market.

Lime reacts with water and clays in the soils to effect physical and chemical changes that improve the characteristics of the soils for handling and engineering purposes. The modified soils can be used as part of the construction. The benefits that the drying action of lime on soils can also deliver on construction sites include the improvement of site efficiency and working conditions.

The development of improved engineering characteristics for lime modified soils can be used to provide highway substructures, replacing imported aggregates and can also reduce the required thicknesses of coated roadstone products in the highway design, thus delivering programme and cost benefits. The existence of the aggregate levy and the increasing restrictions on aggregates extraction also play their part in promoting the use of on site resources, including the existing soils.

In practice the modification of soils in situ on site can deliver environmental benefits as well as cost and programme savings. By reducing the quantities of imported aggregate materials required and the removal of unwanted soils off site this can significantly reduce the number of lorry movements for a construction project. Reductions of over 90% have been achieved.

Other applications of lime based soils modification include railway and highway embankments, surface car parking, sports areas, distribution goods yards and many more. Where temporary working platforms are required for piling rigs or cranes, soil modification using lime can deliver cost effective solutions.

Lime modification of soils can also be carried out at significant depths to provide foundation and ground stabilisation by deep mixing. Where soils characteristics and depths are suitable, deep mixing of soils with lime in combination with other binders can provide bearing capacities to support multi storey buildings and major infrastructure elements.

Laboratory analysis, experienced assessment and binder design, as well as field trials and compliance testing are always required for treating soils. Where soils conditions require, lime is used in combination with other binders to deliver even more significant modification actions, both physical and chemical. Sulphide or sulphate bearing soils can also be successfully modified when professionally assessed and treated.