Civil Engineering

Civil Engineering

Lime improves the workability and mechanical performance of soil for rail tracks, roads, highways, hydraulic works, airports and industrial platforms. Hydrated lime contributes to the durability of all asphalt structures, like roads, highways, walkways, etc.

Lime for soil treatment in earth works

Improvement

In the presence of water, quicklime spontaneously hydrates to form calcium hydroxide. The heat released during this reaction rapidly dries out damp soil. Lime also dissolves the clay particles in the soil into their component parts and forms pozzolanic cements by combining calcium with the silica and alumina from clays. 

Our quicklime products provide long-lasting improvements to soil’s mechanical performance, improving resistance to traffic and adverse weather conditions. It supports effective on-site usage so you can construct embankments, platforms and pavement layers for roads, railway tracks, airports, warehouses, etc. using local soils at low financial and environmental cost.

Stabilization

By adding the appropriate quantity of lime to soils which are suitable for lime stabilization, the engineering properties of these soils can be improved. Soils from temperate to tropical regions (including lean to fat clays, lateritic to non-lateritic classifications) can be stabilized permanently using lime.  

The improved engineering properties include:

  • reduced shrink – swell (volume change) potential
  • increased compressive, tensile and flexural strength
  • increased stiffness (resilient modulus).

These enhancements improve the performance of the lime-treated layers in the pavement system. The stronger, stiffer and more volumetrically stable lime treated subgrade, subbase or base layers provide protection for weak and deformation-susceptible natural subgrades. The result is better support for unbound aggregate bases and asphalt surfaces, which enhances their performance.

Our lime products:

  • reduce the extraction of primary aggregates
  • eliminate disposal of excavated soils
  • decrease work site traffic by up to 95%, saving the local road network
  • reduce construction time and cost.

With our very low dust emission quicklime, soil in urban areas can be more easily treated. To deal with clay soil in dry climate conditions, we have also developed products in liquid form.

Quicklime improves soft soils in the deep soil stabilization process (lime-treated columns), reducing settling and increasing stability.

Hydraulic road binders

Lime valorizes and speeds up the reaction of puzzolanic raw materials (fly ash, cement, slags, etc.). Hydraulic road binders composed of a significant amount of lime are used for a wide range of soils, since they offer greater flexibility in terms of soil quality. They combine the water reduction of the natural soil with the hydraulic reaction of the puzzolanic raw materials.

Hydraulic binders in which lime is incorporated create high performance foundations for roads and rail tracks.

Trenches

Earthwork activities, trench cutting and roadwork excavations produce spoil or aggregates which are often dumped. Environmental regulations and cost pressures seek to limit this landfill disposal and the associated heavy truck traffic. Lhoist has developed both dry and liquid solutions to enable the reuse of excavated soil on site by making it suitable for backfilling or road construction.

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Dry process

Lhoist has developed a solution that enables onsite improvement of excavated soil. It comprises a dry treatment process that involves the mixing of dosed quantities of quicklime (usually 0.5% to 3% by dry weight of soil) to render the resulting material suitable for conventional backfilling and compaction. We have proven logistics arrangements for just-in-time deliveries. Lhoist can also recommend the best mechanical equipment for soil treatment (mobile units and fixed installations) for specific applications. 

Liquid soil

Lhoist has developed products that treat and condition excavated soil to enable reuse as backfill. The resulting treated soil is temporarily flowable and self-compacting. It makes pipe placement in trenches much easier. Compaction time, cost and the need for additional equipment are also reduced and pipes are less likely to be damaged. The lifespan of sewer lines is increased substantially through the use of liquid soil.

Recycling

Lime improves unsuitable and heterogeneous by-products from excavations. They can then be used to backfill trenches and other urban excavations. This process can be implemented in situ, close to the site or in a central plant, increasing resource efficiency. It therefore more readily enables conformance to new sustainable environmental policies.

To optimize the use of lime and facilitate recycling, a proprietary on-site system developed by Lhoist allows lime to be dosed directly from super sacks into a screening bucket.

Aggregate improvements

Our quicklime products improve aggregates using a dry technique rather than a washing operation (with all its inherent disadvantages). Some quarried materials and/or recycled products contain useful aggregates, but they are difficult to process in the crusher/screener due to their extremely sticky clay content. As a result, they are removed at the primary crushing stage. The processability of such clay-clogged materials is even more difficult in wet conditions (see pictures before and after treatment). Our lime products produce better aggregate quality which makes them more valuable in the marketplace. It also results in a higher yield of commercialized quarry output. These products are available in powdered form and can be delivered in bulk or super sacks.

Suitable mixing equipment can be installed to complement or complete existing quarry primary crusher/screener processing units (fixed or mobile). With Lhoist products, material flow is simply side-conveyed to the mixer, after which it rejoins the usual process route. Together with external partners, we have developed different types of mixing equipment to treat, recycle and upgrade difficult materials. The lime-enriched parts of these materials, after screening aggregates, can be used as an ideal filling material that features excellent mechanical compaction properties.

Tunnels

Mortars 

In tunnel construction, in addition to the calcium that is used as filler, hydrated lime improves the rheology of mortars, reducing the amount of expensive special organic additives required and lowering the cost of grout formulation. It also creates binders for injection works.

Dredging Sludges

Quicklime dries out the drilling mud that comes from excavation processes, making handling easier. It improves soft soils, reduces settling and increases stability.

Synergies between clay and lime provide opportunities for recycling.

Hydraulic works

Our lime-based product for hydraulic works, such as dikes and dams, is proven to improve erosion resistance while maintaining soil permeability. The enhanced workability and mechanical stability of treated wet and clay soil helps reduce financial and environmental costs. 

Asphalt

Our solution for longer-lasting roads

As a road manager or professional in the paving industry, you are always looking for new long-lasting and economical ways to build roads and walkways. Lhoist offers a line of hydrated lime products used in hot and cold mixed asphalt for road construction and maintenance. Hydrated lime added to asphalt mixtures has been proven to increase pavement durability by 25 % or more. In addition, the use of our hydrated lime improves asphalt's resistance to water stripping, freeze-thaw cycles, de-icing salt, age-hardening and rutting.