1. SOIL STABILISATION

"soil stabilisation" is achieved if an in-situ Soil has been rendered usable for risk free application in any earthwork. However, we have to distinguish between "soil improvement" (a not very significant increase in quality, particularly of the workability of a soil) and the real "soil stabilisation" (an actual change of the soil properties to a considerable degree).

2. Soil Stabilisation - how is it achieved?

In the past 50 years many attempts at improving the behaviour of soils have been undertaken with the aim to avoid the substitution of conventional construction material for unsuitable in-situ soil, i.e. soil of lower quality. The products chosen for this purpose can be divided into the following groups:

– Products gluing together the soil particles, such as binding agents, and

– Products gluing at a change of the chemical composition of the soil, thus reacting with the soil, and improving its properties.

Some products out of these two groups show both effects, e.g. hydraulic binders.

What all these products have in common is the fact that they can be used only under certain conditions, i.e. with certain soil types and certain granulations of the soil. They often fail to yield satisfactory results because soils rarely have a homogeneous composition, and this makes it impossible to anticipate the effect. Consolid's soil stabilisation system is different.

3. Are there any of these products still on the market?

Cement and lime are in use for soil improvement, mainly as curing aid, as well as for soil stabilisation. The great bulk of these products, however - approx. 200 are known to us - disappeared as fast as they turned up. A number of them had not been developed for soil stabilisation anyway, but were mere industrial waste products to be 'buried' on such sites of application. Some others were limited in their effectiveness to certain soil types only and of insignificant or short term effect, and thus of little or no value.

4. What are the advantages of the CONSOLID Soil Stabilisation System?

This soil stabilisation system, comprising the combinations CONSOLID 444/CONSERVEX and CONSOLID 444 / SOLIDRY, was developed and devised specifically for the purpose of soil stabilisation, avoiding the paths other products (binders and chemical reactants) had gone and which had prevented a success.

Any cohesive soil has a tendency to petrify again; all it needs to achieve this goal is a very, very long time span and very high pressure. It is possible, however, to accelerate this procedure by catalytic processes. If the soil can be activated by catalysts or pseudo-catalysts and influenced in complex processes in its undesired behaviour, a considerable improvement can be achieved with nearly all kinds of soil and with the same quantities of additives.

And this is what the CONSOLID Soil Stabilisation System does: The use of CONSOLID 444 results in an irreversible agglomeration of the fine particles and in this way a reduction of the active soil surface. The adhering water film is destroyed to a high extent, thus activating the inherent binding power of the soil. The water content in the soil, especially its capillary saturation, is highly diminished and slowed down. An additional treatment of the soil with CONSERVEX or SOLIDRY enables a 'tailored' degree of soil stabilisation in accordance with the requirements of each particular construction site.

5. What types of soil can be treated with the CONSOLID soil stabilisation system?

Principally all types of cohesive or semi-cohesive soils can be influenced to the required ex-tent. The degree of soil stabilisation is determined by the requirements of the construction. Supposition: the soil must be mechanically mixable. Very heavy sticky clays (such as some organic clays, e.g. black cotton soil) may cause problems and have to be adapted by adding sandy material.

6. Is there an optimal soil composition existing for CONSOLID?

Normal physical conditions may be taken into account: the better the granular composition, i.e. the sieve curve, the higher the mechanical stability of the soil. An unfavourable granulation or an overrate of a certain fraction can be improved by mixing in other soil available nearly in order to reach the starting point for a high mechanical stability, because the better the starting point with regard to the bearing capacity, the greater the effect of the treatment with the CONSOLID soil stabilisation additives.

7. How to treat non-cohesive soils (sand) with CONSOLID Soil Stabilisation Products?

Since the CONSOLID soil stabilisation products interact with the fine particles that thanks to the treatment can be used as natural binders, sand has to be mixed with cohesive soil prior to the treatment with the CONSOLID soil stabilisation additives in order to obtain a content of fines of approx. 20 to 30%. The soil mix prepared in this way can then be treated just as any other soil.

8. Where is the soil to be treated - on the construction site?

The mixing-in of CONSOLID 444 and CONSERVEX / SOLIDRY into the soil available on the site is one of the application possibilities. The soil can however also be mixed with the products in any kind of mixing plant, stored for unlimited time and on demand be built-in from this material stock. The CONSOLID soil stabilisation system is, to our knowledge, the only soil stabilisation or consolidation process that allows both possibilities.

9. What is the depth of a treated layer?

Generally CONSOLID 444 is mixed with the soil in a depth of 20 to 25 cm, and a standard quantity of 0.2 litres per m2 is recommended in 95 to 98 out of 100 cases. The upper 10 cm of this layer already treated with CONSOLID 444 receives an additional treatment with CON-SERVEX or SOLIDRY. The standard quantities for CONSERVEX lie between 1 and 2 litres per m2, for SOLIDRY between 2 and 4 kg per m2.

The actual depth as well as the horizon where the treatment shall start is determined by the soil properties, the tasks a road has to perform and the load the road has to bear, in accordance with the static aspects. It must however be taken into consideration that the bearing capacity of a treated soil layer is much higher than that of an untreated one, which may result in considerable cost savings.

10. Is it beneficial to incorporate a sand layer beneath the treated layers in order to facilitate the water drainage?

A treatment of soil with the CONSOLID soil stabilisation system renders the soil to a high extent water-resistant, i.e. reduces its water content substantially. Nevertheless, adequate drainage must be provided for the whole construction prior to building up the single layers.

11. What consistency does the soil need before treatment?

Here the normal standards for earth constructions apply: soil should always be worked with at its Proctor optimum or slightly above, but never at too low a moisture content. The CONSOLID soil stabilisation system frees the bound water, which easies the compaction process enormously, especially with gravel and rock-containing material that can be wedged.

The treated soil loses its ability to take up water to a high extent. This results in a constantly increasing compaction by the traffic, even if the initial compaction has taken place at too high moisture content. This continuous compacting effect can no longer be disturbed by the destructive impact of swelling soil when taking up water, the density increases constantly and the effect of the CONSOLID soil stabilisation system remains a permanent one.

12. Are any temporal limitations to be considered when using CONSOLID for soil stabilisation?

None - provided the soil in question is workable. If rainfall is expected, the work can be interrupted at any time and continued at the same stage after an improvement of the weather occurs. CONSERVEX or SOLIDRY can be incorporated immediately after CONSOLID 444.

13. Can any increase of bearing strength be expected?

A soil loses its bearing strength by taking up water. Therefore any diminution of such water absorption will yield increased bearing capacities. Is the CBR value (California Bearing Ratio) taken as an indicator for the bearing capacity of a soil, a CBR value of three to five times that of an untreated soil can be expected by the CONSOLID soil stabilisation treatment.

14. Can such increase in bearing strength be achieved with any soil?

Experience gathered throughout the globe with many different soil types confirm that improvements can be expected with all kinds of soil, from low-class types up to good soils. With the latter the CBR value generally exceeds a value of 230, which is the usual measuring range. Such treated soil can already be called a high-quality mineral concrete.

15. How to apply the CONSOLID products?

CONSOLID 444 and CONSERVEX are liquid soil stabilisation products, which have to be diluted with water to obtain the working solutions. This is done on the construction site, taking into account the actual moisture content of the soil. I.e., is the soil moist, less water has to be added; is it dry, more water is necessary. Yet the quantities of additives determined in the laboratory always remain the same.

If SOLIDRY is used in addition with CONSOLID 444, this product is applied in dry state and mixed into the soil. This is an advantage particularly on sites where due to an already high moisture content in the soil the addition of aqueous solutions might cause problems in terms of compaction.

16. Can CONSOLID 444, CONSERVEX, and SOLIDRY also be injected?

No! Since a thorough mixing of the products with the soil is indispensable, it is not possible to work with injections.

17. Does the CONSOLID Soil Stabilisation System reduce the permeability of soil?

Yes - on the one hand by better compactibility of the soil and on the other by rendering the soil water-resistant up to any required extent, even to full impermeability.

18. Can the CONSOLID Soil Stabilisation System be of assistance on swamps?

Yes, to a considerable extent. Since such soil frequently contains high amounts of silt, they are extremely water-sensitive and highly suitable for a treatment with CONSOLID soil stabilisation products . It is understood, however, that despite this ideal situation a correct planning must be elaborated, including drainage, construction of the embankment (at least one metre above water level), compaction of the sub grade, etc.

19. At what point does compaction to take place?

Also here the rules applicable in conventional earth constructions hold true, i.e. the compaction should be performed with a moisture content at Proctor optimum or slightly above (or, e.g. in cases of imminent rain showers, immediately after construction). If for whatever reasons the compaction cannot take place immediately so that the soil dries too much, the missing moisture has to be incorporated by means of a tank car and the soil subsequently compacted.

20. How to calculate the quantities of CONSOLID additives to be applied?

Has the specific weight of the soil and its moisture content to be considered?

No; products used in soil stabilisation should not be delicate or problematic in their application. Natural soils keep changing in their granulation, and a correspondingly changing application rate of the additives on the site would hardly be possible. We recommend working with the following values:

1 m3 of soil 2000kg (2 tons)

1 m2, 25 cm deep; therefore 500 kg

1 m2, 10 cm deep; therefore 200 kg

As standard quantities of the additives, empirical tests have revealed the following amounts for the overwhelming majority of existing soils:

for CONSOLID 444: 0.2 litre per m2

for CONSERVEX: 0.5 to 1% of soil weight = 1 to 2 litres per m2

for SOLIDRY: l to 2% of soil weight= 2 to 4 kg per m2.

CONSOLID 444 and CONSERVEX are diluted on the construction site with as much water as the soil will accept for optimal compaction.

21. Can the effect of CONSOLID) 444 be observed on the soil?

Yes; if a mix of water with fine soil particles is prepared and CONSOLID 444 added, the irreversible agglomeration of the fines can clearly be observed. The mineral phase immediately separates from the water phase; the coarsening of the fines is visually and physically measurable.

22. Are certain significant values of the soil changed by the treatment (such as dry density, Proctor optimum, etc.)?

This depends on the soil. Normally the optimum moisture content will shift to a lower figure, while the dry density increases by 5 to 10%. With certain soils these values do not change, the voids, however, increase.

23. Are the CONSOLID additives dangerous to the environment?

No. Already in the development stage high priority was given to this issue and secured that no harm would be caused either to human beings or to the environment, provided the products are correctly used. Due to the fact that a treated soil is rendered highly impermeable, the transportation medium for the distribution of any polluting agents - the water - is even eliminated.

24. Do roads built with the CONSOLID additives turn slippery in rainy periods?

Yes, they might. Since owing to the treatment the clayey fines are kept within the soil and not washed out, a treated soil surface may turn slippery in wet stage. Yet this fact is of no importance, as the treated soil layers are not normally used as a wearing course. For this latter purpose we strongly recommend to apply a thin surface coating, e.g. with split, which realises a durable coating on the stable soil layer and keeps the road dust free.

25. What are the advantages of the System over cement stabilisation?

Cement can be used as a drying aid for over moist soils and as a compacting aid. It is also suit-able as a stabilising agent with certain non-cohesive soils. With cohesive soils, however, whose clay content differs and which may even contain organic pollutions, one may run into troubles with cement. On the other hand, by incorporating too large amounts of cement, a brittle layer of weak concrete may build up which tends to break into lumps, caused by the dynamic load of the traffic (by vibration). This can lead to a very unpleasant situation in the sub grade, since such cracks do not heal any more and frequently force their way up to the wearing course.

With the CONSOLID Soil Stabilisation / Consolidation System these objections can be completely neglected. The soil stabilisation products additives change the soil permanently and provide it with properties, which it did not have before and which it will not lose any more.

26. How do treated soils behave with regard to swelling and shrinkage?

The CONSOLID soil stabilisation additives have an enormous impact on the water sensitivity of a soil material and reduce it to a minimum. Thus the soil loses its natural conduct to a high degree, i.e. shrinkage when drying out and swelling through the incorporation of moisture. Once compacted and subsequently slowly drying out, a permanent moisture content can be attained, which is around Proctor optimum or slightly below. This means that the bearing capacity of a treated layer can also be maintained in wet periods.

27. Do the Attenberg limits change by the treatment?

Yes. Normally these limits (plasticity and liquidity) are no longer visible, since a treated soil can only be brought into these ranges by forced mixing with water. Wherever measurements have been performed, no significant changes could be observed.

28. In what cases is the CONSOLID Soil Stabilisation System of benefit?

In all cases where soil is used as the basic construction material or where soil causes stability problems, particularly in soil road construction and maintenance (subgrade, subbase and base layers); rail embankment construction or maintenance; in any other kind of soil construction; against wind and water erosion; in irrigation channels to prevent oozing losses; in the production of high quality soil bricks for housing.

29. In which layers of a soil construction are the additives to be built in?

Their use is of benefit in all cases where local soil is to be used and where costs should be saved by avoiding pricey soil exchanges. It must be called to mind that most road damages result from the soil material beneath the surface - damages that can only be repaired by removing this soil, and for this purpose the entire road must be destroyed. Thus an in-situ soil is often the most expensive part of a road body, a fact that unfortunately becomes visible only when it is too late. This is why any sub grade, sub base, and base course layer should advantageously be treated with the CONSOLID soil stabilisation products additives.

30. Are the CONSOLID soil stabilisation additives only effective with fine particles?

The major effect of the CONSOLID Soil Stabilisation System aims at a high influence on the fines in a soil, because it is these fines which are chiefly responsible for any instability; the coarse parts do not cause problems.

31. How to determine the correct dosage of the CONSOLID soil stabilisation additives?

In 95 to 98% of all cases the standard quantities of CONSOLID 444, CONSERVEX and SOLIDRY will yield the desired effect. Only in very few and rare cases it may be necessary and advisable to adapt the dosage. For this purpose, a simple laboratory tests are conducted, a point which is being discussed below.

32. What kind of tests shall be conducted?

In a first step the soil is to be classified, its granulation and dry density evaluated, and its special properties such as content of salt or organic matter determined.

Subsequently, a series of test blocks are produced, which comprise an untreated block and blocks treated with the standard quantities of additives. The blocks are then dried and tested regarding the following points:

– Dry pressure resistance;

– Capillary rise of water (by putting them on a water-saturated sand bed or by partly immersing them in water and observing their behaviour under water);

– Remaining pressure resistance after capillarity test;

– CBR test: for this purpose the blocks have to be dried first and then immersed in water (in deviation from the usual specifications for CBR testing).

33. What effects can be expected from such laboratory tests?

In most cases already the standard quantities yield a better compactibility of the soil, a diminished capillary rise of water and a reduced destruction under water. The soaked CBR value is three to five times higher than that of a comparable untreated soil, provided, however, that the CBR test blocks had been dried before testing.

34. Do these improved values affect the planning and the cost of a project?

Yes. The improved behaviour of the soil allows not only its use but avoids the import of borrowed material for exchange. Depending on their quality before treatment, it is therefore possible to upgrade in-situ soils for use in the sub grade, sub base, and base layers using the Consolid soil stabilisation products.

If e.g. for a road body three layers of different materials are projected to reach the required bearing strength (representing together a layer of 600 mm depth), a reduction of this depth to a total of 350 mm can be achieved with the CONSOLID Soil Stabilisation System. The cost savings obtained only by this usability and improvement of the in-situ soil and the reduced layer depth are in the range of 20 to 50% of conventional constructions involving soil exchange.

35. What content of fines does a soil need in order to he suitable for a treatment with the CONSOLID additives?

Since we aim at a very dense soil material, the content of fines (clay/silt) should not be lower than 20 to 30%. This yields a satisfactory mechanical stability.

The maximum content of fine particles, especially clayey soil, is exceeded, if the material can no longer be mixed mechanically. In this case the addition of sandy and coarse material is required to render the soil better workable.

36. What is to be done with heavy-traffic roads?

The consulter knows the condition of the existing sub base, the construction material, the required bearing strength, the traffic to be expected, and makes his calculations on this basis. Since every soil can be significantly improved by the CONSOLID soil stabilisation additives (see CBR value), the consulter can take advantage of this fact by using material available on the site, which otherwise he would have to replace.

37. Is an application on low-traffic roads advisable?

Yes; especially on such roads it is important to maintain the degree of compaction once reached and to prevent re-destruction of the road by the take-up of water, since for cost reasons it is usually necessary to work with in-situ soils on secondary roads.

38. Are the additives effective only against the impact of water on soils?

No. Water sensitivity is only one of the properties of soils that can be influenced. As complex as a soil itself is in its behaviour, as complex has to be any method influencing this behaviour, e.g. by better compactibility, coarsening of the grain size, or activation of the inherent binding power of the soil.

39. What is the effect of each particular additive?

CONSOLID 444 does the essential work in consolidating or stabilising the soil (soil stabilisation), particularly by irreversibly agglomerating the fine particles and thus reducing specifically the effective soil surface and by heavily diminishing the rise of capillary water.

CONSERVEX is a complementary product to CONSOLID 444 and reinforces the protection against water by blocking the capillaries. In addition, surface water will be pre-vented from penetrating the treated layer.

SOLIDRY is effective in a similar manner as CONSERVEX; it is however a dry product and therefore of advantage in cases of high moisture content in the soil to be treated and also in areas of high flood occurrences or with soils of higher salt content.

40. Does CONSERVEX not reduce the consolidating effete of CONSOLID 444?

Soil improvement can never be expressed in absolute figures; it is always relative to the soil in question. There are many undesired properties one has to cope with, and sometimes a desired effect can also have some undesired side effects. In the case of CONSERVEX, such an undesired effect is the reduction of the inner friction of the soil, which is however more than satisfactorily compensated by the positive effects the treatment yields. Yet the quantities used shall always be kept as low as possible.

41. Is it recommended to work with moisture contents above optimum?

A moisture content slightly above the Optimum is of no harm and preferable to one below optimum. With more moisture the CONSOLID 444 solution can be better distributed and can penetrate the clay lumps more easily. Of special importance is a thorough pulverisation of the soil since CONSOLID 444 is effective only on the soil surface it can reach. The better the distribution, the higher is the effect. Sometimes it may be advantageous (e.g. with heavy, lumpy clays) to add 1 to 2% of cement or lime hydrate to support this effect.

42. Is it advisable to test a soil in the laboratory ahead of a treatment in the field?

Although in 95 to 98 out of 100 cases the same low quantities of CONSOLID soil stabilisation additives will yield the desired effect, it is recommendable to examine each soil with regard to its inclination to be influenced. Visually very similar soils may show very different properties and may also react very differently.

43. What are the application fields apart from road construction?

In all cases where stable soil material is required, it is recommendable to make use of the CONSOLID soil stabilisation additives, such as in:

– the production of high-quality soil bricks,

– the protection of slopes from soil erosion,

– the protection of pound and lakes from seepage,

– etc.

44. Soil bricks: what criteria shall be applied?

In principle the same as in road construction; every cohesive soil can be processed in order to obtain high-quality soil bricks and thus a valuable construction material. The standard quantities used in road construction are also applicable for soil bricks.

45. How stable are treated soil bricks?

The dry stability of soil bricks depends upon the natural stability of the used soil in its compacted, dry stage. Values between 20 and 100 kg/cm2 have been measured. By a treatment with the CONSOLID soil stabilisation additives these values can be maintained, even if walls built with such bricks are exposed to water attacks.

46. When can the soil bricks be used after production?

Soil bricks have to be dried, a process, which usually takes 1 to 4 days, depending on the humidity of the air. Produced on the soil brick plant CLU 3000, the bricks are so dense that they can even be used for wall-laying right after emerging from the press. Drying is nevertheless recommendable whenever possible.

47. What is the lifetime of such soil bricks?

Once treated, the effect will be maintained. The bricks can only be destroyed by mechanical means. Soil is a very solid construction material, unless disturbed and destroyed by water. There exist many soil constructions, for example in Egypt, which have lasted for centuries.

48. How are walls built with soil bricks?

Ordinary lime and/or cement mortars are used.

49. What are the costs of a soil brick plant?

There are a number of different machines and equipments for the production of soil bricks on the market, from small hand presses to large stationary plants. We believe that a mobile plant is best suited, i.e. a machine on which a crew of 4 to 5 workers can produce in a one-shift Operation about one million bricks per year right on the construction site. This means a daily output of approx. 3000 bricks (representing 12 tons or 6 m3 of soil). Our mobile soil brick plant CLU 3000 reaches this output. The investments for such a mobile plant is in the range of SFr. 50'000.--.

50. How can the stability of soil bricks be increased?

In case higher values than the natural dry value of a given soil are required, these can be achieved by adding small percentages of cement and/or lime hydrate. With some types of soil, cement and lime alone may even suffice. Their brittle binding power is less harmful to soil bricks than to roads since the dynamic load on buildings is far lower than it is on roads.

51. What is the weight of a soil brick compared to that of a burnt brick?

Thanks to the high compactibility and the absence of a burning process, soil bricks can obtain a density up to 30% higher than that of burnt bricks. This high density is a very desirable effect in view of the climate of soil constructions, i.e. the transfer of heat/cold is temporally considerably reduced. This renders soil houses pleasantly cool at daytime and warm at night.

52. What are the costs of soil bricks?

The costs vary to some extent, depending upon the local conditions. It can however be assumed that savings of up to 50%, compared with burnt bricks, can be achieved.

53. Can treated soil be used as plastering mortar?

Yes, this is possible; we recommend, however, to increase the natural abrasion stability of the soil by adding cement/lime. One may also use unplastered soil bricks produced on the CLU 3000 for this end; they show a very regular surface upon extruding from the press and are well suited for visible walls. Still, it may be of advantage to protect such walls from abrasion and dusting with a colourless painting. Wallpaper paste, e.g., is well suited for interior walls; for exterior walls CONSOLID emulsion can be used in order to obtain best possible water stability.

54. What happens if a soil brick house is flooded?

If the soil bricks have been manufactured correctly and water resistance obtained, nothing will happen. In highly flood-inflicted areas it may be recommendable, if one wishes to be on the very safe side, to erect the walls up to the height, which can be expected to be flooded with particularly water-resistant bricks.

55. Are soil bricks fireproof?

Yes, soil does not burn. However, should a soil brick building or part of it ever become glowing by a conflagration, this glowing part will be transformed into a more or less burnt-brick building, while the unaffected part remains as it was before.

56. Protection from soil erosion: how to use the additives for this purpose?

Especially the fine particles of a soil can be blown and carried away very fast by wind and water, leading to soil erosion and the loss of substantial quantities of fertile land. The best protection from soil erosion is vegetation, i.e. an area in danger of erosion should be covered with plants as fast as possible.

The CONSOLID soil stabilisation additives enable the production of a soil mortar, which, applied on the earth, dries to a water-resistant crust, thus protecting the soil underneath from being carried away. However, in order to ensure a successful re-cultivation, the dead soil must be covered with a layer of fertile soil (a few centimetres may already suffice). In this fertile layer seed and fertilizers will be incorporated and subsequently covered with treated soil mortar, of which two layers of each 5 to 10 cm thickness should preferably be applied with a mortar spray gun.

57. In- what size containers are the products (CONSOLID 444, CONSERVEX, SOLIDRY) available?

Usually the products are shipped m 200 litre drums (CONSOLID 444, CONSERVEX) or in paper bags with 25 to 50 kg, SOLIDRY, if the size of the site is not asking-for a-delivery in bulk by tank trailer.

58. What is the price of the products?

The local prices can be given you by our local partners only because they are based on the local added costs for custom duties, VAT, etc. But you will find enclosed a leaflet which shows minimum/maximum application rates for the typical road application an based on it the approx. price per m2.

59. Is it possible if we only apply CONSOLID 444 (without CONSERVEX) in road construction?

The CONSOLID soil stabilisation system is a total system, not only compaction aid or something else - it allows to change the behaviour of the treated soil completely. Water is the most effective enemy of stability; CONSOLID fights against the capillary rise of water and agglomerated the fines irreversible. Due to the fact that the capillaries still exist, surface water could penetrate into the treated layer and reduce mechanically the effectiveness of the, treatment with CON-SOLID 444; therefore to prevent this, we add in the top layer CONSERVEX (CONSERVEX) or SOLIDRY (SOLIDRY) to avoid this filling up of the voids with seeping in water. CONSOLID is used alone only in the deeper layers; in the top we need the combination of both additives to get the full protection besides other effects due to the complexity of the stability problems.

60. If we still have to use CONSERVEX (CONSERVEX) or SOLIDRY (SOLIDRY) can we apply it together (as a mixed blend material) with CONSOLID 444 instead of applying it after we apply CONSOLID 444 first?

The separate application of the additives is for economic reasons only, because when we treat a 250 mm layer with CONSOLID, usually only the top 100 mm of the treated soil will be additionally treated with CONSERVEX (CONSERVEX) or SOLIDRY (SOLIDRY). Due to the perfect performance more and more customers are using both additives (CONSOLID 444+CONSERVEX or CONSOLID 444+SOLIDRY) in full depth and in this case both additives can be mixed into the soil together at once. If a god professional mixer is available (like Wirtgen, Bomag, CMI, Caterpillar, Bitelli, etc.) it is often possible to reduce the added additives to 50% only because we need only their presence and not the quantity but less additives needs better mixing quality which can be achieved with these equipment.

61. Has the product (CONSOLID 444) the ability to penetrate after the application?

Aqueous liquids have the natural ability to penetrate into soil; CONSOLID is spreading very wide because 1 It of CONSOLID 444 can theoretically, diluted in sufficient water coat monomoleculary a surface up to 25 Mio m2 Anyway we do not need further penetration because by proper mixing into the soil we get a spontaneous agglomeration with the soil particles, which makes the treatment impossible for being leached out by water. The soaked CBR values of a treated soil are usually improving 3 to 5 times, with more than 50% more than 5 times; preparing the in-situ soil by adding missing fractions ahead of the same treatment al-lows to get at higher mechanical stability further substantial improvements. See in this respect our documentation.

62. Is a CONSOLID system treated surface slippery when wet?

When not used as it should be used, YES. Any clayey soil, stable or instable, be comes slippery when wet. Therefore it is necessary to, prepare for the base course a soil mix where the clay content is not dominant (you need a real Macadam) mix of clay, silt, sand and stones. To prevent slippery condition as well as mechanical abrasion (dusting) treated soil roads should always be paved with a thin layer of asphalt to serve the preserve the investments in the betterment and avoid also dusting. Due to the fact that the properly treated soil layer will become the "bridge" of the road, the wearing course can be dramatically reduced and the savings are outperforming the CONSOLID soil stabilisation costs in a way that the total calculation gives savings in the range of 20% to 50% of the construction costs.

63. Can CONSOLID Soil Stabilisation System be applied during wet weather (in the rain)?

Real contractors will be very careful in ripping-off a soil road when rain may occur, because over moistened soil needs weeks to become workable and compactable again; therefore, when you are working with the CONSOLID Soil Stabilisation system you will have to interrupt the work quickly and close the open road with all rolling equipment as fast as possible to avoid this over moistening of the soil. After the rain you can continue the application; there will be no leaching out or run away of material.

During long- rainy seasons, when work at roads will be not possible, you will have the alternative to premix the soil mix you need later on the road, stockpile it and import it when, the conditions allow to work at the site.

64. How soon after application can a surface (road surface) withstand the traffic?

Due to the fact that the CONSOLID soil stabilisation / consolidation treatment has no "potlife" the application can be interrupted any time, not only when it rains but also when you have to open the road temporarily for the traffic because there is no diversion (detour) existing. You can even prosper from such traffic, it is compacting your layers like a tire roller. Supposition is that the soil is compactable and not over moistened.

65. How long- will the CONSOLID soil stabilisation system last? Will applications be required regularly?

The CONSOLID soil stabilisation treatment is a permanent one. This means, a soil once treated remains treated, which makes it possible to use treated material several times e.g. when used as a temporary road. In a road the density increases over tune far more than 100% mod. AASHO density - we have impressive examples of roads, which have existed for more than 25 years and are still in perfect condition following treatment with Consolid's soil stabilisation products. See in this respect our documentation. Therefore treated sub-grade, sub base and base courses will need no repeated treatment. The only requirement will be to take care of the wearing course, but also there the maintenance will be strongly reduced due to the fact that the treated embankment will protect the wearing course against destruction from the ground.

66. Does the CONSOLID soil stabilisation system perform well in conditions affected by salt water (sea water)?

Salty soils usually do not cause great problems regarding stability as long as the salt content is not too high - laboratory tests show very easily and impressively the limits and also the way how to improve it by preparing mixes with other types of soil. We have plenty of excellent results with the CONSOLID soil stabilisation system in the neighbourhood of the sea like the Container Terminal in Manila/Philippines or a plant and container yard in Holland, to name a few only. The possibility of treating a soil completely to impervious conditions will avoid that sea (salty) water can penetrate like fresh water. All these features can easily be demonstrated on soil samples already in the laboratory before you start any application in the field. Therefore field application will never be a failure if you follow your lab-findings.

67. What is the difference between the CONSOLID soil stabilisation system and stabilisation with binders (cement, lime, asphalt)?

Any artificial binding system is heavily dependent on the quality of the soil and will show only under specific conditions with limited numbers of soils satisfying results; the CONSOLID soil stabilisation / consolidation system activates the soil itself towards petrificaction and can improve 100% of all kinds of soil, as long as the content of fines is large enough or increased to 20% to 30%

68. Soil stabilisation with Cement - disadvantages:

For certain non-cohesive soils and in arid areas cement can be a suitable stabiliser provided the treated layer is thick enough and the underlying sub grade does not move under the dynamic forces of the traffic. Otherwise the weak cementation of the treated soil will lead to cracks and slabs, which "swim" on the subgrade and will cause deformation / heavy deflection with no chance of self-healing of the treatment. Once broken it remains broken.

With the CONSOLID soil stabilisation system we use, in such cases clayey material as a natural binder and the treatment controls the water sensitivity of the soil mix, if necessary up to full impermeability. Once treated the soil remains treated, can be relevelled and even re-used on other places without loss of the improved behaviour.

69. Where is the CONSOLID soil stabilisation system the right choice?

In any earthwork where the water sensitivity of the soil causes stability problems and where -the soil should be improved permanently with the capability to further increase stability, the CONSOLID soil stabilisation system is indicated. Due to the fact that treated soil will get an increased CBR which is 3 to 5 times higher than the soaked value of the same untreated soil, this opens up the opportunity to replace lots of borrowed material with in-situ soil, change the design completely and save in this way 20% to 50% of the construction costs compared with the same quality of a conventionally built road.

Any soil can be brought to any desired behaviours; it can be 'tailored' to the requirement on the site, and the CONSOLID soil stabilisation system offers the unique advantage that it can be used 'in place' as well as 'in-plant' where pre-mixed soils can be stockpiled even for years before being used on the site without losing any of the improving effects of the treatment.

70. Can the CONSOLID soil stabilisation system prevent seepage?

The most spectacular visual effect of the CONSOLID soil stabilisation / consolidation system is the substantial reduction of the influence of water to the treated soil. The capillary rise can be reduced close to zero, the soil gets fully impervious when properly treated and the soil mix contains sufficient fines to allow a dense packing of the soil to avoid voids in the soil as far as possible. K-values in the range of 1.10-6 to -7 can be brought to fully impervious behaviour with values of 1.10-9 to –11.

Due- to- this advantage, the CONSOLID soil stabilisation system is very successfully used in avoiding seepage in artificial lakes, ponds, and in constructing impervious soil layers in the bottom of disposal areas to avoid the seepage of effluents from the waste into the ground water.

71. Can the CONSOLID soil stabilisation system avoid or reduce deformation and deflection, measured with the Benkelmann Beam?

Deflection and following deformation in the formation of a road is mainly caused by the behaviour of the base, sub-base and sub-grade; the more sensitive to moisture, the more -deformation, and this becomes visible in the deflection tests. When properly designed, the deflection can be reduced substantially and the level of the road remains close to the value at the time of construction. The treated soil will not be saturated with moisture and change density by swelling and shrinking; the stable conditions in the treated formation will allow to put a lighter wearing course on top, which also will contribute to less deflection and deformation.

72. How to calculate dosage of the CONSOLID soil stabilisation system?

Any earthwork must be seen as a complete project - not the single layer cost is important; important is, what change in the design is possible with the CONSOLID soil stabilisation system to make full use of the advantages of this unique system.

Cost effective single steps are:

a) Using as much as possible in-situ soil instead of borrowed material;

b) Avoiding excavation of in-situ soil and replacing with borrowed material and both importation costs;

c) Possibility of pre-mixing material and save construction time;

d) Due to higher loading capacity of the treated formation the wearing course can be substantially reduced in size, which contributes to better performance in avoiding the deformation caused by the accumulation of heat.

If all aspects are respected, substantial savings compared with conventional construction methods can be realised already during construction, irrespective of the further savings due to greater durability and lower costs for maintenance.

73. Why should an in situ soil be improved by adding missing fractions ahead of a treatment with the CONSOLID SYSTEM?

Usually in situ soils cannot be used for any layer in a formation because certain parameters are required for each layer and need to be respected. E.g. pure fine sand cannot be used in a formation; it will never develop the desired loading capacity, and it will be the weak link in a formation. But if such find sand is bound with clayey fines, you will get higher density and compressive strength and with the treatment you will keep the soil mix stable even in moist periods.

This means that with any in-situ soil it is of advantage to look around the site, for materials available that can improve the sieve curve of the in-situ soil to better mechanical stability. Such improvement of the mechanical stability will pay substantially, because the CONSOLID soil stabilisation system works in most cases with the same quantities and costs - the better the starting point the more you get from the treatment. E.g. a soil with CBR 7% can be brought with the treatment to CBR 20% to 35%; but if the same soil is ahead of the treatment improved by adding clayey soil and/or coarse material to a CBR 15% the same, treatment will lead to soaked CBR values of 50% to 75% and even more.

74. How can the effectiveness of the CONSOLID Soil Stabilisation System be proved?

The CONSOLID soil stabilisation system offers the unique possibility of checking in simple laboratory tests the full effectiveness of the treatment ahead of any use in the field - therefore a failure in the field becomes impossible. You know in advance what you will get and already in the laboratory you can develop the proper soil mix, which satisfies all your requirements.

All standard soil tests as specified can be used. The only modification we recommend is that all samples, untreated as well as treated, have to be dried back from OMC to approx 50% OMC to show realistic behaviour in the tests, comparable with the performance in the field. Especially samples with clay content, as is always the case with treated soil samples, perform with misleading results if tested at OMC; such samples become sensitive to water only after they have been dried back, which is always the case in the field, where it is impossible to keep the OMC as standard.

75. Is Erosion control possible with the CONSOLID soil stabilisation system?

A treated, clayey slurry on be applied with a plastering pump on slopes and protect them with a crust against wind and water erosion. Usually ahead of this plastering a fertile soil layer is applied and seed spread before the application of the clay slurry is done - in two applications of each 5-7 mm, where the second application closes the shrinkage cracks of the first application. The formed crust helps to keep the fertile soil moist and speeds up germination; the plants have no problem to grow through the crust and take over in the following the erosion control. There where a recultivation is not possible, the protection layer may have to be repeated, according to the requirements, from time to time.

76. How to get A4 soils (silt)under control with CONSOLID soil stabilisation system?

Silty soils are most difficult for construction because they are very sensitive to moisture, show swelling and shrinkage, and are difficult to work with. Especially these types of soil work excellently with the CONSOLID soil stabilisation system and can become fully impervious when properly treated. These soils can also be used as a natural binder for sands and coarse material. Some silt with single corn size may require the addition of clay for better compressive strength and density but altogether cause no problems in getting them fully under control and upgrade them to risk-free construction material.