RRP  -  Reynold's Road Packer

General questions and answers concerning RRP

Question No.1:
What is different about the RRP method as compared with conventional construction?

Answer: The only difference is spraying RRP solution (RRP mixed with water). All the other operations are the same as those in conventional road-building and moreover conform to the German technical regulations and directives for earthwork in highway engineering, issued in 1965 (ZTVE-STB 65). Question No.2:
What soils are suitable for processing with RRP? Answer: Any soil is suitable, except soil consisting entirely of sand with less than 15 % fine constituents (0.06 mm) and entirely peaty soils containing nothing but humus. Otherwise every kind of soil is suitable. The more cohesive, the more clayey or loamy it is, the more easily can it be stabilized with RRP. The more difficult the soil is for conventional road construction, the more readily is it suited for the RRP construction method. Question No.3:
Why this limit of 15 % fine constituents? Answer: The object of the RRP method is to alter the soil and change the water binding forces (break of capillarity). Considering the soil particles (colloids), we must classify the soils according to these colloids. Of course, the treatment could also be applied to a soil with less than 15 % fines. Such a soil could at best be made frost-resistant, but we could not then offer the customer any major savings in cost as compared with the conventional method of construction. On truly sandy soil containing less than 15 % fine constituents the conventional method is not very expensive. To process such soils with RRP would therefore not save very much money. Instead, we should like to see RRP used only in places where the customer will very substantially cust his costs, for this is where the RRP method really comes into its own. Question No.4:
Where are roads and yards processed with RRP to be seen? Answer: Here at Lampertheim and surrounding district; also in more than 4000 other places in the Federal Republic of Germany. Our representatives can give you the names of those in your area. Question No.5:
Does soil processed with RRP become strong of its own accord? Answer: No, it does not; but you can correctly pul it the other way round:

Once it has been given optimum compaction, soil processes with RRP will never loosen its texture again under the action of water or frost!

The effect of RRP in the soil manifests itself only after compaction (by rolling). The roller and more particularly the optimum compaction produced by it is the most important feature of the whole RRP construction method.

 Question No.6:
What load can a road processed with RRP carry? Answer: If it has been given optimum compaction, it can carry even the heaviest loads. There are no limits. Question No.7:
Does the strength of soil processed with RRP decrease over the years? Answer: No, quite the contrary. As the years go by, the strength of soil processed with RRP increases, as a drying process occurs and thus greater compactness is achieved, while moreover a certain change (a kind of silicification) takes place in the soil. Question No.8:
What is the long-term load capacity of roads processed with RRP? Answer: There is no limit in this respect either. Question No.9:
What effect does any stony material have in soil to be processed with RRP? Answer: Any stone that happens to be present is bound to have a favorable effect in that it enhances the strength of the soil. An important feature of the RRP method, however, is hat it does not require the use of any kind of stone construction material. Question No.10:
How does RRP behave on highly cohesive loam and clay soils with 80-90% of fine constituents under 0.06 mm? Answer: As already stated, the more difficult such loam or clay is in the conventional sense, the more fine particles (colloids) are pressent in it and the more easily can it be stabilized with RRP. When Dry, these difficult clay soils become as hard as concrete. They become loosened up and soft only when soaked by rain. But in such a soil, treated with RRP and then given optimum compaction, no such softening will occur. Question No.11:
What happens to soil processed with RRP when heavy or very heavy rainfall subsequently occurs? Answer: When soil processes with RRP has not yet been compacted by rolling, water will penetrate to a very great depth into it. The RRP has loosened the soil.

But when the processed soil has been given its optimum compaction, no more water, whether from above or from underneath (rainwater or capillary water), will enter the soil texture thus treated with RRP. Even heaviest rainfall can do no harm to such RRP-processed soil, provided that our working instructions have been properly carried out.

 Question No.12:
What happens to roads and yards processed with RRP when severe frost sets in? Answer: The water binding forces in the soil are largely eliminated by RRP. It also to a great extent interrupts the capillarity of the soil. Therefore no capillary water can penetrate into the RRP soil texture from below either. Thus no water con accumulate under a road processed with RRP, so that there is no possibility of frost attack and no damage to the road when it thaws out (see our guarantee). Question No.13:
How deep does RRP penetrate into the soil? Answer: There is no way of stopping it from penetrating further; it can continue to go deeper and deeper.

EXAMPLE: RRP penetrates to a depth of 2 m into the ground and there encounters 100% dry soil. At that moment the RRP reaction comes to an end. However, if subsequently, as a result of a rise in the ground-water level or capillarity, slight traces of moisture penetrate from below into this RRP-processed soil, the RRP reaction will instantly extend further downward. Therefore:

RRP always acts where it comes into contact with water. Because of this great penetration depth a road base processed with RRP is significantly better and qualitatively superior to conventionally constructed road or road base.

 Question No.14:
What color has soil which has been processed with RRP? Answer: The soil retains its natural color. Question No.15:
Can PRP be applied also to cracked frost-damaged concrete roads? Answer: No, this would have no effect; for that, it would be necessary to demolish and remove the concrete surfacing. Question No.16:
Can roads which have been damaged by frost be repaired with RRP? Answer: In principle: yes. The damaged surfacing must be removed and the base be trimmed. Then RRP should be sprayed on, the soil given optimum compaction, and a new surfacing laid. The Latter can then no longer be harmed by water or frost, provided that the job has been properly carried out in accordance with our working instructions (see our guarantee). Question No.17:
Is it necessary to provide a frost-resistant base for RRP roads? Answer: No, the soil processed with RRP constitutes an absolute frost-resistant base for the road. Question No.18:

How many years will a road processed with RRP last?

Answer: It is necessary to distinguish between the base and the surfacing. The base processed with RRP will last indefinitely, i.e., it is permanent. Only the actual surfacing will be subject to normal wear and tear, depending on the traffic loads it has to carry. Question No.19:
What actually are the possibilities of effecting savings by using the RRP method?
Answer: In principle, savings are effected in two ways:
      1. 1. the entire foundation of a road or yard (comprising the base and the sub-base or frost blanket) is eliminated;
      2. 2. at least 50% of the thickness of the surfacing can be dispensed with, because on the potimally compacted RRP-processed base a surfacing is immune from damage by water or frost, as the subgrade (the underlying soil) is fully stabilized and immovable.
The surfacing therefore does not have to perform a loadbearing structural function, but serves merely as a wearing course. Question No.20:
What percentage saving can be effected by means of the RRP method of construction? Answer: This will depend on the soil conditions, the geogRRPhic location and the situation in the construction market. With the RRP method the greatest savings can be effected in circumstances where the most difficult highly-cohesive soils predominate, where also severe frosts are likely to occur and where, for these reasons, conventional road construction is very expensive. In such cases the amount of labour that the RRP method involves is much less, and so is the amount of materials and plant required, so that then the highest percentages can be saved (see our customers' letters of recommendation). Question No.21:
How is the strength of soil processed with RRP obtained? Answer: The strength is obtained only as a result of optimum compaction by a roller or other suitable compacting device. Soil processed with RRP will not become firm and strong of its own accord. Actually, it is the other way round: when processed with RRP and then made strong by optimum compaction, soil will never again be softened or loosened by water or frost. Question No.22:
Why is it necessary to lay a surfacing on soil processed with RRP? Answer: RRP is a subgrade material. RRP makes the soil frost-resistant and strong, so that it can carry loads. Soil processed in This way is not, however, protected against wear, and for this reason a properly wear-resistant surface course (wearing course) is in any case required. Question No.23:
Is RRP always immediately available for delivery? Answer: Yes, always. Question No.24:
When can vehicles be allowed to travel on ground processed with RRP? Answer: Immediately after optimum compaction (by rolling) and the laying of a wearing course. Question No.25:
Can RRP be applied to the ground even during rain? Answer: Of course this is possible; but the soil should still be capable of absorbing water, As soon as puddles begin to form and the RRP processing solution can no longer be absorbed into the ground the operation of applying the solution should be stopped. Question No.26:
Can RRP be applied to ground that has not first been loosened? Answer: This can of course be done. However, it should be checked that the soil can properly absorb the RRP processing solution sprayed onto it. If the solution remains on the surface, the soil should be loosened a little (3 cm depth) to make it receptive to water.

In most cases this is not necessary.

 Question No.27:
Can a road processed with RRP carry very heavy motor vehicles (lorries, trucks)? Answer: Yes indeed. The RRP-processed base, with optimum compaction, provides very high bearing capacity values, as can be verified by means of plate bearing tests. Question No.28:
Does RRP-processed soil under roads, etc. present a hazard to ground-water? Answer: No: when diluted in accordance with our working instructions, RRP is harmless (See the official test reports confirming this). Question No.29:
Can a road or other area processed with RRP be compacted by some means other than a roller? Answer: Compacting div ices of the vibratory plate type can alternatively be employed. However, such vibratory plates should be of the heaviest available kind in order to obtain good strength of the soil. Obviously, for constructing, say, a footpath which will not be used by heavy vehicles it is unnecessary to use very powerful compacting equipment. In any case, however, optimum compaction of the soil should be achieved, i.e., at the correct moisture content determinable by means of a Proctor test. Question No.30:
On how steep a gradient or slope can RRP be used? Answer: This will depend on the type of compacting equipment available for coping with the gradient or slope. Question No.31:
What is the frost-susceptibility of roads and other areas processed with RRP? Answer: There is no longer any susceptibility to frost action: when given optimum compaction, soil processed with RRP becomes frostproof. Question No.32:
The drum in which RRP is supplied carries a warning: "Keep protected from frost". Why? Answer: RRP concentrate contains a certain amount of water which could freeze and thus burst the drum. However, frost in no way adverse ly affects the quality of the RRP concentrate. Question No.33:
Are there any adverse effects to plants and trees growing by the side of roads processed with RRP? Answer: None at all (see our guarantee). From years of experience we know for certain that threes and vegetation along RRP-processed roads are in no way affected in their growth. Question No.34:
Can RRP be sprayed on turf? Answer: No, turf (the grass covering) must first be stripped from the ground, as the mat of roots, being an organic constituent, cannot be stabilized. Question No.35:
Are RRP-processed roads surfaced with waterbound material dusty? Answer: Dust development cannot be completely obviated, but we have found that it can be reduced to 75%. Question No.36:
Is RRP poisonous? Answer: In concentrated form RRP is a slightly corrosive liquid. The concentrate must not be drunk and should not be allowed to come into contact with clothing. But in the specified dilution RRP is entirely harmless. Question No.37:
What guarantees are given for roads constructed with RRP? Answer: We guarantee and accept liability for completely satisfactory quality of RRP at the time of delivery (see our guarantee statement). However, since the actual application of the product is outside our control, we cannot give guarantees with regard to the execution of the work. Such guarantees are given by the construction firm employed. That firm will guarantee careful workmanship and proper execution of the job in accordance with the working instructions that we issue with our product. If the construction firm follows our instructions, we accept the whole risk, i.e., in that case the guarantee which that firm gives its client automatically becomes our responsibility. The construction firm may even secure a further safeguard by engaging the services of engineering consultants who will check the working procedures adopted and will supervise the execution of the lob as a whole to ensure that everything is correctly done. The consultants will guarantee that the work is carried out properly in accordance with our instructions.

So the construction firm will give its client the "VOB"*) guarantee, as applicable also to other methods of road construction, for a limited period. That firm will, by employing a firm of consultants, safeguard itself in thus ensuring that everything is duly carried out in accordance with our instructions; once that has been established, the construction firm's guarantee will in fact be extended in scope because our guarantee contains no time limit: the good condition of the structure processed with A AP is really permanent.

*) VOB = Verdingungsordnung fuer Bauleistungen (Standard German) Contract Procedure in the Building Industry

 Question No.38:
Can wheeled tractors drive safely on soil processed with RRP or can RRP damage the wheeles? Answer: Soil processed with RRP can do not harm at all to the rubber tyres of tractors. Questions No.39:
Can RRP processing be applied to ground which is covered with an approximately 10cm thick layer of dirt and animal dung? Answer: No, dirt and dung should be removed; organic matter cannot be stabilized. Question No.40:
Can sawdust or peat dust be used as fill material for roads to be processed with RRP? Answer: No, because these are organic materials and therefore unsuitable for stabilizing. Question No.41:
Is RRP suitable for roads consisting entirely of sandy soil? Answer: For processing, the sand should contain not less than 15% of fine grained constituents. This can be determined by testing a sample of the soil. Question No.42:
How do oil, diesel fuel, etc, affect the stability of a road processed with RRP? Answer: These substances have no adverse effects. Question No.43:
Conroads comprising a crushed limestone mixture and prone to become soft in rainy weather be suitably processed with RRP? Answer: When processed, such roads will behave favorably: softening will have been eliminated once and for all, provided that the treatment has been applied correctly, in accordance with our working instructions. Question No.44:
What happens to agricultural land with growing crops adjacent to roads if it is accidentally sprayed with RRP? Answer: This should be avoided if at all possible. However, if it should nevertheless occur, no great harm will be done. At worst, agricultural machinery travelling on ground which has unintentionally been sprayed will, in course of time, cause it to consolidate more. Question No.45:
Can the slope of an earth silo be stabilized with RRP? Answer: Yes, excellently. It will make the slope firm, so that rain can no longer wash it away, of course provided that the treatment is correctly applied, in accordance with our instructions. Question No.46:
Can an existing forest road which has a waterbound surfacing, but has been damaged by frost and water, be reconditioned with the aid of RRP? Answer: Of course it can, and it will put an end to all objectionable potholing due to thawing. The road should be trimmed, sprayed with RRP, and given optimum compaction. That is all. Question No.47:
How does RRP behave on forest roads under trees whose tops meet, so that the ground never gets direct sunshine, but nevertheless gets heavy rainfall (1500 mm and more per year), while moreover the ground slopes steeply and the soil consists of very heavy and highly-cohesive loam? Answer: These awkward roads, which used to be always in a soggy condition, never drying Out properly, provide the best example of the effectiveness of the RRP treatment. If the process is correctly applied, in accordance with our instructions, such roads will henceforth always remain dry and be immune from damage by frost. Question No.48:
Can RRP be used in connection with pipeline laying? Answer: Yes, of course. Substantial savings can certainly be effected because, with RRP, the soil excavated from the trench can be used for backfilling after the pipe-line has been installed. This backfill material should be deposited in the trench layer by layer, each layer being treated with RRP and then compacted. Alternatively, the excavated material beside the trench can be sprayed with RRP, which should be allowed to soak in. When the materials is then put back into the trench, it has in fact been transformed by the RRP into a compactable and frostproof backfill Question No.49:
Can soil which has been processed with RRP subsequently be broken open with picks in order to get at drains, pipes or other services underneath? Answer: It is indeed possible, but it will cost much effort. It is better to use a mechanical excavator for the purpose, as the RRP-processed soil, once it has been given optimum compaction, is immensely strong. Question No.50:
Can RRP be used for footways (sidewalks) and similar purposes? Answer: Yes, of course - and in various ways. Either as an ordinary earth path or track which has been processed with RRP or, alternatively, as a paved footway, i.e., comprising a surfacing of slabs or asphalt. In these cases, too, the whole foundation structure is dispensed with. The subsoil in situ is treated just as it is or, alternatively, it is shaped to the required levels either by excavation or by addition of fill material available in the vicinity. Question No.51:
Can RRP be used in combination with block paving? Answer: Yes, of course. Here again the foundation structure is dispensed with, and even the thickness of the block paving itself can be reduced. The RRP-processed and optimally compacted subgrade is completely firm and unyielding, so that the thinnest available. Question No.52:
Is it possible with RRP to construct a car park out of an ordinary field? Answer: Yes, of course. This is in fact an ideal case, because it does not require any excavation work. All that what is necessary is to remove the vegetable earth at the top and to level the in-situ underlying soil (subgrade). The latter is then treated with RRP, given optimum compaction, and the desired surfacing or wearing course is laid over it. Substantial savings should thus be effected. Question No.53:
Can an asphalt-surfacing or concrete road in need of repair be treated with RRP? Answer: No, not directly. Such treatment is possible only if the defective surfacing has first been removed. Then the underlying soil can be impregnated with RRP and given optimum compaction, followed by re-laying of the surfacing. The latter will then no longer be in any danger from damage by water or frost action. Question No.54:
Can cemetery roads be improved with RRP? Answer: Certainly. As we have heard from cemetery administration authorities, RRP processing of their roads not only removes the need for repairs recurring each year, but also the need for regular spraying with weedkiller, because weeds cannot grow in optimally compacted RRP-processed soil in which the water to sustain their growth is lacking. For this type of work, too, it is essential closely to follow the working instructions for the use of RRP. Question No.55:
Can RRP be used for the construction of footpaths for recreational walks? Answer: Yes. most certainly. After all, one of the requirements applicable to such paths is that the people using them should at all times be able to do so with dry feet. With RRP you can be quite sure that this requirement will be fulfilled. Question No.56:
What to do about roads which have suffered frost damage? Can RRP bring help? Answer: In such cases RRP is an ideal remedy. Of course, the surfacing must first be removed, just as it would have to be for conventional repairs. Then the subgrade is suitably trimmed or filled in to the required level and is sprayed with A AP. Next, after optimum compaction of the subgrade, the road is re-surfaced. The new surfacing will be immune from damage by frost or water in the future. The only effect that can now harm it is natural wear and tear at the surface. Question No.57:
Can a timber storage yard of a saw-mill be stabilized with RRP and can heavy fork-lift trucks be allowed on it? Answer: Yes, of course. However, in a storage yard of this kind it is necessary first to remove any waste wood material, sawdust, etc. Then the subgrade should be trimmed to its required level, sprayed with RRP and optimally compacted. This will have given the ground very high bearing capacity. Next, a surfacing or wearing course should be installed, which will have to possess good wear resistance to cope with the fork-lift truck traffic. As for the bearing capacity of the RRP-processed subgrade, this imposes no limitations on the nature or intensity of that traffic. Question No.58:
Can RRP be used for constructing a factory road which is constantly used by very heavy motor vehicles (lorries, trucks,) mobile cranes and stacker trucks? Answer: Yes, that is possible and indeed recommendable. In such circumstances RRP-processed soils can show what heavy loads they are capable of carrying. Even on such very heavily trafficked roads the entire frost blanket or sub-base and base can be dispensed with. All that is necessary is a surfacing, and even this can be substantially reduced in comparison with that required in vonventional road construction. Question No.59:
Is it possible to use RRP for strengthening the floors of factory buildings? Answer: RRP is eminently suitable for this purpose. Our experience gained in the construction of ground-level floors is very favorable. In such cases, too, the ordinary in-situ ground is utilized: it is trimmed to the required level, processed with RRP, and given optimum compaction. The floor surfacing is then laid on this. A saving in the thickness of the surfacing can also be effected. From experience we know that even a plain concrete surfacing, i.e., without reinforcement, will prove excellently durable on a base consisting of soil processed with RRP. We also know of another instance, where the floor of a storage shed was merely given a waterbound surfacing laid on RRP-processed ground. In that particular case a substantial saving in the cost of heating the building was effected, because the RRP-processed subsoil prevents any moisture from rising. Quesion No.60:
Can RRP be used for the construction of a parking area for heavy motor vehicles (lorries, trucks) and a turning area for 30-ton truck-trailer combinations? Answer: Yes, of course. Here, too, no foundation structure is need. The in-situ soil, processed with RRP and optimally compacted, provides the necessary support. The type of surfacing to be used can be chosen to suit the customer's particular requirements. Question No.61:
A factory road (slag mixed with earth) always becomes soft and full of deep potholes after frost. Can RRP bring help? Answer: Yes, of course. The road should be levelled, treated with RRP, and optimally compacted. It is then ready to carry traffic. It is necessary to ensure proper discharge of rainwater and to provide for overall drainage as for a conventional road. The working instructions for RRP should be duly conformed to. Question No.62:
Does RRP work only in in-situ (natural) soil or can it also be used to treat a macadamized surface constantly affected by potholing and frost damage? Answer: RRP can of course be applied to such macadam (crushed-stone) surfaces it they are not stable but become soft and vielding.
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World Exclusive Coordinator for RRP Reynold’s Road Packer - Germany
Pasea Estate
Road Town
British Virgin Islands
Email: trade@ch-non-food.com

Managing Director:
Peter Pressmar
Phone: +1 206-201-2420
Fax: +1 240 376-5581 / 1-360-235-1848