AU2021303585A1

AU2021303585A1 - Apparatus and method of treating soil

Info

Publication number: AU2021303585A1
Application number: AU2021303585A
Authority: AU
Inventors: Juha LEPPÄNEN
Original assignee: Betolar Oy
Current assignee: Betolar Oy
Priority date: 2020-07-09
Filing date: 2021-07-06
Publication date: 2023-02-09
Also published as: LT4179153T; EP4179153A1; EP4179153B1; DK4179153T3; CN115812118A; PT4179153T; FI20205742A1; WO2022008798A1; US20230250596A1; BR112023000370A2

Abstract

Apparatus and method of treating soil. The apparatus (24) is a movable vehicle (25) having a blade device (26) for removing the soil. The removed soil is transferred into a loading space (28) in which the soil is homogenized. One or more binders are mixed to the soil, after which it is taken back to ground by a spreading device (34). Stabilization of the soil is thus carried out in the movable apparatus.

Description

Apparatus and method of treating soil

Background of the invention

The invention relates to a new solution for utili zation and treatment of hardenable materials and masses.

More specifically, the invention relates to the use of stabilizing materials in road and foundation structures and to an apparatus and a method applicable to this purpose.

The object of the invention is described in more detail in the preambles of independent claims of the appli cation .

The length of the whole road network in Finland is approximately 454000 kilometres. The road network consists of state-owned roads, streets maintained by municipalities and privately maintained private roads. The roads are clas sified according to their importance as class I main roads, class II main roads, regional roads and connecting roads. Finland is a sparsely populated country with long geograph ical distances to municipal centres. Funding for maintenance of the general road network has been cut down, whereby the main emphasis of road maintenance has had to be focused on developing the main road network. This has led to deterio ration of the condition of the lower-grade road network. The challenges in road network maintenance include, in ad dition to the reduced funding, an increasing traffic load exerted on the road structure and availability of good- quality stone material. In cold northern conditions a de termining factor in the total thickness of the road pavement structure is often the frost heave. However, in old lower- grade roads the structural layers are relatively thin and partly blended with the soil. In these types of roads there commonly occurs softening, which is a result of repeated freezing and melting cycles, whereby the fine material is blended with a structural layer and the structural layer sinks into the soil. As thick structural layers require much material and consume natural resources, the problems related to the bearing capacity and frost heaving of the lower- grade roads have been attempted to be solved by stabiliza tion. Cement has traditionally been used as a stabilizing binder when improving the bearing capacity of gravel roads. In the current road repair solutions, several defects have been observed.

Short description of the invention

The idea of the invention to provide a new and im proved apparatus and method for road and earth construction.

The characteristic features of the apparatus ac cording to the invention are disclosed in the characterizing part of the first independent apparatus claim.

The characteristic features of the method according to the invention are disclosed in the characterizing part of the independent method claim.

The idea of the proposed solution is that the road or foundation structure is stabilized by means of a movable apparatus. Thereby soil or stone material is removed from ground or from the structure and it is treated in the ap paratus with one or more binders to improve its compression strength. The apparatus is a movable vehicle which com prises a blade device for removing the soil from ground surface or road structure. The apparatus has a loading space for receiving the removed soil and a transfer device for transferring the removed soil from the blade device into the loading space. One or more binders may be fed into the removed soil arranged in the loading space or generally carried by the apparatus by a feeding device. The materials in the loading space may be mixed by a mixing device to form a homogeneous mass. The formed binder-treated mass may be spread by a spreading device of the apparatus back to the ground surface from where it was earlier removed by the blade device.

In other words, the apparatus is configured to re move soil from the ground, foundation structure or road surface, to circulate it through a mixing process and to install the treated stabilized soil back to the place from where it was taken. After the treatment, only one or more binders and optional water to moisten the mixture may have been added to the soil. No external stone material is thus added to the soil in the treatment.

One advantage of the proposed solution is that by the apparatus, soil may be treated significantly faster and more efficiently as compared to a stabilization treatment in which the stabilizing material is spread onto the ground surface and mixed with the surface soil. In the proposed solution, the treatment may be performed as a unitary and continuous process in which the soil is removed, taken onboard the apparatus for treatment and laid back after stabilization. By means of the solution the treatment of the soil is smooth and it provides a cost-efficient method for refurbishment and construction of roads, streets, tracks, fields and foundations. Further, the proposed so lution is logistically efficient and thus environmentally friendly.

The idea of one embodiment is that the apparatus is an autonomously movable vehicle having its own driving equipment and power supply. The apparatus may thus be an autonomously operating mobile unit or a movable work ma chine.

The idea of one embodiment is that the apparatus is a trailer, a towable vehicle which may be moved by means of a separate work machine, such as a tractor or a bucket loader.

The idea of one embodiment is that the apparatus is configured to treat soil as a continuous process and wherein the treatment of soil is carried out while the vehicle is moving forward in relation to the ground surface. The pro cess stages of removal, mixing, binder feeding and spreading back are performed while the vehicle is moving.

The idea of one embodiment is that the apparatus further comprises a compacting device. By the compacting device, the treated soil which has been installed back to the ground may be compacted right after the spreading de vice. The compacting device may be for example a vibrator.

The idea of one embodiment is that the blade device comprises a cutting blade. The blade is configured to scrape a portion of a selected depth off the ground surface by the effect of movement between the vehicle and the ground sur face. In terms of its operating principle, the blade may thus resemble a plane having a blade to be positioned rel ative to a body.

The idea of one embodiment is that the apparatus equipped with an unmovable cutting blade is a type of scraper vehicle.

The idea of one embodiment is that the blade device comprises a milling device having a plurality of rotary blades.

The idea of one embodiment is that the blade device may also comprise movable scrapers, chains, cup-like mem bers or corresponding soil-removing projections.

The idea of one embodiment is that the blade device is configured to remove soil to a thickness of 200 - 1000 mm over the whole working width of the apparatus.

The idea of one embodiment is that the blade device is configured to remove soil over a limited area which is narrower than the whole working width of the apparatus. In this case the apparatus is intended for working a groove along the area travelled by the apparatus. The apparatus may also be configured to form two or more separate longi tudinal worked areas over its working width. The depth of such narrower treatment areas from the ground surface may be greater than in the above-mentioned treatment performed over the whole width. The cut may have a depth of 300 - 1000 mm. The apparatus may also be configured to remove the road ditch soil, to stabilize the ditch soil and to shape it back into a ditch.

The idea of one embodiment is that the blade device is configured to remove soil over the whole working width of the apparatus or an otherwise wide area, but in such a way that the bottom of the area being worked has a desired profile. The shape of the profile may comprise for example a corrugated bottom or it may have a plurality of longitu dinal recesses at a distance from each other. When the binder-treated mass is applied to such profiled formation, the structure may be further reinforced.

The idea of one embodiment is that the mixing device comprises a plurality of movable blades and is configured to crush the removed soil in the loading space. In other words, a crushing device of the mixer may break the stones contained in the soil to a smaller size and crush any pos sible asphalt, which are removed and treated by the appa ratus.

The idea of one embodiment is that the mixing device comprises at least one movable or rotatable mixing arm, projection or vane for mixing the soil.

The idea of one embodiment is that the feeding de vice is arranged in connection with the spreading device, whereby the binder is fed after mixing of the soil. In other words, the binder is not fed to the treated soil until right before installing it back onto the ground surface.

The idea of one embodiment is that the spreading device comprises a downwardly sloping inclined plane along which the soil is transferred from the mixer to the ground. The soil may be treated during the time it is transferred along the inclined surface. Above the inclined spreading surface there may be a plurality of nozzles or spreading units from which the binder may be applied to the surface of a layer of soil.

The idea of one embodiment is that the feeding de vice for feeding the binder is arranged in connection with the loading space.

The idea of one embodiment is that the feeding de vice is arranged to be part of the mixing device. In this case the binder is mixed into the soil to be treated during the mixing.

The idea of one embodiment is that the feeding de vice is arranged in connection with the transfer device, whereby it is configured to feed the binder into the removed soil before it reaches the loading space.

The idea of one embodiment is that the feeding de vice is arranged before the blade device as seen in the travelling direction of the apparatus, whereby the feeding device is configured to treat the soil with the binder right before its removal and transfer for treatment by the appa ratus.

The idea of one embodiment is that the feeding de vice comprises a pressurizing device for pressurizing the binder and at least one nozzle for spraying the pressurized binder to the soil. Said pressurizing device may be a pump. If the binder has a powdery structure, the binder may be fed by means of a powder feeding unit.

The idea of one embodiment is that the apparatus may comprise binder feeding at two or more of the abovemen- tioned feeding sites. Thereby the feeding site may be se lected in a suitable manner according to the soil treatment to be performed at a given time. Further, it is possible to feed binder simultaneously from two or more feeding sites. When two or more binders are fed to the soil, it is possible to feed these different binders at the same feeding site or at different feeding sites.

The idea of one embodiment is that the apparatus comprises at least one container for the binder. In other words, the apparatus is configured to carry the binder to be needed in the treatment onboard the vehicle.

The idea of one embodiment is that the container is a liquid tank for storing a liquid binder.

The idea of one embodiment is that the container is intended for storing a powdery binder. The idea of one embodiment is that the container is a removable and replaceable unit. Thereby the container may be quickly replaced with a new one after it has become empty or when switching from one binder to another. In connection with the container, the apparatus may comprise a replacement mechanism which may comprise a mechanical quick coupling for the container and quick connections to the feeding mech anism.

The idea of one embodiment is that the apparatus is intended for road layer stabilization, wherein soil mate rials of the load-bearing structure of the road are homog enized and stabilized. In other words, the apparatus is intended for stabilizing road repair in which the existing load-bearing structure of the road is treated to improve its strength and bearing capacity.

The idea of one embodiment is that the apparatus is sized to the width of a road lane.

The idea of one embodiment is that the apparatus is configured to feed to the soil at least one activator ma terial which together with the soil being treated is con figured to form a hardenable geopolymeric or alkali-acti- vatable mixture. In other words, the binder to be used is an activator used in the hardening of a geopolymer or an alkali-activated material.

The idea of one embodiment is the use of binders and binder mixtures made from side streams and wastes in road construction. The life-cycle costs of pavement struc tures containing base layers stabilized with such industrial side-stream and waste-based binder mixtures may be signif icantly lower as compared to pavement structures constructed from natural stone materials. A further advantage of the proposed new solution may be that difficultly treatable side-stream materials may be efficiently and safely pro cessed and utilized at a road and earth construction site. In the method, the mass may be prepared at a road construc tion site in one operation into a ready castable batch and applied to the road pavement structure.

The idea of one embodiment is that the proposed apparatus is also suitable for a stabilization treatment using ashes, such as fly ash and cement or fly ash and lime. Also other ashes formed in biocombustion may be utilized as the binders or stabilization subcomponents.

The idea of one embodiment is that the spreading device comprises a device for feeding the mass into a geo tube or a corresponding sleeve structure.

The idea of one embodiment is that the spreading device comprises a device for feeding the mass over or under one or more earth construction films or fabrics, or alter natively between two or more films or fabrics.

The idea of one embodiment is that the apparatus comprises an applicator device by which an insulating ma terial may be arranged to the surface of the abovementioned geotube, sleeve structure, earth construction film or fab ric. Said insulating material may be for example paint or paint-like material to be applied with a brush, a roller or by spraying and having a good thermal insulation capacity. The material may comprise for example nanomaterial or na noparticles .

The idea of one embodiment is that the apparatus comprises a surfacing device by which a wearing surface layer or a corresponding top surface layer may be arranged directly to the surface of the geotube, sleeve structure or the like. The surfacing may be for example asphalt, concrete or geopolymeric material. The surfacing device may lay the surfacing simultaneously with the abovementioned stabilized structural layer. Alternatively, the surfacing device may lay the surfacing over the abovementioned stabilized struc tural layer immediately after this structural layer has been laid off the apparatus. In both cases the road or other earth construction site being stabilized is completed in a single operation up to the surface layer.

The idea of one embodiment is that in addition to the renovation and construction of roads, the proposed so lution is also applicable to the stabilization of founda tions for streets, fields, yards and buildings and struc tures.

The idea of one embodiment is that the solution relates to a method of stabilizing soil with a binder. In the method, soil is treated with at least one binder to improve its compression strength. Further in the method the treatment of soil is performed in a movable apparatus. In other words, the stabilization treatment is performed while the apparatus is moving forward in its driving direction.

The idea of one embodiment is that the stabilization is performed as one continuous process and is completed in a single operation.

The idea of one embodiment is that homogenization and stabilization treatment of the load-bearing structure of the road are performed in the movable apparatus. In other words, the soil being treated is in this case road aggre gate.

The idea of one embodiment is that no new natural stone material is added to the road aggregate or pavement structure in the stabilizing road repair method being per formed. Therefore, natural stone materials may be saved and transports reduced.

The idea of one embodiment is that only one or more liquid or powdery binders are added to the existing road material in the stabilizing treatment.

The idea of one embodiment is that the stabilization of the load-bearing structure of the road is performed in a single operation and using a single apparatus.

The idea of one embodiment is that the proposed apparatus and method are also applicable to stabilization of the load-bearing structure of a new road. In this case, soil is drawn from the desired road line and it is stabi lized while the movable apparatus is moving along the se lected road line.

The idea of one embodiment is that the proposed apparatus and method are applicable to stabilization of a single-use or temporary road structure or area. By means of the proposed solution, for example a diversion, emergency access road, forest road, loading area, turnaround or the like may be constructed quickly and at a low cost.

The idea of one embodiment is that the soil is sta bilized to a compression strength of at least 0.1 MPa by means of the proposed apparatus. Thereby the other geotech nical properties of the treated soil are generally improved as well.

The idea of one embodiment is that the material being treated is stabilized to a compression strength of 0.1 - 100 MPa by means of the proposed apparatus.

The idea of one embodiment is that the load-bearing structure of the road is stabilized to a compression strength of at least 4 MPa by using as the binder an acti vator that forms together with road aggregate a hardenable geopolymeric or alkali-activatable mixture.

The idea of one embodiment is that the road aggre gate is stabilized to a compression strength of 0.1 - 100 Mpa.

The idea of one embodiment is that the road aggre gate is stabilized to a compression strength above 6 Mpa.

The idea of one embodiment is that soil is removed by a movable removing device and the removed soil is trans ferred into a loading space of the movable apparatus; the removed soil is treated by a mixing device of the movable apparatus for its homogenization; at least one binder is fed to the soil; and the removed soil is returned back to ground after the treatment by a spreading device. In other words, the soil is circulated in the method through the processing device of the movable apparatus and returned back to the place from where it was taken.

The idea of one embodiment is that base layer sta bilization is performed for the road by removing soil of the road in a layer of a predetermined thickness and by treating the removed layer by providing it with only binder to increase the compression strength of the existing soil.

The idea of one embodiment is that composition of the road aggregate is analysed and the binder and dosage of the binder to be used are selected based on the analysis.

The idea of one embodiment is that composition of the soil to be treated is analysed before starting the stabilization of the road.

The idea of one embodiment is that composition of the soil being treated is analysed during the stabilization and binder feeding is adjusted based on the analysis.

The idea of one embodiment is that moisture of the soil being treated is determined and if necessary, water is added to the soil being treated to obtain a desired moisture content.

The idea of one embodiment is that at least one industrial side-stream material or product prepared from a side-stream material is mixed into the soil in the movable apparatus.

The idea of one embodiment is that in addition to the binder, at least one fibre material is mixed into the soil in the movable apparatus. The fibre material may be pulp-based fibre, such as lignin. Alternatively, the fibre material may be recycled textile fibre.

The idea of one embodiment is that in addition to the binder, textile fibre is mixed into the soil in the movable apparatus as fibre reinforcement. The textile fibre may be recycled fibre, such as modified fibre from cast-off clothes or other textiles. The recycled fibre may also have been prepared from surplus clothes or surplus material of textile industry processes. Textile fibre has been found to be particularly well suited for reinforcing at least foun dation structures of which the required lifetime is limited. Such structures include for example various temporary roads, support structures and protective embankments.

The idea of one embodiment is that in addition to the binder, waste fibre being produced in the demolition of wind turbines is mixed into the soil in the movable appa ratus as fibre reinforcement. The blades and also other structures of wind turbines include reinforced plastic in which the plastic material is reinforced with glass fibres, carbon fibres or the like. Especially the dismantling of the blades produces a large amount of glass-fibre plastic waste which after crushing may be used as such as a filler in a foundation structure. Further, the glass-fibre plastic waste may be processed in such a way that mainly just the fibre material is used as fibre reinforcement in the foun dation structure. The wind turbine demolition waste may be used for extension and repair construction of the surround ings of the wind turbine being demolished and of the wind park, whereby the waste need not be transported over long distances. In other words, for example foundations of new wind turbines and service roads may be constructed from the proposed solution. It is also possible to use the proposed solution in the construction and renovation of the road network and other foundation work in the surrounding area. The treatment of the wind turbine blades may comprise crush ing by a movable crushing device in the immediate vicinity of the wind turbine being demolished. The movable apparatus according to the solution or the road construction machine may comprise a feeding device for feeding this fibre mate rial having been separated by crushing into the mass.

The idea of one embodiment is that in addition to the binder, at least one crushed non-stone material is mixed into the soil in the movable apparatus as a filler, thermal insulation layer and/or drainage layer. The crushed mate rial may be for example crushed tires, crushed concrete, crushed asphalt or crushed foam glass.

The idea of one embodiment is that in addition to the binder, reinforcement elements which may be for example bar-like or mesh-like objects are mixed into the soil in the movable apparatus. For example re-bars or steel wire meshes may be fed to the structure to be stabilized by means of a feeding mechanism in the movable apparatus in order to form steel reinforcement. Alternatively, geosynthetic re inforcements, such as bars, profiles or meshes, may be fed to the structure to be formed in the work machine by means of a feeding mechanism. The movable apparatus may thus per form both of the mass stabilization treatment and instal lation of the reinforcement elements at the same time.

The idea of one embodiment is that the stabilization treatment is performed for an edge portion of the road by means of the movable apparatus.

The idea of one embodiment is that the road shoulder is stabilized.

The idea of one embodiment is that the road ditch at the edge of the road is stabilized and shaped.

The idea of one embodiment is that the counter em bankment of the road is stabilized and shaped to support the road structure. Further, an edge portion may be formed from the stabilized mass at the edge of the road to prevent the growth of vegetation close to the road. The stabilized edge portion may also serve as a foundation for installa tions of the road structure, such as, for example, traffic signs, guide signs, street lights and railings.

The idea of one embodiment is that the solution is suitable for renovation and construction of lower-class and gravel roads. However, the proposed solution may also be used in the renovation and foundation of main roads and other larger roads. It is to note that in this application a geopolymer may also mean an alkali-activated material. In this type of material, silicon oxide Si0₂ and aluminium oxide A1₂0₃ have reacted and formed a compression-resistant solid structure. Sometimes geopolymers are also referred to in literature as a subset of alkali-activated materials. In this type of material, silicon oxide S1O₂ and aluminium oxide AI₂O₃ have a central role in the formation of so-called geopolymer cement which is a cement-like binder. Geopolymer cement may be utilized in the manufacture of a compression-resistant, concrete-like material.

Further, it may be stated that a geopolymer is a cementitious binder which may be utilized for the manufac ture of a concrete-like material, and which is produced from a silicon- and aluminium-containing material, for example a side-stream material in alkaline or acidic conditions. A concrete-like strong material produced in a reaction of industrial mineral side-streams and alkaline components is also generally called a geopolymer.Alkaline components such as sodium-based solutions are used as reactive agents in the manufacture.

The idea of one embodiment is that in addition to the abovementioned binders, all kinds of other available and suitable binders and activating materials may be applied in the proposed solution.

The idea of one embodiment is that the proposed apparatus and method are designed and intended particularly for utilization and use of industrial side-stream materials in layer stabilization.

The idea of one embodiment is that in addition to roads and streets, the proposed apparatus, method and the numerous embodiments described above are also applicable to the treatment and improvement of geotechnical properties of the foundation soils for buildings.

The idea of one embodiment is that in addition to roads and streets, the proposed apparatus, method and the numerous embodiments described above are also applicable to the treatment of soil foundations of parking spaces, storage spaces, pools, clamps, terminals, sports fields and indus trial parks and to the improvement of geotechnical proper ties of their soils.

The above-disclosed embodiments and their features may be combined to provide desired configurations.

Short description of the figures

Some embodiments of the proposed solution are il lustrated in more detail in the following figures, in which

Fig. 1 is a schematical and simplified diagram pre senting different layers of a road structure,

Fig. 2 is a schematical and simplified diagram pre senting a composition of one binder-stabilized structural layer,

Fig. 3 is a schematical and simplified diagram pre senting some additional features and components which may be included in a stabilized structural layer,

Fig. 4 schematically illustrates a cross-section of one road structure as seen from a longitudinal direction of the road,

Fig. 5 schematically illustrates a cross-section of one road structure and its edges as seen from a longitudinal direction of the road,

Fig. 6 schematically illustrates one stabilized structural layer with reinforcements as seen from a longi tudinal direction,

Fig. 7 and 8 schematically illustrate some apparat uses for stabilizing soil as seen from the side,

Fig. 9 is a schematical and simplified diagram pre senting features of yet one apparatus used for stabiliza tion, and

Fig. 10 is a schematical and simplified diagram presenting features relating to analysis of soil. For clarity reasons, some embodiments of the pro posed solutions are illustrated in the figures in a simpli fied form. The same reference numbers are used in the fig ures to refer to the same elements and features.

Detailed description of some embodiments

As seen in Fig. 1, a road structure 1 typically comprises a subsoil 2 over which a pavement structure 3 of the road is provided. The pavement structure 3 comprises a plurality of successive layers 3a which may include a sur face layer 4, a base layer 5, a sub-base layer 6 and a drainage layer 7. There may be fewer of more of the struc tural layers 3a depending on the circumstances. The struc tural layers 3a may be as known per se in structure and properties. One or more of these structural layers may be treated with a hardenable binder to stabilize the structural layer. This is referred to as a so-called layer stabiliza tion.

In Fig. 2 it is presented that a stabilized struc tural layer 8 comprises a hardenable binder 9 by which stone material 10 of the structural layer 8 is reinforced. The stone material 10 may be for example sand, gravel, broken stone, crushed material or the like. The stabilized material or mass may further be applied in a space delimited by a sleeve structure 11. The sleeve structure 11 may be a tub ular structure. Alternatively, the stabilized structural layer may be applied over or between one or more filter fabrics or earth construction films.

Fig. 3 lists additional features which may be in cluded in the binder-stabilized structural layer. As men tioned above in this document, the stabilized mass may com prise a fibre reinforcement 12 and the mass may be foamed 13. Further, for example a geopolymer or an alkali-activat- able mixture 14 may be used for the stabilization of the stone material. Additionally, a filler 15 may be mixed in the mass and its strength may be improved by using separate reinforcement elements 16. The mass may be electricity- conducting 17 and storing. The stabilized mass may be ap plied between, over or under protective layers 18, which protective layers may be a tube or a sleeve structure, a filter fabric and various other films and wovens. Further, various inserts 19 such as, for example, technical instal lations, devices, sensors, cables, anchoring elements and coupling elements may be arranged in the stabilized mass and structure. Thermally insulating material, paste or paint may be applied to the surface of the structure.

Fig. 4 illustrates one road structure 1 in which the binder-stabilized structural layer 8 is the base layer 5 over which a levelling layer 20 is further applied. The levelling layer 20 may be a protective layer or a layer that enables shaping of the road surface and protects the sta bilized layer 8. The levelling layer 20 may be crushed material. On top there is a surface layer 4 which may be crushed material, oil gravel, concrete or asphalt. Under the structural layer 8 there may be the normal sub-base layer 6 and drainage layer 7 which are part of the pavement structure 3 and of course the subsoil 2 under the pavement structure 3. Further, the stabilized structural layer 8 may be arranged in a space delimited by a sleeve structure 11. The sleeve structure 11 may protect the structural layer 8 against moisture stress and it may be a type of geotube that participates in shaping the cross-section of the structural layer.

Fig. 5 illustrates one road structure 1 having a binder-stabilized structural layer 8 in its pavement struc ture 3. Additionally, the edges of the road structure 1 are also provided with binder-stabilized edge portions 8c, 8d. These edge portions 8c, 8d may form the embankment or shoul der of the road structure and may thereby speed up the construction of the road and facilitate road maintenance. Further, the edge portions 8c, 8d may be provided with a ready ditch profile 21 or ditch beam, technical installa tions 22 or supports 23. The technical installations 22 may be for example conductors, measuring devices and fixing elements. The supports 23 may be for example elements in tended for supporting and fixing railings, lampposts, traf fic signs and the like. Further, the edge portions 8c, 8d may be provided with integrated or separate extension por tions 8e which also comprise a binder-stabilized structure. The counter embankment of the road structure may be sup ported and construction of the road speeded up by means of the extension portion. Further, maintenance of the road may be facilitated and safety improved when vegetation at the edges of the road may be prevented.

Fig. 6 illustrates a binder-stabilized structural layer 8 having a plurality of longitudinal reinforcement elements 16 arranged to its base P side. Due to bending, the base P side of the structure is subject to tensile stress that is well absorbed by the reinforcements 16. The reinforcements 16 may have a desired profile and they are fixed to the surrounding hardened mass.

Fig. 7 illustrates an apparatus 24 for treating a structural layer of a road structure 1 or any ground soil. The apparatus 24 comprises a movable vehicle 25 having a blade device 26 for removing the soil from the surface of the road structure 1 or ground while the apparatus 24 is being moved in a driving direction A. The blade device 26 may be for example a milling machine. Alternatively, the blade device 26 comprises a cutter plate 26a which is pushed into the soil while the apparatus 24 is moving and removes the soil by scraping. The soil may be cut for example to a depth of 200 - 400 mm. The removed soil is transferred into a loading space 28 of the apparatus by a transfer device 27, which loading space is provided with a mixing device 29. The mixing device 29 may not only mix the soil but also crush its larger constituents, such as stones. The mixing device 29 may comprise a plurality of movable blades 29a. The transfer device 27 may be a conveyor or an inclined surface. A feeding device 30 is configured to feed one or more stabilizing materials into the soil. The apparatus 24 may comprise one or more containers 31 for the stabilizing material. After mixing and homogenization, the mass may be transferred by means of conveyors 32 and 33 from the loading space 28 to a spreading device 34 which spreads the mass onto the ground surface as a structural layer having a desired layer thickness and width. The mass may be compacted by means of a vibrator V.

As seen in Fig. 7, the binder or binder mixture being used in the stabilization may be fed from a feeding device 30 into the loading space 28, from a feeding device 30a to the conveyor 33 or from a feeding device 30b to the spreading device 30b.

For analysis of the soil to be removed, the appa ratus 24 may comprise a sensor SI and an optical measuring device 35 or a camera. In connection with the loading space 28 there may be a sensor S2 to identify properties of the mass and the soil. Sensors and measuring devices may also be arranged in connection with the transfer device 27 and the conveyors 32, 33. The measurement data are transmitted to a control unit CU of the apparatus 24. Alternatively or additionally, measurement data may also be transmitted to one or more external control units CU^", servers or elec tronic terminal devices.

The apparatus 24 may comprise a feeding device 36 for feeding a film, fabric, geotube or the like together with the stabilized mass. Further, the apparatus 24 may comprise a feeding device 37 for feeding reinforcements or cables onto the ground surface together with the mass.

Fig. 8 illustrates another apparatus 24 having a slightly different construction than the scraper vehicle illustrated in Fig. 7. However, the main components and the operating principle are the same. The difference is that after mixing, the mass is fed from the loading space between two films 38a, 38b. In this case, the spreading device 34 comprises film feeding devices 39a, 39b and a coupling de vice 40 for joining the edges of the films to each other. Alternatively one film is used, the longitudinal edges of which film are guided to the upper surface side of the mass and coupled to each other. In both cases, the spreading device 34 feeds the tubular structure along the conveyor surface 32 onto the surface of ground. The tubular structure is a geotube or sleeve structure 11 which protects the stabilized structural layer 8.

Fig. 7 and 8 further introduce a foaming device 41 by which the mass may be foamed to reduce its density.

Fig. 9 further lists the features of one apparatus 24. The apparatus differs from those illustrated in Fig. 7 and 8 in that the blade device 26 comprises a boom and a bucket. The boom may be movably coupled to the chassis 25 of the apparatus 24 and different buckets may be coupled to its outer end. The blade device 26 may thus be the boom of an excavator.

Fig. 10 presents the stages, devices and features relating to analysis of the soil being treated. These as pects have already been described above in this document.

Although the invention is illustrated in the figures in relation to a road structure, the apparatus is also suitable for other earth and foundation construction. Sev eral examples of this have been introduced under short de scription of the invention of the specification.

The figures and their description are only intended to illustrate the idea of the invention. However, the scope of protection of the invention is defined in the claims of the application.

Claims

1. An apparatus for treating soil, which apparatus (24) is a movable vehicle (25) and comprises: a blade device (26) for removing the soil from ground surface; a loading space (28) for receiving the removed soil; a transfer device (27) for transferring the removed soil into the loading space (28); a feeding device (30) for feeding at least one binder into the soil; a mixing device (29) configured to mix the soil in the loading space (28); and a spreading device (34) for spreading the binder- treated soil back to the ground surface from where it was removed by the blade device (26); characterized in that the apparatus (24) is configured to feed to the soil at least one activator material which is together with the soil being treated configured to form a hardenable geopol ymeric or alkali-activatable mixture.

2. The apparatus according to claim 1, charac terized in that the blade device (26) comprises a cutting blade

(26a), which blade (26a) is configured to scrape a portion of a selected depth off the ground surface by the effect of movement (A) between the vehicle and the ground surface.

3. The apparatus according to claim 1 or 2, char acterized in that the mixing device (29) comprises a plurality of movable blades (29a) and is configured to crush the removed soil in the loading space (28).

4. The apparatus according to any of the preceding claims 1 - 3, characterized in that a feeding device (30b) is arranged in connection with the spreading device (34), whereby the binder is fed after mixing of the soil.

5. The apparatus according to any of the preceding claims 1 - 4, characterized in that the apparatus (24) comprises at least one container (31) for the binder.

6. The apparatus according to any of the preceding claims 1 - 5, characterized in that the apparatus (24) is intended for road layer sta- bilization, wherein soil materials of the load-bearing structure of the road are homogenized and stabilized.

7. A method of treating soil, in which method: soil is treated with at least one binder to improve its compression strength; and the soil is treated in a movable apparatus (24); characterized in that the load-bearing structure of the road is stabilized to a compression strength of at least 0.1 MPa by using as the binder an activator which forms together with road ag gregate a hardenable geopolymeric or alkali-activatable mixture.

8. The method according to claim 7, charac- terized in that homogenization and stabilization treatment of the load-bearing structure of the road are performed in the movable apparatus (14).

9. The method according to any of the preceding claims 7 or 8, characterized in that soil is removed by a movable removing device (26) and the removed soil is transferred into a loading space (28) of the movable apparatus (24); the removed soil is treated by a mixing device (29) of the movable apparatus (24) for its homogenization; at least one binder is fed to the soil; and the removed soil is returned back to ground after the treatment by a spreading device (34).

10. The method according to any of the preceding claims 7 - 9, characterized in that layer stabilization is performed for the road by removing soil of the road in a layer of a predetermined thickness and by treating the removed layer by providing it with binder to increase the compression strength of the existing soil.

11. The method according to any of the preceding claims 7 - 10, characterized in that composition of the road aggregate is analysed and the binder and dosage of the binder to be used are selected based on the analysis.

12. The method according to any of the preceding claims 7 - 11, characterized in that at least one industrial side-stream material or product prepared from a side-stream material is mixed into the soil in the movable apparatus.

13. The method according to any of the preceding claims 7 - 12, characterized in that the stabilization treatment is performed for an edge portion of the road by means of the movable apparatus (24).