Technology | URETEK

Lifting and levelling of aerodrome surface covers

The covering of taxiways and take-off and landing runways on aerodromes may sink

When using classical methods, restoring damaged sections along with strengthening the subsoil and replacing cover plates takes several weeks or even months, during which aerodrome cannot operate at full capacity. When using URETEK materials, restoration works take only a few days or even just a few hours.

Subsidence of aerodrome concrete slabs is a common problem in many airports across the world. Aerodrome surface slabs may be subject to subsidence due to increased volume of passengers and cargo, deteriorated drainage system, natural wear and tear of materials, etc.

Subsidence of concrete slabs within permitted limits is not dangerous and does not cause accident-prone situations. But if the weakening of soil under the aerodrome and subsidence of certain runway sections exceeds permitted limits, immediate intervention is required. Even if the condition of aerodrome cover slabs is not yet unsafe, it may lead to danger situation in case of sudden change in weather conditions. For instance, if water in the recesses of aerodrome surface freezes, it may cause planes to slide.

Strengthening of the soil under airfield

In order to restore concrete slab surface of aerodrome, it is necessary to strengthen the soil under the slabs. Traditionally, stabilisation and levelling of aerodrome surface slabs requires partial or complete dismantling, closing unsafe section for major repairs and involving heavy duty vehicles. After dismantling of the slabs, soil strengthening procedures are performed, followed by restoration of aerodrome surface.

When using modern URETEK technology and materials, it is not necessary to dismantle or replace the aerodrome surface in order to strengthen the soil under aerodrome and stabilise and level the position of concrete slabs, neither is it necessary to deploy heavy machinery.

For strengthening the soil, a certain number of holes with 16 mm diameter are drilled in aerodrome surface used for inserting geopolymer material to required depth.

Principle of the technology

URETEK material contains special geopolymer resins, which expand and harden when inserted in soil, achieving great strength in merely 15 minutes. That way, the soil under the airfield is strengthened, whereas restored section can be used almost immediately after performing the injections.

Technology allows restoring the site with only minor changes in flight plan that do not interfere normal functioning of the aerodrome. It is sufficient to plan repair works for the period when there are not many take-offs and landings. Due to the dimensions of equipment required for URETEK geopolymers injection and autonomous nature of transport equipment, it does not limit the aerodrome resources during restoration works.

Variations in technology

URETEK technology can be used in two ways to lift and stabilise airfield cover plates. Methods differ from each other in terms of the depth of geopolymers injection. Deep Injection method is used to restore former soil properties at the depth of several meters. For immediate stabilisation and levelling of concrete slabs, geopolymer material is inserted in the gap between soil and slab by using Slab Lifting method. In both cases, the position of aerodrome surface and concrete slabs is adjusted by means of laser levels with precision of ±1 mm.


Stabilisation of railway tracks

URETEK geopolymers injection technology allows repairing railway embankments in the shortest time, while not affecting train traffic

Geopolymer resins help to strengthen and stabilise sunken crushed stone layer, also level concrete slabs of railway tunnels, stations, crossings and depots and lift them to designed height where necessary.

Railway infrastructure consists of many objects, including sections with railway tracks, tunnels, bridges, stations, depots, repair workshops, etc. All these objects suffer from loads caused by train traffic, as well as weather conditions and surface water.

Construction regulations prescribe establishment of groundworks consisting of crushed stone before installing rails. Railway embankment is made of bulk material (e.g. crushed stone). Regular load on rails and crushed stone causes uneven subsidence of different track sections. When subsidence exceeds maximum limits, the position of rails changes and using the tracks becomes unsafe. By using modern URETEK geopolymers injection method, it takes only a couple of hours to restore safe condition of tracks and strengthen crushed stone layer.

Stabilisation of crushed stone layer of railway embankment

Using geopolymers allows strengthening of soil under railway tracks and stop subsidence of crushed stone layer without dismantling rails and sleepers. Meanwhile, stabilisation of railway embankment does not require adding crushed stone. It is sufficient to insert geopolymer resin directly in railway embankment or the soil under it. Geopolymer material expands and exerts pressure vertically, thus lifting the tracks to their designed height.

Lifting of reinforced concrete slabs

In several sections (crossings, tunnels, stations, depots, etc.) tracks are mounted on reinforced concrete slabs. Such slabs can also sink due to changes in surface water level or soil erosion resulting from disruption of drainage systems.

Sections with concrete slabs can also be levelled and stabilised, using URETEK technology to strengthen subsoil. For that purpose, geopolymers are injected through holes drilled in concrete slabs. Meanwhile, there is no need for dismantling slabs and railway embankment. Soil deep under reinforced concrete slab is strengthened by using Deep Injection method, slabs are lifted and levelled by using Slab Lifting method.

Specifics of geopolymers injection

For injection of geopolymers, holes with diameter of 12–16 mm are drilled in crushed stone layer of railway embankment or in reinforced concrete slabs. Geopolymer material is inserted through hoses into pipes with diameter of 8–14 mm. Immediately after injection, geopolymer material expands, filling cavities and voids in soil and thus ensures lifting and stabilisation of structures. The process of lifting is monitored in real time by means of laser level.

Geopolymer achieves required durability in only 15 minutes. This allows quick completion of all works without altering train schedule.


Levelling and repair of roads and parking lot surface

Geopolymer resins injection technology gives an opportunity to repair concrete road surface in a very short time

Geopolymers allow strengthening the soil under concrete road slabs and also lift sunken elements and adjust their position.

Constant use of roads causes deterioration of their condition over time. Roads are affected by dynamic loads caused by heavy duty vehicles, but also by various environmental factors.

Concrete slabs used in construction of roads and parking lots may sink and create accident-prone situations. Such places are most common on high-traffic roads, parking lots, manoeuvring spots and loading areas.   In that case, roads need repair, which can be performed by using URETEK geopolymers injection technology.

Injection under concrete slabs

For restoring the concrete slab pavement, it is recommended to use geopolymers injection method Slab Lifting. This allows lifting sunken concrete slabs, but also level and adjust entire pavement of road section or parking lot. Slab Lifting method makes it possible to repair unsafe road sections adjacent to bridges, railway tracks, docks, loading bays, etc.

Slab Lifting method is much more efficient than traditional road repair methods, because geopolymer resins resist dynamic load well. It is also important that when using geopolymer resins, it takes only a few hours to a couple of days to restore the surface of roads or parking lots.

Meanwhile, works can be performed in stages, without closing all lanes and at the most convenient time, when road traffic is minimal.

Road section repaired using geopolymers can be used even by heavy duty vehicles already 15 minutes after completion of works. As a comparison, restoration of road section with concrete pavement, including dismantling and reinstalling of slabs can take weeks and even months.

Deep strengthening of soil

Geopolymers injection technology allows to restore concrete surface of roads and parking lots as well as strengthen the soil under the road. For that purpose it is best to use Deep Injection method. In that case geopolymers are used for increasing the load-bearing capacity of soil. Deep Injection method can also be applied to construction of new roads and highways. When geopolymers are inserted in excessively humid soil, they force excess liquid out and thus increase the load-bearing capacity of soil.

Work process

For lifting roads and stabilisation of pavement by using geopolymers, only a few holes with diameter of 12–16 mm are necessary for injection.

Injection is performed through special pipes inserted in drilled holes. When reaching soil layer or under concrete slab, geopolymer material extends, fills void and cavities and strengthens weakened soil, forces water out and lifts sunken concrete slabs gradually upwards. Lifting is monitored by using laser level with precision of up to ± 1 mm.


Lifting and stabilisation of port facilities

Geopolymers do not react with water, they remain stable even in humid environment. This allows using geopolymers for levelling and strengthening of jetties, embankments and berths.

URETEK geopolymer resins are suitable for stabilising infrastructure objects of seaports and river ports. In order to lift concrete structures and stabilise them, geopolymers can be injected under the concrete slabs of jetties, embankments and berths as well as in water-saturated subsoil of these structures.

Strengthening the soil under jetties, embankments and berths

Construction of concrete jetties and embankments generally requires installation of a vertical support wall that would retain filling material necessary for installing concrete slabs. Due to constant water influences, surface water level changes dynamically, meaning that there are also changes in the moisture content of soil under the structure.

As a result of that, filling material can slowly become more compact and horizontal surfaces are subject to movement and uneven subsidence. Concrete slabs of jetties, embankments and berths are also affected by heavy duty vehicles, gantry crane, transporters, loaders and other additional loads. Total weight of port loader with transmission container reaches up to 100 tons. Naturally, such weight causes increased compaction of the filling material under concrete base and soil under the entire structure. Thus, different sections of concrete surface may suffer from uneven subsidence.

In order to level concrete slabs and stabilise the structure of jetties, embankments and berths, filling material and subsoil of the structures must be strengthened. Load-bearing capacity of soil is improved with geopolymers in stages and without disrupting port operation.

Lifting and stabilisation of concrete slabs

URETEK geopolymer resins are suitable for levelling and strengthening of parking lots and manoeuvring areas for heavy duty vehicles, loaders and gantry cranes. Furthermore, geopolymers can be used to repair concrete floors and covers of port warehouses and docks, the condition of which has deteriorated due to exposure to water.

Concrete slabs are levelled by using Slab Lifting method. For more efficient stabilisation of port structures, Deep Injection method is used. It enables strengthening of soil under the structure. Geopolymers force out excess water, thus increasing the load-bearing capacity of soil.

Advantages of URETEK methods

Formerly, repair of concrete surfaces meant removal of all cover slabs, compacting of filling material and reinstallation of concrete slabs. In that case, major repairs are similar to new port construction, involving not only high cost, but also long-term stoppage of port operations, causing additional costs and loss.

URETEK technology makes it possible to perform work without dismantling concrete slabs and interrupting port operations. Materials and equipment required for geopolymer injection fit in a single truck. For injecting geopolymers under concrete slabs and deep in soil, holes with diameter of 12–16 mm are drilled. These holes are simply closed later. Stabilised and repaired sections can be used 15 minutes after completion of works.


Repairing cracks in walls and floors of private houses

Cracks can occur in walls and floor of a house as a result of foundation subsidence due to weakening of subsoil.

In order to eliminate cracks, the reason why they occurred needs to be dealt with first, i.e. strengthen the soil and lift foundation to its designed height. This can be easily done by using URETEK geopolymers injection technology.

Among other things, the condition of a private house depends on the condition of the soil under the building. Foundation exerts pressure on the soil and may therefore gradually sink. The house remains stable as long as subsidence does not exceed permitted limits. If these limits are exceeded and foundation subsidence is uneven, it is necessary to take steps to solve the problem.

In case of foundation subsidence there is a danger of damaging floors, load-bearing and non-load-bearing walls, ceilings and partition walls. These structures may crack, window apertures and doorways may bend, utility lines break, etc. In cases like these, patching cracks in floor and walls is ineffective, because it does not eliminate the reason why they occurred – in many cases it is due to weakening of soil under the structure.

Soil weakening may be caused by irresponsibly performed construction works, e.g. insufficient compaction of soil under the structure. Naturally, there are cases where soil properties are altered because of breakage of water and sewer pipes or underground reservoirs. Weakened soil may also result from changes in surface water level.

Strengthening of soil and stabilisation of foundation

Traditionally, heavy machinery has been used to strengthen the soil under the structure and lift the foundation. Residents had to move out for the time of repairs and extensive earthworks were required to access the foundation. In that case, works performed for strengthening soil and securing foundation take 1–1.5 months.

Now, due to URETEK geopolymers injection method, soil can be strengthened, and foundation lifted with only two to three days. Meanwhile, there is no need for repairs and residents can remain in the building. All works related to geopolymers injection are performed outside the building, around its perimeter or indoors without using heavy machinery.

Geopolymers injection

There are two methods of URETEK geopolymers injection used for eliminating cracks in floors and walls of private houses. Deep Injection method allows lifting the foundation and strengthen the soil at remarkable depth. Meanwhile, Slab Lifting method makes it possible to lift concrete slabs on the ground floor by injecting geopolymer resin directly under the concrete slab, between slab and soil.

After injection, geopolymer resins expand quickly, filling all voids and cavities, strengthening soil and exerting vertical pressure. Resin achieves its final structure and hardens within 15 minutes. If geopolymers are injected in excessively humid soil, they force moisture out and strengthen the soil.

The course of lifting structures and eliminating cracks is monitored by using laser level with only ±1 mm deviation. Injection is performed though technical holes with diameter of 12–16 mm, bored in the concrete floor on the ground floor or in the ground around the building.


Comparison of cementing (and silicating) and URETEK technology. Pros and cons of cementing.

Compared to cement mixtures, URETEK materials are more elastic, which is a huge advantage.

As the soil expands and shrinks (depending on its moisture content), cement mixture crumbles and loses its properties, turning to dust. Use of cement mixtures and silicating is not possible in case of soil with porous structure and high content of organic substances. Depending on soil acidity and humidity, the time required for concrete and silicate mixture to harden can be rather unpredictable. Cement mixtures exposed to impact and vibration loads turn to dust. URETEK materials do not have these problems and they are not affected by chemical composition of soil. All components necessary for reaction are mixed together during the injection process, reaction time can be predicted and controlled, and reaction does not depend on external factors.

Soil layers can expand and shrink as their moisture content changes. When strengthening foundation with concrete, a rigid structure is formed, which rises and falls according to changes in soil water content. Constant vertical and horizontal movement of soil leads to occurrence of cracks and damage to the structure under the building. Uneven soil layers further increases the risk of site destruction.

Silicating and cementing is prohibited in various soil types, e.g. porous soils due to surface water, which makes it impossible to achieve required properties by using these formulae. Due to chemical composition of soil, silicate and cement mixtures might not achieve required durability and turn into powder, which further deteriorates the load-bearing capacity of soil.

Advantages of cementing (and silicating):

  • Presence of traditional engineering technology and knowledge;
  • Wide technical application, as there are many theoretical studies available since post-war years.

Disadvantages of cementing (and silicating):

  • it can be slow, because the result is not predictable even after project approval;
  • dirty work, because cement behaviour in its liquid state is not predictable. This can be seen when taking a look at the overalls of cementing technician;
  • labour-intensive process that requires numerous staff;
  • outcome – whether the solution works or not – can be checked only after a certain while. This means that it is a long-term project in most cases;
  • cementing is not an option in loamy or other soils that move and change over time, because it does not eliminate the reason of the problem;
  • outcome of levelling and lifting of structures is not predictable.

URETEK’s solution:

This is a modern and proven method for strengthening foundation (used since 1978). Method encompasses injecting ecologically neutral resin under the foundation through small holes (diameter of 12–32 mm). Resin is inserted in soil, where it expands and hardens, filling all voids and cavities. During resin injection the building or other structure is lifted higher.

Process is closely monitored by technicians who use very sensitive laser equipment. Resin formula is carefully chosen according to climatic and soil conditions and purpose of works.

Advantages of URETEK:

  • clean workspace: no need for excavation works, meaning that there is no dirt and waste;
  • operative and fast: most projects are carried out within two to three days;
  • works do not need major preparations and clients can continue using the site during works.

This method for strengthening foundations has been tested worldwide for more than 35 years and it will protect your object in future.


Elimination of floor subsidence in stores and warehouses without changing their opening hours

Concrete floors of large warehouses, supermarkets and logistics centres may also suffer from subsidence or tilting

Modern URETEK geopolymers injection method allows lifting concrete floor slabs and stabilise them without vacating the premises and disrupting daily work.

Floor slabs in large warehouse and commercial areas are designed in view of daily impact of stationary structures. Concrete floor must also handle loads caused by loading machinery and other warehouse equipment. In case of exceeding permitted maximum static or dynamic loads or in case of changes in soil properties under the structure (weakening of soil due to changes in surface water level, breakage of water or sewerage pipes), it is likely that floor slabs sink or tilt.

The damage described above can cause minor discomfort resulting from changed position of commercial and warehouse equipment, but it can also lead to accidents and situations that endanger human health and life.

Complexity of lifting and stabilising concrete slabs

Unfortunately, subsidence of concrete floor in a warehouse or commercial premises is not always noticed in time. Considering that restoration of concrete floor and strengthening of the soil under the floor requires dismantling of concrete slabs when using traditional methods, the repairs are often postponed as they cause major loss to the owners of premises resulting from long-term work stoppage.

Instead of applying systemic measures, owners often seek temporary solution by using all kinds of supports and bases. However, such an approach to the problem may obviously lead to unpleasant consequences.

Lifting and stabilisation of floor by using geopolymers

Sunken sections of concrete floor can be lifted and the soil under the structure can be strengthened by using URETEK geopolymers injection method.

In that case, there is no need for dismantling concrete slabs, involving heavy machinery or performing earthworks. In order to stop subsidence of concrete slabs and levelling them, geopolymer material has to be inserted deep under the floor in the soil under the structure (Deep Injection method) or in the space between soil and concrete slab (Slab Lifting method).

Immediately after injection, geopolymer resins expand and take up all vacant space in the soil under the structure, compact the soil and harden within only 15 minutes. URETEK geopolymers injection technology allows increasing compressive strength of soil up to 10.6 МPа.

Injection can be done without dismantling sunken slabs. It requires drilling just a few technical holes with diameter of 16mm in the concrete for pipes intended for inserting geopolymer material. Meanwhile, URETEK equipment can be located up to 120 m from the actual place of injection.

Geopolymer material is inserted in soil through special hoses that can easily be moved in the room between shelving and other equipment. Thus, it is not necessary to vacate premises from goods and equipment. Furthermore, the hardening speed of URETEK geopolymer resins allows lifting and stabilisation of concrete slabs at night. But warehouse or store does not have to stop work even if the floor needs to be lifted during working hours. Due to mobility and compact dimensions of the equipment, there is only minimum disturbance in daily operation.

Advantages of URETEK technology

The process of lifting and levelling sunken concrete slabs is monitored in real time. This is done by using special laser levels with measurement accuracy of ± 1 mm. Ground floor slabs can be lifted by maximum 20 cm. After restoration of former floor height, cracks can be eliminated in partition walls supported by sunken slabs. Restoring floors by means of URETEK method allows saving up to 25% compared to traditional methods.


Stabilisation and strengthening of foundations of industrial buildings

Geopolymers are extensively used in repair and renovation of production and industrial facilities.

Geopolymer resins are suitable both for reinforcing the foundation of facilities that are already operational and for modernising unused facilities prior to introduction of more powerful equipment.

Many industrial and production facilities are regularly subject to overload. Depending on their specific nature, such overload may have both static and long-term dynamic impact.

Such loads result in compacted soil under the floor slabs of ground floor and various parts of the foundation. This is often accompanied by settlement of foundation and floor, causing damage to building structure. Settlement can be eliminated by using geopolymer resins injection method.

Eliminating structural damage of a building

One frequently recurring issue in the course of work is linked to using bridge cranes. When moving heavy loads, crane supports are subjected to uneven dynamic load. As a result, the soil under some supports may become more compact than under other supports, and entire structure faces uneven subsidence. If crane supports are also elements of load-bearing structure, it may lead to potential collapse of entire structure.

In order to strengthen the load-bearing frame of the building and stabilise the condition of bridge crane, it is necessary to insert geopolymer resin in the soil under sunken foundation support. This will most likely improve not only the condition of the crane, but of the structure as a whole.

Strengthening of the foundation of industrial facilities

Geopolymer resins can be injected for strengthening the soil under the foundation of industrial facilities without disrupting production cycle. Injection is performed by means of small mobile devices, inserting geopolymer material through technical holes drilled in the ground floor or surface adjacent to building (soil). Geopolymer resins injection exploits pipes with small diameter. Material expands and hardens within just a few minutes.

Increasing the capacity of undertakings

Re-commissioning of abandoned or unused industrial sites is often accompanied by the need to introduce more powerful equipment. This entails increased load on ground floor and foundation. If such loads exceed maximum limit, the soil under ground floor or foundation needs to be strengthened.

Strengthening foundation with geopolymers uses Deep Injection method, which allows inserting material deep in the soil. Additionally, when strengthening the ground floor, Slab Lifting method can be used for performing the injection. Injection can be performed both before and after installing new equipment. Geopolymer injection is continued until the load-bearing capacity of the soil under the structure corresponds to standard value.


Repair of underground structures and waterproofing

Geopolymer resins can be used for waterproofing and strengthening of underground structures.

Furthermore, geopolymers allow waterproofing and restoring underground containers, wells, collectors, fuel tanks, pipeline, mines, cellars and other objects.

Such underground structures may develop microcracks, that can be penetrated by utility line liquids or surface water. In many cases the structure cannot be fully waterproofed by quick repairs, replacement of damaged components and patching cracks. The cracks may also develop in a structure due to changes in soil properties.

In the event that the walls of an underground structure have started leaking, it is rather likely that the soil has weakened or eroded or become less compact. Under such circumstances, besides patching cracks and restoring the site, soil needs to be strengthened. This can be done by increasing soil compactness by means of URETEK geopolymers.

Advantages of geopolymer resins

Major advantage of URETEK geopolymers consists in the fact that the material does not react with water. Geopolymers simply force water to the surrounding environment. When injecting geopolymers in weak humid soil, the water is forced out, while the soil itself becomes stronger and more compact.

Additionally, the soil strengthened and compacted by use of geopolymers has reduced water absorption capacity. Furthermore, when using geopolymers, structure will be waterproof in areas of injection.

Processing the walls in mines and tunnels

Tunnels, pipeline, mines and other similar structures are often assembled by using prefabricated elements. Geopolymer resins can be used to waterproof damaged components of such a structure and fill joints and connections between prefabricated elements. Resins are introduced by injecting them in soil that is in contact with damaged sections and connections between elements.

Injection can be made from the surface without excavating the damaged structure and directly inside the tunnel or mine (where possible). During injection, geopolymer material may even reach the mine or tunnel cavity – this indicates high work quality. Excess material can be removed from internal surfaces.

Reduction of water capacity of soil

Another reason for deteriorated waterproofing of underground structures (cellars, foundations, etc.) consists in substandard quality of compaction of soil adjacent to the walls of the structure. Such soil loses its waterproof qualities and becomes wet more often, which in turn affects the walls of the structure.

This process can be stopped by compacting the soil by using geopolymers injection. Geopolymers injection reduces water capacity of soil, indirectly making the structure waterproof.


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