Infrastructures

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.

Keywords

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.

Keywords

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.

Keywords

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.

Keywords

Operative and efficient solutions that help to preserve and strengthen important infrastructure facilities

Local utility companies and government bodies are responsible for a large number of facilities from roads and bridges to water supply, sewerage and drainage systems. In order to ensure the safety and efficient uninterrupted servicing of residents, it is crucial to keep these facilities in good working order. Continuous monitoring and technical servicing is important not only for occupational safety and efficiency, but also from the aspect of long-term reliability.

According to a recent study, interruptions in the provision of main utility services such as electricity and water supply have great impact on both business and domestic activity. Additionally, deterioration of the condition of main and minor roads can reduce expediency of freight transport, increase costs related to servicing of vehicles and increase risk of accidents.

After realising the increase in the cost of maintaining and renovation of infrastructures, many European local governments and public bodies have recognised URETEK’s innovative technological solutions as fast and most sustainable method to maintain and restore various objects that often have complex structure.

When choosing suitable solution, it is important to consider factors affecting the safety, ease of use and durability of infrastructure objects. Examples of innovative solutions provided by URETEK for servicing infrastructures:

Stabilisation of public buildings and underground infrastructure

URETEK’s non-invasive resin injection technology was used when building Moskva City to fill large cavities and voids adjacent to heating main and restore the soil under a structure, increase load-bearing capacity of the soil and prevent its further subsidence. In the course of these works, heating pipeline was efficiently stabilised and supported within less than a week, without disturbing the functioning of adjacent pipelines.

Clients often address URETEK to stabilise state and public structures suffering from uneven land subsidence under the foundation. For instance, after discovering the sinking of the foundation and floor of a building belonging to local government used as a restaurant in Belgorod oblast, causing large cracks in the walls, URETEK managed to restore the building in an operative and sustainable manner. Lifting, re-levelling and supporting of the building took only ten days when using geopolymer resin.

Discarding of reserve pipes

URETEK light resin represents a tried-and-tested and innovative solution for filling bulky pipes and other technical reservoirs to be discarded. In Kuzbass region, URETEK technology was used to fill an underground water pipeline in the course of modernising a mineshaft. URETEK geopolymer is so-called flowing material, which can be pumped at great distances (when expanding, the material achieves incredibly high compressive strength at minimum density). Many clients have admired the material’s ability to fill large voids, cavities, pipes and reservoirs quickly and cost-efficiently.

Rapid expansion of the cities of the Russian Federation causes increasing burden on infrastructure. Thus, it is more important than ever to ensure durability of structures in long the long term, while also keeping in mind the impact that solutions and measures applied today have on the quality of structures intended for the future generations.