Kevin, Author at URETEK

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.

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Using URETEK technology for solving problems with industrial and construction platforms

Frequently, the equipment on construction and mining platforms lacks reliability due to their poor quality or ineligibility for particular operation. However, the problem may often be related to land subsidence.

Even the smallest deviations occurring in soil due to subsidence may cause disruptions in the operation of machines and mechanisms that require precision and cause excess burden on such equipment. Eventually, such situation may cause remarkable disturbances in operation and be costly in monetary terms. Ignoring the problem may lead to breakdown of the equipment, resulting in work stoppage and costly repairs (technical maintenance), loss of productivity and, in some cases, risk of danger.

First signs of potential problems

Division operator is recommended to check the alignment of equipment. Frequent deviations include:

Unusual noise generated by equipment;
Abnormal wear and tear of equipment, especially in case of conveyor belts and crane tracks;
Excess wear and tear of tracks and surfaces under equipment due to excess vibration that causes land subsidence.

The most common causes of subsidence (gradual collapse, compaction or sinking of ground surface) include problems related to drainage, poorly compacted filling material and mechanical vibration.

It is crucial to apply early countermeasures

It is always advisable to stop land subsidence before equipment fails, as it allows minimising expenses related to work stoppage and repairs. By using modern soil technology methods, it is much easier and quicker than people would think. For instance, URETEK resin injection technology is a reliable, convenient, effective and cost-efficient alternative solution instead of traditional methods such as concreting or cementing. URETEK technology involves using low pressure to insert resin in unstable soil or rock that has fallen apart or suffered structural damage due to compaction, in order strengthen it. Operative and effective URETEK technology can also be applied in a situation, where it is impossible to intervene in the operations on construction site. Depending on volume, the procedure may take a few days and it can be performed parallel to construction works and without taking breaks. That’s what makes the method so flexible.

Light and yet durable resins used in URETEK technology are sustainable, have low environmental burden and help performing variety of technological and geotechnical tasks. Areas of application include e.g. decommissioning of fuel tanks, underground storages, water pressure pipes, stormwater pipes and tunnels, also filling large cavities, voids and even abandoned mines with bulk material.

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Comparison of concrete works and URETEK technology. Pros and cons

Causes of deformation in building foundation

Formerly, foundation was repaired by cementing, now a new solution is used – URETEK technology. It represents a rapid and secure alternative to concreting and piling of foundation. URETEK technology deploys unique strengthening methods for foundation repairs, somewhat similar to advanced surgery. This technology allows eliminating the reasons for structural subsidence and deformation by re-levelling slab covering of concrete foundations, strip foundations, pile foundations and floor slabs and even solving problems related with access roads.

Work process

URETEK resin is inserted in the soil under a structure through small holes (usually with diameter of 16 mm, only 12 mm in case of interior works).

Then URETEK resins expand, filling cavities, compacting subsoil and stabilising the foundation (or other load-bearing structures), thus allowing re-levelling of the house.

For optimum results and safety purposes, the pressure generated in the course of expansion is constantly checked with laser equipment.

Cracks in the walls usually shrink. However, in case of brick wall, it only requires secondary treatment of joints with mixture or joining with special fixture, patching and painting of cracks in case of plastered walls.
Windows and doors will usually function normally again.
Gaps between floor slats and fixed floors generally disappear as well.

Guarantee

Materials used comply with strict ecological and safety requirements and have been designed specifically to resist drying and subsidence. Quality is guaranteed for more than 50 years.

Strengthening methods using concrete works

Over many years, concrete works have been used as a classical method for foundation repairs. Compared to traditional concrete works, the advantages of URETEK technology include speed, cleanness, durability and predictability, economic efficiency and an opportunity to avoid interfering with normal use of the structure.

URETEK material ensures durable soil stabilisation and building re-levelling faster than concrete works, where nothing can be guaranteed. Now it is possible to heave a house to desired height within a day or two, or a couple of weeks, depending on its construction technology. Furthermore, resin injection does not generate waste, there is no need for excavation works, water, cement or concrete.

It is important to mention that injection works do not require vacating entire room. Unlike concrete works that need lots of preparation and interior works, URETEK technology does not need any of that. Small holes (diameter of 12–14 mm) can be drilled between cover plates and even through carpeting and there is usually no need for moving the furniture.

URETEK method is ideal for foundation repairs even in case of clay and other porous soils, as it solves subsidence problems. The method ensures load-bearing capacity of substrate and uniform properties of load-bearing layers.

In the course of concrete works, it is necessary to improve poor soil conditions, such as unbound, dusty and wet substrate or substrate containing poorly compacted filling material. This is due to the reason that extra weight of concrete may further aggravate the situation.

Cost of concrete works

Besides being more convenient, safer and durable, URETEK injection solution is usually also cheaper than traditional concrete base.

The cost of concrete works depends on many factors, including:

Location of building,
Actual cause of the problem,
Properties and condition of the soil under a structure,
Type and profile of building foundation,
Surroundings, e.g. access to the plot, adjacent buildings and support walls,
Unknown, unpredictable condition of the soil under a structure,
Quantity of required material,
Time spent on work.

If only one corner of the house requires re-levelling, concrete base may be cheaper, but it may still lead to further problems over time. For instance, new cracks may develop in the house if concreting is performed in only one section of the foundation, not to mention additional load on the base affecting the substrate that was used to former loads.

In most cases, resin injection is cheaper than other methods, including concreting of foundation.

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Restoration of historical monuments

Sites of great historical and cultural value are threatened by natural ageing and going to ruin just like any other structure.

Sites belonging to national and global cultural heritage must be restored or reconstructed to keep structural damage to minimum, be it then repair of walls and floor or lifting and strengthening of foundation. Damage of historical buildings can be minimised by using URETEK geopolymers technology.

Manor buildings and palaces, castles and fortresses, churches and temples, but also many other sites of historical interest age, break down and go to ruin. Condition of walls, roofs and ceilings of the building is affected by constantly alternating external factors: pressure, temperature, humidity and airborne gases.

Equally dangerous are changes in soil on which the site of historical interest has been erected. Thus, weakening of soil under the structure may cause subsidence of ground floor and reduce stability of foundation, which leads to damaging other structural elements of the structure.

Complications related to strengthening soil

Subsidence of foundation and floor of sites of historical interest often causes occurrence of cracks in floor and walls. In that case, simple cosmetic repairs of walls and floor are not enough to improve the situation, because the cause of cracking is not eliminated. Without improving the condition of substrate and lifting foundation or floor, the situation continues to worsen and may ultimately result in complete destruction of architectural monument.

Although sites of historical and cultural interest are generally renovated by using state-of-art technologies and building materials, lifting of floors and strengthening of foundation in these structures is often performed using traditional methods. However, traditional technology along with involvement of heavy machinery and concrete and earthworks may damage the site of historical or cultural interest.

Elimination of cracks in the floor and walls of an architectural monument, as well as strengthening of substrate and lifting of foundation or floor is much more efficient when using URETEK geopolymer resins injection technology. That technology makes it possible to perform works without affecting the historical and cultural value of the site and also reduces the budget for repair and restoration procedures.

Provided technology

There are two URETEK geopolymers injection methods that can be used for strengthening the soil under historical monument and eliminating floor and foundation subsidence – Deep Injection and Slab Lifting. In the first case, geopolymer material intended for strengthening the soil and lifting the foundation is inserted deep into the soil under the structure, in the second case geopolymer is inserted immediately under ground floor.

Geopolymers are injected in soil or under the floor through special pipes with diameter of 12–16 mm, inserted in holes drilled in ground floor or soil around the perimeter of the building. Borehole diameter may be 12–32 mm. No other interventions are required on the site. The equipment for injecting geopolymer resins is compact and mobile. Using it has no effect on the historical or cultural value of the site. Injection holes can be easily eliminated later on.

All procedures performed with URETEK geopolymer resins, be it then strengthening of soil, securing or lifting foundation or floor, do not take long. After injection, geopolymer material expands, filling all cavities in soil and hardens within just 15 minutes, exerting vertical pressure. Lifting of foundation and floor is monitored in real time by using laser level.

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Re-levelling and stabilization of the concrete slabs of the Niitvalja railway crossing

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Strengthening of soil at the shores of natural and artificial waterbodies

URETEK geopolymers stand out for their ability to preserve their properties even in humid environment. Due to their special composition, geopolymers are protected against water. Therefore, geopolymer resins can be used for strengthening the shores of waterbodies.

Water gradually breaks the materials it encounters. Such natural process is called water erosion and that is why special attention should be paid to strengthening soil when erecting buildings near shoreline. This applies also to artificial waterbodies, e.g. ponds-reservoirs and wastewater treatment plants. Accidents resulting from soil erosion or collapsing embankments can be avoided when using URETEK geopolymers injection technology.

Special features of strengthening shores

In many cases, strengthening of soil near waterbodies and securing the shoreline is considered insignificant. Rather frequently only temporary solutions are used to strengthen the shores of waterbodies, e.g. covering eroded area with crushed stone or other filling material.

As a result, failure to reconstruct unsafe section may create a need for regular repairs of shoreline, which also means significant costs. Equally expensive is the traditional method of embankment repairs, which requires using special heavy-duty machinery and earthworks.

Alternative solution for proper strengthening shore-side soil is URETEK geopolymers technology. It does not require using heavy duty vehicles. Geopolymer resins can be injected by using small mobile devices that allow inserting material in soil through drilled holes with diameter of 12–16 mm.

Process of strengthening soil

Washed or eroded sections of shoreline and destroyed embankments (such as stone dykes) are restored by using Deep Injection method. Geopolymers are inserted in soil according to scheme starting from the depth of 1.5 m and deeper. After series of several injections at different depths, a solid waterproof wall is formed in soil.

Geopolymers achieve required strength with only 15 minutes. During that time, they spread across the soil and form a waterproof barrier that resists rather great loads. When exposed to water, geopolymers do not change and preserve their waterproofing properties for a long time.

Geopolymers can be injected not only in the shore-side soil but also directly in the embankment made of stones and rocks. In that case, geopolymers fill the voids between stones and for uniform solid structure.

Ecological safety

Huge advantage of URETEK geopolymer resins consists in their ability to achieve great durability even in excessively moist environment. Meanwhile, geopolymers are ecologically safe and absolutely inert materials that do not endanger ecosystem of the waterbody.

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Special features of buildings with pile foundation

Advantages of pile foundation include affordable price and opportunity to get effective results in very short time.

Screw pile resembles a pipe with blades. Inserting such pipe in soil leads to better stability of structures and buildings. Using piles provides the foundation with great resistance, it is not affected by surface water and it does not sink. In terms of quality and financial gain, pile foundation is often considered better than technically complicated foundation replacement. Moreover, foundation strengthened with piles creates an opportunity to build additional storeys above the foundation.

When does it become necessary to use screw piles?

Foundation can be strengthened with screw piles under any conditions, regardless of the location of the building. Foundation with screw piles allows erecting metal and concrete structures, whereas it involves nearly no earthworks. Strengthening of foundations located on complex subsoil often exceeds all expectations, because works are performed rather quickly and at low cost.

Currently, using screw piles for supporting foundation is considered the most optimal and universal way to increase load-bearing capacity of structures quickly and with high quality, so that they would endure any external factors for a long time.

What are the problems solved by using screw piles?

Main function of screw piles is to support structures in problem areas and unstable soil. Due to wide blades at the bottom of piles, it is possible to further increase the bearing surface in soil. Screw piles ensure resistance to pressure exerted by force exceeding 20 tons.

Usually, piles are used for achieving the following goals:

Increased load-bearing capacity of multi-storey building. Piles can be used to support a building, foundation of which cannot be fully replaced.
Strengthening of old foundation to allow building more floors in the future.
Stabilisation of sunken soil under the structure: pile is screwed in soil, thus remarkably increasing its stability.

Are there any more contemporary methods for strengthening foundation?

Screw piles represent unquestionably popular method for strengthening the load-bearing capacity of a foundation, but there are new technologies that allow different approach. URETEK’s new Deep Injection method ensures strengthening of foundation by stabilising the soil on which the structure stands.

For that purpose, special geopolymer mixture is inserted in soil. As it expands, it forces water out of the soil and fills all voids. Problem soil is levelled, subsoil is stabilised. Method allows remarkably quicker completion of repair works, it excludes earthworks, even in case of repairs performed in unsafe buildings.

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Stopping subsidence of concrete pools and elimination of cracks

Water level may drop in concrete pools. In hot summer, it is sometimes explained by natural vaporisation. But it may also result from occurrence of cracks in pool structure due to foundation subsidence.

Problem can be solved by using geopolymers injection.

Unlike other structures, pool structure does not prescribe even minimum subsidence of concrete frame. If the pool subsidence has occurred due to insufficient compaction of soil or excess humidity of the soil under the structure, cracking of concrete is inevitable. As a result of cracking, water starts to leak gradually. This, in turn further aggravates the condition of soil around the pool. It may become unsafe and the site cannot be used any more.

When repairing a pool, just patching the cracks is not enough. It does not remove the initial cause of damage. If the cracks occurred due to weakening of soil under the structure and subsidence of pool frame, it is necessary to address the problems with soil and foundation first.

In that case, soil is strengthened before eliminating cracks, foundation lifted and stabilised if necessary. It is worth noting that when using modern URETEK geopolymers injection methods, the work cycle lasts only a day or two and it does not require earthworks or concrete works.

Deep injection

Cracks in concrete pools can be eliminated by using Deep Injection method, which allows filling cavities and voids in the soil under the pool with special geopolymer resins. After reaching the soil, geopolymers expand and harden quickly, exerting vertical pressure. That way it is possible to strengthen weakened and excessively humid soil under the structure.

Furthermore, geopolymers can be used to stop pool subsidence and stabilise its position, or even lift it to its former height where necessary. Due to their structure, geopolymers do not react with water, but force it into surrounding soil. Therefore, geopolymer resins not only strengthen the soil, but also function as waterproofing material.

Cracks in concrete can be patched only after strengthening soil and stabilisation of foundation.

Works algorithm

Geopolymer resins are injected through special holes (diameter of 12–16 mm), drilled in concrete or soil around pool’s perimeter. Holes are quickly closed after completing the injection.

URETEK geopolymer resins are not destructive. They are suitable for strengthening soil, lifting and levelling concrete structures. Everything related to altering the position of concrete frame is monitored in real time by using laser level (precision up to ±1 mm).

Due to their physical and chemical properties, geopolymers remain stable for a long time, including in humid environment. Material is chemically inert, ecologically safe and tested across the world during long term use.

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Huge impact of extreme weather events on the foundation and the soil under the structure

Extreme weather events, natural disasters, long periods of drought, rain and cold have strong effect on the soil under the structures and on the foundation.

The summer of 2018 was extraordinarily warm, and the heat lasted for a long time. At the same time, January was one of the coldest in history. While some people were exhausted from record high temperatures, other regions suffered from flooding. Rainstorms and cyclones had a devastating effect on many buildings and population in general.

How weather phenomena affect soil

Soil types vary by properties and their response to weather conditions, and they may have serious impact on load-bearing structures of buildings. Houses built on loose soil, sand and reactive clays (rising soils) may suffer the most due to seasonal or extreme rainfall, floods and drought (or cold).

Reactive clay expands when exposed to moisture and shrinks when drying. This is accompanied by soil splitting during long periods of drought and expansion during humid periods. Clay loses its porous structure as a result of freezing and expansion in cold weather.

Sand and loamy soils tend to subside due to rainfall, because water flushes off small particles and larger particles sink.

Filling material used in construction often consists of soil, but also other materials, such as brick or concrete fragments, also crushed construction materials. When water finds its way through such material and flushes away minor particles, it may cause the soil to sink. The effect of the process can be visually depicted as recess in the ground, whereas it may further deepen due to poor soil compaction and general condition of surrounding soil. In case of changes in the condition of soil under a structure, it can no longer support the foundation and the structures gradually start to sink. Building sinks either partially or entirely, but in any case, unevenly. This is called soil subsidence.

Another important factor is humidity level of the soil. For instance, clay soils in a region with moderate temperature are humid in general. But due to lasting dry weather, soil loses humidity and shrinks, causing the soil to sink. At the same time, such soil absorbs lots of water in rainy season or becomes impermeable. Along with freezing or (subsequent) melting, the soil may also cause risk of subsidence. In the event of a flood or broken utility line, water may carry away or scatter the soil, resulting in erosion and subsidence. All that can cause serious damage to the foundation and load-bearing structures of buildings and special structures.

Extreme climate conditions have become more frequent all over the world. For example, summer with record-breaking high temperatures affected the foundations of many buildings even in regions with mild marine climate (Great Britain). Continuous warm temperatures caused the surface water to dry out, which in turn caused subsidence of buildings. Therefore, insurance companies received from house owners exceptionally many complaints and claims regarding buildings subsidence.

How to combat soil subsidence

Fortunately, there are methods that allow quick, effective and sustainable protection against soil subsidence. Innovative solutions offer an alternative to traditional invasive and labour-intensive methods that use concreting of foundation or piles.

Patented URETEK resin injection technology does not require troublesome excavation works or cause major discomfort, because residents can often continue to live in the house while the works are performed.

Keep in mind that in case of discovering signs of subsidence you should immediately consult with specialists-designers or engineers-geotechnicians and obtain information and facts necessary for choosing appropriate solution.

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Not all cracks are the same. Identification of the cause of a problem requires considering the type, size and location of cracks

Not all cracks are the same. In order to identify the cause of a problem and find a solution, it is important to consider the type, size and location of cracks.

Assessment of the success of renovation project is also based on the estimation of combination of direct and indirect advantages, disadvantages and risks.

Different types of cracks in the walls

The most common types of cracks are:

– internal cracks that damage plasterboard, plaster, brickwork or monolithic slabs;

– external cracks in brickwork (and other stone wall), monolithic slabs or plaster of exterior walls.

If the cracks in the walls of the building have occurred unexpectedly (not to be mistaken with discovering cracks that have been present for a long time but you just did not notice them before), they may refer to a major structural issue.

Smaller hairline cracks are commonly found in the walls and they usually do not cause concerns in the owner of the property. However, bigger cracks that radiate from windows, doorways or corners of the building may indicate that the foundation of the building has sunken or lost its designed durability, resulting in subsidence of entire building or part thereof.

Pay attention to whether the crack is open or not, is it horizontal or vertical, zigzag, gradual (e.g. in brickwork) or follows joint seams in assemblies. If the crack is at any point wider than 5 mm or if you notice full detachment from the structure of the assembly (in mixture or cement between bricks), you should consult a professional. Signs of degradation should not be ignored in other instances either. In any case, you should prepare a monitoring plan and check the structure at least once a month, registering its condition at the time of inspection.

Restoration

If main cause is subsidence (soil subsidence) or reduced load-bearing capacity, it is always necessary to consider several solutions. They include traditional strengthening method and non-invasive injection method, which is remarkably more operative and environmentally sustainable, also more effective.

URETEK resin injection method has been designed so that it can be used precisely in the weak spots of subsided soil under a structure. Using an almost surgical method improves the load-bearing capacity of soil and levels the base of the structure. The direction of cracks and condition of soil under the structure determine whether the cracks in the wall will be gone entirely or not. Main question is whether the structure is able to handle straightening force. In most cases, URETEK technology allows re-levelling of buildings and structures within a day, whereas the process is constantly monitored, using laser level to ensure precision.

Cheap monitoring method

In everyday life, structural changes are monitored not only by using professional devices but also a special indicator tape attached to bigger cracks in the wall. That visual indicator is one of many methods of measurement used by specialists to monitor changes during entire restoration process. Any movement or deformation of the tape attached to the structural components is visible even to an untrained eye. Movement occurs as a result of displacement or deformation of structural components. Indicator may also show how the structure moves in response to restoration of foundation, including the direction and level of elevation.

However, one has to consider that indicator is very sensitive to environmental conditions. Humidity, variations in temperature and other external factors may damage the fixtures and distort objective information. For best long-term results after restoration works, it is recommended to arrange geodetic surveillance of the condition of the building and regular inspection of assemblies and structures.