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(March 29, 2018)

Otso Lahtinen shares exciting news about Geobear

Otso Lahtinen Geobear CEO

I’m Otso Lahtinen, CEO of Geobear – recently rebranded from Uretek and I want to share with you some exciting information about our company that you may not be aware of.

For over 30 years, we have been using the incredible properties of expansive geopolymers to permanently strengthen the ground, control groundwater flow and remediate settlement damage suffered by the built environment on over 200,000 projects across the globe. In December 2017, we rebranded our business to align all our core skills under one umbrella, this enables us to demonstrate to the market our strong desire to offer this sustainable solution across every industrial sector- including major infrastructure projects.

Adaptability of Geobear Solutions

Unlike cementitious grouting methods which generally require large scale drilling and pumping methods, the Geobear solution uses the power of a multicomponent chemical reaction delivered via small diameter injection tubes. We can choose from a wide range of geopolymers to tailor the solution to the problem. If we want to permeate and strengthen weak granular soils, then we will use a slow reacting mix of geopolymers which can penetrate the pore space and bind it together. If we want to create immediate movement in a stiff clay (such as London Clay), we will select a fast reacting mix which delivers instantaneous results.

This technology is also highly scalable, the notion that our solutions are only applicable to the residential housing sector is far from true. Whilst the residential market is important to us, we can demonstrate an impressive track record across all industrial sectors; when Airbus, for instance, needed the concrete slab of their assembly building to be relevelled to within a tolerance of 0.5mm, we delivered with no disruption to their production.

In addition to the remediation of pre-existing conditions, we now offer a Real-Time Displacement Control system which is designed to protect the built environment from movement caused by adjacent construction activities, such as tunnelling or shaft sinking. This newly patented process known as GroundShield™ was invented by Professor Colin Eddie (formerly Engineering Director at Morgan Sindall and MD of UnPS).

Geobear challenges conventional methods

Even today, many engineers remain unsure of this technology and often favour traditional cementitious grouting solutions as these are “tried and tested”. Whilst undoubtedly these have their place, there are very many circumstances in which using geopolymer solution will deliver a significantly more cost-effective solution, with minimal or no disruption to our clients.

The most common perceived concerns we hear from designers and contractors are:

Control – how can the chemical expansion be controlled?
Modelling – how can the in-situ behaviour of geopolymers be numerically modelled?
Durability – what lifespan can be scientifically proven for the cured geopolymer?
Standards and Specification – what can we use?

We take responsibility for not having adequately addressed these concerns and we now wish to take the opportunity to rectify this.

Control – precise control is achieved by first selecting the correct product for the prevailing ground conditions. Using our data logged pumps and real-time monitoring, our technicians are able to precisely deliver the product. The expansion process is highly predictable for each product and the chemical reaction is effectively complete within minutes of injection to a sub-millimetre tolerance.

In recognition of the importance that monitoring plays in providing confidence to all the stakeholders, for the last twelve months we have been working with Cambridge University to develop innovative new surface and subsurface monitoring solutions by using an array of technologies including fibre optics. To ensure a long-term commitment to develop the science of geopolymer injection, this month we became proud members of Cambridge Centre for Smart Infrastructure and Construction (CSIC).

In May 2017, Thames Tideway Construction JV BMB (Balfour Beatty, Morgan Sindall and BAM Nuttall) kindly allowed us to undertake a full-scale proof of concept trial within their 30m diameter main tunnel drive shaft at Carnwath Road. The trial, among other things, proved that London clay can be fractured with expansive geopolymer at a significant depth and with precise control.

Modelling – for nearly 30 years, researchers have studied the use of expansive geopolymer injections into the ground. Today, a combination of empirical data and reflective practice, combined with classical cavity expansion theory and advanced numerical modelling, is used to predict ground response. The right approach is, however, always project specific, like with any ground engineering method. A simple reflective practice approach may be suitable for the remediation of a residential property, but an advanced multistage 3D numerical model may be more appropriate for a large infrastructure project.

Durability – In addition to the 35 years of empirical data, numerous independent studies have demonstrated that the geopolymers we inject into the ground are hydro-insensitive, have excellent creep characteristics and are highly resistant to chemical and microbial attack. This means that we are confident that we can deliver permanent solutions which will last significantly longer than the service life of the assets we protect (>120 years).

Standards and Specification – European standards already exist, which enable us to undertake a physical characterisation of our materials for design purposes. In all practical respects, for design purposes, the injected materials should be handled in the same way as the soils or rock they are injected into. To aid understanding of the typical nature of our materials, we provide the following general guidance for a preliminary design purpose:

  • Expansion force up to 10000 KPa 5-30 times expansion
    95% strength achieved within 30-60 seconds
  • Geopolymers can be injected in air temperatures from -15 deg C to 60 deg C
  • Modulus of elasticity 10 – 80 MPa
  • Compression resistance is greater than its expansion force providing permanent support
  • Approximately 10% the weight of concrete

It must be stated that expansive geopolymers cannot solve all problems, and if specified incorrectly by incompetent people, they can create more problems than they solve, just like with any other soil grouting method. After all, there are numerous examples of structures that have heaved as a result of poor control during cementitious grouting, along with examples of collapses of structures for similar reasons.

Follow me on Linkedin https://www.linkedin.com/in/otso-lahtinen-a83b6b24/

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We deliver projects on any sort of building or structure – from conservatory extension problems to 80,000m2 warehouses and road infrastructure. In most cases we will have the best solution, so get in touch today.

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