Issue 7 – October 2016

The Structural Concrete Alliance has shortlisted three projects for the 2016 Structural Concrete Alliance Award for Repair and Refurbishment, with the winner to be announced by journalist Kate Silverton at the Concrete Society Awards Dinner to be held at the Grosvenor Hotel, Park Lane, London on 17th November.

The winners were chosen from entries received from members of the three trade associations which make up the Structural Concrete Alliance: the Concrete Repair Association (CRA); Corrosion Prevention Association (CPA); and the Sprayed Concrete Association (SCA).

The shortlisted projects include Sika Ltd for its restoration of Poplar Baths in London; CCL (GB) Ltd for its upgrading and strengthening work at National Grid PLC’s Isle of Grain site near Rochester, Kent; and Volkerlaser for the refurbishment and strengthening of the Woodhouse Tunnel in Leeds.

Commenting on the award, the judges stated:

“The annual Structural Concrete Award aims to identify innovative structural concrete repair and refurbishment solutions that overcome demanding engineering challenges, while advancing technology and understanding.

“Choosing the winners was extremely difficult this year due to the high quality and diversity of the entries.  CCL’s solution for the Isle of Grain bund was selected as we were impressed by the innovative approach to safely detensioning the existing wire system, which we recognised as being extremely technically challenging.

“Sika’s sympathetic restoration of Poplar Baths and the complexity of the logistics required in Volkerlaser’s refurbishment of the Woodhouse tunnel served to highlight the innovation and flexibility our specialists must offer in developing repair and refurbishment solutions”

Poplar Baths were recently subject to major refurbishment works after a public campaign raised awareness and helped to secure funding to conserve the listed building, which had fallen into an advanced state of disrepair.

The building had previously serviced members of the public for 55 years, but had stood unoccupied since 1988. The iconic baths required extensive structural repairs in order to bring the building back to a state fit for redevelopment as a community leisure resource centre and residential apartments.

APA Concrete Repairs Ltd were employed from the design stage through to completion. Providing early contractor involvement from the outset, APA brought its specialist experience along with befitting installation and application knowledge for structural repairs and protection of steel frame and reinforced concrete buildings. APA was part of the delivery team alongside stakeholders including Historic England, Tower Hamlets Council and Guildmore Construction.

There were many challenges to overcome throughout the project. APA Concrete Repairs installed an impressed current cathodic protection system (ICCPS) to the steel frame sections of the building, and completed structural concrete repairs including galvanic anodes to the reinforced concrete middle section of the building, a unique arrangement of curved reinforced concrete columns forming a series of supporting arches. Once the concrete repairs had been completed APA applied protective anti-carbonation coatings to the columns (manufactured by Sika) and restoration grade renders (manufactured by Keim Mineral Paints) to provide a finish sympathetic with the original construction.

Beton Bauen Ltd is currently carrying out refurbishment works to existing concrete tanks at Burryport, Llaneli for the end client Welsh Water. The works include structural concrete repairs, spray applied waterproof coatings and the installation of a hypalon bandage system, installed over existing expansion joints.

The spray applied waterproofing material Penetron has full Drinking Water Inspectorate (DWI) approval and has been used for similar applications for other water authorities, including Dee Valley, Severn Trent and Thames Water. For further information on Penetron and the other services offered by Beton Bauen Ltd visit our website www.betonbauen.comor call our technical team on 02920 862596

Beton Bauen Ltd are leading specialists in concrete refurbishment, protection and structural waterproofing. With over 25 years’ experience in specialist contracting, we operate throughout the UK and overseas. Alongside our materials supplier company Wasser Werk, we are the appointed distributor and specialist applicator for all Penetron products in the UK.

High performance webercem spray DSF by Saint-Gobain Weber is the smart choice for repairs to large areas of structural concrete such as bridges, marine structures, roadways, tunnels, towers and embankments that require stabilisation.

webercem spray DSF is a polymer modified structural repair concrete specially designed for fast and efficient dry process spray application. Its formulation achieves higher tensile and flexural strengths, increased resistance to impact and abrasion, reduced rebound and minimises application thickness.  Recommended for use in thin sections of 25-50mm on columns, beams and soffits, webercem spray DSF can be applied up to a thickness of 300mm in just one pass.

“The major advantage with this product is that the added fibre reinforcement reduces shrinkage with improved crack control, better strain relief and stress distribution,” says Tracey Dempster, Head of Marketing, Saint-Gobain Weber.  “We have introduced this technical product in direct response to demand from the industry and we are delighted with the results of our in-house tests and site trials.”

Pre-bagged and ready to use webercem spray DSF conforms to BS EN 1504-3 meeting the challenging requirements of a Class R4 repair product and is designed for remedial work and repairs.  Compliant with Highways Agency specifications it is fully suited to the repair of highway structures such as bridge columns, beams, abutments, tunnels and viaducts.  On marine structures it is ideal for piers, quays, seawalls and docks, as well as repairs to fire damaged concrete. webercem spray DSF provides structural enhancements to mineshafts and structural encasement of steel sections.

Concrete Repairs Limited has recently been awarded the contract to repair the spalling concrete and install a cathodic protection system to the Coronation Parade promenade/breakwater in Folkestone.

This is the second such breakwater to be built on this site (the first being built in 1920). The current structure was built in the 1930s and is enjoyed by thousands of locals and tourists. The arches provide a great picnic area and shelter from the wind and sun and those who wish to stay away from the sand and sea can have a relaxing stroll along the upper walkway.

The structure consists of a series of concrete arches and a promenade with a retaining wall to the rear. Its primary purpose is to stop the cliff from eroding and it also protects a significant number of homes and businesses. The breakwater also acts as a roadway which allows vehicles access to carry out maintenance and emergency repair work.

All things being considered the breakwater has stood up remarkably well to the harsh conditions, however it is now in need of repair. The £2m contract began on the 23 May and has a programme duration of 35 weeks. Working conditions are likely to be extremely difficult, particularly during the winter months.

The works consist mainly of marine management, winter working, tidal working, extensive sympathetic structural repairs and the installation of an impressed current cathodic protection system.

BAM Ritchies has provided a reinforced sprayed concrete solution to protect a cliff face slope against tidal erosion at Swanage in Dorset.

Following excavation, BAM Ritchies fixed vertical strips of drainage membrane at 2m centres, followed by two layers of A393 weldmesh. A single layer of approximately 175mm of accelerated sprayed concrete was then applied to the prepared face.

The ground excavations were undertaken in 2.5m high sections to facilitate the dimensions of the weldmesh, thereby minimising mesh waste on site.

The original design detail showed soil nailing being undertaken prior to the sprayed concrete overlay, but after discussions between the engineer and the sprayed concrete team, it was decided to install the soil nails after spraying.

This revised method removed the risk of any drilling vibration damage to the sprayed concrete layer, which may have occurred when drilling through freshly placed concrete. It also avoided potential difficulties in placing two layers of mesh over the soil nail heads.

To facilitate the soil nail drilling, 200mm diameter pipes were installed at the required centres prior to the sprayed concrete application. These pipes enabled the drilling operations to be undertaken with no damage to the sprayed concrete lining.

A total of approximately 400 sqm of slope was stabilised over a 6 week programme.

Working with Aone+, Freyssinet undertook work on the M1 motorway at River Swift bridges. The bridge had problems with its concrete edge beams and concrete up-stand parapets, which required removal using a combination of hydro-demolition and mechanical methods.

Once removed, Freyssinet undertook the drilling and installation of starter bars, installation of new reinforcement and related concrete works required to form new parapets. New bolt clusters were also installed in conjunction with the in situ temporary formwork and concrete repairs were carried out to the soffit.

As well as the concrete repairs, the works included site clearance operations; enabling earthworks; provision of access scaffold and temporary barriers; and provision of temporary access bridge across the River Swift.

On completion of the concrete repair works, the project was finalised with earthworks reinstatement, drainage works, fencing replacement and finally removal of the temporary concrete barriers which were placed to protect the workforce.

The project was a success for all involved. The works were carried out with resources being utilised efficiently to ensure that the project was completed in accordance with the client’s requirements.

Freyssinet has been at the forefront of specialised civil engineering technology, design, build and installation since 1950. With origins in bridge components and post-tensioning, Freyssinet has successfully expanded its portfolio of products and services to include the repair, protection and strengthening of structures, diagnostic surveys and cathodic protection in the building, civil and marine sectors.

Skyform Specialist recently carried out concrete repairs and Liquid Plastics Waterproofing works to three MKIII multi-storey housing blocks in Clydebank, Glasgow.

A survey was carried out on the blocks prior to commencement to ensure our teams were aware of the entire scope of the project. All exposed concrete including nibs, floor slabs, balcony edges and soffits etc. were hammer tested and defective concrete was broken out and safely disposed of.

A bonding agent and then a primer was added to the concrete balconies before the Liquid Plastics Waterproofing system was applied.

Small defective repairs were patched in, including on corner columns, balcony soffits, stairs and in the landings with additional brick repointing and replacement where deemed necessary. The balcony surfaces were pressure washed and prepared for the Liquid Plastics system.

Skyform Liquid Plastics Specialists applied a Vulkem Quick Membrane system, ensuring all small detailing was coated effectively. Cracks and fractures were cleaned out and filled with Vulkem Quick Membrane.

Skyform Access Division provided electric hoist powered cradles for this project, a prime example of the synergy and effectiveness of our teamwork within Skyform.
Skyform (Scotland) Limited was formed in 1995 as a Power Access provider. We have since expanded and diversified now operating as Skyform Group, with five core specialised divisions including; Access, Eco, Wind, Roofing and Specialist.

Here at Skyform we firmly believe that there is always a way, if a customer requests it; we get it done.

VolkerLaser has delivered specialist protective and refurbishment works to a multi-storey car park as part of a new development in the town of Southport; renovating an old supermarket into a major sporting retailer and state of the art gym in Tulketh Street.

As well as essential concrete repair, VolkerLaser utilised the capabilities of specialist cold liquid applied systems provider, Triflex UK Ltd, to deliver 12,000sqm of waterproofing works.

A challenge was encountered on the project when it was discovered that the first floor of the car park had collapsed in one area above the old supermarket bakery. This area was consequently stripped, screed re-laid and Triflex ProPark® HD solution was applied to offer primary waterproofing to the area where the asphalt had been removed.

During the works, the 480-space car park was completely closed to the general public, allowing VolkerLaser to deliver works quickly and efficiently without disruption. The contract was completed within 4 months to be opened for public use over the busy August bank holiday weekend.

SIKA has provided a total corrosion management concrete repair solution for residential buildings on the Heathcote Estate in Norwich.

Concrete spalling had occurred throughout the Heathgate Estate, a series of 50-year-old residential buildings situated near Norwich city centre, with steel reinforcement exposed in many areas. With the health and safety of the occupants at risk, the buildings’ owners, Norwich City Council, required a proven concrete repair and protection system with long-term corrosion control measures to extend the structures service life.

Sika offered the total solution. Sika® Monotop®-610, a high-performance, one-component, cementitious polymer-modified primer was applied to exposed repair area surfaces in preparation for concrete repairs using Sika® Monotop®-615. Both products simply required mixing with water to provide superb, reinforcement corrosion protection.

To address the carbonation induced corrosion within the concrete, Sika ® Margel VPI 580, a patented vapour-phase corrosion inhibitor and part of Sika’s Total Corrosion Management portfolio, was also installed to all concrete elements.

Sikagard®-550 W Elastic, a one component plasto-elastic anti-carbonation coating system provided the final application over the existing sound well-adhering coating. Sikagard®-550 W Elastic is solvent-free, and even at low temperatures, offers superb crack-bridging properties in concrete structures.

Sika’s high-performance concrete repair system, which carries a 10-year guarantee, has provided peace of mind for Heathgate residents as well as eliminating the long-term risk of costly maintenance works on behalf of Norwich City Council.

Cathodic Protection Co Ltd (CPCL) introduced a new Switch Mode Power Supply for summer 2016 resulting in multiple orders and approvals. Designed and developed specifically for cathodic protection installations, the SMPS converts the available unregulated AC or DC input voltage to a regulated DC output voltage.

The 144W SMPS can provide stable, accurate outputs of a few millivolts and milliamps up to a maximum of 24V and 6A or 12V and 12A, making it ideal for steel in concrete applications. It supports simultaneous switching of an unlimited number of units in less than 10 milliseconds, perfect for taking instant off potentials on large systems.  It is also designed to be fully compatible with our Remote Monitoring and Control System (RMCS), allowing it to be controlled over fibre optic, wired and wireless networks on a variety of mobile devices.

With an operating temperature range of -20 to +70˚C, the unit can be used in a wide variety of indoor and outdoor locations and is designed and built to meet applicable EMC and safety standards, as well as the requirements of BS EN 12696.

The wider benefits of the SMPS include a standardised design that can be adapted to a client’s requirements.  This means that it is a low cost, yet highly efficient, unit with lower running costs.  It is also small in size, allowing for easy configuration of multiple channel systems.

For further details of how our SMPS can help your installation, contact Ed Sparks at cpc@cathodic.co.uk

In order to improve their service and subsequent delivery coverage, Resapol, an independent distributor of construction chemicals, has moved its Head Office and Leeds Sales Depot into new, improved and fully furbished depot locations.

The new Head Office depot is set to be utilised as a super centre. Boasting close to double the square footage of their previous warehouse space, this new facility will therefore allow for more quantity and variety of materials to be stocked and readily available for their growing customer base. The new Head Office is located at Unit D4, Moss Industrial Estate, Leigh, Lancashire, WN7 3PT; Tel: 01942 609 001; E-mail: leigh@resapol.com.

The new Leeds depot also comes with a bigger warehouse space, as well as improved facilities for staff members. This allows the Yorkshire based depot to offer a bigger variety of materials, complete with same and next day delivery options on selected product lines.  The new Leeds Office is located at Unit 3, Aintree Court, National Road, Leeds, West Yorkshire, LS10 1TF; Tel: 0113 276 2306; E-mail: leeds@resapol.com

These new expansions follow on from the previous news that Resapol has also recently ventured into Scotland, opening a brand new sales depot within Glasgow during February.

For more information on Resapol’s quality construction chemicals, including its extensive range of concrete repair materials, please visit their technical website at www.resapol.com, or keep up to speed with everything Resapol on Twitter, @resapol.

The Corrosion Prevention Association (CPA), one of the associations that comprise the Structural Concrete Alliance, has released a new guidance document which highlights the most commonly used corrosion testing techniques for reinforced and pre-stressed concrete structures.

Explaining that corrosion is rarely an issue affecting the whole structure uniformly, Technical Note 27: Corrosion Testing of Concrete Structures aims to enable the user to better understand how to assess corrosion risk and therefore make informed decisions about repair strategy based upon a broad base of information.

The guide explains that the initial cause of corrosion is commonly the result of a number of interrelated variables:  changes in the concrete permeability, caused by local differences in composition, compaction and curing; construction errors leading to areas with low concrete cover to reinforcement; and variation in the exposure environment, leading to areas with elevated chloride ion content or high carbonation depth.

It states that the aim of comprehensive corrosion testing should be to understand the exposure variability, ascertain risk and develop a repair and maintenance strategy that provides the best technical and commercial solution for the structure.

For each type of testing the guide outlines typical methods, advantages and disadvantages and explains what the obtained results may mean.

The document is available for free download from the Corrosion Prevention Association website. To see the full range of available CPA publications and Technical Notes visit: http://www.corrosionprevention.org.uk/publications.php