Those fighting construction’s never ending war against cock-ups on site have just been handed a powerful new weapon: cements that have been precisely blended to do the job that they’re supposed to
There is a quiet revolution taking place at Lafarge Cement UK. The company has been undertaking extensive research and development, and it has come up with a range of innovative cement blends to meet the increasingly complex requirements of the building industry.
“We are now mapping our customer base so that we can second-guess their requirements,” says Andy Murphy, Lafarge Cement’s marketing manager. “We are coming up with a solution before customers realise they need one.”
The company is providing more customer-orientated solutions in two ways. It is making products that are easier to use, and it is offering bulk buyers the opportunity to tailor the cement to their needs before it leaves Lafarge’s factories.
Blue Circle Colourtex S is an example of such a solution. It is a one-coat decorative render that uses a blend of sand, limestone, cement, admixtures and silicone to create a high degree of waterproofing and durability.
Blue Circle Quality Assured Mortar Mix is a pre-blended cement that has proved popular with professionals and self-builders because it is easy to use and has a consistent quality. Workers using it on site need only to add water to start working with it, it is compliant with BS 5838 and ISO 9002, and the inclusion of specially graded sand and lime helps to ensure high workability and a long board life.
Bulk buyers of cement will have noted Lafarge’s readiness to provide pre-blended products that match their requirements. The Blue Circle Portland Limestone Cement used on the Combined Universities of Cornwall project demonstrates how pre-mixed cement can eliminate headaches for those working further up the supply chain.
Another pre-blended cement is helping one company, building materials supplier Tudorstone, to create realistic architectural stone. Blue Circle Snowcrete is a white-coloured Portland cement that guarantees consistent neutral tones for cast stone. By specifying Snowcrete, Tudorstone can reduce the amount of mixing it does. “Basically it means that we need to add less pigment to the cement to achieve a neutral finish, which reduces our cost and allows us to pass on these savings to our customers,” says Bill Howe, Tudorstone’s managing director.
Lafarge Cement announced recently that it had signed a three-year partnership to supply Tuderstone with Blue Circle Snowcrete and Blue Circle Portland Concrete Products Grade.
Lafarge hasn’t just been examining how it can improve its cement mixes. Every element of its product solutions has been scrutinised, right down to the humble cement bag. Lafarge recently introduced plastic packaging, which has transformed the way cement is stored on-site.
The waterproof plastic is rip, tear and puncture-resistant and reacts better to contact with corrosive materials than paper packaging. The bags allow all year round storage on site and greatly reduce the risk of cement being damaged while being transported and unloaded.
The plastic packaging is used on four product lines: Blue Circle Extra Rapid, Blue Circle Postcrete, Blue Circle Slablayer and Blue Circle Quality Assured Mortar Mix.
Lafarge is continuing to develop even more flexible solutions for its customers. For example, it is currently trialling a dial-a-blend facility at its factory in Dewsbury, West Yorkshire, where specifiers will be able to select coloured architectural renders. Keep tabs on the Specifier section of Building for more ideas from Lafarge in the future.
How the Hub was formed
Blue Circle Portland Limestone cement has been specified for “The Hub”, a building for the Combined Universities of Cornwall that was designed by Cardiff-based architect Percy Thomas. The concrete was chosen to complement the local stone that was also specified for the £50m building.
The Hub is built into the side of a hill at Tremough near Falmouth. The concrete frame follows the contours of the hill in a series of terraces, and to give the impression that the college is embedded in the landscape, the roof has been covered with plants and rocks.
Percy Thomas opted to use used concrete instead of the local natural stone to prevent the large-scale project monopolising local raw materials suppliers.
The concrete for the site came from RMC South West. That used on parts of the building’s interior was mixed using Lafarge’s Blue Circle Portland Limestone cement to achieve a pale appearance that matches the local stone.
By using Lafarge’s technical expertise, RMC ensured that every batch of concrete had a consistent tone.
The first stage of the 17,000 m2 Hub incorporating a design centre, opened in October 2003. The second stage will be opened this month when the University of Exeter transfers its operations in Cornwall to Tremough.
The Colourtex system
Once Blue Circle Colourtex S has arrived on site, the subcontractor need only to add water and it can apply the render in one coat. The pre-mixed blend of sand, lime, cement, admixtures and silicone is waterproof and hard-wearing, and the inclusion of silicone has the advantage of reducing lime bloom on site.
Colourtex S comes in 10 colours and can provide a decorative finish to most brick or block walls. Lafarge says that the product can be easily textured using a special scratching float, or it can be made to look like coursework by cutting grooves in the render surface.
The render was recently used by Center Parcs on a Roman Spa-style building in Sherwood Forest. The photograph above shows the exterior of a two-story aqua centre, which was covered in its natural cream tone to complement the building’s stonework.
DS Baxter Plastering was subcontracted to carry out the rendering. “Although this was the first time we have used Blue Circle Colourtex S, we will definitely be using it again,” says Dan Baxter, the firm’s managing director. “It only required one coat to achieve an even coverage and its through-colouring means that it doesn’t need painting.”