Leca UK

The College of Social Science & Public Policy at King’s College London undertook a renovation and extension project along the busy stretch of Aldwych, Strand in London. The developers faced significant space constraints and needed a lightweight, efficient concrete solution to reduce the load on the mezzanine structure. They specified Leca® Uno lightweight concrete to address these challenges.

Leca LWA was recently used to fill a disused subway beneath Vauxhall Bridge Road, near Victoria Station in London. The subway, which is 52 meters long and features internal dimensions of 3.05 meters in width and 2.23 meters in height, supports two roads with normal, unrestricted traffic flow. This infill project was crucial for reinforcing a busy passenger access point. The selection of Leca LWA for this project was strategic, aiming to minimize the load on the underlying London Underground tunnels, a critical factor given the subway's location. The material was pneumatically delivered at a rate of 40 cubic meters per hour through an advanced hose piping system, ensuring swift and efficient delivery in the congested area of London. Feedback from Contractors This method of delivery not only sped up the process but also simplified it, as Leca LWA requires minimal compaction. The groundwork preparation involved using a wacker plate for just four passes, highlighting the ease of installation. Tim Greenbury from CBS (Construction and Civil Engineering) commented on the effectiveness of the material and the efficiency of the application, noting, "We were impressed with the LECA material and the application was rather efficient. The only real constraint was the number of shifts required to complete the fill, which was influenced by the unloading times at the origin in King’s Lynn. The blower truck performed excellently, enabling us to consistently service the project each morning."

Leca® Lightweight Fill 10-20mm (LWA) was recently specified for a swimming pool complex at Currie Community High School. This in the first phase of the Scottish Government’s Learning Estate Investment Programme and is going to be delivered in Spring 2025. The new school is being developed to Passivhaus standards which provides comfort but uses little energy for heating and cooling - aiming to be the first Passivhaus secondary school with a swimming pool in Scotland. Leca® LWA was pneumatically delivered to fill the voids around the perimeter of the new swimming pool - due to limited access of the facility, with a piping system reaching up to 50m to deliver the material.

Video: We recently delivered Leca® Insulation Fill (50L Bags) to a property development in Nottingham for a new underfloor system. Two layers of Leca® Insulation Fill raised the floor by 300mm over a 50m2 area – this was followed by a PIR Board and a Concrete Screed Slab Finish. The underfloor installation took only 2 hours to complete and eliminated the need for wheel barrows and traditional hardcore entering the property – saving time and reducing the environmental damage to the surrounding area.

Leca® Insulation Fill was utilised for the renovation of a 3-bedroom terrace house in Liverpool. This project was an upgrade and refurbishment to make the property a more energy efficient property with a reduction in fuel bills and carbon emissions, whilst increasing the comfort levels. Over 20m3 of Leca® Insulation Fill was utilised by local contractors Penny Lane Builders (PLB) for the whole ground level of the property. Leca® Insulation Fill is a lightweight expanded clay insulation that typically cuts foundation time by hours, and this was further accelerated through the unique pneumatic delivery option, which completed the ground floor within 45 minutes. The natural compaction of the material to find its place when delivered as an aggregate increased the efficiency of the delivery.

Over 11,000m3 of Leca LWA has been specified and delivered for a £16 million improvement scheme on the A595 next Moresby Hall. Over several years the local authorities have been monitoring localised areas of movement within the embankment supporting the A595. A developed scheme was planned and funding was secured to deliver a repair to the embankment and create 1300m of new drainage which allowed for the improvement and maintenance on the A595. A.E Yates Contracts Manager, Ruairi Flynn MCIOB provided an overview on the specification of Leca LWA, “Due to height of embankment we required material that would limit settlement and significantly reduce load risk on new drainage infrastructure installed below the embankment. The material also had to possess internal load bearing stability to take construction and traffic loads. It needed to be lightweight, high angle of internal friction and reasonably easily manageable on site.”

Rugby fans will alight from the Edinburgh tramway system right outside the hallowed gates of the famous Murrayfield Stadium, home of Scottish Rugby, thanks to the advantageous properties of Leca® LWA. The tram stop is a key part of the new inner city tramway linking Edinburgh airport with the heart of the City. GRAHAM Construction, responsible for the creation of the Murrayfield tram stop as part of the Edinburgh Trams Project, faced challenges on the project not least of all the ability to raise the structure seven metres above the existing ground level. Normal traditional fill would have imposed severe overburden threatening the stability of the existing Network Rail line and other established buildings. Consulting engineers to this project, Parsons Brinkerhoff, determined that the replacement of traditional fills with Leca® LWA was the preferred option to overcome bearing and settlement issues associate with the soft ground conditions underlying the site. Tristan Morgan, Geotechnical Engineer at Parsons Brinkerhoff, said: “One of our main issues was to get such a large earthworks structure founded within the underlying soft ground conditions without significant ground improvement being undertaken. The light weight attributes of the Leca® LWA satisfied these criteria, with significantly lowering bearing/settlement at formation compared to traditional fills. It also interacted with the Tensar elements of the structure without difficulty.” A Tensar Geogrid wall system in conjunction with Leca® LWA was designed and subsequently constructed to raise the ground level and form the platform surfaces. More than 14,000m³ of Leca® LWA was required for the Murrayfield tram stop construction which was shipped directly into the Port of Leith Docks ready to be trucked to the site as and when required. Contractor Feedback Andrew Henry, Construction Manager GRAHAM Construction pointed out the advantages of Leca® LWA. “Faced with the complications of the Murrayfield site, especially the potential expense of excavating unsuitable ground, Leca® LWA has proved exactly the right choice of material for this technical project. Access to the platform site was difficult but Leca® LWA is a versatile and easy material to handle and this enabled us to meet the project targets.” A totally natural product, Leca® LWA is formed by heating and firing natural glacial clay in a rotary kiln at temperatures up to 1150oC. This process transforms the clay into lightweight ceramic granules with a hard shell and porous core. With a bulk density of just 0.3 tonnes per cubic metre, Leca® LWA has excellent insulation properties, is free draining, fire resistant, frost resistant and chemically inert with no hazardous properties. Used as a lightweight aggregate fill in many civil engineering applications Leca® LWA reduces the weight on weak substrates and against retaining structures by up to 75% over traditional fill and eliminates expensive settlement delays, is easily handled and quickly installed

Over 3,500m3 of LECA® lightweight fill has been specified and delivered for the Lea Viaduct section of the new Preston Western Distributor Road (PWDR) development - providing a robust lightweight solution for a bridge abutment section over delicate ground conditions. This £200m scheme is being undertaken by Costain Group PLC on behalf of Lancashire County Council and will link North West Preston and the Fylde to the M55 motorway.

he Kelpies Revisited: The Helix project in Falkirk transformed a tired and lifeless environment into one of the most expansive and attractive community locations in Europe. It was named Best Environment Project at the National Lottery Awards. Over 2000m3 of LECA® Lightweight Aggregate (LWA) was installed below the surface - enabling construction access and land raising directly over a Scottish Water fresh water trunk main. The specification of LECA® LWA avoided substantial additional costs that would have arisen from the rerouting of Scottish Water’s assets.