First publishedin World Highways
Aggregate Industries Lytag lightweight concrete reduces the dead weight of the Acton Swing Bridge
The 84-year-old Acton Swing Bridge in the UK recently underwent a major renovation that included the use of Aggregates Industries’ Lytag lightweight concrete.
The bridge - cared for by the Canal & River Trust, a charity operating in England and Wales - carries the busy A49 road over the River Weaver Navigation canal, near Cheshire in England.
The €1.7 million complete refurbishment included strengthening the underside of the bridge as well as improvements to its appearance.
Core to the project’s success was the ability to enhance the bridge’s structural integrity to allow for heavier traffic. This was to be done without causing an increase in the bridge’s weight and maintaining the required 2.5m allowance for boats passing underneath.
Kier Construction, working for the Canal & River Trust, chose Aggregate Industries’ Lytag secondary aggregate that is reportedly up to 50% lighter than normal aggregate. By using Lytag to replace the infill with the framework, the weight was reduced from 2400kg/m³ to 1650kg/m³. This gave increased flexibility and durability for Kier, while increasing overall strength. It also negated the need for quarried aggregate, helping to reduce material requirements and ensure efficiencies.
With works now complete, the contract saw Aggregate Industries supply 100tonnes of 0/14mm Lytag, a tailored blend of aggregates designed to reduce concrete density. Steve Curley, general manager for Lytag at Aggregate Industries, said that Lytag offers the same structural performance as normal weight concrete but it is significantly lighter which reduces the dead load of a structure.
“In projects such as Acton Swing Bridge, where strengthening works need to be achieved without resulting in an increase to size or mass, this product can really make the otherwise infeasible achievable.”