Concrete and Composites: A Powerful Partnership

At the end of 2016, the UK government unveiled a record infrastructure spend pipeline of £500 billion-plus, £300m of which will be invested by 2020/21[1]. Composite materials play a growing role in this, with expected growth in the construction industry of 42-78% by 2020 (to £510-640m) and £1240-1520m by 2030[2].

Precast concrete trench systems are used extensively in infrastructure to provide protection for and easy access to underground services. As composites adoption grows, many precast trench manufacturers are extending their product lines to offer GRP covering options.

Precast Concrete Trenches

Precast concrete trenches (also known as troughs, ducts or channels) are used extensively to carry cabling and piping, (instead of direct burying) protecting them from external factors like damage and adverse weather conditions; while allowing access for maintenance. Precast concrete trenches are frequently favoured over concrete cast in-situ to reduce install time and skilled labour required on site.

Historically precast concrete trenches have only been covered with concrete or metal covers. Where high load ratings are required (like road crossings) covers can weigh hundreds of kilograms. Over time environmental factors can cause covers to crack, fracture, crumble or corrode.

                                             All Fibrelite trench covers can be safely removed manually

As specifications are changing to favour GRP access covers, precast trench and composite cover manufacturers are working together to bring joint offerings to the market.

Custom Composites Covers

GRP composite cover pioneer Fibrelite serves as strategic partner on a number of large scale developments specifying composite covers. Their UK design and manufacturing teams work with contractors, architects and end-users to create custom covering solutions for each trench layout.

Fibrelite covers weigh a fraction of concrete or metal alternatives, and offer load ratings up to F900. This means all trench covers can be safely manually removed by two people no matter what the load rating. The composite material is inert, eliminating deterioration from corrosion and extreme temperatures in service (including freeze thaw).

Fibrelite has formed a number of strategic partnerships with major precast manufacturers in Europe and the USA to provide a range of covers to fit each company’s trench layouts.

Recent Install: Garreg Lwyd Wind Farm

Fibrelite created bespoke covers for 40 linear metres of precast trenches on a new wind farm’s substation. The D400 load rated covers can now be safely removed by two people while a concrete cover would have weighed approximately 400 kg.

                                              Bespoke ‘stepped’ Fibrelite covers to fit precast trenches 

[1] Gov.uk website, Published December 2016, https://www.gov.uk/government/news/uk-infrastructure-investment-to-reach-record-high

[2] National Composites Centre Study, 2015, https://compositesuk.co.uk/system/files/documents/Strategy%20final%20version_1.pdf