Circular construction with fibre reinforced concrete and asphalt

Circularity is one of the spearheads of Rijkswaterstaat and an increasing number of municipalities and provinces. Fibre reinforcement of concrete and asphalt contributes to circular objectives in multiple ways. This article explains how.

What does circular construction mean?

Circular construction is about minimising the use of primary (new) raw materials, maximising the reuse of materials, and preventing waste. Rijkswaterstaat aims to be fully climate-neutral and circular by 2030, with 50% less use of primary raw materials — to be achieved through extending the service life of existing infrastructure and the development of new circular materials.

Fibre reinforced asphalt and circularity

• Better recyclability than PMB. Polymer modified bitumen (PMB) is harder to recycle than standard penetration bitumen. Fibre reinforced asphalt, which is produced with penetration bitumen, therefore fits better with the existing, well-functioning recycling chain for asphalt.

• Extending service life means fewer replacement cycles. Every asphalt layer that lasts longer needs to be milled and replaced less often — which directly reduces demand for primary raw materials over the service life of a road.

• Compatible with high reuse percentages. Fibre reinforced asphalt can be combined with a high proportion of reclaimed asphalt pavement (RAP) in the mixture, without this limiting the effectiveness of the fibres — relevant for projects that apply circular tender requirements.

Fibre reinforced concrete and circularity

• Less steel use. Steel is readily recyclable, but its production (ore extraction, smelting) is relatively raw-material- and energy-intensive. Every kilogram of steel reinforcement replaced by fibre reinforcement reduces demand for new or recycled steel for that specific project.

• Combinable with other circular concrete innovations. Fibre reinforcement fits well with other circular developments in concrete, such as the use of recycled cement, plant-based aggregates (such as elephant grass) and circular concrete products with a low MPG contribution. A concrete mix can contain both circular raw materials and fibre reinforcement instead of steel at the same time.

A combined approach

For clients who want to give circularity real substance, combining several circular measures is more effective than relying on a single solution:

• Fibre reinforcement (asphalt) — better recyclability, longer service life.

• Fibre reinforcement (concrete) — less steel use.

• High RAP percentage — reuse of existing reclaimed asphalt.

• Bio-based binders — reduces dependence on fossil raw materials.

• Circular aggregates (concrete) — reduces cement use and primary raw materials.

Case in point

On the A73, it has been demonstrated that fibre reinforced asphalt with penetration bitumen combines well with the regular recycling routes of asphalt plants, without any adaptation of existing production or paving equipment — a practically important point for the scalability of circular solutions.

In summary

Fibre reinforcement is not a stand-alone circular measure, but one that combines well with other circular developments in both asphalt and concrete. For clients working towards Rijkswaterstaat's 2030 objective, combining fibre reinforcement with bio-based binders, high reuse percentages and circular aggregates is the most promising route.

Want to know how fibre reinforcement fits within your circular ambitions? Dutch Fiber Trading is happy to think along with you, free of charge.

Sources

• Rijkswaterstaat, "Klimaatneutraal en Circulair" (rwsinnoveert.nl)

• CEDR FIBRA project, Deliverable 6.2, 2021