Testing basalt fibre as a rebar substitute

A new method of replacing traditional steel rebar with basalt fibre in the concrete public stairways at the local park Hjorthagsparken has reduced both material use and climate impact. This approach, tested in Stockholm Royal Seaport, marks one of the first applications of basalt fibre reinforcement in the Stockholm region.

During the construction of the new stairways, the project team implemented a new method to reduce the carbon footprint of concrete slab casting. According to the conventional technical handbook, traditional stairway construction requires a 330-millimetre-thick concrete slab with steel rebar. However, new calculations demonstrate that this thickness can be significantly reduced in this context.

The tested method uses basalt fibre reinforcement minibars as a substitute for traditional steel rebar. While fibre reinforcement is common, the use of basalt fibre, a natural material, remains a novel choice. The concrete slabs for the stairways in Hjorthagsparken have been cast in three different thicknesses: 100, 150 and 200 millimetres.

This rebar replacement method enables substantial savings in both materials and costs. For example, the 100-millimetre-thick slab uses 70% less concrete compared to the 330-millimetre-slab. This project shows how even small-scale interventions can make a meaningful difference.

In addition to reducing climate impact, the method has improved working conditions at this challenging site, particularly by reducing the need for heavy lifting.

The initiative is a collaboration between the Development Administration and the Traffic Administration. The aim is to apply this rebar replacement method, where appropriate, across both Stockholm Royal Seaport and other City of Stockholm projects.

Article Published: 15/04/2025 Updated: 18/06/2026