Evaluating the Low-Carbon Potential of Imported Silica Fume in the UK Construction Sector

As the construction industry strives to achieve long-term carbon neutrality, using alternatives to cement has become a critical area of focus. Like GGBS and silica fume, it not only improves the strength and durability of concrete but also allows for the partial replacement of cement, thereby reducing the overall carbon footprint of concrete.

Against this backdrop, Arcas & Callisto Consulting (A&C) commissioned the University of Salford to conduct a comparative study on the carbon emissions linked to importing silica fume from various countries, including China, to the UK. The goal of this study was to evaluate the actual impact of transportation on environmental sustainability. The methodology used in this report is also applicable to assessing the transport emissions of imported GGBS.

Evaluation of carbon emissions in the transportation of silica fume from China to the UK.p

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Does the carbon cost of transport cancel out the carbon savings?

—— No, reducing emissions from using silica fume in concrete far outweighs the transport emissions.

The study was based on the European standard BS EN 15804:2012+A2:2019, focusing on Stage A4 (transport). It modelled transportation routes from major producing countries—China, Japan, India, and the United States—to the UK. As expected, carbon emissions varied between suppliers, with Japan having the lowest emissions due to its proximity to major ports.

China’s selected sample city was Wuhan, an inland city. Its longer overland transport distance resulted in the highest emissions among the four case studies.

However, even with this longer route, the total carbon emissions from transporting one kilogram of silica fume from Wuhan to the UK were only 0.00011537 kg CO₂e, negligible when viewed in the full lifecycle context.

When silica fume from China is used to replace 10% to 15% of cement in concrete, each 100 tonnes of concrete can reduce embodied emissions by approximately 2.4 to 3.6 tonnes of CO₂e.

Even after accounting for the additional emissions from transporting 3 to 4.5 tonnes of silica fume (the amount needed for 100 tonnes of concrete at 10–15% substitution), the transport emissions only amount to around 0.35 to 0.52 tonnes CO₂e.

This still results in a net reduction of 2.05 to 3.08 tonnes CO₂e per 100 tonnes of concrete, clearly demonstrating the environmental benefits even with long-distance import.

Can sustainability be improved further?

——Yes, the study offers several recommendations:

• Prioritise manufacturers located close to international ports to reduce road transport.

  
  

• Explore low-carbon alternatives such as rail freight for inland transport.

  
  

• Promote the use of densified or compacted silica fume to reduce volume and improve logistics efficiency.

  
  

• Tailor packaging (bulk or bagged) based on project size to optimise transport impact.

In the context of increasingly efficient and green global supply chains, materials like silica fume and GGBS offer both environmental and economic value. Even when imported from distant countries such as China, these materials remains a highly effective solution for lowering carbon emissions in concrete.

Moreover, China’s large-scale production capacity and cost competitiveness make it an attractive source of sustainable construction materials for the international market, especially in light of rising global raw material costs. This reinforces GGBS and silica fume as a practical, cost-effective, and sustainable choice for the future of low-carbon construction.