Scottish granite

From Graniet Import Benelux and Antwerp Stone Terminal Bontrup Antwerp Stone Terminal Bontrup granite from Glensanda Quarry, one of Europe's largest quarries with more than 750 million tons of reserves of high-quality stone. With high production and loading capacity and great water depth, Bontruplargest seagoing vessels can be loaded directly and provide large-scale transport to the terminals.

Scottish granite is characterized by its high strength and good resistance to abrasion and crushing. The material contains no chlorides, rust-forming particles, chlorides or other impurities. Scottish granite is not Alkali-Silica-Reactive (ASR) and frost-resistant. This makes it very suitable for applications with high durability requirements, in aggressive environments (e.g. sea walls) and for use in fire-resistant concrete. The material has a good particle shape, providing high workability and pumpability of the concrete.

In cooperation with Delft University of Technology and SGS Intron, Bontrup investigated the use of Granite Premix (a crushed 0/5 mm fraction) as part of the sand fraction in concrete. The results show that replacement of approx. 35% river sand with Premix leads to:

• improved mix grading leading to higher strength and a denser grain matrix;
• cement savings of 20-40 kg/m³, resulting in 3-6% lower ECI (Environtal Cost Indicator) value and CO₂ reduction;
• better workability and smoother surface texture;
• No negative impact on frost/thaw resistance or chloride intrusion.

The study confirms that Granite Premix as a "manufactured sand" reduces the environmental impact of concrete, without loss of performance.

Scottish granite is characterised by its low porosity, high thermal stability and absence of clay minerals or organic components. As a result, the stone retains its strength at high temperatures considerably better than river-dredged sand or sea-dredged gravel mixtures. These properties make Scottish granite ideally suited for fire-resistant concrete, like in tunnels, viaducts and buildings with increased safety requirements. For example, Scotch granite is used in the fire-resistant concrete of the new tunnel structures in the A9 highway near Amstelveen.

In summary, the use of Scottish granite in concrete offers the following advantages over traditional river and sea-dredged gravel:

• Constant quality thanks to its homogeneity and controlled crushing and screening process
• No chloride, rust-forming particles, organic material → no risk of corrosion or staining
• Not sensitive to ASR, making it safe for applications where durability is critical
• Optimal grading with use of premix leading to higher strength and lower cement use
• Hard and wear-resistant → high durability and resistant to abrasion and freeze-thaw effects
• Fire-resistant → suitable for fire-critical structures
• Low environmental footprint due to the large-scale production and sea transport

Scottish granite: pure and homogeneous, the best alternative to gravel.