Underground tunnel in the Go4Zero project — Obourg

Penetron contributes to the waterproofing of a unique sustainable concrete structure in Belgium 

In the context of Go4Zero, Holcim's ambitious climate-neutral transformation project in Obourg, is currently becoming an underground concrete gallery built. This gallery is part of a larger cement production infrastructure of the future, with a focus on net-zero emissions by 2030 — a first in Belgium and Europe.

A collaboration between innovative players

This unique project comes about thanks to a strong collaboration between DECISION, Denys, Holcim and Penetron Benelux. For the waterproofing of the in-situ cast concrete tunnel structure, a integral crystalline system based on Penetron Admix SB.

The tunnel is partly below the groundwater level, which causes significant water pressure on the concrete structure. The combination of sustainability, complexity and chemical stress requires an efficient and self-healing system that ensures waterproofing — both during construction and in the future.

Why Penetron Admix SB?

✅ Permanent integral waterproofing thanks to crystal formation in capillaries
✅ Self-healing capacity for cracks up to 0.5 mm
✅ Resistance to external water pressure and chemical stress
✅ No external membranes required - simpler design, increased safety
✅ Perfectly combinable with sustainable types of cement

On-site application

• Zone-wise implementation: floor plate, walls and roof plate are poured sequentially per tunnel zone
• Concrete C30/37 with cement type CEM V/A 42.5 NM L/H HSR LAB, durability class EE3
• Penetron Admix SB is added to the concrete plant
• Placement of Penebar SW type A and B in the cold joints

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