What is SubLay C?

SubLay C is protective soil for buried reinforced concrete from SubLay. It is a mineral protective bedding system in the soil next to the structure: around the sides and under the base of poles, foundations, cable chambers, and similar assets. In plain terms, it turns ordinary backfill in that contact zone into a mineral corrosion shield without changing the concrete mix design.

The idea is simple. Most durability work focuses on the concrete itself: mix design, cover, coatings, or the steel. SubLay C works on the layer engineers often treat as an afterthought: the backfill and native soil pressed against the structure. That soil can carry chlorides, sulfates, moisture, and other drivers of corrosion. SubLay C is engineered so that contact zone behaves more like a protective mineral bed than like ordinary aggressive ground.

What you can pilot today: SubLay C Form 1

SubLay C Form 1 is engineered protective backfill. It is a loose mineral bedding you place, compact, and backfill around, with thickness and QC agreed for the job. You do not need to change the concrete mix design or reopen structural approvals to add a soil-side protective layer.

We describe the material at a high level as a mineral / silica-based matrix with corrosion inhibitor and hydrophobic agents. Where regulation allows, we can use qualified industrial side streams; a virgin-mineral grade is available when you need it. Every delivery includes placement guidance and QC notes your contractor can follow on site. Form 1 is a soil-side layer: it is not a substitute for coatings or membranes where your design requires them, but it avoids reopening structural approvals to add protection in the backfill envelope.

Forms 2 and 3 (precast biscuit / mosaic tiles, and cast formats from the same material system) are on the roadmap. Form 1 is the format we scope for pilots today.

How placement fits the job

Think of three zones in the trench:

1. The buried concrete structure.
2. A SubLay C protective bed on the sides and base where soil touches concrete.
3. Regular soil filling the rest of the excavation.

Typical steps: prepare the contact zone, place SubLay C Form 1 at the agreed thickness, compact to spec, backfill remaining zones with ordinary soil, and on pilots record lot ID, thickness, and date. Pilots can include a practical monitoring plan (for example half-cell or sampling per protocol). That monitoring supports learning on the job; service-life outcomes depend on site, design, and the full durability programme.

Who it is for first

Year 1 we are focused on Finnish buried infrastructure: foundations and chambers for energy, transport, agriculture, municipal, and industrial assets, placed by asset owners and their civil contractors. The same Form 1 placement method applies wherever reinforced concrete sits in aggressive soil.

If you bury and maintain concrete in aggressive coastal ground, sulfate-bearing or acidic soils, or salt-loaded roadside environments, SubLay C is aimed at the problem: reduce the soil-side acceleration of corrosion without redesigning the structure.

How SubLay C is different

Other products often protect the steel, the concrete mix, or the concrete surface. SubLay C treats the soil that attacks them.

What is ready vs in progress

The validation table on the SubLay C product page is the live source. In short, as of this article:

• SubLay C Form 1 product and placement method: ready to scope with partners
• Independent EU laboratory programme: in progress
• Finnish infrastructure owner and contractor pilots: open for partners
• Construction-product conformity path: on the roadmap
• Circular feedstock qualification: on the roadmap

How to engage

If you have a buried asset and an upcoming placement, start with a pilot request or email [email protected]. Tell us the asset type, region, and timing. We will review the fit and, if it works, propose a pilot pack: material, application guidance, and monitoring plan.

SubLay C is a soil-side protective layer for buried infrastructure. Your structural engineer and conformity strategy stay in your lane; we help you treat the ground that presses against the concrete.

For deeper engineering context, see Technical notes on buried concrete durability.