Silo and hopper linings for concrete or steel: abrasion and material flow

A silo or hopper lining is chosen by wear mode and how the stored material behaves: a smooth low-friction lining solves flow problems, ceramic resists severe sliding abrasion, polyurethane and rubber absorb impact. On concrete, the degraded substrate is repaired first, then lined. All internal work is done as confined space entry, with feeders locked out and the engulfment hazard controlled.

Ore, concentrate, clinker, cement, lime, wood chip or aggregate silos; loading, weigh and transfer hoppers: these structures wear quietly until the day the material stops flowing or a wall perforates. This guide helps maintenance managers and project managers at mines, cement plants and industrial plants in Quebec and Ontario choose suitable protection. It is part of our protective coatings offering.

Why do silos and hoppers wear?

They wear because the material rubs, strikes and sometimes chemically attacks the walls at every fill and discharge cycle. Wear concentrates where material slides fastest or falls from highest: discharge cones, impact areas under feed points, outlet edges, transitions.

Four mechanisms combine:

• Sliding abrasion. The material slides on the wall and wears it like an abrasive. This is the dominant mode in cones and chutes.
• Impact. Lumps falling at the feed crush and tear the lining and substrate.
• Chemical attack. Moisture, sulfates and acids from some concentrates or agricultural products attack concrete and corrode steel.
• Freeze-thaw cycles. On outdoor concrete silos, water entering through cracks spalls the concrete surface.

Diagnosis starts by identifying the dominant mechanism in each area, because a single silo can need two or three different solutions.

How does a lining improve material flow?

A smooth low-friction lining reduces adhesion of the material to the wall and helps it slide instead of forming arches or ratholes. Flow problems often come from a wall that has become rough through wear, corrosion or deposits.

Typical problems:

• Arching. Material locks up above the outlet.
• Ratholing. Only a central column flows; the rest stays stuck to the walls, compacts and degrades.
• Build-up. Wet or fine materials stick and reduce live capacity.

A smooth, low-adhesion wall promotes flow but does not correct unsuitable geometry. Common options are smooth-surface filled epoxy linings, linings containing low-friction fillers, and mechanically fastened ultra-high molecular weight polyethylene sheets. The choice accounts for temperature, abrasion and cleaning.

Before selecting a low-friction lining, gather what the operator already knows about the material: moisture content through the seasons, particle size, temperature at loading, and where and when hang-ups occur. Material that flows well in summer can freeze to the walls in a Quebec winter, and a lining that performs on dry concentrate can behave differently once fines and water are present. Where the stakes justify it, a flow property test on a sample of the material against candidate lining surfaces helps compare options before committing to a full installation. The result is a lining choice tied to observed behaviour rather than to a catalogue claim.

Which solution suits which wear mode?

Choose first by the dominant wear mode, then by flow, temperature and substrate. The table summarizes generally recognized directions; each product's data sheet and the structure's history decide.

To go further, our rubber lining service covers impact areas, and our supply and installation service covers installation of ceramic tiles and wear plates. At mines, mining equipment painting completes exterior protection.

How is degraded concrete repaired before lining a silo?

Repair the concrete first, then line it: a lining applied over friable, cracked or damp concrete disbonds along with the concrete it covers. Repair starts by removing all degraded concrete down to sound concrete.

Usual steps:

1. Survey. Mapping of degraded areas, cracks and exposed reinforcement, by hammer sounding and observation.
2. Removal of degraded concrete. By hydrodemolition, chipping or grinding depending on extent, down to a sound substrate.
3. Reinforcement treatment. Cleaning and protection of exposed rebar.
4. Repair. Compatible repair mortars and concrete crack injection for active or dormant cracks depending on diagnosis.
5. Surface preparation. Per SSPC-SP 13 / NACE No. 6 and the concrete surface profile set by ICRI 310.2R.
6. Moisture check. For example per ASTM D4263, as explained in our article on concrete moisture before epoxy coating.

Our concrete protection page presents lining systems suited to concrete structures.

What are the differences between steel and concrete silos?

The difference lies in the substrate: steel corrodes and thins, concrete cracks, crumbles and suffers chemical attack. Lining choice and preparation follow from that.

In both cases, thickness readings or sounding before the work avoid lining a substrate that needs repair first.

How is inspection and confined space work done in a silo?

Work inside a silo follows a full confined space procedure, compliant with the RSST in Quebec or the confined spaces regulation in Ontario, and often with CSA Z1006. A silo carries its own hazard: engulfment by the stored material, including material hung up on the walls that can break loose.

Essential measures:

• Emptying and verification. The silo is emptied; hung-up material is located and dealt with from outside or from a safe position before entry.
• Lockout. Feeders, conveyors, vibrators, air cannons and outlet gates are locked out.
• Atmosphere. Oxygen, gas and dust are tested before entry and continuously; mechanical ventilation.
• Access and rescue. Access from the roof or hatches, harness and retrieval system, rescue plan specific to the structure.

For inspection, visual examination, thickness readings and concrete sounding are combined and, after lining, thickness checks and holiday testing when the system calls for it. Our coating inspection service documents these checks.

How to get a quote?

Our crews and qualified subcontractors work from LaSalle, including Abitibi-Témiscamingue and Sudbury, at mines, cement plants and industrial plants. Send photos, dimensions, the stored material, wear areas and the shutdown window through the request a quote form: pricing on consultation, reply within 24 business hours.

Frequently asked questions

Which lining suits a highly abrasive silo cone?

For severe sliding abrasion, alumina ceramic tiles are generally selected. If the area also takes heavy impact, ceramic is combined with an elastomer or a suitable polyurethane is chosen.

Can a lining fix arching or ratholing?

It can reduce it by making the wall smoother and less adhesive. If the cause is hopper geometry or material moisture, the lining alone is not enough and the outlet design has to be reviewed.

Can a concrete silo be lined without repairing the concrete?

No. A lining applied over degraded concrete disbonds with it. Friable concrete is removed down to a sound substrate, cracks are treated and moisture is checked before application.

Does the silo have to be fully emptied for inspection?

For internal inspection, yes, and material hung up on the walls has to be dealt with before entry. Part of the external inspection, such as crack mapping, can be done with the silo in service.