Aluminium vs Steel Crane Mats: How to Specify the Right One

Steel is stiffer and stronger than aluminium alloy, section for section, by a wide margin. Steel's modulus of elasticity sits at roughly 200,000MPa; a high-strength aluminium alloy like the 6005A we use in ALIMATS comes in around 69,000MPa — call it a third of the stiffness. Its yield and tensile strengths run ahead of aluminium's too, for a given section size. Anyone claiming aluminium is "just as strong" as steel in the abstract isn't being straight with you.

What matters is what a manufacturer does with that raw material once its properties are known. We engineer ALIMATS from 6005A aluminium alloy — 280MPa compressive strength, 270MPa tensile — worked into a patented modular interlocking geometry and independently verified against real crane loads with a Fellow of the Institution of Structural Engineers. That gives safe working loads up to 80 tonnes, comfortably covering cranes up to 150 tonnes. It isn't aluminium overtaking steel's material properties — it's careful geometry and rigorous engineering making a lighter material perform to a genuinely high standard for the loads a mat actually sees. Steel mats reach their numbers a different way, through sheer section thickness and mass, and for some jobs that's exactly the right approach.

None of that stiffness advantage is academic. There are real jobs on real UK sites where steel is the more sensible specification, and a good specifier should be able to say why rather than defaulting to habit. The clearest case is a permanent or semi-permanent installation — a mat going down for the life of a structure, or for a multi-year programme where it will never be lifted out and redeployed. In that scenario a lighter material's transport and handling advantages count for very little, because the mat only moves once, and steel's raw stiffness under sustained, repeated loading becomes the property that matters.

The same logic holds for extremely high concentrated point loads — outriggers or crawler tracks bearing down on a small footprint at the very top end of what any trackway mat is asked to do — and for indoor or controlled environments such as a factory floor, a power station outage or a covered fabrication yard, where the mat never sees weather and corrosion simply isn't a factor. Strip out the transport penalty and the corrosion question, and steel's case is a strong one. Rule it out reflexively, purely because aluminium is the newer or more talked-about option, and you're not specifying properly.

The other side of that stiffness advantage is mass, and mass has to go somewhere. A steel mat built to genuinely useful dimensions under real crane loads is heavy — heavy enough that it typically needs a telehandler, excavator or similar plant to lift and place it, and heavy enough that repositioning it mid-programme means booking that plant again. That's not a minor inconvenience to wave away. On a site where mats move every few days as the programme progresses, the cost of the plant and its operator, and the time lost waiting for both to be free, is a real and recurring cost — and it has to be set against steel's strength advantage, not ignored.

We engineered ALIMATS around the opposite trade-off. Individual modules run from 13kg for the Mini unit up to 48kg for the Long and Extra Long modules, building into configurations from 1.34m² to 8.07m², and every module in that range is handleable by two people with no plant needed. On a site reconfiguring a crane pad weekly, or shifting mats between several positions across a programme, that difference compounds fast — it's the gap between a five-minute job for two groundworkers and a job that needs a machine, an operator and a slot booked into the day's plan.

Left bare, steel rusts, and a crane mat spends its working life in exactly the conditions that bring that on fastest — wet ground, standing water, mud and repeated abrasion from tracked plant driving over it. Steel mats meant for long service are usually galvanised or painted, and that protective layer is itself a maintenance item. It gets scored and chipped by the very plant traffic the mat exists to support, and once it's breached, corrosion starts at that point regardless of what's happening elsewhere. Keeping a fleet of steel mats properly protected over years of hire or ownership means a genuine, ongoing programme, not a one-off treatment.

Aluminium's advantage here isn't a coating at all. It's a natural oxide layer that forms on the surface on exposure to air and effectively stops further oxidation — no paint, no galvanising, no applied treatment. That's a basic property of the metal, and it's why our mats don't carry the same recurring maintenance overhead. It matters for anyone hiring mats for a long programme, or buying a fleet for repeated redeployment across sites. We inspect, clean and check every ALIMATS module before it goes back out, but there's no galvanising or repainting cycle sitting behind that inspection.

The strength-to-weight difference between the two metals shows up most directly in transport, and transport is where a lot of the real cost of running mats actually sits — not in the purchase or hire rate, but in how many loads it takes to get a given area of trackway to site, and how much plant is needed once it's there. A lighter mat means more area per lorry load, fewer deliveries, and less fuel and driver time spent moving the same footprint of protection around the country.

It changes what's needed once the mats arrive, too. Because ALIMATS modules top out at 48kg and interlock into configurations without fixings or heavy plant, a two-person team can lay, lift and relocate them by hand — no telehandler booked for the day just to shift trackway a few metres, no waiting on plant that's busy elsewhere. Over a programme with several remobilisations, that saving in transport loads and on-site handling adds up to a meaningful sum, and it's the main reason aluminium has taken real market share on sites where mats move often, even among contractors entirely comfortable with steel.

Reduced to something you can use on a Monday morning, the choice comes down to how long the mat stays put and what's driving the load. Steel earns its keep where a mat goes down once and stays down — permanent hardstanding, long-duration outage work, a semi-permanent crane pad on a multi-year build — or where the load sits right at the extreme end of concentrated point loading and the site is sheltered from the weather, inside a building or a covered yard. If the mat is handled once, by a machine already on site for other reasons, steel's cost per tonne of raw strength is competitive and its corrosion resistance is irrelevant.

Aluminium makes the stronger case wherever a mat moves — utilities and infrastructure programmes with mats shifting weekly or between sites, projects run on tight access without a telehandler permanently available, and anywhere months or years of outdoor exposure would otherwise mean a galvanising or repainting cycle. ALIMATS is built for exactly that pattern: safe working loads up to 80 tonnes covering cranes up to 150 tonnes, modules handleable by two people with no plant, and a hire or purchase model backed by 24/7 UK delivery, suited to programmes where the mat requirement changes as the job progresses. Over 80% of the UK's top twenty Tier 1 contractors now specify it — not because steel has stopped being useful, but because most live programmes move their mats often enough that the maintenance-free, plant-free case for aluminium is hard to ignore.