All About Concrete Albury Wodonga
Concrete slab options and requirements for polished concrete
Concrete slab options and requirements for polished concrete
A great polished concrete floor starts well before we arrive on site. The mix you specify, how the slab is placed, finished and cured, and the aggregate you choose all have a direct effect on what we can achieve when we grind and polish.
This page covers the things worth knowing before your slab goes down, and how to use those choices to get the floor you’re after.
MPa stands for megapascals, a unit used to measure the compressive strength of concrete. In simple terms, it indicates how hard and strong the concrete is after curing — higher MPa means the concrete can withstand greater loads and delivers improved durability and performance.
Increasing a concrete mix to 32 MPa provides a better polish and better durability. During curing, concrete naturally contains calcium hydroxide in the paste. When we polish, a silicate densifier reacts with that calcium hydroxide and forms more of the hard binding material right where the wear happens. A richer, stronger paste in 32 MPa mixes supports that reaction and helps the floor hold its clarity and surface strength over time.
The practical upside of specifying 32 MPa is that it also provides performance headroom that can help minimise shrinkage related cracking when combined with correct placement and curing. Strength alone isn’t a silver bullet though — pour quality and curing are still critical.
It is important to only use approved admixtures. Some curing agents and retarders can interfere with the densifiers required for the mechanical polished concrete system. If additives are being considered, check with us before ordering so we can confirm compatibility.
Want the deep dive on reaction pathways or densifier choices? Customers, architects and builders are welcome to contact Dale for a technical chat about polishing chemistry and specification details.
One of the best things about polished concrete is that the design decisions start before the slab is even poured. A few considered choices early on can give you a floor that feels genuinely tailored to the build rather than just whatever came out of the truck.
The bottom line: the slab itself is a design element if you treat it that way. We’re happy to work through these options with you, your builder and your concrete supplier well before the pour so the slab is set up to deliver the result you’re after.
Red oxide, Wodonga Quarry mix with extra blue metal aggregate.
Black oxide, Tarrawingee aggregate mix.
How much we grind the surface changes the whole look of the finished floor. The three main options are zero, partial and full exposure, and a couple of millimetres is often all that separates them. Getting the slab right before we start gives us the best chance of landing exactly where you want to be.
Zero, partial and full exposure options
Vibration: The concrete needs to be properly vibrated to push out trapped air and make sure the mix fills evenly around the reinforcement. Skip this step or rush it and you get voids and weak spots in the paste that show up later as inconsistent exposure or surface defects when we grind.
Level and flat: Our grinder follows the surface of the slab. If there are high and low spots, the grinding depth changes across the floor, which changes how much aggregate is revealed in different areas. Even a few millimetres of variation can make an even exposure very hard to achieve.
Finishing: Machine trowel timing is especially critical for zero and low exposure floors. Too much finishing, not enough, or adding water to the surface late in the pour can all weaken the paste layer and limit what we can achieve with the polish.
Letting the chemistry finish: Curing is the process of keeping moisture in the slab so the concrete can keep developing its strength. If it dries out too quickly, that process stops early and the near-surface ends up weaker and less able to polish well.
Slow and even drying: Controlled drying reduces shrinkage and surface dusting. Polished concrete is typically ready at the 28-day mark for the best results. Rushing this leads to poorer polish quality and a floor that won’t hold up as well over time.
Simply put: the flatter, denser and better cured the slab is, the better the finished floor will be. We include slab guidelines and process documents with every quote so your build team knows exactly what’s needed.
Our gallery is a great way to see what different mix and finish combinations actually look like on a finished floor. Browse real projects from around the region and find a look that works for your build.
We’ve completed floors right across the Albury Wodonga region and beyond. Browse our project pages online or visit some of our floors in person to see the finish quality firsthand before you commit.
Tell us about your build and what you’re hoping to achieve. We’ll point you in the right direction and provide a quote along with slab and process documentation for your build team.