The current trend for colouring concrete is leaning towards oxide in the mix. Seems an easy choice, the concretor orders the cement truck, they throw some colour in the truck and right before your eyes you have a poured coloured slab. The world is now at peace, everyone is happy, end of story, right?
For some, and I would like to think the majority, this is the case and all that is left to do is to apply the protective Concrete Sealer and stick to a maintenance / sealing plan and your concrete will continue to look good for many years.
Experience however shows a different reality.
Lets start with a quick definition of the two.
Colour Hardener is a blend of cement, sand and oxides that is trowelled into the surface of fresh poured concrete and can be used with stencil patterns or by itself to create a hard wearing, bright solid colour. Colour Hardener cures two to three times harder than the plain concrete and if regularly sealed should never fade or wear through to the grey concrete underneath.
Oxide in the mix on the other hand is an oxide colour. That’s it!
The main benefit of using oxide in the mix is in case your surface gets damaged. If your surface gets chipped or scratched for example you will continue to see the colour as the entire depth of the concrete has the same colour throughout. The other benefits appear to be for the concretor. Since the colour is mixed at the concrete plant the concretor doesn’t have to throw Colour Hardener on the surface of the plain concrete and work it in.
You get what you order with Colour Hardener. It is a solid surface coating so when you pick a colour that is the colour you get.
With oxide, you pick a colour then that colour is diluted in grey concrete and when cured is usually a lot lighter or weaker in colour than you expected. If you have multiple pours the grey concrete can be a different each time giving a different colour shade for each poured section.
Oxide can also fade, adds no extra strength to the concrete, is more expensive, brings a truck washing fee, and if left unsealed will wear faster than Colour Hardener. If the colour turns out not to your liking you end up putting on a Coloured Sealer to get your strong colour. Did I mention it is easier for the concretor?
In the end neither product is the wrong one to use and in my opinion the smartest option would be to go ahead and put the oxide in the mix and then, for added strength for the surface and to guarantee a strong colour, apply the Colour Hardener over the top.
Once you finish you still apply a clear Concrete Sealer to protect your surface and you will have the strongest and brightest Coloured Concrete available.