Concrete floors in high traffic areas – dry-shake hardener or high performance concrete

Areas where concrete floors need to be resistant to high traffic loads include various terminals, warehouses, car parks, and many industrial facilities where metal and other heavy items are handled. In high traffic areas, the finishing of concrete floors is often based on dry-shake hardener or a separate high performance concrete topping.

In practice, dry-shake hardener is a concrete product that does not contain water. It contains cement and various hard aggregates. When the hardener is applied over a fresh concrete floor, it absorbs the water it needs from the concrete substrate.

Dry-shake hardener is applied on the fresh concrete with a float and forms a homogenous structure with the top concrete layer, which means it is not a separate coating like high performance concrete.

High performance concrete is a dry product that contains cement, aggregates, possibly admixtures and fibres. Water is then added in this dry compound on the site. The fresh high performance concrete is applied either on a partly cured concrete substrate or as a separate topping on fully cured concrete. High performance concrete toppings are usually about 12–20 mm thick. A high performance concrete topping is also thick enough and has a sufficient compression strength to make it highly impact resistant.

A dry-shake hardened surface is usually always characterised by variations in the shade of colour due to how it mixes with the fresh concrete substrate. High performance concrete topping is thicker and thus more uniform in colour than a dry-shake topping, and of the same colour across its thickness.

Deep grinding is not possible with a thin dry-shake topping. Generally dry-shake hardened floors are just lightly polished and finished with a protective coating to ensure the floor retains it concrete character with some fine aggregate material visible on the surface. High performance concrete can be ground and polished more deeply.

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