What is a dry-shake hardener?
A dry-shake hardener (topping) is a factory-made dry hardening mix of cement, a hard wear-resistant aggregate and modifying admixtures, often with a pigment. It is spread evenly over freshly placed concrete once the concrete can bear a worker’s weight, and worked in with power trowels: the mix draws water from the concrete, hydrates together with it and forms a dense, hardened surface layer that is integral with the slab. Such a floor has no separate coating that could delaminate.
A dry-shake hardener increases the resistance of the surface to abrasion and impact, reduces dusting and makes it possible to obtain a coloured floor in a single operation with the concreting. It is the main solution for new floors in warehouses and logistics centres, engineering workshops, car parks, hangars, and retail and exhibition halls where there are no aggressive chemicals.
Types of dry-shake hardener
Quartz
The aggregate is quartz. Suitable for light and medium loads: foot traffic, trolleys, forklifts on pneumatic and polyurethane tyres.
Corundum and synthetic aggregates
High-hardness aggregates — corundum, emery and other synthetic minerals — give greater abrasion resistance. They are chosen for intensive forklift and trolley traffic.
Metallic
A metallic aggregate increases resistance to impact and to abrasion from steel wheels, dropped heavy parts and dragging. This is an option for heavy-duty workshops and rolled steel stores; the service conditions under which a metallic aggregate is acceptable are stated in the data sheet.
Coloured and decorative
Pigmented mixes allow traffic aisles and storage areas to be marked out in colour. The colour of a dry-shake hardener is never as uniform as that of a resin floor: the shade depends on the concrete, the weather, the trowelling technique and the curing.
Classification to EN 13813
Manufacturers designate dry-shake hardeners as cementitious floor materials to EN 13813: the designation states the binder type — CT — and property classes, for example compressive strength (C), flexural strength (F) and wear resistance. Wear resistance is determined by different methods: by the BCA method — wear depth in micrometres and the AR class; by the Böhme method — volume loss in cm³ per 50 cm². Materials can be compared only on the same indicator and method; the values for specific products are given on the catalogue cards.
Application procedure
- The concrete is placed, compacted and levelled to screed rails or with a laser screed; the surface must not be over-wet.
- Application of the dry-shake hardener begins once the bleed water has evaporated and the concrete bears a worker’s weight with a shallow footprint; the exact timing and signs are given in the data sheet.
- With manual application, the quantity is usually split into two passes: the first portion is spread and floated with a pan, then the remainder is applied and floated again; with mechanical spreading, the mix can be applied in a single pass — as instructed in the data sheet.
- The surface is finished with the blades of power trowels in several passes, increasing the blade pitch, until it is dense and smooth.
- Immediately after trowelling, a curing product — a membrane-forming compound or an impregnation recommended by the manufacturer — is applied, and the floor is protected from sun, wind and draughts.
- Shrinkage joints are cut at the times specified in the design, before random cracks form in the slab.
In summer in Uzbekistan, concrete loses moisture quickly: wind, sun and low air humidity shorten the time available for trowelling and increase the risk of cracking. Concreting is scheduled for the morning hours or carried out inside a closed building, and curing starts without delay.
How to choose a dry-shake hardener
By load
The more intensive the traffic and the harder the wheels, the harder the aggregate should be and the closer the consumption should be to the upper end of the range in the data sheet. For the materials in the catalogue, consumption ranges from 3 to 7 kg/m², depending on the product and the method of application; one manufacturer shows explicitly in its data sheet that the wear resistance of the surface increases with consumption.
By service conditions
A dry-shake hardener is a cementitious material: acids, sugars and many aggressive media attack it. For food and chemical plants, polyurethane cement or epoxy systems are chosen instead.
By concrete
A dry-shake hardener will not fix weak concrete: the concrete class, its workability, the absence of segregation and the setting time determine the result no less than the mix itself. Concrete with a high entrained air content and excessive bleeding is not suitable for a dry-shake hardener.
Curing and service
- The curing compound is applied immediately after final trowelling, and the surface must not be allowed to dry out during the first few days; the times and method are as per the data sheets for the dry-shake hardener and the curing product.
- Forklift traffic and storage begin once the concrete has reached the strength specified in the design.
- To reduce dusting and oil absorption, the surface is additionally treated with a hardening impregnation or sealer compatible with the dry-shake hardener.
- The floor is cleaned regularly with scrubber-dryers: abrasive dirt and sand under wheels wear down any surface.
Common mistakes
- Spreading the mix over surface water — segregation, dusting, scaling.
- Spreading too late, when the concrete no longer releases moisture — the mix does not bond to the slab.
- Spraying water onto the surface during trowelling — a weak surface layer.
- Consumption lower than the data sheet specifies for the actual load.
- No curing during the first day — map cracking and dusting.
- Late joint cutting — random cracks across the slab.
- A dry-shake hardener in a workshop with acids or sugars — rapid deterioration of the surface.
See also: resin flooring — overview, impregnations and sealers, epoxy floors.
Materials in the catalogue
- Sikafloor-3 QuartzTop — Sika — mineral quartz dry-shake hardener for fresh concrete, class AR1, 3–5 kg/m².
- Sikafloor-2 SynTop — Sika — non-metallic synthetic dry-shake hardener for fresh concrete, CT-C70-F7-AR0.5 to EN 13813.
- Sikafloor-1 MetalTop — Sika — metallic dry-shake hardener for heavy-wear floors, AR0.5 and Böhme A1.5.
- Fosroc Nitoflor Hardtop — Fosroc — quartz dry-shake surface hardener for fresh concrete floors, 3–5 kg/m².
- Fosroc Nitoflor Emeritop — Fosroc — emery-aggregate dry-shake hardener for fresh concrete, 9 Mohs, minimum 5 kg/m².
- Mapetop N AR6 — Mapei — quartz dry-shake surface hardener for fresh concrete, 3–5 kg/m², Böhme class A6.
This list is not exhaustive. The final choice is made on the basis of the manufacturer’s documents and the project requirements.
Frequently asked questions
Can a dry-shake hardener be applied to old concrete?
No: a dry mix only works together with fresh concrete. Old floors are hardened with impregnations or covered with a polymer system.
Does a floor with a dry-shake hardener need curing after trowelling?
Yes, it is a mandatory part of the procedure. Without curing, the surface layer dries out, cracks and dusts; manufacturers recommend compatible curing compounds and impregnations.
Which dry-shake hardener should be chosen for a warehouse with forklifts?
For forklifts on polyurethane and pneumatic tyres, a quartz or corundum dry-shake hardener with consumption close to the upper end of the range in the data sheet is usually sufficient. With steel wheels, dragging and impact, a metallic dry-shake hardener or a thicker polymer coating is considered.
Why does a floor with a dry-shake hardener dust?
Usually because of the workmanship: the mix was spread over surface water, water was added during trowelling, no curing product was applied, or the floor dried out during the first day. A weak surface layer can be hardened with an impregnation; if it has broken down, it is removed by grinding and protected with a polymer coating.
Which is better: a dry-shake hardener or a polymer coating?
For a new warehouse or workshop floor without aggressive chemicals, a dry-shake hardener is more economical and is carried out together with the concreting. If chemical resistance, a hygienic seamless surface or a bright, uniform colour is required, a polymer coating over prepared concrete is chosen.
We will select a dry-shake hardener and its consumption to suit the loads on your floor and calculate the supply — call us or message us on WhatsApp/Telegram: +998 94 094 52 27.