Laying Stelcon concrete slabs

Application
The product specification sheets state the maximum permissible load for each type of industrial floor slab. These loads are only permissible if the sub-base and foundation meet the conditions set out below. The installation method, joint width, joint filling and proper drainage are also important.

Stacking
Three support points (concrete slabs or pavers of equal thickness) must be laid on a flat, stable surface. The first slab is placed on these, and must remain clear of the ground. Three further support points are then laid on this slab, directly above the first. The slabs must be stacked in this manner, one by one. The maximum stacking height is 1.5 metres.

Substrate / foundation / bedding
The industrial floor slabs are laid on a bedding which, together with the underlying layers, must have sufficient load-bearing capacity. The structure of the layers must be such that uniform settlement behaviour can be expected. For foundation advice, it is recommended to consult a consultancy firm specialising in soil mechanics.

Load-bearing capacity requirement
Minimum bedding number: 0.06 N/mm³ (approx. 15% CBR)
Sub-base thickness: minimum 100 mm

Sand recommendation

• Sand must comply with the description: “Sand with a permanent drainage function”. (Standard RAW provisions, Art. 22.06.02);
• Sand median (Mz) ≥ 210, meaning the sand can be characterised as ‘coarse’ (NEN 5104, Classification of uncompacted soil samples, Art. 4.3);
• Uniformity coefficient (Cu) ≥ 2. This value characterises the spread in the grain size distribution (NEN 5104, Classification of uncompacted soil samples, Art. 5.2). 

Compaction recommendation
In order to fully utilise the material properties of the sand bed and the foundation, it is advisable to achieve a compaction degree (Proctor value) of at least 95% and an average value of 98% at a depth of less than 1.0 metre below floor level.

Drainage advice
When the foundation layers become saturated with water, the bearing capacity decreases significantly. This is also often adversely affected when frost and subsequent thaw occur. The groundwater level must therefore often remain sufficiently deep below the floor surface. Recommended water level: 0.6 metres below the top of the floor.
 

Advice on laying concrete slabs

1. The laying bed must be carefully fine-profiled. Laser-guided equipment can be used to achieve the required accuracy.
2. The industrial floor slabs must be lifted and laid using a vacuum lifting system. If the slab is fitted with lifting holes, a lifting system with lifting keys may also be used. The product specification sheets provide further information on this.
3. Outdoor floors must be laid with a gradient of 1.0% to 1.5%.
4. Lower the panels horizontally and slowly onto the sub-base.
5. Always use spacers. These (waterproof) wooden or plastic spacers must ensure a 5 mm joint between the floor elements.
6. The grid size of the floor is a multiple of 2 metres. With a panel size of 1995 mm and a 5 mm joint (spacer), this grid size is achieved.
7. It is recommended to edge the floor all round. Edge beams can be used for this purpose if required.
8. Finally, the joints must be swept full of sand. Later, during use of the floor, this sweeping should be repeated as necessary.