South African Conference on Polymers in Concrete, Berg-en-Dal, Kruger National Park Jun 20-23, 2000

4. Additional Benefits and Layer Thickness

A cost-benefit analysis should be applied to weigh the benefits of sealing against the disadvantages. This is made more difficult by the absence of quantitative measurements on the relevant properties. The relevance of the properties is often unknown. There is, for example, no agreement between the German sealant manufacturers, of whom there are in excess of 50. International standards - apart from the German AGI worksheet AGI A 80 - are not generally recognised. The matrix from the RILEM TC "Industrial Floors" provides an initial starting point, if it is adapted for the special properties of sealants.

Industrial Floors: Product Properties and Other Basic Data for Benchmarking of Reaction Polymers and Mortars

1. Designation
2. Main characteristics

Basis (composition)
Solvent
Use
Components
Fibers (% by weight)
Thickness, min
max
Density (event. of binder)

Price per kg (max package)
Price per L (max package)
Average (Ø) thickness
Price per m² (Ø thick: material)
Price of application per m²

Setting time (start of production)

Layers, min
Impregnation (Primer)
Waiting time 1 (20°C) • min
max
Topcoat (sealing)

Abrasion
Testing device
Strength (4*4*16) N/mm²
Package, max

3. Other technical data

Quality system
Flow behaviour
Testing device
Outdoor use
Wet substrate
Filling, min
max
Aggregate grain, min
max
Cleaning

4. Safety data sheet

Health hazards
Symbol(s)
R- and S-sentences
Transport prescriptions

5. Application

Time per m² and worker
Mixing on site
Potlife (20°C)

6. References

Start of production
Object reports

7. Sources of knowledge

Date of technical data sheet
Technical data sheet
Temperature behaviour
Safety data sheet
Label(s)
Instructions for application
Cleaning instructions

8. General properties

Skid proofness
Package, min
Temperature min
max
Characterisation (fingerprint)
Video instructions

9. Samples

Before setting (1 kg)
After setting (4*4*16) max filled

If the properties of the surface of a substrate cannot satisfy the user's wishes, an additional layer can be applied as a sealant. The customer, however, must receive additional benefits that are high enough to justify the costs involved. The question arises of whether the customer always realises how short the life of sealant can be. For instance, the high level of wear makes sealant less suitable for sales floors and museums. Important additional benefits include:

The question arises as to how these additional benefits can be achieved without using sealant. Systems using water-based epoxides, a further development of ECC mortars, can provide additional layer thickness allowing sealant to be omitted. They can therefore be expected, in the light of their favourable physiological and ecological properties, to have a significant future. It should however be noted that, until now, the application process is not sufficiently foolproof.

Sealants are defined as thin layers, 0.1…0.3 mm thick, most often manually applied by roller. They are also applied in multiple coats in order to increase the layer thickness. In this case, minimum and maximum waiting times depending on the material and on the climatic conditions in the building between application of the layers must be carefully observed: if this is not done, separation can follow from inadequate adhesion between the layers. This calls for the workforce to receive careful and testable training. Adhesion between the layers cannot be reproduced with precision in the laboratory, so that further work is required in this field.