Industrial Floors 1991, International Colloquium Jan 15-17, 1991

2. The composition of concrete

Variability of binder and aggregates
The construction of an industrial floor using concrete (in contrast to, for example, asphaltic concrete with bitumen as binder or polymer concrete with reaction polymers as binder) really ought to be quite straight-forward, just as the principle already mentioned for the basic demands made on a floor appear very simple. One can sum it up in terms of a six-step method:

Then the factory can begin production and the fork-lift trucks can drive around.

In reality, however, the construction of an industrial floor poses many difficulties owing to the variety of service conditions and the variability of the materials used. This is demonstrated by the high incidence of damage. In the case of floors made of concrete with added reaction polymer at least 10 variabilities can be listed:

This list does not include the type of moisture barrier under the concrete slab. Practical experience shows that failure to with polythene sheeting, as the minimum measure, can be detrimental to the quality of the concrete slab in many respects seal.

Why does concrete not always succeed?
There are many possible errors which can occur when placing concrete. I have summarized the most frequently occurring causes of defects and damages in the following list:

The simple 6-step method described above is not enough by itself if one wishes to avoid all the causes of errors and defects. That is undoubtedly one of the reasons why this colloquium is again being attended by more than 100 participants who have come to find out which methods produce the right industrial floor and/or how existing methods can be improved.

What do cement and concrete cost?
Let us take a look at the cost side of concrete and reaction polymers. Costs rise by approximately a factor of 10 in each case from aggregate through to cement and polymer dispersions for modification purposes and on to reaction polymers.

If one assumes the following prices (in Germany) ex works:

and if one assumes the following concrete mix proportions (e.g. for vacuum concrete):

or if the above is abbreviated to the following % by weight composition per 1 cu.m. ready-mix concrete:

One obtains the following characteristics:

My aim in quoting these figures is to encourage you to apply the method of constructional value analysis to concrete slabs. No doubt various savings can be made here.