Most concrete is rated in terms of "mix"...the percentage of cement to aggregate being the determining factor. The "mix" is normally listed in pound denominations. Normally, here in the "states" the lowest "mix" that I have ever encountered is 3500 lb. That would be the weight per square foot that this material would support in a 4 inch thickness. Normally, in the states here again, the minimum thickness allowable for a garage floor would be four inches. Thus if you have questions about the ability of the floor to sustain the load, I would recommend contacting a concrete contractor as to the local codes and material characteristics. Here in the US I would have no reluctance in putting an enlarger of this size on any garage floor which has been installed to "code".