ABSTRACT
ABSTRACT. The paper presents some technological problems concerning porous water-permeable concrete, and concludes with a proposal for a method of its design. First of all, the main tendencies in the application of this special concrete were presented. Then the requirements regarding its properties answering the purpose of efficiency and durability were defined. They were confined to four basic concrete characteristics: water permeability, strength and frost resistance of hardened concrete and workability of concrete mix. They were assessed during tests carried out for varying concrete composition (above all the nature and granulation of the aggregate as well as the amount and quality of the added cement paste). The results of the investigations identified the best composition formula - that was done using the multi-criterial optimisation method - and then they determined the designing procedure. The latter makes use of the diagrams with permissible areas presented in the paper and equations for the analytic prediction of values defining the basic properties of concrete.
