2.3.1 Influence of joint fillings With the research of the correlation between infiltration performance and the kind of aggregates used for joint fillings the results for permeable paving blocks with widened joints and with openings are analyzed together with a sample size of 50 testing areas. Tested were aggregates shown in Table 1 with a theoretical permeability on the basis of an idealistic grading curve after BEYER (Borgwardt, Gerlach and Koehler 2000)