Impact of calendering process on nonwoven geotextiles hydraulic properties

Abstract

The influence of the calendaring process of nonwoven geotextiles on the water permeability normal to their planes, including influence of different loads, as well as pore characteristics investigated by two different methods has been studied. Methods of pore characteristics differ in obtaining different pore parameters. Two groups of samples were produced whereas first group is bonded by needle punching, while second group is needle punched samples taken from first group and additionally bonded by calendaring. Mass per unit area for both groups is in range of 150 to 500 g/m2, with increasing by 50 g/m2 for the next sample within groups. Calendaring process decrease water permeability of geotextile, but also decreases interval of geotextile water permeability change due to the applied pressure. Calendared geotextiles have controlled and predictable compressibility, respectively structure which will not significantly change in the practical application.