This article presents test results for hydraulic conductivity and porosity structure of hardening slurries prepared of Portland cement, betonite, water and fluidal ashes from the combustion of hard and brown coal. The slurries were exposed to persistent filtering action (180 days) of liquids chemically aggressive to cement binders, i.e. distilled water, 0.5% solution of nitric acid, 1% solution of sodium sulphate, 1% solution of magnesium nitrate and 1% solution of ammonium nitrate. Samples exposed to filtration of tap water constituted the reference base. The research was into relations between hydraulic conductivity and pore structure parameters in slurries, as well as into the influence of the type of aggressive medium on leak tightness of slurries (their porosity and hydraulic conductivity).

This article presents ways of possible utilization and application of fl uidal combustion wastes as active additives to hardening slurries which are used to seal environment protection structures, i.e. cut-off walls in waste dumps and wastewater treatment plants. Cut-off walls are often exposed to fi ltrating action of eluates - polluted (aggressive) waters. Results of hydraulic conductivity tests of slurries after their long-term (210 days) fi ltration with eluates from a municipal waste dump and with tap water are presented. Porosity tests were also conducted to show the porosity structure of the fi ltered slurries. Additionally, compressive strength of slurries maturing in tap water and waste dump eluates was tested in parallel.