DIN Permeability Test and Effect of Concentration of Alkali on the Water Penetrability of Geopolymer Mortar

This paper represents the experimental investigation done on the permeability characteristics of geopolymer paste. The geopolymer mortar is made by using class F fly ash and Zone 3 sand. The alkali activator fluid used is the mixture of Sodium Silicate (Na₂SiO₃) solution and Sodium Hydroxide (NaOH) solution. Samples having dimensions 150mm*150mm*150mm with varying fluid to fly ash ratio and concentration of the alkali in the solution were prepared. After casting, the samples were kept in room temperature until 28 days DIN 1048 part 5, 1991 Permeability Test and Ultrasonic Pulse Velocity Test conducted on the specimens. The variations in water permeability and ultrasonic pulse velocity for samples with variation in fluid to fly ash ratio are observed. An effort is made to draw the interlink between UPV test results and permeability test results and their significance in identifying the quality and water penetrability of geopolymer paste.