Geosentetik kil örtülerin (GKÖ) kalsiyum klorür çözeltilerine karşı bariyer performansının birim alan başına bentonit kütlesi ve iğneleme yoğunluğu açısından incelenmesi

In the content of this study, barrier performance tests were conducted on geosynthetic clay liners (GCLs) to examine the influence of mass per unit area of bentonite (MPUA) and needle-punching density (NPD) on the hydraulic conductivity. In the first part, two types of original GCLs provided by the manufacturer, sodium-bentonite GCL (Na-GCL) and polymer-bentonite GCL (P-GCL), were subjected to tests. The MPUA of original GCLs were 3.0 kg/m2, 4.0 kg/m2 and 5.0 kg/m2. On the other hand, a laboratory type GCL needle-punching apparatus was designed and produced to determine the influence of NPD on the hydraulic conductivity of GCLs. Artificial GCLs (A-GCLs) that have 5, 10 and 15 /cm2 NPD was produced with the apparatus. To resemble P-GCL, the same type of geotextiles and bentonite were used while manufacturing A-GCLs. Deionized water (DIW) and different concentrations of calcium chloride (CaCl2) solutions were used in the tests. According to the results, the MPUA of GCLs was observed to have a significant effect on the hydraulic conductivity tests when GCLs were permeated with high concentrations of CaCl2 solutions. Especially, MPUA influence the hydraulic breakthrough. That is, hydraulic conductivity of GCLs started to increase later when MPUA increased. The hydraulic breakthrough for the P-GCL was late when compared to Na-GCL. This means that using polymerized bentonite in GCL delay the increase in the hydraulic conductivity. In addition, the influence of NPD on the hydraulic conductivity of GCLs was slightly seen when comparing original GCLs with A-GCLs. As an overall, existence of bundles of fibers are the principal factor that allow increase in the hydraulic conductivity. To overcome their incremental role on hydraulic conductivity, MPUA may be increased furthermore.