The relationship between RMD and ionic strength for the CCR leachates is shown in Figure 2 along with leachates in the Electric Power Research Institute (EPRI) leachate database reported by Chen et al. (2018, 2019). The CCR leachates in this study (closed symbols in the figure) predominantly have ionic strengths in the upper portion of the ionic strengths in the EPRI leachate database and tend to have lower RMD (more polyvalent). Geosynthetic clay liners Seven commercially available BPC GCLs were evaluated in this study. All of the BPC GCLs are manufactured by dry mixing one or more granular proprietary polymers (cross-linked or linear polymers) with granular sodium bentonite. The BPC GCLs are labeled as BP4.0, BP5.8, BP6.3, BP8.6, BP8.9, BP9.0 and BP9.7, with the numerical suffix representing the polymer loading in percent by dry mass as measured based on loss of ignition (LOI) of the BPC and NaB using the procedure in Scalia et al. (2014). Hydraulic conductivity of GCL Hydraulic conductivity tests were conducted on 6-inch (150-mm) diameter GCL specimens using flexible-wall permeameters in accordance with ASTM D6766. The falling headwater-constant tailwater method was used (Figure 3). GCL specimens were trimmed from the FIGURE 3 Author Yu Tan conducting a hydraulic conductivity test Combigrid® some things are better together SOIL STABILIZATION, REINFORCEMENT, SEPARATION AND FILTRATION COMBINED IN ONE GEOSYNTHETIC Geogrid with integrated nonwoven www.naue.com www.GeosyntheticsMagazine.com 15http://www.naue.com http://www.GeosyntheticsMagazine.com