The EC was determined to be relatively unchanged during the hydration tests irrespective of the concentration of the hydration solution. Electrical conductivity as an indication of chemical equilibrium between influent and effluent is used in experimental determination of hydraulic properties of GCLs with aqueous solutions (ASTM D6766). A low threshold variability between influent and effluent EC serves as a termination criterion for GCL flux/hydraulic conductivity tests. In this test program, EC did not provide an indication of the variation of cation exchange processes and bound cation fractions in the GCL specimens, and thus the use of EC as a termination criterion may not be a proper indication of attainment of chemical equilibrium. 100 1000 10000 100000 DI 10 1 5 10 15 20 Elapsed Time (days) FIGURE 15 Variation of electrical conductivity of hydration fluid with time 25 30 35 2 mM CaCl2 50 mM CaCl2 200 mM CaCl2 HARNESS THE POWER OF VALUE ENGINEERING AP-9196 Determine the Best Porous Pavement Option for Site Conditions and Expected Use Presto Geo P3 is a free, web-based suite of geotechnical calculation tools designed to support landscape architects in completing value engineering evaluations using porous pavements. This free project planning tool helps you determine the best pavement options for site conditions and expected use. Based on a few simple input parameters, including loading conditions and soil information, the software displays a full cross-section and specifies all infill and base materials. For gravel infill pavements, the tool calculates the available stormwater retention depth. If a certain storage depth is required, additional base material can be added. GEOBLOCK® GEOPAVE® GEOWEB® Sign Up Today for Presto Geo P3 Start building smarter, faster & more sustainably www.prestogeop3.com GeosyntheticsMagazine.com 19 Electrical Conductivity (µS/cm)http://www.prestogeop3.com http://www.GeosyntheticsMagazine.com