The effects of heat on Subtitle D composite liner systems

By Timothy D. Stark

Q: What effect does heat have on a Subtitle D composite liner system?

A: Heat can have many detrimental effects on a Subtitle D composite liner system. For example, heat can adversely affect the compacted low permeability soil liner by reducing its moisture content, leading to an increase in hydraulic conductivity and possibly cracking. Heat can also adversely impact a GCL by causing desiccation and cracking of the bentonite under certain conditions, such as low normal stress and high temperature gradient. Similarly, high heat can adversely impact the overlying geomembrane because heat can accelerate depletion of the anti-oxidants in the polyethylene geomembrane which reduces the time before polymer degradation begins. In general, high density polyethylene geomembrane manufacturers recommend a temperature less than 150°F in containment applications.

Tim Stark is a professor in the Department of Civil and Environmental Engineering at the University of Illinois at Urbana-Champaign.