Short for linear low-density polyethylene, specified at 0.939 g/cm3 or below for geomembranes, it has no sharp yield point and takes far more multiaxial strain than HDPE before it fails. It copes well with differential settlement, so it is popular for landfill caps, ponds and covers. It welds with the same equipment as HDPE but gives up some chemical resistance and puncture stiffness.
Use LLDPE on the cap, it'll ride the settlement where HDPE would end up in tension.
Also heard as
- linear low-density polyethylene
- LL
- LLDPE liner
Related terms
HDPE
High-density polyethylene: the stiff, chemically resistant polymer used for most landfill and mining geomembranes.
Geomembrane
Low-permeability polymer sheet used as a liquid or gas barrier in liners, covers, ponds and tunnels.
Cap
Final cover system placed over a closed landfill or waste area to keep water out and control gas.