Lately, instead of concrete sewage shunts more often are used plastic sewage shunts from PEHD.
The reason to it is that plastic shunts are absolutely waterproof and non-porous, significantly lighter, easier to set up, and most importantly it is possible to secure sealing between shunts and sewage pipes, weather the pipes are of PEHD or PVC.

Besides, plastic shunts have enough elasticity so that certain movements of the ground won’t cause rupture of shunt made of plastic.