I just watched the Rhino liner episode and then thought back to the one where they made concrete road barriers from Aerated concrete. The barriers didn't work because the soft concrete collapsed and formed a launch ramp for the car. They DID however lessen the impact G forces.
I think they could have something for those road barriers if they cast blocks of aerated concrete and coated it all over in Rhino liner. The blocks would be tough enough to move and handle but in an impact the core would crush but be held together by the Rhino liner stopping it forming the launching ramp it did last time.
