a floating roadway assembly adapted to support road vehicles is formed from a plurality of pontoons consisting of concrete material and connected together by a plurality of elongated metal carrying rods which extend longitudinally through each of the pontoons to join them together to form the roadway . the rods are resistant to traction and pressure and the connection between the rods and each of the pontoons is made so as to enable relative movement therebetween longitudinally of the rods .