Abstract: A highway sound barrier formed by one or more panels mounted in a vertical abutting relation, each of the panels being formed from one or more self-supporting foam cement blocks. Each of the blocks having a foam core, a reinforcement grid mounted on the exposed surfaces of the core and a cementitious coating applied to the reinforcement grid for securing the grid to the foam core and to increase the compressive strength of the blocks. Thicknesses of the blocks being sufficient to form a load bearing structure. The panels being anchored to the ground by a helical screw anchor rod embedded in a concrete pad, with the support posts being mounted in either a common verticle plane or alternately offset.