Manufacture of construction materials and precast concrete products to the order and specification of others, namely, underground power and telephone vaults, bridge beams, floating docks, modular prefab security structures, three sided bridges, controlled environmental vaults, highway barriers, water and sewer manholes, fuel containment vaults, oil-water separator vaults, box culverts, mine cribbing, drainage pipes, modular buildings, above-ground huts, double tees, septic tanks, pipes and fittings therefor