Utilization of Iron Lathe Waste and Post-Tensioned Steel Reinforcement in Lightweight Concrete Ribbed Slabs

The ribbed slab unit system of lightweight concrete provided a lighter and stiffer than the equivalent conventional slab system. Ten ribbed slabs were tested under two-point load as simply supported up to the failure. In this work, the lightweight concrete was produced by omitting the coarse aggregate and increasing the fine materials, approaching to a desired strength- to-density ratio. All the slabs have the same area of the cross-section and the steel reinforcement ratio. The studied parameters were a ratio of the rib depth to the overall section depth, volumetric fraction ratio of iron lathe waste, and use post-tensioned steel wires as an additional tension reinforcement. A mechanical drag technique was used to apply the initial prestress force in the post-tension system. The results showed that the increase in the rib depth to the overall section depth ratio increased the ultimate load capacity by (54.17%) up to certain limits. Also, the use of iron lathe waste improved the load-carrying capacity by about (40.54%). It was found that the better ratio of the rib depth to the overall section depth was approached to (0.835), and the ratio of iron lathe waste of (2%) was suitable without the occurrence of balling and agglomeration. On the other hand, the use of lightweight concrete as a prestressed concrete led to a clear improvement in the structural performance of the slabs. The load factor that represents the ratio of ultimate strength to the service load was found approximately equal to (4).