Moment capacity for steel and recycled waste plastic ducts in post-tensioned beams

Abstract

Generally, in post-tension construction practices, the contractors tend to use galvanized steel ducts for cost and availability reasons. An experimental study was conducted on two duct types, galvanized steel, and recycled waste plastic. Four post-tensioned beams (PTB) were prepared 7.87 in. (200 mm) wide, 11.8 in. (300 mm) deep, and 16.40 ft (5000 mm) in length. Different parameters were used to clarify the advantage of recycled waste plastic ducts against galvanized steel. The PTB, provided with strands of 0.5 in. (12.7 mm) diameter, were tested up to flexural failure using 3 points bending machine. Minimum reinforcements were used to reinforce the PTB and resist the applied loads. The moment capacity results were compared to ACI provisions. The lower friction related to galvanized steel ducts as opposed to those of recycled waste plastic ones gives a result with a significant reduction in prestressing steel needed, regardless of the length of the system. However, it was proved that there is no loss of moment capacity by using recycled waste plastic ducts. The experimental studies were modeled using finite element software to compare the obtained results. A good correlation was noticed between both experimental and numerical results. This paper shed light on the advantages of using recycled waste plastic ducts such as corrosion resistance, lightweight, friction losses, and durability. However, the use of recycled waste plastic materials for manufacturing plastic ducts contributes effectively to sustainability and saving the environment and natural steel resources.