Application of Post-Tensioning in Building Construction Comparative Study of Material Use in Post-Tensioned and Conventionally Reinforced Concrete Slabs

Abstract

The construction industry is a major contributor to global environmental impact, and material-efficient structural systems are therefore important for reducing embodied car bon in buildings. This thesis investigates post-tensioned concrete flat slabs in com parison with conventionally reinforced concrete flat slabs, with focus on material use and CO2 equivalents. A case study was carried out for span lengths of 6 m, 9 m and 12 m, where the two systems were analysed under comparable geometric and loading conditions. The structural design was performed with numerical FEM model and the resulting quantities of concrete, ordinary reinforcement and prestressing steel were used to calculate CO2 equivalents for the product stage A1–A3 of the life cycle analysis. In addition, a parametric study was performed to evaluate how slab thickness and concrete strength class influence the total environmental impact. The results show that the ben efit of post-tensioning becomes more pronounced for longer spans where reductions in both concrete and reinforcement can be achieved. The study also shows that the most favourable concrete strength class depends on the span length and the required slab thickness, meaning that the lowest concrete class possible does not necessarily result in the lowest total CO2 equivalents.