STRUCTURAL BEHAVIOR OF HOLLOWCORE REINFORCED CONCRETE ONE WAY SLABS WITH PLASTIC PIPES

Abstract

Reinforced concrete hollow-core slab is a new type of lightweight slabs which has longitudinal voids through the long direction of the slab. The hollow-core concrete slab has many advantages over the solid slab; however, the longitudinal voids provide the ability to reduce the concrete amount, resulting in reduction the dead loads which consequently leads to cost-saving, fast construction and getting long-span. Also, eliminate the concrete contributes in the sustainability process due to reducing the CO2 emitted from the cement industry. This thesis presents an experimental study to investigate the structural behavior of hollow-core reinforced concrete one-way slabs. The experimental program includes casting and testing twelve reinforced concrete one-way slab with dimensions 1700mm×435mm×125mm, to study the effect of longitudinal voids number (two, three and four), longitudinal voids diameter (50, 63,75mm) and type of concrete strength (normal and high strength) on the structural behavior of hollow core slabs. The experimental results showed that elimination the concrete with percentages 16.25%, 24.37%, and 32.5% from the hollow-core slabs using two, three, and four longitudinal voids with diameter 75mm respectively, result in decreased the first crack load with percentages 6.06%, 11.36%, and 16.67% in normal strength slabs and with percentages 8.84%, 13.49%, and II 17.21% in high strength slabs, and saving the ultimate strength with percentages 93.47%, 87.63%, and 82.92% in normal strength slabs and with percentages 89.29%, 85.07%, and 80.61% in high strength slabs. Also, elimination the concrete with percentage 10.83%, 17.20%, and 24.37% from the hollow-core slabs using three longitudinal voids with diameters 50mm, 63mm, and 75mm respectively, result in decreased the first crack load with percentages 2.27%, 5.30%, and 11.36% in normal strength slabs and with percentages 5.58%, 8.37%, and 13.49% in high strength slabs, and saving the ultimate strength with percentages 93.37%, 90.01%, and 87.63% in normal strength slabs and with percentages 90.06%, 87.84%, and 85.07% in high strength slabs. In the field of sustainability, using the hollow-core slabs can reduce the raw materials weight up to 30% with cost-saving up to 23% in normal strength slabs and 28% in high strength slabs. Also, using the hollow-core slabs can reduce the CO2 emission and the embedded energy by about 33%.