Long-term deflection of prestressed SCC hollow core slabs

An experimental investigation on developing prestressed hollow core slabs (HCS) using self-compacting concrete (SCC) has been conducted at King Saud University with the collaboration of industrial partner. The investigation includes short and long term behavior of the developed SCC-HCS. This paper presents the long term deflection of the developed slabs. Six full-scale HCS were manufactured and tested. Four of the slabs were produced using SCC while the remaining two slabs were produced using the dry cast concrete (DCC) technique for the sake of comparison and verification. The HCS were tested under sustained uniform load for a period of 730 days. The study was carried out on two slab sizes: 300 mm and 470 mm thickness. The long term deflection of the slabs was compared with the predictions of the effective modulus approach considering the creep and shrinkage models prescribed by ACI 209 Committee. SCC-HCS units showed comparable long term deflection behavior to that of DCC-HCS units. The effective modulus approach along with ACI 209 creep and shrinkage coefficients were found to reasonably predict the additional long term deflection of the slabs.