Conventional and lightweight aggregate one-way reinforced concrete slabs subjected to fire and repeated loads: comparative experimental study

Abstract

ABSTRACT This study presents experiments on nine one-way, reinforced concrete slabs with a slab weight reduction approach utilising lightweight expanded clay aggregate (LECA). All slabs’ sizes, steel reinforcing, and concrete mix composition were equal. They were subjected to the same repeated linear load and high-temperature conditions. The slabs were classified into three groups based on the presence of LECA. The main variables were the LECA ratio (0, 20, 40) % of coarse aggregate and the exposure temperatures (ambient, 400, 700) ℃. The repeated load was applied according to the ACI-19 code, 50% of the ultimate load for seven cycles. The results showed that the presence of LECA reduced flexural strength and fire resistance. The deflection of the slabs increased with the LECA. The most significant reduction in ultimate load capacity was approximately 35.1%, with a maximum increase in slab deflection of 37.2%. However, the stiffness decay was significant, about 50%.