Structural Behavior of a Traditional Concrete and Hollow Tiles Mixed Floor Reinforced with HPFRC

Abstract

The use of high performance fiber reinforced concrete (HPFRC) in structural strengthening is widely accepted. The presence of steel fibers inside the cementitious matrix provides the hardened matrix enhanced resources in terms of strength and toughness, avoiding brittle crisis in favor of hardening/softening post-peak behavior. These performances open different scenarios in structural rehabilitation, e.g. RC column jacketing, shear strengthening of RC beam, slab reinforcement. However, the quality of the intervention is highly dependent on the technique considered for the element strengthening and on the HPFRC performance, which is strongly related to the mix design. This paper presents the results of an experimental campaign carried out on the flexural response of 4.5 × 1 m2 one-way floor elements reinforced with a commercial HPFRC material. The mechanical performances of the HPFRC adopted have been qualified following the Italian guidelines published in January 2019 for the identification and qualification of FRC products. The effect of the FRC strengthening was evaluated by comparing the performance of unreinforced and retrofitted floor elements, both using traditional r.c. and HPFRC topping. The effectiveness of the intervention is evaluated in terms of flexural strength, slab deflection and visible damage.