Title: Flexural Behavior of Lightweight Self-Consolidating Concrete Beams Strengthened with Engineered Cementitious Composite
Author(s): Tayseer Z. Batran, Mohamed K. Ismail, and Assem A. A. Hassan
Publication: Materials Journal
Appears on pages(s): 39-50
Keywords: engineered cementitious composite (ECC); flexural performance; lightweight self-consolidating concrete (LWSCC) reinforced concrete (RC) beams; strengthening
This study investigated the structural behavior of lightweight self-consolidating concrete (LWSCC) beams strengthened with engineered cementitious composite (ECC). Four LWSCC beams were strengthened at either the compression or tension zone using two types of ECC developed with polyvinyl alcohol (PVA) fibers or steel fibers (SFs). Three beams were also cast in full depth with LWSCC, ECC with PVA, and ECC with SFs, for comparison. The performance of all tested beams was evaluated based on loaddeflection response, cracking behavior, failure mode, first crack load, ultimate load, ductility, and energy absorption capacity. The flexural ultimate capacity of the tested beams was also estimated theoretically and compared to the experimental results. The results indicated that adding the ECC layer at the compression zone of the beam helped the LWSCC beams to sustain a higher ultimate loading, accompanied with obvious increases in the ductility and energy absorption capacity. Higher increases in the flexural capacity were exhibited by the beams strengthened with the ECC layer at the tension zone. Placing the ECC layer at the tension zone also contributed to controlling the formation of cracks, ensuring better durability for structural members. Using ECC with SFs yielded higher flexural capacity in beams compared to using ECC with PVA fibers. The study also indicated that the flexural capacity of single-layer and/or hybrid composite beams was conservatively estimated by the ACI ultimate strength design method and the Henager and Doherty model. More improvements in the Henager and Doherty model’s estimates were observed when the tensile stress of fibrous concrete was obtained experimentally.