Flexural performance and ductility of RC beams made using natural LWA

• Published in: Case Studies in Construction Materials Vol. 16; p. e00942
• Main Authors: Alshannag, Mohammad J., Charif, Abdulhamid, Alqarni, Ali S., Nasser, Salman
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2022; Elsevier
• Subjects: Beams; Curvature; Ductility; Flexure; Lightweight aggregates; Reinforced concrete; Flexure; Beams; Ductility; Curvature; Lightweight aggregates; Reinforced concrete
• ISSN: 2214-5095; 2214-5095
• DOI: 10.1016/j.cscm.2022.e00942

This paper evaluates experimentally the feasibility of utilizing local natural lightweight aggregates (LWA) for designing reinforced concrete (RC) beams. The aggregates investigated were of scoria origin, with an absorption capacity of 10%, and dry densities ranging between 860 and 1120 kg/m3. A series of full-scale 16 simply supported RC beams of rectangular cross section were designed using two concrete strengths, normal and high, and two tension steel ratios of the balanced reinforcement ratio, following ACI code requirements. For the lightweight concrete (LWC) mixes designed, the replacement level of normal weight aggregates (NWA) with coarse LWA was 100%, whereas the replacement level for fine LWA was 62.5%. Data presented include load-deflection, and moment-curvature graphs, cracking behavior, mode of failure and ductility indexes. Test results indicated that the flexural response of LWC beams was similar to that of normal weight concrete (NWC) beams. All the LWC beams tested failed in ductile flexural mode, exhibited relatively larger mid span deflections, higher curvatures, and wider cracks, compared to NWC beams of equal concrete strength and steel ratio. The most influential parameter on the ductility indexes of LWC beams was the steel ratio. Moreover, the scoria LWA investigated can be used successfully in structural design. •Natural lightweight aggregates of Scoria origin are recommended for producing RC beams suitable for structural applications.•For the same strength and steel ratio, the load-deflection and moment-curvature graphs for normal and LWC beams were similar.•The lightweight concrete beams designed exhibited flexural failure associated with larger ductility relative to normal weight concrete beams.