Ductility analysis of graded concrete beams on maximum reinforcement ratio

Ductility has a vital role in determining earthquake forces on building structures. The buildings with higher ductility have higher earthquake resistance than the brittle on. During loading, structures with high ductility can deform inelastically without significant loss of strength. Various approaches have been attempted to increase the ductility of structural elements, either by modifying material properties, modifying the configuration of rebars and detailing and another engineering approach. In previous research, graded concrete (GC) has been proven to improve material properties so that related studies continue to be developed. The presence of a concrete layer with higher strength on the compression fibre of GC beams is predicted to increase the ductility of the beam. This study aims to investigate the ductility of GC beams using maximum reinforcement. This research was conducted experimentally by testing GC beam specimens and controlling specimens through flexural testing. The results showed that: 1) An increase in cross-sectional dimensions was proven to increase the resulting ductility. Specimens with a cross-sectional dimension ratio of 1/2 can absorb more energy than that of 2/3; 2) An increase in reinforcement area accompanied by an increase in the concrete strength in compression fibres can increase the ductility performance; 3) In terms of cost-saving, the use of GC results in a decrease in load capacity but a significant increase in ductility is obtained compared to the normal concrete; and 4) In terms of material properties improvement, the GC can increase load performance and ductility proportionally. GC can change the behaviour of the beam from a brittle manner to be more ductile which is beneficial for the structure than normal concrete.