Flexural/Tensile‐Strength Ratio in Engineered Cementitious Composites

In this paper the flexural behavior of a strain‐hardening engineered cementitious composite (ECC) is studied and compared with that observed in a regular fiber‐reinforced cementitious composite (FRC). Unlike concrete or regular FRC, ECC materials are characterized by their ability to sustain higher levels of loading after first cracking while undergoing additional straining. This strain‐hardening behavior gives ECCs a significant advantage under flexural loading. In quasi‐brittle material such as regular FRC, the ratio of flexural strength (the modulus of rupture) to tensile strength is known to vary between 1 and 3, depending on the details of the reinforcement and the geometry of the specimen. In this paper, the strain‐hardening behavior observed in an ECC led to a high flexural‐strength‐to‐tensile‐strength ratio. In a third‐point bending test, the flexural strength of an ECC was measured to be five times its tensile (first‐cracking) strength. This result was also predicted by a simple theoretical model. The model can be used for the purpose of optimizing the flexural strength of ECCs.