Tension stiffening of rebar‐reinforced coarse aggregate ultra‐high performance concrete (R‐ <scp>CA</scp> ‐ <scp>UHPC</scp> ): Tension capacity prediction and crack width calculation

Abstract Coarse aggregate ultra‐high performance concrete (CA‐UHPC) requires characteristic tensile properties for structural design practices both in the serviceability and ultimate limit states. Through uniaxial tension testing, this study aims to identify the post‐cracking performance of rebar‐reinforced CA‐UHPC (R‐CA‐UHPC), including cracking, tension stiffening, and tension capacity. Utilizing experimental data derived from average tensile responses, a tension‐stiffening model of cracked CA‐UHPC was developed, considering scenarios with and without the shrinkage effect. The findings demonstrate that the restrained shrinkage effect significantly influences the tension stiffening of cracked CA‐UHPC in the pre‐yielding phase, while becoming negligible for the post‐yielding behavior. The shrinkage‐corrected model exhibits reinforcement ratio independence. Furthermore, the non‐shrinkage‐corrected model demonstrates superior predictive accuracy of R‐CA‐UHPC's global tensile response compared to the CA‐UHPC tensile constitutive model. Subsequently, a tension‐stiffening‐based approach was derived and validated to calculate crack widths in rebar‐reinforced UHPC members.