Relationship between tensile Young’s modulus and strength of fly ash high strength concrete at early age

•Mechanical properties of fly ash high strength concrete at early age were investigated.•A model between uniaxial and splitting tensile strength at early age was proposed.•A model between tensile and compressive Young’s modulus at early age was proposed.•A model between tensile Young’s modulus and uniaxial tensile strength was proposed.

This paper presents an experimental investigation on the tensile properties of hardening fly ash HSC at different ages and quantifies the uniaxial tensile strength and tensile Young’s modulus of fly ash HSC. Test results showed that: (1) the axial compressive strength of hardening fly ash HSC at early age was lower than cubic compressive strength at the identical age; (2) the uniaxial tensile strength of hardening fly ash HSC at early age was lower than splitting tensile strength at the identical age; (3) the tensile Young’s modulus of the hardening fly ash HSC at early age was approximately 1.06–2.02 times of the compressive Young’s modulus at the identical age; (4) the tensile Young’s modulus of hardening fly ash HSC at early age increased with the increase of uniaxial tensile strength. The prediction models showed good accuracy with the experimental results.