The limit state design of reinforced concrete was introduced in India by IS 456 (1978). The fourth edition IS 456 (2000) incorporated important changes, such as durability considerations, revised formula for estimating modulus of elasticity, requirements for fire resistance, and regulations for deflections in flexural members. the Code recommends the use of the limit state design approach; However, it does not recommend the use of high-performance concrete for flexural members. The bending moment in the column may be caused by eccentric loading, lateral loads, or slenderness. This experimental study develops stress-block parameters for high-performance concrete based on tests on three series of specimens: Axially loaded columns, eccentrically loaded columns, and columns subjected to axial load with biaxially bending. The tests covered concrete strengths of 60 MPa to 80 MPa, with respect to cylinder and cube strengths. The experimental data of 81 columns (100mm x 150mm x 1300mm) is compared with the interaction curves developed using stress-block parameters of ACI 318 (2008), IS 456 (2000), and the present study. The new parameters are found to be more accurate. In simpler terms, the study developed new parameters for designing high-performance concrete flexural members, which are more accurate than the existing codes.