The research and development of high-performance concrete (HPC) that can give both high flow characteristics and high strength have attracted wide interest in Taiwan. The construction of the 101-storey Taipei Financial Center and the 85-storey Tungtxt & Chingtai (T&C) Tower requires the slump to be in the range of 230 – 270 mm, the initial slump flow in the range of 580 – 620 mm and slump more than 230 mm after 45 minutes, as well as a 56-day compressive strength of over 56 MPa. The HPC mix is designed using a densified mixture design algorithm which aims to achieve the lowest cement content. With the addition of pozzolanic materials such as fly ash, the workability is much improved because the shape of fly ash is spherical. After one-year of strict quality control, the HPC achieve consistent workability and excellent strength. This indicates that the appropriate use of local industrial by-product materials can produce HPC of the required design strength.