High stiffness concrete for tall buildings under severe conditions: Mix design and structural member test

A new type of concrete, which contains volcanic aggregate and well-graded river sand, having both high strength and ultra-high modulus of elasticity has been developed for tall buildings under severe conditions, and its properties were characterized. The structural deformation of high-rise buildings can be substantially reduced by using this type of concrete, thereby decreasing the cross-section area of the structural members and increasing the economic benefits, not to mention alleviating shrinkage and creep problems of concrete. Uniaxial compression test, static elastic modulus test and scanning electron microscope test were conducted to characterize the properties of concrete specimens with different mix proportions. The experimental results showed that volcanic rock as coarse aggregate, well-graded river sand as fine aggregate, sand ratio around 43%, silica fume content about 10% as well as some mineral admixtures such as metakaolin and nano-silica led to higher modulus of elasticity of concrete. A particular type of concrete with the compressive strength of 146 MPa and modulus of elasticity of 53.5 GPa was developed, which is much stiffer than normal concrete in the code of practice. Four concrete mixtures including C45, C80, high modulus and ultra-high modulus concrete were applied in producing structural members, verifying the advantages of utilization of high stiffness concrete.