In general, the higher the strength the greater the influence of mix proportions and materials for concrete on compressive strength. Therefore, the selection of mix proportions and materials is more important in high-strength concrete than in normal-strength concrete.
The purpose of this study is to investigate experimentally the compressive strength properties of high-strength concrete with various concrete proportioning. Selected test variables are cement content, water-cement ratio, fine aggregate ratio, cement type and aggregate type. Specimens were tested for compressive strength at 3, 7 and 28 days with 3 cylinders for each age. One slump test was also performed for each mix.
As the cement content increased from 500kg/㎥ to 700kg/㎥ for a given water-cement ratio, the compressive strength was reduced by about 50kg/㎠. The reduction of the watercement ratio from 35% to 30% was shown to increase the compressive strength by more than 100kg/㎠. And the compressive strength was also shown to be greatly influenced by cement type. For the production of high-strength concrete, crushed stone was more suitable than rounded gravel.
