Concrete used for steel reinforced concrete composite structure and having C230 strength grade

Concrete used for a steel reinforced concrete composite structure and having the C230 strength grade is disclosed. A ratio of cement, fine aggregate, coarse aggregate, water, a water reducing agent, a defoaming agent, silica fume, fly ash, an activator, an expanding agent and a composite plastic retaining agent is 495:755:1284:100.5:20:1.4:98:122:10.5:51:0.60. The preparing method includes fully mixing the water reducing agent, the activator and the composite plastic retaining agent with the water to obtain a mixture, adding the fine aggregate and one third of the mixture into a stirrer in order, fully mixing, adding the coarse aggregate one third of the mixture in order, fully stirring, adding the cement, the expanding agent, the silica fume and the fly ash, fully stirring, adding the defoaming agent and the rest of the mixture, stirring and discharging. The concrete significantly improves adhesion performance between section steel and concrete under natural states, effectively exerts mechanical properties of the steel and the concrete and synergistic properties, greatly improves bearing capacity, using performance and durability of structural components, and has good high size stability and economical performance.