Concrete having strength grade of C240 and used for steel reinforced concrete combined structure

Abstract

The invention discloses a concrete having a strength grade of C240 and used for a steel reinforced concrete combined structure. The concrete is prepared from cement, fine aggregate, crude aggregate, water, a water reducer, an antifoaming agent, silicon powder, fly ash, an exciting agent, an expanding agent and a composite plasticity-maintaining agent in a ratio of 500: 760: 1293: 101: 20.2: 1.4: 97: 123: 10.5: 51: 0.60. The preparation method comprises the following steps: uniformly mixing the water reducer, the exciting agent and the composite plasticity-maintaining agent with water so as to obtain a mixture, successively adding the fine aggregate and one third of the mixture into a mixer according to weight proportion and carrying out uniform mixing; adding the crude aggregate and another one third of the mixture and carrying out uniform mixing; adding the cement, expanding agent, silicon ash and fly ash and carrying out uniform mixing; and adding the antifoaming agent and the residual mixture and carrying out stirring and discharging. The concrete prepared in the invention can substantially improve bonding between section steel and concrete in a natural state, gives full play to respective mechanical properties and mutual cooperation performance of the section steel and concrete, greatly improves the bearing capability, usage performance and endurance of a structural element, and has high volume stability and economic performance.

Description

technical field [0001] The invention belongs to the technical field of building materials, and relates to an ultra-high-strength and high-performance concrete with a strength grade of C240 ​​for steel-concrete composite structures. Background technique [0002] The invention of Portland cement in 1824 led to the rapid development of concrete technology. Its consumption is large and its scope of application ranks the highest in the world. Although concrete is a traditional man-made building material, because of its irreplaceable advantages (abundant raw materials, simple production process, high cost performance, etc.) and the continuous progress of concrete material science and technology, concrete has become the main body of civil engineering materials. , It will also be one of the indispensable main materials in future civil engineering and national construction. At the same time, with the continuous expansion of the city, the continuous increase of the population, the co...

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Problems solved by technology

[0005] The strength grades of concrete used for steel-concrete composite structures in the prior art include low-strength high-performance concrete of C30, C35, C40, C45, C50 and C55, high-strength high-performance concrete of C60, C70, C80, C90 and C100, and C110, C120, C130, C140, and C150 ultra-high-strength high-performance concrete, as well as the preparation technology of C160, C170, C180, C190, and C200 ultra-high-strength high-performance concrete. ) between the high-strength concrete, and improve the durability of the structure; however, there are still ultra-high-strength high-performance concrete that cannot be extended to higher strength, and when it is used in steel-concrete composite structures, it cannot solve the problem of steel The problem of poor natural bonding performance with ultra-high-strength and high-performance concrete, so it cannot meet the requirements of civil engineering buildings extending to the air, underground and water, that is, super / ultra-high buildings, super / ultra-large spans, underground, sea or Underwater, ultra-durable and heavy, giant and novel structural engineering and other applications and development trends

In addition, in the prior art, there are also some preparation technologies for super / ultra-high strengthening and super / ultra-durability of concrete, but none of them involve or solve the natural relationship between section steel and ultra-high-strength high-performance concrete when used in SRC structures. The problem of poor bonding performance

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