Self-compacting concrete applicable to joint section of steel structure concrete composite beam

Abstract

The invention discloses self-compacting concrete applicable to the joint section of a steel structure concrete composite beam. The concrete is prepared from the following components in parts by mass:100 to 150 parts of water, 450 to 500 parts of cement, 50 to 55 parts of a mineral admixture, 675 to 725 parts of fine aggregate, 1000 to 1100 parts of coarse aggregate, 5 to 10 parts of a high-performance polycarboxylate superplasticizer and 50 to 55 parts of a composite expanding agent, wherein the cement is ordinary Portland cement with a grade of 42.5 or above; the mineral admixture is fly ashwith a grade of national standard I or above; the fine aggregate is natural medium sand or machine-made sand; the coarse aggregate is broken stone with a particle size of 5-25 mm; the water reducingrate of the high-performance polycarboxylate superplasticizer has to be 25% or above. According to the invention, automatic compaction and no shrinkage of concrete in the joint section of a hybrid beam are realized; and the concrete has stable working performance and mechanical performance, and can be applied to concrete structure construction under occasions like construction space is narrow, only self-compaction concrete pouring can be adopted and concrete can only be conveyed from the outer side.

Description

technical field [0001] The invention relates to the technical field of building materials, in particular to self-compacting concrete suitable for the joint section of a steel structure concrete joint beam. Background technique [0002] Composite beams are two or more building materials with different mechanical properties connected together through a special structure, and can ensure joint force and deformation coordination to form a combined structure. Generally speaking, in order to adapt to the change of span, mixed girder continuous beam, structural steel structure and mixed girder cable-stayed bridge are a typical composite structure. The mid-span steel girders are connected. Therefore, the scientific and reasonable structure of steel-concrete joint section is conducive to improving the internal force transmission and stress distribution between the steel beam and the concrete beam, so as to make full use of the respective mechanical properties of the two materials, im...

AI Technical Summary

Problems solved by technology

Since the steel grid room is a closed box-shaped structure, the pouring space is narrow, and there are generally many connectors such as perforated plates and shear nails in the steel grid room, and the existing design generally uses prestressed Connecting steel beams to concrete beams will inevitably lead to difficulties in concrete pouring and vibration, and the phenomenon of voids between concrete and steel cells will easily occur; at the same time, the grade of concrete commonly used at present is relatively high. Indoor concrete is generally difficult to maintain, and it is prone to strong shrinkage and creep, which leads to the lack of close contact between the concrete and the steel grid.

If the quality of concrete pouring is poor, it will easily lead to defects such as voids in the concrete, which is not conducive to the bearing and durability of the structure, and will have a certain impact on the smooth construction and safe operation of the bridge

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