Long-life concrete used in the negative moment zone of steel-concrete composite beams and its preparation method

Abstract

The invention discloses long-service-life concrete for a steel-concrete composite beam hogging moment area and a preparation method of the long-service-life concrete, and relates to the field of long-service-life concrete preparation. The long-service-life concrete comprises, in parts by mass, 456-520 parts of a cementing material, 1748-1813 parts of aggregates, 0.80-1.50 parts of imitation steel fibres, 2.05-2.86 parts of a toughening material, 4.10-5.72 parts of a water reducer and 142-148 parts of water; the 28-d compressive strength of the long-service-life concrete is not less than 69.0MPa, the 28-d breaking strength of the long-service-life concrete is not less than 7.0MPa, the 28-d splitting tensile strength of the long-service-life concrete is not less than 5.0MPa, the 28-d elasticity modulus of the long-service-life concrete is not less than 36.0GPa, the 56-d chloride ion diffusion coefficient of the long-service-life concrete is less than 4.0*10<-12>m<2> / s, the cracking resistance rank of the long-service-life concrete achieves L-IV rank, and the 28-d bend ductility index I20 of the long-service-life concrete is not less than 8. The flexural strength, bend ductility and crack resistance of the long-service-life concrete are high, the fragility of the concrete is changed, and the concrete is good in structure durability, long in service life, low in cost, and convenient to massively use.

Description

technical field [0001] The invention relates to the field of long-life concrete preparation, in particular to a long-life concrete used in the negative moment zone of a steel-concrete composite beam and a preparation method thereof. Background technique [0002] With the development of society, steel-concrete composite beams (that is, the combination of steel beams and concrete slabs) are widely used in large bridges. Compared with bridges with other structural forms, composite beam structures have many advantages in terms of construction, maintenance and service life. . Compared with general steel-concrete composite beams, the concrete of steel-concrete composite beams in the marine environment has a harsh working environment. erosion etc. Therefore, the concrete of the steel-concrete composite girder in the marine environment needs to have excellent toughness and structural durability; There are large differences in properties such as weight, deflection deformation, fat...

AI Technical Summary

Problems solved by technology

[0006] (1) The steel fiber itself is easy to rust and cannot meet the durability requirements in the marine environment, and the cost of steel fibers (such as copper-plated fibers) is relatively high, which is inconvenient to use in large quantities

[0007] (2) The tensile strength and elastic modulus of the organic polymer fiber itself are low, and it is difficult to solve the problem of crack resistance of the composite beam bridge deck in a specific environment. The bridge deck concrete in the negative moment area of ​​the steel-concrete composite beam is made of organic When polymer fibers are prepared, structural damage will occur due to insufficient bending resistance and toughness, resulting in a shorter service life

However, a large number of engineering practices have shown that the addition of mineral admixtures will increase the self-shrinkage of concrete while improving the performance of concrete and the performance of chloride ion penetration resistance, thereby making concrete prone to cracks and providing a source of protection for erosive chloride ions and carbon dioxide. channels, accelerate the rate of harmful ion erosion, cause concrete deterioration, and reduce the durability of concrete structures

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