Method for solving shrinkage cracks of UHPC thin web box girder

Abstract

The invention discloses a method for solving a shrinkage crack of a UHPC thin web box girder, and relates to the technical field of bridge construction, and the method comprises the following steps: carrying out a UHPC mix proportion test to obtain a UHPC mix proportion meeting a shrinkage requirement; the UHPC powder is cooled; the box girder formwork is heated; preparing a box girder in the box girder template by adopting UHPC (Ultra High Performance Concrete), and mounting a box girder web anti-cracking reinforcing mesh on the box girder; a recording system is adopted to monitor and record the'heat-humidity-force 'change condition of the box girder in real time, and the processing environment of the box girder is monitored and adjusted; and after the box girder is formed, the UHPC box girder is obtained, and then the UHPC box girder is subjected to high-temperature steam curing. According to the invention, through the UHPC mix proportion, the heat-humidity-force three-field monitoring, the heat preservation system, the moisture preservation system and the heating system, and in combination with the space structure and the size of the UHPC box girder, the heat-humidity-force three-field space-time effect in the whole prefabrication process is analyzed and researched, and the influence of shrinkage and cracking is reduced.

Description

technical field [0001] The invention relates to the technical field of bridge construction, in particular to a method for solving shrinkage cracks of UHPC thin-web box girders. Background technique [0002] UHPC is a new type of cement-based composite material whose strength, toughness, volume stability, and durability are much higher than ordinary concrete. The cement used in it has a high strength grade and a large amount, resulting in a greater shrinkage than ordinary concrete; [0003] In engineering construction, concrete shrinkage is the main cause of concrete cracking. After concrete cracking, it will have a great impact on the structural bearing capacity, water resistance and durability. [0004] Shrinkage is the main cause of concrete cracks. The shrinkage of UHPC is divided into plastic shrinkage, autogenous shrinkage, chemical shrinkage, drying shrinkage and other shrinkage types, and the formation mechanisms are different. Contents of the invention [0005] Th...

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Problems solved by technology

[0007] How to deal with the complex problem of UHPC hydration reaction and the complex temperature field of the box girder caused by the heat of hydration; the humidity field of the box girder is affected by the process of the hydration heat and the space size of the box girder, resulting in obvious spatio-temporal characteristics;

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