High-durability concrete product with gradient structure and preparation method thereof

Abstract

The invention relates to a highly durable concrete product with a gradient structure and a preparation method thereof. The concrete product is prepared by the following methods: 1) mixing concrete: replacing part of the cementitious material with a dense admixture to mix to obtain concrete; 2) mixing the concrete Pour it into a mold to form it, and then obtain a concrete specimen after curing and demoulding; 3) Dry the surface of the concrete specimen, then place it in an autoclave for carbonation curing under a carbon dioxide atmosphere, and then perform standard curing to obtain a gradient Structural highly durable concrete products. The present invention forms a gradually dense gradient structure from inside to outside on the surface of concrete specimens through carbonization curing treatment. The carbonized dense layer on the surface can improve the corrosion resistance of concrete materials and prolong the service life, and due to the high strength of the outer layer, a hoop effect is formed. The hoop effect can improve the deformation resistance of the specimen and accelerate the hardening of the concrete specimen.

Description

technical field [0001] The invention belongs to the technical field of building materials, and in particular relates to a highly durable concrete product with a gradient structure and a preparation method thereof. Background technique [0002] Concrete material is a complex porous heterogeneous body, its pores mainly include gel pores (mainly refers to the pores between gel particles), capillary pores and a small amount of internal defects and microcracks of cement stone, harmful gases or liquids from the outside It is easy to transmit or diffuse to the interior of the concrete through the pore structure of the concrete. Therefore, although there are many factors affecting the durability and the damage erosion process is complicated, the durability of the concrete is mainly related to its ability to resist the penetration of external harmful gases or liquids into its interior. At present, domestic and foreign proposals to modify concrete materials to improve durability mainl...

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Problems solved by technology

At present, domestic and foreign proposals to modify concrete materials to improve durability mainly include three aspects: one is to use a large number of active admixtures, such as the patent "a composite admixture for improving the durability of ordinary concrete and its preparation method" (application No.: 201510876654.5) and "An Anti-corrosion Agent for Concrete and Its Preparation and Application" (Application No.: 200910045612.1) replace cement with a large proportion of active admixtures such as fly ash, waste residue, tailings, etc., reducing the porosity of concrete , but due to the reduction of cement, it is not conducive to the early strength; the second is to properly adjust the cement clinker mineral system, such as the patent "Erosion-resistant Low-calcium Portland Cement and Its Preparation Method" (application number: 201510729601.0) by improving the cement Belite content, reduce the content of tricalcium aluminate to improve its anti-ion erosion performance, and introduce micro-expanded MgO to improve the crack resistance of the material; the third is to adopt surface protection measures, such as "An anti-carbonation and anti-chloride ion elastic Architectural Coating" (Application No.: 201020263050.6) and "A Protective Coating for Reinforced Concrete Substrates Used in Chloride Corrosion Environments" (Application No.: 201520631929.4) use a variety of polymer coatings to brush multi-layer protective layers on the concrete surface to improve The anti-carbonization and anti-ion erosion ability of the material, such protective measures are direct and efficient, but it is easy to age under light conditions, and it is easy to peel off due to the huge difference in thermal expansion coefficient at the interface with the substrate, and there is a problem of insufficient durability

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