Ultrahigh-strength self-compaction micro-expansion steel pipe-encased concrete and preparation method thereof

Abstract

The invention discloses ultrahigh-strength self-compaction micro-expansion steel pipe-encased concrete and a preparation method of the ultrahigh-strength self-compaction micro-expansion steel pipe-encased concrete. The steel pipe-encased concrete comprises the following raw materials in parts by weight: 580-680 parts of cement, 30-60 parts of pulverized fuel ash microbeads, 25-50 parts of silica fume, 20-35 parts of an expanding agent, 700-750 parts of manufactured sand, 800-1050 parts of macadam, 0.4-1.2 parts of a shrinkage reducing functional material, 3.5-7 parts of an additive, 120-160 parts of water and 4-5.5 parts of copper plated short and fine steel fibers. The manufactured sand with a high stone powder content is used for replacing natural river sand; the stone powder serves as an inert admixture; the high activity pulverized fuel ash microbeads and silica fume are adopted; and workability, compactness, and homogeneity of the concrete are improved by using a ball effect and amicro-aggregate effect of the high activity pulverized fuel ash microbeads and the silica fume. A novel expanding agent is prepared from the pulverized fuel ash and phosphogypsum; the strength is improved; moreover, an air content is further reduced by using the additive to improve the compactness. The obtained manufactured sand concrete with the high stone powder content is excellent in serviceability, mechanical property, volume stability and crack resistance.

Description

technical field [0001] The invention belongs to the technical field of materials, and in particular relates to an ultra-high-strength self-compacting micro-expansion steel pipe concrete and a preparation method thereof. Background technique [0002] At present, my country is vigorously promoting the construction of the western region. Considering the natural conditions of many mountains in the western region, there is an urgent need for a batch of long-span bridges with good quality, excellent mechanical properties, economical cost and easy construction in the western region. In summary, the steel pipe concrete arch bridge It is the best choice for many conditions. Usually, natural river sand is required to prepare high-performance fair-faced concrete for bridges. However, river sand resources in the western region are scarce, and in order to protect the river bed, it is planned to use local abundant machine-made sand resources to replace river sand. [0003] Machine-made sa...

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Problems solved by technology

[0003] Machine-made sand is artificially crushed, and some fine stone powder and mud powder with a particle size of ≤0.75 μm will inevitably be introduced during the production process. The concrete prepared by this method has a large amount of adsorption of admixtures, and the concrete has poor workability and homogeneity. Concrete is prone to bottoming and bleeding, and the shrinkage of concrete is significantly increased, and it is easy to crack in the early stage. For this, the national standard "Technical Specifications for Highway Bridge and Culvert Construction" JTG TF50-2011 has made restrictions on the content of stone powder in machine-made sand for concrete

However, the measures of washing machine-made sand to remove fine powder will seriously pollute the environment and increase the cost of concrete raw materials and project cost

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