Ultra-high performance concrete column permanent formwork and preparation method thereof

Abstract

The invention discloses an ultra-high performance concrete column permanent formwork which comprises a hollow columnar ultra-high performance concrete layer and a steel reinforcement cage arranged in the ultra-high performance concrete layer. Dents with the depth not lower than 5 mm are formed in the inner surface of the ultra-high performance concrete layer. The cross section of the ultra-high performance concrete layer is in the shape of a hollow column and a hollow square column. The dents are in strip, grid, dot and spiral shapes. The invention further discloses a preparation method of the ultra-high performance concrete column permanent formwork. By preparing the ultra-high performance concrete column permanent formwork with the dents with the depth not lower than 5 mm in the inner surface, the binding powder between ultra-high performance concrete and post-cast core concrete is enhanced, so that the column component bearing capacity is improved; the ultra-high performance concrete column permanent formwork is good in integrality, convenient to prepare, low in cost, remarkable in economic benefit and excellent in endurance quality.

Description

technical field [0001] The invention belongs to the technical field of building materials, and in particular relates to a permanent formwork for an ultra-high performance concrete column and a preparation method thereof. Background technique [0002] When pouring concrete, formwork is required to obtain concrete members of the designed shape. Traditionally, formwork such as wooden formwork, steel formwork, and aluminum alloy formwork are used. The formwork needs to be installed before pouring concrete, and the formwork needs to be removed after the concrete reaches its strength. Form work is an important part of concrete structure construction, which has a long construction period and high cost. [0003] After World War II, in order to increase the construction speed, permanent formwork was developed. The formwork will not be dismantled after use, and it will be used as a part of the structure. Due to its simple construction and time-saving construction, permanent formwork...

AI Technical Summary

Problems solved by technology

[0010] However, when the ultra-high-performance concrete permanent formwork is centrifugally formed, since there is no coarse aggregate in the ultra-high-performance concrete, the denser steel fibers will be concentrated and distributed on the outer layer of the permanent formwork under centrifugal action, and even cause a large amount of steel fibers to be exposed On the outer surface, and corroded to reduce the crack resistance, toughness and durability of ultra-high performance concrete

At the same time, the uneven distribution of steel fibers will lead to uneven mechanical properties of ultra-high performance concrete components, damage the integrity of the outer permanent formwork concrete, increase the uncertainty of component bearing capacity, and affect the strength design of related components. Reduced ability of members to resist shear and normal section bending

The above-mentioned problems will make the safety, durability and even bearing capacity of the centrifugal ultra-high performance concrete members fail to achieve the expected purpose, and pose a threat to the safety of structural engineering.

[0011] When the pouring method is formed, due to the high density of ultra-high-performance concrete, the inner surface of the permanent formwork of ultra-high-performance concrete is very smooth after demoulding, and the permanent formwork and the post-cast core concrete are poorly bonded during use, often resulting in two materials Cannot work together, the cracking load is too low, the performance of the material cannot be fully exerted, cracks appear prematurely, resulting in a decrease in durability, especially under repeated loads, the two work separately, and the mechanical properties are greatly reduced

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