A kind of ultra-high strength and high bonding performance fiber reinforced concrete and its preparation method

Abstract

A fiber-reinforced concrete with ultra-high strength and high bonding performance and a preparation method thereof. The fiber-reinforced concrete is prepared according to the following weight ratio: cement: water: silica fume: quartz powder: quartz sand 1: quartz sand 2: quartz sand 3: quartz Sand 4: Water reducer: steel fiber = 850: 180-200:180-210:200:127:190:222:317:20-30:150-250. The preparation method is as follows: first pour all the quartz sand, cement and silica fume into the mixer in sequence, and stir; add water and water reducing agent, stir; add steel fiber, stir, and discharge. Under the condition of outdoor curing for 28 days, the compressive strength of the concrete is ≥140MPa, and the bonding strength with the deformed steel bar is ≥60MPa, which greatly improves the compressive strength of the concrete, and the bonding strength between the steel bar and the concrete can greatly improve the reinforced concrete components. Reinforcement ratio, reducing the thickness of the protective layer, improving the bearing capacity and durability of structural components, has good economic benefits.

Description

technical field [0001] The invention belongs to the technical field of building materials, and relates to a fiber-reinforced concrete with ultra-high strength and high bonding performance under outdoor curing conditions and a preparation method thereof. Background technique [0002] Since the invention of Portland cement in 1824, concrete has been rapidly applied because of its easy molding and low price. Although concrete is a traditional man-made building material, because of its irreplaceable advantages (abundant raw materials, simple production process, high cost performance, etc.) and the continuous progress of concrete material science and technology, concrete has become the main body of civil engineering materials. , It will also be one of the indispensable main materials in future civil engineering and national construction. However, with the continuous expansion of the city, the continuous increase of the population, the continuous increase of the land price, the h...

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Problems solved by technology

[0004] In recent years, building structures have developed towards high-rise, super-high-rise, long-span and heavy-duty, and many structures are exposed to harsh environments such as seaside, freeze-thaw areas, and corrosive atmospheres. This has a great impact on the mechanical properties and durability of concrete materials and components Higher requirements have been put forward. Traditional concrete materials have low strength, poor ductility and durability, which obviously cannot meet the requirements. Therefore, more and more domestic and foreign scholars have started to study high-performance concrete.

High-performance concrete includes high-strength high-performance concrete and high-performance fiber-reinforced concrete. High-strength high-performance concrete has excellent properties such as high compressive strength, high impermeability, good durability and workability, but the defect of high-strength high-performance concrete is brittleness Large and low tensile strength, in order to improve its tensile ductility, researchers added fibers (synthetic fibers or steel fibers) to the matrix to develop high-performance fiber-reinforced concrete, high-performance fiber-reinforced concrete not only compressive, The tensile strength is high, the bonding strength, toughness and durability have been greatly improved, and the preparation of high-performance concrete uses industrial waste such as fly ash and silica fume, which is sustainable, so high-performance fiber-reinforced concrete has broad applications. Application prospects

[0005] In the domestic existing technology to produce high-performance fiber-reinforced concrete under outdoor maintenance conditions, P·O 52.5 or P·O 62.5 cement is generally used to prepare ultra-high-strength (compressive strength exceeding 120MPa) high-performance fiber-reinforced concrete. As an aggregate, the active powder concrete produced with a steel fiber content of 3% has a compressive strength of 178.8MPa, but this preparation technology has high requirements for raw materials. For example, the cement currently available on the market is P·O42.5 Mainly cement, P·O 52.5 or P·O 62.5 cement is difficult to buy in the market due to the small demand; standard sand is a strategic material exclusively controlled by the state, and any unit or individual is not allowed to operate it without permission. Standard sand has strict requirements on the selection of raw materials and processing technology, and is expensive, so this preparation technology is difficult to promote on a large scale

The compressive strength of concrete prepared by other researchers does not exceed 140MPa, which is enough to show that the preparation technology of concrete with a compressive strength exceeding 140MPa under outdoor curing conditions is still a difficult point, which also limits my country's high-performance fiber-reinforced concrete to a certain extent. Development and Application of Concrete

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