Method for repairing concrete crack with multi-cracking cement-based composite

Abstract

The invention belongs to the technical field of concrete reinforcement and relates to a method for repairing a concrete crack, which uses multi-cracking cement-based composite to be covered on the outer surface of the concrete as a repairing layer and is characterized in that firstly, the periphery of the crack on the outer surface of the concrete is polished smooth or an isolating layer is arranged, and then the multi-cracking cement-based composite slurry is poured or a thin layer of slurry is poured first and then a precast slab is covered; and the weight ratio of components of the multi-cracking cement-based composite is that: cement: water: fine aggregate: fly ash: silicon ash: granulated blast furnace slag: metakaolin =1:(0.27-2.2):(0-3):(0-6.9):(0-0.3):(0-0.55):(0-0.4), and fiber of which the volume accounts for 1-3% of the total volume of the composite is also blended. The repairing layer leads the width of the crack to be less than 0.05mm under the action of the external shrinkage stress, can prevent the forming of penetrating cracks and can be widely used for repairing concrete structure cracks of concrete pavement, airport runways, anti-cracking belt of dam and bridge surface plate.

Description

technical field [0001] The invention belongs to the technical field of concrete reinforcement, and relates to a method for repairing concrete cracks by using a multi-crack cement-based composite material capable of producing multiple fine and dense cracks under the action of tensile load. Background technique [0002] The commonly used concrete crack repair technology is to chisel the old concrete and use mortar, fiber concrete and other plastering repairs. However, due to the low tensile strength of repair materials such as mortar and fiber concrete, the repair layer is easy to crack and form a wide main crack that runs through the cracks of the old concrete, causing harmful erosive substances to penetrate into the old concrete structure, and cannot fully achieve crack arrest, The purpose of protecting the building structure. [0003] Multi-cracked cement-based composite material is an ideal concrete reinforcement material, also known as multi-cracked strain-hardened cemen...

AI Technical Summary

Problems solved by technology

[0008] The existing technology for repairing concrete cracks is to grout the old concrete cracks, then chisel the old concrete repair surface to enhance the interface bonding strength between the old and new concrete, and then cover a layer of repair materials, but due to the general The repair materials (ordinary mortar, epoxy mortar, concrete, fiber concrete, etc.) have low crack resistance and single crack damage characteristics. Once the repair layer cracks, it is easy to form main cracks

When the above-mentioned multi-cracked cement-based composite material is used as a repair material, the material has a microscopic crack pattern of multiple fine cracks, which are smaller and denser than other repair materials; however, due to the external load and temperature stress Under normal circumstances, there is a large stress around the old concrete cracks, which is likely to cause stress concentration in the repair layer at the upper end of the crack, resulting in penetrating main cracks, which eventually lead to the destruction of the repair layer.

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