CN106478024A - A kind of high ductility, high-adhesion cement based reinforcing and repairing material and preparation method thereof - Google Patents

Abstract

A high-ductility, high-cohesion cement-based reinforcement and repair material and a preparation method thereof belong to the technical field of building reinforcement and repair materials. The components and contents of each raw material are calculated by weight percentage: 15%-30% of cement, 30%-40% of fly ash, 10%-25% of fine quartz sand, 15%-25% of water, and 0.3% of viscous inhibitor ‑0.8%, adhesive resistance agent 0.5%‑1.5%, thixotropic agent 0.5%‑0.8%, rubber powder 2%‑11%, and the volume of polyvinyl alcohol short fiber is 2% of the total volume of the repair material. The preparation method is as follows: put cement, fly ash, fine quartz sand, rubber powder, viscous resistance agent, bonding resistance agent, thixotropic resistance agent, shrinkage reducing agent, water reducing agent into the mixer and stir for 2 minutes, Add water and stir for another 3 minutes, and finally put in short polyvinyl alcohol fibers and stir for 5 minutes. The invention can remarkably improve the bonding performance of cement-based materials under the premise of maintaining high ductility, and the raw materials are easy to obtain, and the process is simple, and can be used in repairing and strengthening projects.

Description

A kind of high ductility, high cohesion cement-based reinforcement and repair material and preparation method thereof

technical field

The invention belongs to the technical field of building reinforcement and repairing materials, in particular to a cement-based reinforcement and repairing material with high ductility and high cohesiveness and a preparation method thereof.

Background technique

Under the long-term effects of man-made and natural environments, masonry structures will experience varying degrees of deterioration and damage. When the damage or defects accumulate to a certain extent, the bearing capacity and durability of the structure will decrease, affecting the normal working performance and use of the overall structure. life expectancy and bring safety hazards to the people. Therefore, rebuilding or strengthening and repairing existing structures are necessary measures. However, rebuilding after demolition often involves many factors such as economy and society, and it is difficult to realize. In contrast, reinforcement repair restores the original structure or enhances the bearing capacity to prolong the service life, which is more suitable for the needs of modern society, can greatly shorten the construction period, and reduce a large amount of manpower and capital investment. Therefore, seeking economical and efficient structural reinforcement repair materials is not only a technical problem to be solved urgently, but also a social problem related to sustainable development.

The fiber cement-based composite material is designed according to the principle of micro mechanics, so that it not only has good tensile deformation resistance under low fiber content, but also can significantly control and disperse cracks, ensure its high toughness, and has good energy dissipation capacity. It has become a reinforcement repair material that many scholars have studied in recent years. In the process of strengthening and reinforcing the existing structure, the bonding state between the reinforcement material and the existing structure is directly related to the reliability of the overall project quality after maintenance and reinforcement. In the "Code for Reinforcement Design of Masonry Structures" (GB50702-2011), it is stipulated that the 28d positive tensile bond strength between polymer modified cement mortar and sintered brick or concrete is greater than 1.8MPa, and ordinary fiber cement-based materials are added to improve tensile ductility. A large amount of fly ash greatly reduces the bonding performance between the reinforcement repair material and the existing structure, seriously affecting the reinforcement effect. Based on the above factors, we have invented a high ductility, high adhesion Cement-based reinforcement and repair material and preparation method thereof.

Contents of the invention

The object of the present invention is to address the deficiencies of the prior art, and propose a high-ductility, high-viscosity fiber cement-based reinforcement and repair material and a preparation method thereof. The raw materials are easy to obtain, the production process is simple, and the effect is remarkable.

A cement-based reinforcement and repair material with high ductility and high cohesion, characterized in that the components and contents of each raw material are calculated by weight percentage: 15%-30% of cement, 30%-40% of fly ash, fine quartz sand 10%-25%, water 15%-25%, viscous resist 0.3%-0.8%, bonding resist 0.5%-1.5%, thixotropic resist 0.5%-0.8%, shrinkage reducing agent 0.3%-1.2% , rubber powder 2%-11%, water reducer 0.3%-1.1%, the sum of the weight percentages of the above raw materials is 100%, the volume of polyvinyl alcohol short fibers is 2% of the total volume of the above raw materials; the length of polyvinyl alcohol short fibers is less than 12mm, fine quartz sand is fine sand under a 160μm sieve.

The above-mentioned various materials are characterized in that: cement is ordinary silicate 42.5; fly ash is secondary, specific surface area 4013cm ² /g, density 2.31g/cm ³ ; fine quartz sand is fine sand under a 160um sieve; rubber powder It is made of vinyl acetate-ethylene copolymer emulsion by spray drying (powder, white powder); the viscosity inhibitor is xanthan gum (colorless, powder); the adhesion inhibitor is acrylic acid-methyl acrylate-hydroxypropyl acrylate Ester copolymer (colorless, powder); thixotropic agent is attapulgite (colorless, powder); shrinkage reducing agent is Beijing Haiyan Xingye SY-AEA type (powder, yellow powder); water reducing agent is Guangdong Longfor Technology P29 polycarboxylate superplasticizer (powder, white powder); the fiber is polyvinyl alcohol short fiber.

When in use, mix cement, fly ash, fine quartz sand, rubber powder, viscous resistance agent, adhesion resistance agent, thixotropic resistance agent, shrinkage reducing agent, and water reducing agent in proportion and put them into the mixer for 2 minutes after stirring , add water and stir for 3 minutes, and finally add polyvinyl alcohol short fibers and stir for 5 minutes to obtain this product.

The invention is non-combustible, non-toxic and harmless, has no corrosive effect on existing structures, can be used for strengthening and repairing building structures such as beams, columns, walls, etc., and has a wide application range. At the same time, the 90d tensile ductility of the present invention is above 2.5%, and the 90d bonding strength exceeds 2.5MPa.

detailed description

The present invention will be specifically described below in conjunction with the examples, but the present invention is not limited to the following examples. Ordinary fiber cement-based materials are used as a comparison, numbered as benchmark 1, benchmark 2 and benchmark 3. Ordinary fiber cement-based materials, the main components of which contain mass fractions:

The volume of polyvinyl alcohol fibers is 2% of the total volume of the repair material.

Preparation of a high-ductility, high-viscosity fiber cement-based reinforcement and repair material:

The cement is ordinary silicate 42.5; the fly ash is grade 2, the specific surface area is 4013cm ² /g, and the density is 2.31g/cm ³ ; the fine quartz sand is 90 mesh; the rubber powder is vinyl acetate-ethylene copolymer emulsion spray-dried into (powder, white powder); viscosity inhibitor is xanthan gum (colorless, powder); adhesion inhibitor is acrylic acid-methyl acrylate-hydroxypropyl acrylate copolymer (colorless, powder); The variable resistance agent is attapulgite (colorless, powder); the shrinkage reducing agent is Beijing Haiyan Xingye SY-AEA type (powder, yellow powder); the water reducing agent is Guangdong Longhu Technology P29 polycarboxylic acid type superplasticizer ( Powder, white powder); water is tap water; fiber is 12mm Kuraray polyvinyl alcohol short fiber. The preparation method is as follows: mix cement, fly ash, fine quartz sand, rubber powder, viscous resistance agent, adhesion resistance agent, thixotropic resistance agent, shrinkage reducing agent, water reducing agent, etc. in proportion and put them into a mixer and stir for 2 Minutes later, add water and stir for another 3 minutes, and finally add polyvinyl alcohol short fibers and stir for 5 minutes to obtain this product. Each component content is as table 1 (all by weight percentage):

Table 1 Contents of each component

Cement 15%-30%, fly ash 30%-40%, fine quartz sand 10%-25%, water 15%-25%, viscous inhibitor 0.3%-0.8%, bonding inhibitor 0.5%-1.5 %, thixotropic agent 0.5%-0.8%, shrinkage reducing agent 0.3%-1.2%, rubber powder 2%-11%, water reducing agent 0.3%-1.1%,

2. Performance test

2.1 Test method: The specimen for tensile ductility is a 300mm×60mm×13mm plate, the tensile speed is 0.5mm/min, and the extensometer mark is 50mm. The specific experimental methods for testing the bonding performance are carried out in accordance with the "Standards for the Basic Performance Test Methods of Building Mortar" (JGJ/T70-2009).

2.3 Test results: related performance indicators are shown in Table 2:

Table 2 Related performance indicators

As can be seen from the above examples, compared with the benchmark test piece, the high ductility and high cohesion cement-based reinforcement and repair material of the present invention can significantly improve the bond strength while maintaining high ductility, and conform to the "Masonry Structure Reinforcement Design Code (GB50702-2011) standard requirements, can be fully used in the reinforcement and repair of building structures.

Claims (3)

1. a kind of high ductility, high-adhesion cement based reinforcing and repairing material it is characterised in that each raw material components and content by weight Percentages are：Cement 15%-30%, flyash 30%-40%, fine quartz sand 10%-25%, water 15%-25%, stickiness hinders Agent 0.3%-0.8%, bond resist 0.5%-1.5%, thixotroping resist 0.5%-0.8%, economization agent 0.3%-1.2%, rubber powder 2%-11%, water reducer 0.3%-1.1%, above raw material weight percentage ratio sum is 100%, and polyvinyl alcohol chopped fiber volume is The 2% of above raw material cumulative volume；Polyvinyl alcohol staple length is less than 12mm, and fine quartz sand was the lower fine sand of 160 μm of sieves.

2. material as claimed in claim 1 it is characterised in that：Cement is normal silicate 42.5；Flyash specific surface area 4013cm²/ g, density 2.31g/cm³；Rubber powder is that vinyl acetate-ethylene copolymer emulsion is spray-dried to be formed；Stickiness resist is Xanthan gum；Bonding resist is acrylic acid-acrylic acid methyl ester-Hydroxypropyl acrylate copolymer；Thixotroping resist is attapulgite.

3. prepare the method for material as claimed in claim 1 it is characterised in that：By cement, flyash, fine quartz sand, rubber powder, stick Property resist, bonding resist, thixotroping resist, economization agent and water reducer, after putting in blender stirring in proportion 2 minutes, add water again Stirring 3 minutes, is finally putting into polyvinyl alcohol chopped fiber and stirs 5 minutes.