Adhesives for building reinforcement and reinforcement engineering

2020-03-10 18:19

With the development of science and technology, how to correctly apply reinforcement adhesive drilling agents in construction projects plays an important role in the normal operation and safety of construction projects. This article discusses the application methods and innovations of building reinforcement adhesives in the construction field.
At present, reinforced concrete structures are widely used in China. However, due to the extension of service life or various reasons such as natural disasters, cracks and damages frequently occur in reinforced concrete building components due to insufficient strength and stiffness. In China, many buildings built after the founding of the People's Republic of China have reached the peak of maintenance and reinforcement after about 50 years of use. How to ensure the continued normal and safe use of buildings is a frequently encountered problem in the construction industry. On the other hand, in recent years, due to changes in use, there has been an increasing number of projects to reconstruct and strengthen the original structures and components of buildings. Through long-term efforts by engineering and technical personnel, a relatively complete and feasible set of engineering reinforcement methods has gradually been formed, and has been widely applied and developed in practical reinforcement projects. At the same time, with the rapid development of science and technology, the emergence of various new building materials has also provided favorable conditions for the continuous innovation and upgrading of reinforcement technology and methods.
Using building structural adhesives to reinforce buildings that require reinforcement is a widely used reinforcement method recently. This type of method mainly uses structural adhesive, a bonding material, to firmly bond steel plates or profiles for reinforcement, or other reinforcement materials to various reinforced concrete components, so that the reinforcement material and the original components form a collaborative work mode to meet the original design strength, stiffness, and durability requirements of the structure and components. Applying architectural structural adhesives to connect, strengthen, or repair various components has many outstanding advantages over traditional connection and reinforcement methods:
1. Using synthetic resin adhesives to connect and strengthen components is more uniform in stress than conventional riveting and welding methods, and the material does not produce stress concentration phenomena (such as thermal stress during welding), making it more resistant to fatigue. In particular, it can better ensure the integrity of the component and improve crack resistance, while integrity is fundamentally related to the bearing capacity and stability of the component.
Structural adhesives can firmly connect materials with different properties, which is an advantage that traditional methods cannot compare to today's diverse construction materials.
3. Using adhesives for construction can greatly shorten the construction period and can be used in 1-2 days or less, especially in the reinforcement of various components, enabling the repair and reinforcement of components that cannot be reinforced by traditional methods; It is particularly important for certain important military projects and transportation facilities. And its excellent aging resistance can meet various requirements; During construction, it can also improve efficiency, reduce costs, and save energy.
Long term reinforcement adhesives are classified into Grade A and Grade B adhesives based on their basic properties. For important structures, cantilever components, and structures and components subject to dynamic action, Grade A adhesives are used. For general structural components, Grade B adhesives can be used. At the same time, according to the different materials used for adhesive cable bonding, it can be roughly divided into safety performance indicators of adhesives for carbon fiber composite material impregnation/bonding, adhesives for steel and external bonding, and adhesives for anchoring.
Since the introduction of architectural structural adhesives in the 1990s, it has undergone more than 20 years of development, opening up an increasingly broad field:
1. The application of building structural adhesives in adhesive reinforcement. This type of application mainly involves using structural adhesive as a bonding material, such as steel plates or profiles for reinforcement, or other reinforcement materials (such as carbon fiber, aramid, and chloroprene) that are firmly bonded to various reinforced concrete components, such as beams, columns, joints, bracket panels, tunnels, and arch roofs. The reinforcement projects that have been completed have achieved satisfactory results. Taking beams as an example, they can be ordinary load-bearing beams on buildings, beams for lifting cranes, beams and slab beams for highway bridges, reinforced concrete beams for railway bridges, etc. The effect of strengthening and thickening through careful design and construction is very good.
2. Application of building structural adhesives to chemical bolts or anchor bars. This is another widely used field as a chemical adhesive material in post anchoring technology. It embeds bolts, steel bars, plastic rods, and other anchoring materials in concrete, rock, brick, stone, and other substrates, giving play to the adhesive strength of building structural adhesives, making the post anchor firmly embedded in the substrate, and playing a bearing role under external forces. This is one of the application fields that have developed rapidly in recent years, ranging from the planting of seismic reinforcement to the bonding and embedding of a decoration screw, and building structural adhesives have come into play.
3. Application of building structural adhesives in grouting and repair bonding. It can be a steel plate for external steel reinforcement, and applied to concrete components by pouring adhesive. The building structural adhesive firmly connects the steel plate and concrete to achieve a joint work effect. It can also be used to seal cracks in general components to meet the original design requirements and prevent further expansion of cracks. This type of application is also a large and wide-ranging field, which can be used not only in building components, but also in repairing and repairing various structures such as hydraulic engineering and military engineering.
4. Application of building structural adhesives in on-site construction bonding components. This application range is just beginning for structural adhesives. "It has been used in the splicing and assembling of the concrete roof of the Sydney Opera House in Australia, and there are also practical examples of column lengthening and ground pile lengthening in China. However, due to the initial stage of basic research on design theory and calculation methods, it is still in the use period, but the development and application prospects of this field are very broad.".
5. Application of building structural adhesives in bonding and repairing various buildings. Adhesives can also be used to bond and repair various types of old buildings and ancient buildings (wood structures, concrete structures, stone structures, brick structures, etc.), as well as to repair and repair certain unit components. The repair process is simple and the repair effect is good. There are many examples of such applications. In addition, it has been used for decades in the repair of highway surfaces and airport runways. Underwater bonding in hydraulic engineering also has broad prospects.
6. Application of building structural adhesives in other fields. This aspect is applied in architecture and engineering. Such as the application of various projects in emergency rescue, waterproof and leakage stoppage, sealing and moisture-proof, and anti-corrosion. Building structural adhesives integrate the achievements of advanced technologies such as chemistry, mechanics, materials, structure, and photoelectric measurement, and are applied to the reinforcement of building structures by bonding steel, anchor bolt planting, and on-site pouring construction, demonstrating their outstanding advantages and importance. After years of unremitting efforts, domestic companies have successfully mastered the technology of creating doors and applied it to actual building construction, solving some problems that are difficult to solve with traditional methods in building reinforcement, creating enormous economic and social benefits. I believe that such materials and technologies as building structural adhesives will have a bright future.