A method for repairing and protecting concrete guardrails from corrosion

Abstract

This application discloses a method for corrosion prevention and repair of concrete guardrails, relating to the field of highway traffic safety facility maintenance technology. The method includes four steps: base surface cleaning, mortar repair, surface protection, and post-treatment curing. First, the damaged concrete is removed and ground, and the exposed reinforcing steel is derusted. Then, a special mortar is used to fill the pitted and damaged areas of the guardrail and smooth the surface, ensuring that the guardrail's cross-sectional dimensions are consistent with the original structure. Finally, a silane paste is applied to the guardrail surface for protection. After the paste is applied, it needs to be cured for a certain period before the guardrail can be put into use. This invention does not require altering the original guardrail's detailed dimensions, significantly improves the corrosion resistance, durability, and water resistance of concrete guardrails, effectively prevents the intrusion of water and harmful media, delays corrosion damage, extends the service life of the guardrail, is simple to operate, and has controllable costs, making it suitable for corrosion prevention and repair projects of various types of highway concrete guardrails.

Description

Technical Field

[0001] This application relates to the field of highway traffic safety facility maintenance technology, and in particular to a method for corrosion prevention and repair of concrete guardrails. Background Technology

[0002] With the rapid growth of my country's economy and the booming development of highway transportation, traffic volume has increased rapidly, and vehicle types have become more diverse, directly leading to an increase in the frequency of use and load on highway traffic safety facilities. As the last line of defense for traffic safety, highway guardrails play a crucial role in ensuring safe travel, and concrete guardrails are one of the most commonly used forms of highway guardrail protection.

[0003] However, as highways age, concrete guardrails are exposed to the natural environment for extended periods, constantly subjected to de-icing agents and rainwater, leading to corrosion on the concrete surface. The corroded concrete surface gradually develops cracks, damage, and spalling, eventually exposing the internal reinforcing steel layer. The exposed steel then corrodes, causing rust expansion, further exacerbating the concrete damage and creating a vicious cycle of "corrosion-damage-rust-more severe damage." This severely impacts the structural stability and service life of the concrete guardrails, reduces their safety performance, and may even necessitate frequent replacements, increasing highway maintenance costs.

[0004] Currently, most existing repair methods for concrete guardrails only involve simple filling of surface damage without targeted anti-corrosion treatment. This results in the guardrails remaining susceptible to corrosion after repair, leading to poor repair effectiveness and short service life. Some repair methods alter the original guardrail's detailed dimensions during the filling process, affecting the overall structure and protective performance. Other anti-corrosion repair methods use film-forming coatings, which are prone to peeling and cracking, failing to fundamentally prevent water and harmful media from penetrating the concrete. Therefore, there is an urgent need for a concrete guardrail anti-corrosion repair method that can effectively improve the anti-corrosion performance and extend the service life of guardrails without altering their original dimensions. Summary of the Invention

[0005] This invention addresses the problems of poor corrosion resistance, easy alteration of original fence dimensions, and short service life in existing technologies for repairing concrete guardrails. It provides a method for corrosion prevention and repair of concrete guardrails, achieving efficient repair and long-term corrosion protection while maintaining the original fence's structural dimensions and protective performance, and reducing maintenance costs.

[0006] The objective of this invention is primarily achieved through the following approach: A method for corrosion prevention and repair of concrete guardrails includes the following steps: Step S1: Base surface cleaning First, conduct a comprehensive inspection of the concrete railing surface to identify the affected areas. Use tools such as an electric hammer and chisels to remove the damaged concrete, including cracked, broken, detached, and corroded concrete. Remove the concrete down to the solid base layer to avoid leaving any loose or corroded concrete that could affect the repair results. After removal, use sandpaper or a grinder to polish the surface, removing surface dust and loose particles to make the base surface smooth and rough, facilitating the bonding of subsequent mortar. If exposed rebar is found, use mechanical rust removal (such as wire brush grinding) or chemical rust removal (such as rust remover spraying) to remove the rust. After rust removal, ensure the rebar surface is free of oxide scale and rust products, revealing the natural color of the rebar. For the rust-removed rebar, a thin layer of anti-rust primer can be applied to further improve its corrosion resistance. Finally, use a blower or brush to clean the base surface, ensuring it is flat, dry, free of loose debris and oil stains.

[0007] Step S2: Mortar Repair The preferred mixing ratio for the anti-corrosion repair mortar is cement:sand:water:anti-corrosion admixture = 1:2.5:0.45:0.03~0.05. The anti-corrosion admixture is an organosilicon-based agent, which improves the mortar's corrosion resistance and waterproofing performance, and enhances its adhesion to the substrate. The prepared repair mortar is then evenly applied to the pitted or damaged areas of the guardrail surface. During application, the mortar is gently compacted with a trowel to avoid air bubbles. After filling, the entire surface of the guardrail is smoothed with uniform pressure to ensure the repair layer is flush with the original concrete guardrail surface, free from unevenness, air bubbles, and cracks. The cross-sectional dimensions of the original guardrail must be strictly maintained, without altering its detailed structure or protective performance.

[0008] Step S3: Surface Protection After the mortar repair layer has cured naturally until completely dry, a dryness test is performed on the surface of the repair layer to ensure that the moisture content is ≤8%, thus avoiding moisture affecting the protective effect of the silane paste. Subsequently, a silane paste protective layer is evenly applied to the surface of the guardrail. The silane paste is a non-film-forming, non-flowing material that can penetrate into the concrete, giving the concrete surface good hydrophobicity, preventing water and other harmful media (such as chloride ions in de-icing agents) from entering the concrete, delaying the corrosion and damage of the concrete structure, and not filling the capillary structure of the concrete, thus not affecting the permeability of the concrete. The thickness of the silane paste coating is controlled at 0.3~0.5mm, with two coats applied, and the interval between the two coats is 2~4 hours to ensure that the protective layer is uniform, continuous, and free of missed areas or bubbles.

[0009] Furthermore, to improve the repair effect and the service life of the guardrail, this method also includes maintenance steps: After the mortar repair is completed, natural curing is carried out for no less than 7 days. During the curing period, avoid rain, collision and sun exposure. Plastic film can be used for curing to ensure that the mortar repair layer is fully hardened. After the silane paste is applied, it is cured for more than 24 hours. The guardrail can be put into use after the protective layer is completely cured.

[0010] In summary, compared with the prior art, the present invention has the following beneficial technical effects: (1) This invention achieves thorough repair of defects such as damage and exposed reinforcement in concrete guardrails through step-by-step operations of base cleaning, mortar repair and surface protection. It also achieves long-term corrosion protection through the silane paste protective layer, effectively solving the problems of poor corrosion protection and short service life of existing repair methods. It can significantly extend the service life of concrete guardrails and reduce highway maintenance costs. (2) In the mortar repair process, the present invention ensures that the cross-sectional dimensions of the guardrail are consistent with the original guardrail by precise filling and overall smoothing, without changing the detailed structure and protective performance of the original guardrail, thus solving the defect of the existing repair method that easily changes the size of the guardrail and ensuring that the safety protection function of the guardrail is not affected. (3) The silane paste used in this invention is a non-film-forming paste material that can penetrate into the concrete to form a hydrophobic layer, rather than just forming a coating on the surface. This avoids the problems of coating peeling and cracking, and fundamentally blocks the intrusion of water and harmful media, resulting in a longer-lasting anti-corrosion effect. At the same time, the silane paste does not fill the capillary pores of the concrete and does not affect the permeability of the concrete, thus avoiding secondary corrosion caused by the inability of water inside the concrete to be discharged. (4) The present invention is easy to operate, has a clear process, requires readily available materials, and has controllable costs. It does not require complex construction equipment and is suitable for corrosion prevention and repair projects of various highway concrete guardrails, with broad application prospects. Attached Figure Description

[0011] Figure 1 This is a flowchart of a method for corrosion prevention and repair of concrete guardrails according to the present invention. Detailed Implementation

[0012] The technical solution of the present invention will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any modifications and / or alterations made to the present invention will fall within the protection scope of the present invention.

[0013] Example 1: A method for corrosion prevention and repair of concrete guardrails like Figure 1As shown, this embodiment addresses a concrete guardrail on a highway that has been in use for eight years. The guardrail has been affected by de-icing agents and rainwater, resulting in multiple cracks and damages on its surface, with exposed and corroded reinforcing steel in some areas. The method of this invention is used for corrosion prevention and repair. The specific steps are as follows: Step S1: Base surface cleaning A comprehensive inspection of the concrete guardrail section was conducted, marking out areas of cracking, damage, and looseness. The damaged concrete was removed using an electric hammer and chisels, reaching the solid base layer with an average depth of 20mm. The chiseled edges were sanded to ensure a smooth transition. Exposed reinforcing bars were mechanically derusted using a wire brush to remove oxide scale and rust, revealing the original steel. After derusting, an epoxy anti-rust primer was applied. Finally, a blower was used to clean the surface of the base layer, removing dust and loose particles to ensure the base layer was flat, dry, with a moisture content of 6%, and free of loose debris and oil.

[0014] Step S2: Mortar Repair Prepare an anti-corrosion repair mortar with a ratio of cement:sand:water:organosilicon anti-corrosion admixture = 1:2.5:0.45:0.04. Use 42.5 grade ordinary Portland cement, medium sand, and sodium methylsilicate as the organosilicon anti-corrosion admixture. Mix the cement, sand, and anti-corrosion admixture thoroughly, then add an appropriate amount of water and stir until a uniform paste is formed. Evenly fill the prepared repair mortar onto the pitted or damaged areas of the railing, gently compacting it with a trowel to remove air bubbles. After filling, smooth the entire surface of the railing with a trowel, ensuring the repair layer is flush with the original railing surface, the railing cross-sectional dimensions match the original structure, and there are no uneven areas or cracks.

[0015] Step S3: Surface Protection The mortar repair layer was covered with plastic film and allowed to cure naturally for 7 days. After curing, the moisture content of the repair layer was tested and found to be 5%, which met the coating requirements. A silane paste protective layer was then evenly applied to the surface of the railing using a brush. The silane paste used was isobutyltriethoxysilane paste, and the coating thickness was 0.4 mm. After the first coat was applied, the surface was allowed to stand for 3 hours until it was dry before applying the second coat to ensure that the protective layer was uniform, continuous, and without any missed areas.

[0016] Step S4: Post-treatment maintenance After the silane paste is applied, allow it to cure naturally for 24 hours until the protective layer is fully cured. The anti-corrosion repair work on this section of the concrete guardrail is then complete.

[0017] After the repair was completed, the section of guardrail was monitored. Six months later, there were no cracks, damage or corrosion on the guardrail surface. The repair layer was firmly bonded to the base layer, the silane protective layer did not peel off, and the guardrail's corrosion resistance and water resistance were significantly improved, achieving the goal of long-term corrosion protection.

[0018] Example 2: A method for corrosion prevention and repair of concrete guardrails like Figure 1 As shown, this embodiment addresses a concrete guardrail on a municipal road. The guardrail has extensive surface pitting and localized damage, with no exposed reinforcing steel. The method of this invention is used for corrosion prevention and repair. The specific steps are as follows: Step S1: Base surface cleaning Inspect the surface of the guardrail and mark the rough and damaged areas; use a grinder to grind the entire surface of the guardrail to remove surface dust, loose particles and loose concrete. For damaged areas, use a chisel to remove the damaged concrete down to the solid base layer; after grinding, use a brush to clean the base surface to ensure that the base layer is flat, dry and has a moisture content of 7%.

[0019] Step S2: Mortar Repair Prepare an anti-corrosion repair mortar with a ratio of cement:sand:water:organosilicon anti-corrosion admixture = 1:2.5:0.45:0.03. After mixing evenly, fill the pitted and damaged areas of the guardrail, compact it, and smooth the entire surface to ensure that the repair layer is flush with the original guardrail surface and has the same dimensions.

[0020] Step S3: Surface Protection After the mortar repair layer has been naturally cured for 6 days and the moisture content is tested to be 7%, a silane paste protective layer is applied by roller with a thickness of 0.3mm. It is applied in 2 coats with an interval of 2 hours to ensure that the protective layer is uniform and without any omissions.

[0021] Step S4: Post-treatment maintenance After 24 hours of curing with silane paste, the guardrail was put into use. After 3 months, the guardrail surface showed no corrosion or damage and had good waterproof performance.

[0022] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for corrosion prevention and repair of concrete guardrails, characterized in that, Includes the following steps: Step S1: Base surface cleaning, including chiseling away the defective concrete on the surface of the concrete guardrail, grinding the base after chiseling, and removing rust from the exposed steel bars if there are any. After cleaning, ensure that the base is flat, dry and free of loose debris. Step S2: Mortar repair. Use repair mortar to fill the pitted and damaged parts of the guardrail surface. After filling, smooth the guardrail surface to ensure that the cross-sectional dimensions of the guardrail are consistent with the original concrete guardrail. Step S3: Surface protection. After the mortar repair layer is completely dry, apply a silane paste protective layer evenly to the surface of the guardrail to form a hydrophobic protective structure.

2. The method for corrosion prevention and repair of concrete guardrails according to claim 1, characterized in that, In step S1, the defective concrete includes cracked, broken, detached, and corroded concrete. The concrete is chiseled to the depth of the solid base layer, and the chiseled edges are ground to make the base layer transition smooth.

3. The method for corrosion prevention and repair of concrete guardrails according to claim 1, characterized in that, In step S1, the steel bars are derusted using mechanical or chemical methods. After derusting, there is no oxide scale or rust products on the surface of the steel bars. After the derusting is completed, a layer of anti-rust primer can be applied.

4. The method for corrosion prevention and repair of concrete guardrails according to claim 1, characterized in that, In step S2, the repair mortar is an anti-corrosion cement mortar with a mixing ratio of cement:sand:water:anti-corrosion admixture = 1:2.5:0.45:0.03~0.

05. The anti-corrosion admixture is an organosilicon anti-corrosion agent.

5. A method for corrosion prevention and repair of concrete guardrails according to claim 1, characterized in that, In step S2, the smoothing process is carried out using a trowel with uniform pressure to ensure that the surface of the repair layer is flush with the original guardrail surface, without unevenness, bubbles, or cracks.

6. The method for corrosion prevention and repair of concrete guardrails according to claim 1, characterized in that, In step S3, the silane paste is a non-film-forming paste-like non-flowing material with a coating thickness of 0.3~0.5mm, applied in 2 coats, and with an interval of 2~4 hours between the two coats.

7. A method for corrosion prevention and repair of concrete guardrails according to claim 1, characterized in that, In step S3, before applying the silane paste, the mortar repair layer needs to be tested for dryness to ensure that the moisture content of the repair layer is ≤8%.

8. A method for corrosion prevention and repair of concrete guardrails according to claim 1, characterized in that, The method also includes a curing step. After the mortar repair is completed, natural curing is carried out for no less than 7 days. During the curing period, rain, collision and sun exposure should be avoided. After the silane paste is applied, it can be put into use after curing for more than 24 hours.

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