Amino acid ester triggered local disease repairable composite high performance cementitious grout material and preparation method thereof

Abstract

The application belongs to the field of road engineering and discloses a composite high-performance cement-based grouting material for local disease repair excited by carbamate, which is characterized in that the adding amount of each component is as follows in terms of weight fraction: cement 45-50 parts; water 20-25 parts; composite polyurethane 2.0-2.5 parts; nano-silica ash 0.9-1.0 parts; fine sand 2.3-2.5 parts; water reducing agent 0.2-0.25 parts; and defoaming agent 0.2-0.25 parts. The application also discloses a preparation method. The application has the following main beneficial effects: the hydration reaction and hydration speed are improved, and the formation of early strength is promoted; the strength and interfacial bonding strength after hardening, the toughness and stability of the grouting material are improved, the bubble content in the grouting material is reduced, the brittle fracture of the road surface is effectively reduced, the cement mortar breaking strength is increased, the mixing is carried out at normal temperature, the required energy consumption is low, no waste gas is discharged, the strength after hardening is high, and the adaptability is good.

Description

Technical Field

[0001] This invention belongs to the field of road engineering, specifically relating to a composite high-performance cement-based grouting material for repairing localized defects induced by carbamate and its preparation method. Background Technology

[0002] With the rapid development of my country's economy, asphalt pavement has gradually become the mainstream pavement type in highway construction. Simultaneously, the number of vehicles and traffic volume in my country have also increased dramatically. This has led to frequent localized pavement defects such as cracking and potholes under the long-term coupled effects of vehicle load, temperature, humidity, and other factors. Potholes not only significantly impact the service life of the pavement, but also cause noticeable bumps when vehicles travel at high speeds over them, increasing the risk of tire blowouts and steering failure. Therefore, potholes not only affect driving comfort but also pose significant traffic safety hazards. It is essential to promptly treat potholes to ensure driving comfort and safety, prevent further pothole development and the occurrence of other pavement defects, and ultimately improve the fatigue life of the pavement.

[0003] Currently, the traditional repair method for localized asphalt pavement defects typically involves temporary, rapid repair using cold-mix asphalt, followed by a more thorough repair using hot-mix asphalt mixtures. However, cold-mix asphalt repair suffers from drawbacks such as insufficient durability, short-term damage, high cost, and a long strength development time. Hot-mix asphalt repair is heavily influenced by weather, involves complex construction processes leading to longer repair times, and requires significant investment of manpower, resources, and time. Furthermore, the limited quantity used makes quality control difficult. Additionally, current adhesive-based asphalt pavement rapid repair materials, such as cement-based, emulsified asphalt, and resin-based materials, generally suffer from poor bond strength, significant shrinkage, low strength, and poor deformation compatibility with the substrate material, making it difficult to achieve satisfactory repair results.

[0004] Therefore, in view of the hazards of potholes in asphalt pavements and the shortcomings of commonly used pothole repair methods and materials, it is necessary to invent a cement-based grouting material with rapid repair characteristics, as well as high adhesion, high strength and early strength properties. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings and deficiencies of the prior art and to propose a composite high-performance cement-based grouting material for the repair of localized defects induced by urethane and its preparation method. This grouting material is based on high-solids content composite polyurethane modification, which has high permeability, high bonding strength, and hydrophilicity. It can react with the moisture inside the pothole to generate cement gel, thereby increasing the bonding strength between the cement grout and the matrix material. At the same time, it has high flexural strength and can have good deformation coordination with the matrix material. In addition, this grouting material has high adhesion and high strength, which can better fill the pores of the matrix material and reduce brittle cracking, ultimately improving and extending the pavement performance and service life of potholes in asphalt pavements.

[0006] To achieve the above objectives, the technical solution provided by this invention is as follows: a composite high-performance cement-based grouting material for localized repair of carbamate-induced defects, characterized in that the addition amount of each component by weight is: 45-50 parts cement; 20-25 parts water; 2.0-2.5 parts composite polyurethane; 0.9-1.0 parts nano silica fume; 2.3-2.5 parts fine sand; 0.2-0.25 parts water-reducing agent; and 0.2-0.25 parts defoamer.

[0007] Preferably, the cement is sulfoaluminate cement with a strength grade of 42.5.

[0008] Preferably, the method for preparing the composite polyurethane is as follows:

[0009] a. Place polytetrahydrofuran ether diol in a vacuum drying oven and dry at 120°C for 2 hours to remove water.

[0010] b. Add isophorone diisocyanate, polytetrahydrofuran ether diol and 2,2-dihydroxymethylbutyric acid to a four-necked flask and purge with nitrogen gas for 30 minutes to remove oxygen and ensure thorough mixing of the raw materials.

[0011] c. Add 0.2 wt% of dibutyltin dilaurate as catalyst, react at 80 °C for 3 h, then add 1,3-dimethylolpropionate and continue the reaction for 1 h.

[0012] d. Add a measured amount of 1,4-butanediol and continue the reaction for 1 hour. Then, lower the reaction temperature to 50°C and add triethylamine for a neutralization reaction for 30 minutes.

[0013] e. Add an appropriate amount of water and emulsify for 30 minutes to obtain a prepolymer emulsion with a solid content of 50%, and preheat it in an 85°C water bath for 5 minutes.

[0014] f. Take 0.8% of the initiator potassium persulfate in a 1:1 mixed solution of methyl methacrylate and butyl acrylate, dissolve it thoroughly in an appropriate amount of deionized water, and set aside for later use.

[0015] g. Slowly add a 1:1 mixture of methyl methacrylate and butyl acrylate and an aqueous solution of potassium persulfate to the prepolymer emulsion simultaneously, completing the addition within 1 hour.

[0016] h. After the addition is complete, continue the reaction for 3 hours to finally obtain the WPUA composite emulsion, i.e., composite polyurethane.

[0017] Preferably, the silica fume is silica fume with a SiO2 content of 98% or higher.

[0018] Preferably, the fine sand is 0.15~0.3mm fine sand.

[0019] Preferably, the water-reducing agent is PC100 polycarboxylate high-efficiency water-reducing agent.

[0020] Preferably, the defoamer is XP-1 inorganic silicone defoamer.

[0021] This invention also provides a method for preparing a composite high-performance cement-based grouting material for repairing localized urethane-induced defects, characterized in that: firstly, the required raw materials are weighed according to the following proportions: cement 45-50 parts; water 20-25 parts; composite polyurethane 2.0-2.5 parts; nano silica fume 0.9-1.0 parts; fine sand 2.3-2.5 parts; water-reducing agent 0.2-0.25 parts; defoamer 0.2-0.25 parts; cement, silica fume, fine sand, water-reducing agent, and defoamer are sequentially added to a mixing pot and dry-mixed for 1-2 minutes until uniform; then water is added and stirred at 1000 rpm for 3 minutes until uniform; finally, composite polyurethane is added and stirring is continued for 5 minutes to obtain a composite high-performance cement-based grouting material for repairing localized urethane-induced defects.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0023] 1. This invention improves the hydration reaction and rate of cement particles through the pozzolanic reaction of nano-silica fume with water, thus promoting the formation of early strength in cement grout. Simultaneously, the pozzolanic reaction of nano-silica fume can absorb excess moisture from the environment, which is beneficial for the strength formation of the grout in humid and rainy environments. Furthermore, the gel generated by the silica fume hydration reaction and its own filling effect improve the hardened strength and interfacial bonding strength of the cement grout.

[0024] 2. This invention improves the toughness and stability of grouting materials by using a self-made high-solids-content composite polyurethane (the main active ingredient being urethane). While waterborne polyurethane is safe and environmentally friendly, it suffers from low strength and poor water resistance. This invention introduces acrylates into waterborne polyurethane using a dual dynamic network principle of chemical covalent networks and physical cross-linking networks, resulting in a composite polyurethane with significantly improved strength, toughness, and solids content. The composite polyurethane can physically or chemically bond with particles or the matrix in cement grouting materials, improving the cohesion and adhesion of the grouting material. Simultaneously, it has a filling effect, filling micropores and microcracks in cement mortar, improving the mortar's density and impermeability, thereby enhancing the compressive and tensile strength and durability of the grouting material.

[0025] 2. This invention, through the addition of a defoamer, can control and stabilize air bubble formation in cement concrete. The defoamer reduces surface tension, hinders bubble formation, disrupts the bubble film, and accelerates bubble expulsion; it can chemically react with or physically adsorb gas molecules in the cement grout, preventing bubble formation; it can penetrate the bubble film, disrupting its stability, causing bubble rupture or deformation, and accelerating bubble expulsion from the cement grout. The defoamer reduces the air bubble content in cement-based grouting materials, improves the overall integrity of the cement-based grouting materials, and ensures the high performance of the cement-based grouting materials.

[0026] 3. By adding a water-reducing agent, the hydrophilic groups in the water-reducing agent are highly polar, so the water-reducing agent adsorption film on the surface of cement particles can form a stable solubilized water film with water molecules. This water film has a good lubricating effect and can effectively reduce the sliding resistance between cement particles, thereby further improving the fluidity of cement mortar, that is, significantly improving the permeability of cement mortar. The addition of composite polyurethane can, on the one hand, improve the bonding strength between cement mortar and matrix material, and on the other hand, make the cement mortar injected into the road surface have high toughness, thereby effectively reducing its brittle fracture.

[0027] 4. By adding composite polyurethane, the present invention can form a framework system composed of organic and inorganic binders, consisting of a polymer film and cement hydrates, inside the cement mortar. This significantly increases the flexural strength of the cement mortar while slightly reducing its compressive strength, thereby improving its toughness by reducing the compressive-flexural ratio of the cement mortar.

[0028] 5. The carbamate-inspired composite high-performance cement-based grouting material for localized repair of lesions provided by this invention can be mixed at room temperature without heating or special treatment, requiring low energy consumption and producing no waste gas. On the one hand, it requires less manpower and material resources, enabling rapid construction and earlier opening of traffic; on the other hand, it conforms to the current theme of environmental protection and has significant economic benefits.

[0029] 6. The composite high-performance cement-based grouting material for localized repair of carbamate-induced defects provided by this invention has fewer requirements for external conditions such as repair environment and time, and can be applied in most environments; at the same time, due to the hydrophilicity of the grout material, it can even be applied after rain and ensure high strength of the cement grout material after hardening, thus having good adaptability. Detailed Implementation

[0030] The technical solution of the present invention will be further described in detail below with reference to specific embodiments, but the scope of protection and implementation of the present invention are not limited thereto.

[0031] The cement used in the following examples is PC 42.5 quick-setting cement produced by Shanghai Huanyu Co., Ltd.; the high-solids composite polyurethane is self-made; the silica fume is produced by Henan Borun New Materials Co., Ltd., with a SiO2 content of 98% or higher; the fine sand is 0.15~0.3mm fine sand produced by Shaoxing Shangyu Kezheng Instrument Co., Ltd.; the water-reducing agent used is PC100 polycarboxylate high-efficiency water-reducing agent; and the defoamer used is XP-1 inorganic silicone defoamer.

[0032] Examples 1-5: A composite high-performance cement-based grouting material for repairing localized urethane-induced defects. The proportions of each component are shown in Table 1. The preparation method includes the following steps: the solid components such as cement, silica fume, fine sand, water-reducing agent, and defoamer in each component raw material are sequentially put into a mixing pot and dry-mixed for 1-2 minutes until uniform. Then, water is added and stirred at 1000 rpm for 3 minutes until uniform. Finally, composite polyurethane is added and stirred for another 5 minutes to obtain a uniformly mixed cement-silica fume-fine sand-composite polyurethane composite binder, which is a composite high-performance cement-based grouting material for repairing localized defects induced by urethane.

[0033] Table 1 shows the weight ratio of each component raw material in the composite high-performance cement-based grouting material for localized repair of carbamate-induced defects described in Examples 1-5.

[0034]

[0035] The composite high-performance cement-based grouting material for localized repair of carbamate-induced defects prepared in Examples 1-5 was tested for fluidity, 7-day and 28-day compressive strength, 7-day and 28-day flexural strength, and 28-day drying shrinkage. The results are shown in Table 2, where d refers to day.

[0036] Table 2 shows the test results of various performance characteristics of the asphalt pavement pothole repair material with high bonding properties and high toughness described in Examples 1-5.

[0037]

[0038] As can be seen from Table 2, the flowability, 7d and 28d compressive strength, 7d and 28d flexural strength, and 28d shrinkage rate of each embodiment of the present invention all meet the relevant requirements of the "Technical Specification for Road Grouting Semi-Flexible Pavement" (TCECS GD51-01-2019). In particular, the flowability, flexural strength, and the ratio of compressive strength to flexural strength are all at a good level.

[0039] Specific observations of the proportions and performance test results of Examples 1 and 2, Examples 1 and 4, and Examples 3 and 5 revealed that reducing the silica fume content by 0.2% or increasing the water-reducing agent (defoamer) content by 0.1% both reduced the various properties of the grouting material. Among these, the negative impact of the water-reducing agent and the defoamer on the grouting material was more significant.

[0040] Specific observation of the formulation and performance test results of Examples 1 and 3, Examples 4 and 5 revealed that an increase of 1% in composite polyurethane reduced the fluidity of the grout by 0.5%, but improved other properties of the grout, including a maximum increase of 3.8% in compressive strength, a maximum increase of 15.6% in compressive strength, and a maximum reduction of 30.6% in drying shrinkage.

[0041] Specific observation of the formulation and performance test results of Examples 1, 4, and 5 revealed that the addition of composite polyurethane can effectively alleviate the negative impact of water-reducing agents and defoamers on the performance of grouting materials, with an alleviation rate of up to 100%.

[0042] After repeated experiments, the applicant found that the following technical solutions can achieve the expected beneficial effects: a composite high-performance cement-based grouting material for localized lesion repair induced by carbamate, characterized in that the addition amount of each component by weight is: cement 45~50 parts; water 20~25 parts; composite polyurethane 2.0~2.5 parts; nano silica fume 0.9~1.0 parts; fine sand 2.3~2.5 parts; water-reducing agent 0.2~0.25 parts; defoamer 0.2~0.25 parts.

[0043] In summary, the cement mortar of the present invention, due to the addition of silica fume, fine sand, water-reducing agent, defoamer, composite polyurethane, etc., exhibits significantly improved fluidity, shrinkage resistance, compressive and flexural strength, and compression-flexural ratio compared to ordinary cement mortar. It is evident that the implementation effect of the present invention is good, has practical application value, and is worthy of promotion.

[0044] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A composite high-performance cement-based grouting material for repairing localized lesions activated by carbamate, characterized in that, The addition amounts of each component, by weight, are as follows: cement 45-50 parts; water 20-25 parts; composite polyurethane 2.0-2.5 parts; nano silica fume 0.9-1.0 parts; fine sand 2.3-2.5 parts; water-reducing agent 0.2-0.25 parts; defoamer 0.2-0.25 parts; The preparation method of the composite polyurethane is as follows: a. Place polytetrahydrofuran ether diol in a vacuum drying oven and dry at 120°C for 2 hours to remove water; b. Add isophorone diisocyanate, polytetrahydrofuran ether diol and 2,2-dihydroxymethylbutyric acid to a four-necked flask and purge with nitrogen gas to remove oxygen for 30 minutes to ensure thorough mixing of the raw materials; c. Add 0.2 wt% of the catalyst dibutyltin dilaurate, react at 80 °C for 3 h, then add 1,3-dimethylolpropionate and continue the reaction for 1 h; d. Add a measured amount of 1,4-butanediol and continue the reaction for 1 hour. Then, lower the reaction temperature to 50°C and add triethylamine for a neutralization reaction for 30 minutes. e. Add an appropriate amount of water and emulsify for 30 minutes to obtain a prepolymer emulsion with a solid content of 50% and preheat it in an 85°C water bath for 5 minutes; f. Take 0.8% of the initiator potassium persulfate in a 1:1 mixed solution of methyl methacrylate and butyl acrylate, dissolve it completely in an appropriate amount of deionized water, and set aside for later use. g. Slowly add a 1:1 mixture of methyl methacrylate and butyl acrylate and an aqueous solution of potassium persulfate to the prepolymer emulsion simultaneously, and complete the addition within 1 hour. h. After the addition is complete, continue the reaction for 3 hours to finally obtain the WPUA composite emulsion.

2. The composite high-performance cement-based grouting material for localized repair of carbamate-induced defects according to claim 1, characterized in that, The cement is sulfoaluminate cement with a strength grade of 42.

5.

3. The composite high-performance cement-based grouting material for repairing localized lesions activated by carbamate according to claim 2, characterized in that, The nano silica fume is silica fume with a SiO2 content of 98% or higher.

4. The composite high-performance cement-based grouting material for localized repair of carbamate-induced defects according to claim 3, characterized in that, The fine sand is fine sand with a maximum size of 0.15~0.3mm.

5. The composite high-performance cement-based grouting material for repairing localized lesions activated by carbamate according to claim 4, characterized in that, The water-reducing agent is PC100 polycarboxylate high-efficiency water-reducing agent.

6. The preparation method of a composite high-performance cement-based grouting material for localized repair of carbamate-induced defects according to claim 5, characterized in that... The method includes the following steps: First, weigh the required raw materials according to the proportions, with the following weight percentages for each component: cement 45-50 parts; water 20-25 parts; composite polyurethane 2.0-2.5 parts; nano silica fume 0.9-1.0 parts; fine sand 2.3-2.5 parts; water-reducing agent 0.2-0.25 parts; defoamer 0.2-0.25 parts. Then, add the cement, silica fume, fine sand, water-reducing agent, and defoamer from the above raw materials into a mixing pot and dry mix for 1-2 minutes until uniform. Next, add water and stir at 1000 rpm for 3 minutes until uniform. Finally, add the composite polyurethane and continue stirring for 5 minutes to obtain a composite high-performance cement-based grouting material for localized repair of carbamate-induced defects.

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