An unsaturated polyester resin mortar repair material and its preparation method

Abstract

This invention belongs to the field of building materials technology, specifically relating to a method for preparing unsaturated polyester resin mortar repair material, whose raw materials are widely available. Copper slag and iron slag are byproducts of metal smelting and industrial solid wastes, exhibiting strong compatibility with resin materials, high density, large specific surface area, and excellent fluidity. Adding them to cement-based materials not only reduces the cost of cement-based materials but also improves solid waste utilization and reduces landfill and land occupation, thus benefiting environmental protection. This invention, on the one hand, promotes the efficient utilization of solid waste and alleviates the shortage of natural sand and gravel; on the other hand, it significantly reduces the emission of greenhouse gases such as carbon dioxide, demonstrating significant economic, ecological, and social benefits.

Description

Technical Field

[0001] This invention belongs to the field of building materials and relates to the utilization of solid waste resources and the creation of building repair materials, specifically to a method for preparing an unsaturated polyester resin mortar repair material. Background Technology

[0002] Concrete is widely used in the construction of various infrastructures. It is suitable for casting components of various shapes and sizes, easily yields components that meet strength requirements, and has good durability. However, concrete components have a limited lifespan. Maintaining or repairing concrete structures at appropriate intervals may be more economical than constructing a long-term maintenance-free structure. Structural concrete will experience cracking, delamination, and spalling as its service life increases, thus often requiring repair. General cement mortar repair materials have drawbacks such as low compressive and flexural strength, poor bond performance, and long setting time, making them unsuitable for rapid repair of concrete structures. Although early-strength cement mortar performs well in rapid repair, this type of repair material has poor crack resistance, insufficient bond strength, and is prone to detachment.

[0003] In recent years, epoxy mortar has attracted widespread attention in the industry as a repair material. Epoxy mortar is a cementitious material mainly composed of epoxy resin, but this type of material is expensive and unsuitable for large-area application. Furthermore, the reaction process requires the addition of curing agents, diluents, and accelerators, which pose certain environmental hazards. In contrast, unsaturated polyester (UPE) resin is cheaper and possesses excellent mechanical and durability properties. Therefore, using UPE resin to prepare unsaturated polyester mortar as a repair material for concrete structures offers a significant cost-performance advantage.

[0004] On the other hand, the rational utilization of multi-source solid waste has attracted much attention. Metal smelting slag, such as copper slag and iron slag, is a solid waste generated by the metallurgical industry. Currently, its disposal methods mainly involve stockpiling and landfilling, which not only occupies land resources but also causes serious environmental pollution. Applying copper slag and iron slag to unsaturated polyester mortar repair materials can improve the mechanical properties of the mortar and reduce environmental pressure, while providing an effective way to utilize multi-source solid waste in the field of mortar repair materials. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing cement-based mortar repair materials by providing a method for preparing an unsaturated polyester mortar repair material. This method uses copper and iron slag as aggregates to reduce environmental pollution while improving mortar performance, enhancing its flexural and compressive strength, durability, and impermeability. The unsaturated polyester mortar repair material prepared by this invention achieves multiple goals, including environmental protection, technological innovation, and cost reduction and efficiency improvement, through the resource utilization of solid waste.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An unsaturated polyester mortar repair material is disclosed, comprising UPE resin, cement, standard sand, copper slag, and iron slag. UPE resin serves as the cementitious material, accounting for 10%–20% of the total mortar mass. Cement, standard sand, copper slag, and iron slag are collectively referred to as fillers, accounting for 80%–90% of the total mass, with the sum of the mass fractions of the cementitious material and fillers being 100%. Cement accounts for 5%–30% of the filler mass; standard sand accounts for 50%–80% of the filler mass; copper slag accounts for 0%–20% of the filler mass, replacing part of the standard sand; iron slag accounts for 0%–25% of the filler mass, replacing part of the cement; and the sum of the mass fractions of all components is 100%.

[0008] Furthermore, the UPE resin uses phthalic anhydride and diol as the main raw materials, is soluble in styrene (content is 45%), has a viscosity of 200~300 mPa‧s, a gel time of 15~25 min, a solid content of 57%~63%, an acid value of 18~24 mgKOH / g, and adds 3 wt% of a composite cobalt accelerator (containing cobalt octoate, dimethylaniline, and stabilizer, wherein the mass fraction of cobalt octoate accounts for 1.6% of the composite cobalt accelerator).

[0009] Furthermore, the copper slag was provided by China Aluminum Southeast Copper Co., Ltd. (Ningde, Fujian), with a specific surface area of ​​912 m². 2 / kg, density is 3.91 g / cm³ 3 The particle size distribution ranges from 0.283 μm to 563.677 μm, with an average particle size of 56.37 μm. The particle size distribution of copper slag is as follows... Figure 1 As shown.

[0010] Furthermore, the iron ore slag was provided by Shaanxi Longgang Group Xi'an Iron & Steel Co., Ltd., and the specific surface area of ​​the iron slag was 902 m². 2 / kg, density is 3.24 g / cm³ 3 The particle size distribution ranges from 0.314 μm to 859 μm, with an average particle size of 400 μm. The particle size distribution of iron ore slag is as follows: Figure 2 As shown.

[0011] Furthermore, in addition to measuring the raw materials of the cementitious material according to the above proportions, it is also necessary to weigh 1% to 3% of 2-butanone peroxide (MEKP) by mass of UPE resin and mix it evenly. Then, add it to the mixture of cement, standard sand, copper slag and iron slag, and stir evenly to obtain UPE resin repair mortar.

[0012] The preparation method of the unsaturated polyester mortar repair material includes the following steps:

[0013] (1) Weigh cement, standard sand, copper slag and iron slag and add them to the mortar mixing pot, and mix at low speed for 30 s;

[0014] (2) Weigh UPE resin and initiator 2-butanone peroxide (MEKP), prepare a cementitious material mixture according to the proportion, and add it to the mixed dry material of cement, standard sand, copper slag and iron slag. Continue stirring at low speed for 2 min.

[0015] (3) The mixed mortar is evenly poured into the mold brushed with release agent and placed on the vibrating table and vibrated for 2 minutes before stopping to obtain unsaturated polyester mortar.

[0016] (4) After the specimen has cured for 24 hours, it is demolded and cured at room temperature for 3 days to obtain the unsaturated polyester mortar specimen.

[0017] The significant advantages of this invention are: using UPE resin as the cementing material, partially replacing standard sand in the aggregate with copper slag, and partially replacing cement with iron slag. Copper and iron slag are characterized by small particle size, high specific surface area, near-spherical shape, and smooth surface, increasing mortar fluidity, reducing resin usage, and exhibiting strong compatibility with resin, thus improving the mortar's compressive strength. Replacing some siliceous materials with waste metallurgical slag as aggregate to prepare unsaturated polyester mortar achieves the effects of comprehensive solid waste disposal, rational resource utilization, and reduced mortar costs.

[0018] The beneficial effects of this invention are as follows:

[0019] (1) The unsaturated polyester mortar repair material prepared by the present invention can be molded in one step and is suitable for curing at room temperature and pressure, low temperature, or rapid curing under heat and pressure.

[0020] (2) As the amount of copper slag and iron slag added increases, the fluidity of the unsaturated polyester mortar repair material prepared by the present invention also increases. While reducing the amount of resin used, it can improve the workability and compressive strength of the mortar.

[0021] (3) The unsaturated polyester mortar repair material prepared by this invention is an environmentally friendly composite material. During the curing process, the UPE resin undergoes a cross-linking reaction, forming a stable three-dimensional network structure that tightly binds the aggregate together, thereby giving the mortar excellent physical and mechanical properties and bonding performance. While ensuring mechanical strength, the unsaturated polyester mortar has excellent bonding ability to the concrete interface and can effectively repair defects in concrete structures.

[0022] (4) The copper slag and iron slag used in this invention are solid wastes with a wide, stable and abundant source. Compared with traditional polymer mortar, they have better fluidity and impermeability. In addition, using copper slag and iron slag to replace siliceous materials has significant cost advantages, which can reduce the amount of natural sand and gravel used and carbon emissions, and has the advantages of low price and green environmental protection.

[0023] In summary, the unsaturated polyester mortar repair material prepared by this invention exhibits excellent workability, mechanical strength, and bonding properties. Furthermore, it cures rapidly and can withstand various harsh environmental conditions. The resource utilization of solid waste copper and iron slag reduces the cost of unsaturated polyester mortar raw materials and alleviates environmental pressure, demonstrating significant application value and promising prospects for widespread adoption. Attached Figure Description

[0024] Figure 1 It is the particle size distribution of copper slag;

[0025] Figure 2 It is the particle size distribution of iron ore slag;

[0026] Figure 3 The curing time of mortar with different initiator dosages;

[0027] Figure 4 It refers to the fluidity of the mortar;

[0028] Figure 5 It is the flexural strength of unsaturated polyester mortar at different curing times;

[0029] Figure 6 It is the compressive strength of unsaturated polyester mortar at different curing times;

[0030] Figure 7 It is the bonding strength of unsaturated polyester mortar;

[0031] Figure 8 This refers to the water absorption rate of unsaturated polyester mortar.

[0032] Figure 9 It is the porosity of unsaturated polyester mortar;

[0033] Figure 10 It is a differential scanning calorimeter of unsaturated polyester resin;

[0034] Figure 11 This is the thermogravimetric loss of unsaturated polyester resin;

[0035] Figure 12 These are scanning electron microscope (SEM) images and elemental surface scans of unsaturated polyester mortar specimens.

[0036] In each chart, the horizontal lines above and below the rectangular bars represent the standard deviation of the data means. The absence of identical letters above the bars indicates a significant difference between the means of the two groups of data; otherwise, the difference is not significant. P >95%). Detailed Implementation

[0037] To further disclose, and not limit, the present invention, the invention will be further described in detail below with reference to examples.

[0038] Raw materials: P·O 42.5 ordinary Portland cement (chemical composition shown in Table 1), purchased from Fujian Jinniu Cement (Group) Co., Ltd.; standard sand, purchased from Xiamen ASE Standard Sand Co., Ltd.; unsaturated polyester resin, purchased from Shangwei (Shanghai) Fine Chemical Co., Ltd.; 2-butanone peroxide (MEKP, 52%), purchased from Shanghai Jingchun (Aladdin) Industrial Co., Ltd.

[0039] The unsaturated polyester mortar repair material is composed of unsaturated polyester (UPE) resin, cement, standard sand, copper slag, and iron slag. UPE resin is the cementitious material, accounting for 10% to 20% of the total mortar mass; cement, standard sand, copper slag, and iron slag are collectively referred to as fillers, accounting for 80% to 90% of the total mass; the sum of the mass fractions of the cementitious material and fillers is 100%; cement accounts for 5% to 30% of the filler mass, standard sand accounts for 50% to 80% of the filler mass, copper slag accounts for 0% to 20% of the filler mass to replace part of the standard sand, and iron slag accounts for 0% to 25% of the filler mass to replace part of the cement; the sum of the mass fractions of all components is 100%.

[0040] The preparation method of the unsaturated polyester mortar repair material includes the following steps:

[0041] (1) Weigh cement, standard sand, copper slag and iron slag and add them to the mortar mixing pot, and mix at low speed for 30 s;

[0042] (2) Weigh UPE resin and initiator MEKP (accounting for 1%~3% of the mass of UPE resin), prepare a cementitious material mixture according to the proportion, and add it to the mixed dry material of cement, standard sand, copper slag and iron slag. Continue stirring at low speed for 2 minutes.

[0043] (3) The mixed mortar is evenly poured into the mold brushed with release agent and placed on the vibrating table and vibrated for 2 minutes before stopping to obtain unsaturated polyester resin mortar.

[0044] (4) After the specimen has cured for 24 hours, it is demolded and cured at room temperature for 3 days to obtain the unsaturated polyester resin mortar specimen.

[0045] Example 1

[0046] The specific steps for preparing unsaturated polyester mortar are as follows:

[0047] Test blocks were prepared according to the JC / T 2381-2016 industry standard for repair mortar. Cement (540 g) and standard sand (1350 g) were placed in a mixing pot and premixed at low speed for 30 s. At the same time, UPE resin (324 g) and MEKP (3.24 g) were poured into a beaker and stirred for 30 s. After the cementitious materials were evenly mixed, they were poured into the mixing pot and stirred at low speed for about 2 minutes until they were fully mixed with the dry materials. The mortar mixture was then poured into a steel mold, placed on a vibrating table and vibrated for 2 minutes. The excess mortar mixture above the surface of the mold was scraped off and smoothed. The test pieces were numbered and placed in a dry place for 1 day before demolding. They were then cured at room temperature for 3 days and 7 days before being tested.

[0048] Example 2

[0049] The specific steps for preparing unsaturated polyester resin mortar are as follows:

[0050] Test blocks were prepared according to the JC / T 2381-2016 industry standard for repair mortar building materials. Cement (540 g) and standard sand (1350 g) were placed in a mixing pot and premixed at low speed for 30 s. At the same time, UPE resin (324 g) and MEKP (6.48 g) were poured into a beaker and stirred for 30 s. After the cementitious materials were evenly mixed, they were poured into the mixing pot and stirred at low speed for about 2 minutes until fully mixed with the dry materials. The mortar mixture was then poured into a steel mold, placed on a vibrating table and vibrated for 2 minutes. The excess mortar mixture above the surface of the mold was scraped off and smoothed. The test pieces were numbered and placed in a dry place for 1 day before demolding. They were then cured at room temperature for 3 days and 7 days before being tested.

[0051] Example 3

[0052] The specific steps for preparing unsaturated polyester mortar are as follows:

[0053] Test blocks were prepared according to the JC / T 2381-2016 industry standard for repair mortar building materials. Cement (540 g) and standard sand (1350 g) were placed in a mixing pot and premixed at low speed for 30 s. At the same time, UPE (324 g) and MEKP (9.72 g) were poured into a beaker and stirred for 30 s. After the cementitious materials were evenly mixed, they were poured into the mixing pot and stirred at low speed for about 2 minutes until fully mixed with the dry materials. The mortar mixture was then poured into a steel mold, placed on a vibrating table and vibrated for 2 minutes. The excess mortar mixture above the mold surface was scraped off and smoothed. The test pieces were numbered and placed in a dry place for 1 day before demolding. They were then cured at room temperature for 3 days and 7 days before being tested.

[0054] Example 4

[0055] The specific steps for preparing unsaturated polyester resin mortar are as follows:

[0056] Test blocks were prepared according to the JC / T 2381-2016 industry standard for repair mortar building materials. Cement (540 g), standard sand (1215 g), and copper slag (135 g) were placed in a mixing pot and premixed at low speed for 30 s. At the same time, UPE resin (324 g) and MEKP (6.48 g) were poured into a beaker and stirred for 30 s. After the cementitious materials were evenly mixed, they were poured into the mixing pot and stirred at low speed for about 2 minutes until fully mixed with the dry materials. The mortar mixture was then poured into a steel mold, placed on a vibrating table and vibrated for 2 minutes. The excess mortar mixture above the mold surface was scraped off and smoothed. The test pieces were numbered and placed in a dry place for 1 day before demolding. They were then cured at room temperature for 3 days and 7 days before being tested.

[0057] Example 5

[0058] The specific steps for preparing unsaturated polyester resin mortar are as follows:

[0059] Test blocks were prepared according to the JC / T 2381-2016 industry standard for repair mortar building materials. Cement (540 g), standard sand (1080 g), and copper slag (270 g) were placed in a mixing pot and premixed at low speed for 30 s. At the same time, UPE resin (324 g) and MEKP (6.48 g) were poured into a beaker and stirred for 30 s. After the cementitious materials were evenly mixed, they were poured into the mixing pot and stirred at low speed for about 2 minutes until fully mixed with the dry materials. The mortar mixture was then poured into a steel mold, placed on a vibrating table and vibrated for 2 minutes. The excess mortar mixture above the mold surface was scraped off and smoothed. The test pieces were numbered and placed in a dry place for 1 day before demolding. They were then cured at room temperature for 3 days and 7 days before being tested.

[0060] Example 6

[0061] The specific steps for preparing unsaturated polyester resin mortar are as follows:

[0062] Test blocks were prepared according to the JC / T 2381-2016 industry standard for repair mortar building materials. Cement (270 g), iron slag (270 g), standard sand (1080 g), and copper slag (270 g) were placed in a mixing pot and premixed at low speed for 30 s. At the same time, UPE resin (324 g) and MEKP (6.48 g) were poured into a beaker and stirred for 30 s. After the cementitious materials were evenly mixed, they were poured into the mixing pot and stirred at low speed for about 2 minutes until fully mixed with the dry materials. The mortar mixture was then poured into a steel mold, placed on a vibrating table and vibrated for 2 minutes. The excess mortar mixture above the mold surface was scraped off and smoothed. The test pieces were numbered and placed in a dry place for 1 day before demolding. They were then cured at room temperature for 3 days and 7 days before being tested.

[0063] Example 7

[0064] The specific steps for preparing unsaturated polyester resin mortar are as follows:

[0065] Test blocks were prepared according to the JC / T 2381-2016 industry standard for repair mortar building materials. Cement (135 g), iron slag (405 g), standard sand (1080 g), and copper slag (270 g) were placed in a mixing pot and premixed at low speed for 30 s. At the same time, UPE resin (324 g) and MEKP (6.48 g) were poured into a beaker and stirred for 30 s. After the cementitious materials were evenly mixed, they were poured into the mixing pot and stirred at low speed for about 2 minutes until fully mixed with the dry materials. The mortar mixture was then poured into a steel mold, placed on a vibrating table and vibrated for 2 minutes. The excess mortar mixture above the mold surface was scraped off and smoothed. The test pieces were numbered and placed in a dry place for 1 day before demolding. They were then cured at room temperature for 3 days and 7 days before being tested.

[0066] Example 8

[0067] The specific steps for preparing unsaturated polyester resin mortar are as follows:

[0068] Test blocks were prepared according to the JC / T 2381-2016 industry standard for repair mortar building materials. Cement (540 g) and standard sand (1350 g) were placed in a mixing pot and premixed at low speed for 30 s. At the same time, UPE resin (388.8 g) and MEKP (7.78 g) were poured into a beaker and stirred for 30 s. After the cementitious materials were evenly mixed, they were poured into the mixing pot and stirred at low speed for about 2 minutes until fully mixed with the dry materials. The mortar mixture was then poured into a steel mold, placed on a vibrating table and vibrated for 2 minutes. After that, the excess mortar mixture above the surface of the mold was scraped off and smoothed. The test pieces were numbered and placed in a dry place for 1 day before demolding. They were then cured at room temperature for 3 days and 7 days before being tested.

[0069] Performance testing and characterization of unsaturated polyester resin mortar repair materials:

[0070] (1) Curing time test: Refer to the curing time test in the "Technical Specification for Epoxy Resin Mortar" (DL / T 5193-2004), and use the stirring time of unsaturated polyester resin mortar to indirectly represent the curing time.

[0071] (2) Mortar fluidity test: The test was conducted in accordance with the "Method for Determination of Flowability of Cement Mortar" (GB / T 2419-2005), and the test instrument was the NLD-3 type cement mortar fluidity tester.

[0072] (3) Mortar mechanical property test: The test shall be conducted in accordance with the "Test Method for Strength of Cement Mortar" (GB / T 17671-2021), using a mortar with a size of 40×40×160 mm. 3 The flexural strength of the rectangular specimens was tested. After the flexural strength test, two half specimens were taken out and compressive strength tests were conducted at 3 days, 7 days, and 28 days using a computer-controlled electronic compression testing machine.

[0073] (4) Mortar bond strength test: Referring to "Repair Mortar" (JC / T 2381-2016), the interfacial flexural strength was used as the evaluation index, and the age of the concrete specimens was 7 days. The substrate test block set up in the experiment was ordinary cement mortar (compressive strength of 40MPa).

[0074] (5) Test of water absorption rate of specimens: The test shall be conducted in accordance with the Test Procedure for Polymer Modified Cement Mortar (DL / T 5126-2001).

[0075] (6) Porosity test of specimens: The mortar specimens were analyzed using the AutoPore IV 9500 high-performance fully automatic mercury porosimeter from Micromeritics, USA.

[0076] (7) Non-isothermal differential scanning calorimetry (DSC): The curing behavior of UPE resin was tested using a DSC 25 differential scanning calorimeter from TA Instruments, Inc., USA. The experimental conditions were: temperature range 0 ℃~250 ℃, heating rate 10 ℃ / min, and nitrogen atmosphere.

[0077] (8) Thermogravimetric analysis: The test was conducted using a Netzsch TG 209 F3 Tarsus thermogravimetric analyzer. The experimental conditions were: the test temperature range was from room temperature to 1000 ℃, the heating rate was 10 ℃ / min, and the atmosphere was nitrogen.

[0078] (9) Scanning electron microscopy analysis (microstructure / energy dispersive spectroscopy): The images were taken using a German ZEISS Gemini 300 field emission scanning electron microscope with an accelerating voltage of 3 kV. Gold sputtering was performed using an Oxford Quorum SC7620 sputtering coating instrument with a gold-palladium alloy target.

[0079] Experimental Results and Analysis

[0080] (1) Curing time

[0081] Examples 1, 2, and 3 all show that the curing time of the mortar gradually decreases as the amount of initiator (stirring time) increases. Figure 3Example 3 shows that the excessive initiator significantly increased the rate of free radical generation, thereby accelerating the polymerization reaction and shortening the workable time, which is suitable for rapid repair environments. Therefore, the amount of initiator can be reasonably controlled to achieve the construction objective based on different construction effects and conditions.

[0082] (2) Mortar fluidity

[0083] With the increase of copper slag and iron slag content, the fluidity of the mortar gradually increases. Figure 4 This is mainly because copper and iron slag have high density, large specific surface area, and small particle size, which fills the voids between large particles in the mortar, increasing the mortar's density and reducing friction and resistance between large particles. Comparing Examples 7 and 8, there was no significant difference in the spreadability of the mortar. It can be seen that under the same target mortar flowability, the addition of industrial waste slag can significantly reduce the amount of unsaturated polyester resin used. Therefore, the appropriate dosage of copper and iron slag can improve mortar fluidity, which is beneficial for construction and reduces mortar costs.

[0084] (3) Mechanical properties of mortar

[0085] Flexural strength of unsaturated polyester resin mortar repair material

[0086] Depend on Figure 5 It can be seen that the 3-day flexural strengths of the unsaturated polyester resin mortars in Examples 2 (without industrial waste residue), 4 (copper slag replacing 10% of the standard sand mass), 5 (copper slag replacing 20% ​​of the standard sand mass), 6 (copper slag replacing 20% ​​of the standard sand mass and iron slag replacing 50% of the cement mass), and 7 (copper slag replacing 20% ​​of the standard sand mass and iron slag replacing 75% of the cement mass) are 27.38 MPa, 28.77 MPa, 27.63 MPa, 27.21 MPa, and 27.83 MPa, respectively, with no significant difference in flexural strength among the five examples.

[0087] The 7-day flexural strengths of specimens from Examples 2, 4, 5, 6, and 7 were 29.40 MPa, 30.86 MPa, 30.35 MPa, 28.67 MPa, and 28.08 MPa, respectively. Compared with Example 2, the flexural strength of specimen 4 increased by 5.0%, that of specimen 5 increased by 3.2%, that of specimen 6 decreased by 2.5%, and that of specimen 5 decreased by 4.5%, but the differences among the five were not significant.

[0088] The 28-day flexural strengths of specimens from Examples 2, 4, 5, 6, and 7 were 37.65 MPa, 36.83 MPa, 35.10 MPa, 34.62 MPa, and 34.47 MPa, respectively. Compared with Example 2, the flexural strength of specimen 4 decreased by 2.2%, that of specimen 5 decreased by 6.8%, that of specimen 6 decreased by 8.0%, and that of specimen 7 decreased by 8.4%.

[0089] The results of the flexural strength test showed that the addition of copper slag and iron slag had no significant effect on the flexural strength of the mortar specimens. The addition of copper slag and iron slag did not affect the mechanical properties of the mortar, indicating that it is feasible to replace some siliceous materials with copper slag and iron slag.

[0090] The compressive strength of unsaturated polyester resin mortar repair material

[0091] Depend on Figure 6 It can be seen that the 3-day compressive strengths of specimens from Examples 2, 4, 5, 6, and 7 are 95.26 MPa, 93.14 MPa, 94.13 MPa, 95.53 MPa, and 96.12 MPa, respectively. Compared with Example 2, the compressive strength of specimen 4 decreased by 2.2%, the compressive strength of specimen 5 decreased by 1.2%, the compressive strength of specimen 6 increased by 0.3%, and the compressive strength of specimen 7 increased by 0.9%. The differences among the five examples are not significant.

[0092] The 7-day compressive strengths of specimens from Examples 2, 4, 5, 6, and 7 were 102.06 MPa, 98.81 MPa, 100.50 MPa, 105.12 MPa, and 106.02 MPa, respectively. Compared with Example 2, the compressive strength of specimen 4 decreased by 3.2%, and that of specimen 5 decreased by 1.5%, with no significant difference among the three. The compressive strength of specimen 6 increased by 3.0%, and that of specimen 7 increased by 3.9%, both significantly higher than those of Examples 4 and 5.

[0093] The 28-day compressive strengths of specimens from Examples 2, 4, 5, 6, and 7 were 103.06 MPa, 104.83 MPa, 106.04 MPa, 108.23 MPa, and 110.19 MPa, respectively. Compared with Example 2, the compressive strength of specimen 4 increased by 1.7%, and that of specimen 5 increased by 2.9%, with no significant difference among the three. The compressive strength of specimen 6 increased significantly by 5.0%, and that of specimen 7 increased by 6.9%, showing a significant improvement over the compressive strengths of the other examples.

[0094] The compressive strength test results show that copper slag and iron slag partially replace siliceous materials, giving the mortar better compressive strength. This is because the smaller industrial waste particles, encapsulated by polymers, fill the pores of the mortar, altering its pore structure. Therefore, industrial solid waste can significantly improve the compressive strength of mortar without affecting its flexural strength, thus reducing the raw material cost of repair mortar.

[0095] mortar bond strength

[0096] Depend on Figure 7 It can be seen that, using ordinary cement mortar as the substrate, the 7-day interfacial flexural tensile strengths of the unsaturated polyester resin mortars in Examples 2, 5, and 7 were 4.08 MPa, 4.16 MPa, and 5.84 MPa, respectively. Compared with Example 2, the interfacial flexural tensile strength of the specimen in Example 5 showed no significant difference, while the interfacial flexural tensile strength of the specimen in Example 7 was significantly increased by 43.14%. Meanwhile, the failure surfaces of the bonded specimens were all located on the substrate, indicating that the unsaturated polyester resin mortar has good bonding performance, exceeding the strength of the substrate specimen. The incorporation of copper slag and iron slag further enhances the mortar's bonding performance, making it suitable for repairing most concrete structures.

[0097] (4) Water absorption rate test

[0098] Depend on Figure 8 It can be seen that the cured unsaturated polyester resin fills the pores of the mortar in the form of particles, resulting in a decrease in the water absorption rate of the unsaturated polyester resin mortar. With the increase of copper slag and iron slag content, the water absorption rate of the specimens decreases. This is because the fineness of copper slag and iron slag is small, which plays a role in filling the pores, thereby reducing the porosity of the mortar.

[0099] (5) Mercury porosimetry experiment

[0100] Mercury intrusion porosimetry is the most commonly used analytical method for testing the pore structure of mortar specimens. Figure 9 As shown in Table 4, the porosity of the specimen in Example 2 was 4.46%, and the average pore size was 65.5 nm. The porosity of the specimen in Example 5 was 3.13% lower than that in Example 2, and its average pore size was 60.6 nm, a decrease of 7.5% compared to the average pore size of Example 2. The porosity of the specimen in Example 7 was 15.47% lower than that in Example 2, and the average pore size was 9.0% lower. These results indicate that the reasonable incorporation of copper slag and iron slag can improve the pore structure of unsaturated polyester resin mortar, reducing its pore radius and resulting in a more reasonable pore structure distribution.

[0101] (6) DSC analysis of unsaturated polyester resin

[0102] Curing curves of unsaturated polyester resins with different initiator dosages are shown below. Figure 10 As shown in Table 5, the curing temperatures of unsaturated polyester resins are as follows. The DSC curves of UPE resins with different initiator dosages all exhibit a strong exothermic peak, indicating that the unsaturated polyester resins underwent a cross-linking curing reaction. With increasing curing agent dosage, the exothermic peak temperature of the cured resin shifts to lower temperatures. The exothermic enthalpy and degree of cure of the cured and uncured resins were calculated using the DSC curves (formulas are as follows). The results show that the unsaturated polyester resins cured relatively completely, forming a tight cross-linked network. Figure 10 ).

[0103]

[0104] In the formula: △H cured and △H uncured These are the exothermic enthalpies, J / g, of the cured and uncured portions of the unsaturated polyester resin, respectively.

[0105] (7) Thermogravimetric analysis

[0106] Depend on Figure 11 It can be seen that the mass loss of unsaturated polyester resin cured at 100℃ is less than 1%, and the mass change is about -0.62%. The TG curve remains almost flat before 300℃, and the obvious mass loss stage begins at 346.4℃. After that, the curve drops sharply and then tends to be horizontal again after 430℃. About 90% of the material by mass is decomposed. The total mass change of the material before 300℃ is less than 5%, which shows that UPE resin has good thermal stability and durability.

[0107] (8) Microscopic morphology analysis and energy spectrum scanning

[0108] Figure 12 In this context, a, b, and c correspond to Examples 2, 5, and 7, respectively. From... Figure 12 In specimen a1, fine pores were observed between the aggregates and were evenly distributed. Its porosity was slightly higher than that of other specimens. The Fe element content in the mortar was 4.4%. Figure 12 (a2) Figure 12 In sample b1, it can be observed that the aggregate has good internal bonding and significantly reduced porosity. At this point, the Fe element content in the mortar is 11.0%, and the Fe element in the mortar is distributed in local clusters, which can be inferred to be copper slag particles. Figure 12 (b2) Figure 12 As can be seen in c1, the matrix is ​​more compact, the porosity is reduced, and its mechanical properties are significantly improved. At this time, the proportion of Fe element in the mortar is 20.8%, which is 9.8% higher than that in Example 5. The Fe element in the mortar is distributed in a large-scale blocky pattern. Figure 12 (c2) can be identified as the presence of both copper slag and iron slag particles, further optimizing the pore structure of the mortar.

[0109] Table 1 Chemical composition of cement

[0110]

[0111] Table 2 Chemical composition of copper slag

[0112]

[0113] Table 3 Chemical composition of iron ore slag

[0114]

[0115] Table 4 Pore parameters of unsaturated polyester resin mortar

[0116]

[0117] Table 5 Curing Temperature of Unsaturated Polyester Resins

[0118]

[0119] Note: T onest This is the initial temperature at which the resin cures. T max This is the highest temperature reached during the resin curing process. T end This is the temperature at which the resin curing process ends.

[0120] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. An unsaturated polyester resin mortar repair material, characterized in that: The unsaturated polyester resin mortar repair material is composed of unsaturated polyester resin, cement, standard sand, copper slag, and iron slag. Unsaturated polyester resin acts as a cementitious material, accounting for 10% to 20% of the total mortar mass. Cement, standard sand, copper slag, and iron slag are collectively referred to as fillers, accounting for 80% to 90% of the total mass. The sum of the mass fractions of the cementitious material and the fillers is 100%. Cement accounts for 5% to 30% of the filler mass, and standard sand accounts for 50% to 80% of the filler mass. The unsaturated polyester resin is synthesized using phthalic anhydride and diol as the main raw materials, with styrene as the solvent. The resin viscosity is 200~300 mPa‧s, the gelation time is 15~25 min, the solid content is 57%~63%, and the acid value is 18~24 mg KOH / g. A composite cobalt accelerator accounting for 3 wt% of the total resin mass is added. 1%~3% of 2-butanone peroxide by mass of the unsaturated polyester resin is also weighed and mixed evenly. Then, it is added to a mixture of cement, standard sand, copper slag and iron slag, and stirred evenly to obtain the unsaturated polyester resin mortar repair material.

2. The unsaturated polyester resin mortar repair material according to claim 1, characterized in that: The main components of the composite cobalt accelerator are cobalt octate, dimethylaniline, and stabilizer, wherein the mass of cobalt octate accounts for 1.6% of the composite cobalt accelerator.

3. The unsaturated polyester resin mortar repair material according to claim 1, characterized in that: The copper slag mentioned above is copper smelting waste residue with a specific surface area of ​​912 m². 2 / kg, density is 3.91 g / cm³ 3 The particle size distribution ranges from 0.283 μm to 563.677 μm, with an average particle size of 56.37 μm.

4. The unsaturated polyester resin mortar repair material according to claim 1, characterized in that: The iron slag mentioned above is waste slag from iron smelting, with a specific surface area of ​​902 m². 2 / kg, density is 3.24 g / cm³ 3 The particle size distribution ranges from 0.314 μm to 859 μm, with an average particle size of 400 μm.

5. A method for preparing the unsaturated polyester resin mortar repair material according to claim 1, characterized in that: Includes the following steps: (1) Weigh cement, standard sand, copper slag and iron slag, and add them to the mortar mixing pot. Mix at low speed for 30 seconds to obtain the filler mixture. (2) Weigh unsaturated polyester resin and 2-butanone peroxide, prepare a gelling material according to the ratio, stir manually for 30 s until uniform, add to the filler mixture, continue to stir at low speed for 2 min, and obtain unsaturated polyester resin mortar repair material.

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