Epoxy resin mortar as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of underwater concrete structure surface repairing, and particularly provides a preparation method of epoxy resin mortar, which comprises the following steps: a preposition step: determining the optimal ratio of each component according to a calculation method; the method comprises the following steps: step 1, weighing cement and river sand as dry materials according to an optimal proportion determined by calculation; step 2, adding part of the weighed dry materials into a stirring pot, and stirring for 3 minutes; 3, according to the optimal proportion determined through calculation, epoxy resin and a diluent are added into the stirring pot to be stirred and mixed, and stirring is conducted for 5 min; 4, according to the optimal proportion determined through calculation, a curing agent is added into the stirring pot to be stirred and mixed, and stirring is conducted for 3 min; and step 5, according to the optimal ratio determined by calculation, adding the remaining dry material into the stirring pot, and stirring for 2 minutes to obtain the epoxy resin mortar which has excellent underwater non-dispersity, has higher early strength than ordinary cement mortar, and has an adhesive property far better than that of underwater non-dispersible concrete.

Description

Technical Field

[0001] The present invention belongs to the technical field of underwater concrete structure surface repair, and in particular relates to an epoxy resin mortar, a preparation method and application thereof. Background Art

[0002] Currently, underwater concrete structure repair materials mostly use underwater non-dispersible concrete and adhesives. However, underwater non-dispersible concrete has problems such as low strength, weak bonding performance, and poor chemical resistance. Adhesives have problems such as high pollution, difficult construction, and high cost.

[0003] The current trenchless underwater pile foundation repair processes mainly include cofferdam method, structural reinforcement method, grouting method and filling method. The cofferdam method is currently used for repair and reinforcement. However, for the actual riverbed, if the bottom is not cleaned, there will be a large amount of gravel. At present, the bottom sealing of pile foundation repair construction has always been a major pain point. The bottom sealing of conventional cofferdam construction often uses materials to be poured and hardened before sealing. Such construction technology has the problem of material waste before the material hardens, and the fixation of the cofferdam often requires anchoring operations on the concrete pile foundation to be repaired. This fixing method has the problem of damage to the original structure.

[0004] Based on this, the present invention provides an epoxy resin mortar, a preparation method and application thereof to solve the above problems. Summary of the Invention

[0005] In order to overcome the deficiencies of the prior art, the present invention provides an epoxy resin mortar, a preparation method and an application thereof, to solve the problems in the prior art.

[0006] One embodiment of the present invention provides a method for preparing epoxy resin mortar, comprising the following steps:

[0007] Step S00: Determine the optimal ratio between the components according to the calculation method;

[0008] Step S10: Weigh cement and river sand as dry materials according to the optimal ratio determined by calculation;

[0009] Step S20: adding the weighed dry material into the stirring pot and stirring for 3 minutes;

[0010] Step S30: adding epoxy resin and diluent into a stirring pot according to the optimal ratio determined by calculation, stirring and mixing for 5 minutes;

[0011] Step S40: Add the curing agent to the stirring pot according to the optimal ratio determined by calculation, and stir and mix for 3 minutes;

[0012] Step S50: According to the optimal ratio determined by calculation, the remaining dry materials are added to the stirring pot and stirred for 2 minutes to obtain epoxy resin mortar.

[0013] In one embodiment, the epoxy resin is a glycidyl ether epoxy resin.

[0014] In one embodiment, the glycidyl ether epoxy resin is bisphenol A glycidyl ether resin, including E44 epoxy resin and E51 epoxy resin.

[0015] In one embodiment, the diluent is a reactive diluent;

[0016] The active diluent is selected from butyl glycidyl ether V501 diluent, or

[0017] Two diluents, butyl glycidyl ether V501 and benzyl glycidyl ether RX-692, were selected.

[0018] In one embodiment, the curing agent is a modified fatty amine epoxy resin curing agent;

[0019] The modified fatty amine epoxy resin curing agent is selected from either W93 curing agent or TV7135 curing agent.

[0020] In one embodiment, the dosage of the curing agent is calculated as follows:

[0021]

[0022] Wherein, ω(α) is the mass fraction of amine curing agent required for 100 mass fractions of epoxy resin; ε is the molecular mass of amine; β is the number of active hydrogen atoms in the amine molecule; and δ is the epoxy value.

[0023] The present invention also relates to an epoxy resin mortar, which is prepared by using any one of the methods described above.

[0024] The present invention also relates to an application of the epoxy resin mortar prepared by the above method in an underwater non-development pile foundation casting process, wherein the casting process comprises the following steps:

[0025] Step 1: Clean and roughen the pile foundation to be repaired;

[0026] Step 2: Place the casting mold to form a casting space between the pile foundation and the casting mold and isolate external water;

[0027] Step 3: Drain the casting space and drain the water into the casting mold so that the casting mold can keep the casting space sealed under the action of water gravity;

[0028] Step 4: pouring the prepared epoxy resin mortar into the pouring space to repair the pile foundation surface;

[0029] Step 5: After the epoxy resin mortar solidifies, remove the formwork to complete the pile foundation repair.

[0030] In one embodiment, the casting mold comprises:

[0031] a hard rubber inner layer, a hard rubber outer layer, and a soft rubber bottom layer;

[0032] The soft rubber bottom layer connects the hard rubber inner layer and the hard rubber outer layer, so that an accommodating space is formed between the hard rubber outer layer and the hard rubber inner layer.

[0033] In one embodiment, in step 3, when draining the casting space, the water in the casting space is drained into the receiving space of the casting mold, and the water level inside the receiving space must be higher than the external water level or flush with the external water level;

[0034] In the step 4, when pouring the pouring space, the height of the poured epoxy resin mortar needs to be higher than the height of the hard rubber inner layer.

[0035] The epoxy resin mortar, preparation method and application provided in the above embodiments have the following beneficial effects:

[0036] 1. The epoxy resin mortar prepared by the present invention has excellent underwater non-dispersibility, and its early strength is higher than that of ordinary cement mortar. Its bonding performance is far better than that of underwater non-dispersible concrete. Its excellent working performance also makes its construction much easier than adhesives.

[0037] 2. The epoxy resin mortar prepared by the present invention is suitable for construction scenarios with different repair volumes. It also has good underwater non-dispersion, causing less water pollution. Its compressive strength, flexural strength, and bond strength are far superior to those of ordinary cement mortar. At the same strength, its fluidity is far superior to that of ordinary cement mortar.

[0038] 3. The amount of curing agent used in the epoxy resin mortar prepared by the present invention is calculated using a stoichiometric formula, thereby reducing the waste of curing agent and overcoming the problem of insufficient curing of the epoxy resin caused by inaccurate curing agent dosage in traditional mix ratios.

[0039] 4. The epoxy resin mortar prepared by the present invention is used in underwater trenchless pile foundation casting processes, overcoming the material waste and damage to the original structure associated with traditional trenchless construction processes. Furthermore, it enables rapid repair of pile foundations, resulting in high early strength, strong impact resistance, and excellent durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0041] Figure 1 The compressive strength test results of the epoxy resin mortar provided in the embodiment of the present invention;

[0042] Figure 2 The test results of the flexural strength of the epoxy resin mortar provided in the embodiment of the present invention;

[0043] Figure 3 The wet bond strength test results of the epoxy resin mortar provided in the embodiment of the present invention;

[0044] Figure 4 The initial setting, final setting and operable time of the epoxy resin mortar provided in the embodiment of the present invention;

[0045] Figure 5 A schematic diagram of step 2 of the casting process provided by an embodiment of the present invention;

[0046] Figure 6 A schematic diagram of step three of the casting process provided by an embodiment of the present invention;

[0047] Figure 7 A schematic diagram of step 4 of the casting process provided in an embodiment of the present invention;

[0048] Figure 8 A schematic diagram of step five of the casting process provided by an embodiment of the present invention;

[0049] Figure 9 Schematic diagram of the PVC mold in the experimental example of the present invention;

[0050] Figure 10 Schematic diagram of a demoulding concrete column in an experimental example of the present invention;

[0051] Figure 11 Schematic diagram of the figure eight mold cast in the experimental example of the present invention;

[0052] Figure 12 Schematic diagram of the cutting groove of the concrete column in the experimental example of the present invention;

[0053] Figure 13 Schematic diagram of the experimental casting mold in the experimental example of the present invention;

[0054] Figure 14 This is a schematic diagram of the simulated actual trenchless riverbed environment in the experimental example of the present invention;

[0055] Figure 15 This is a record of demoulding and slurry leakage in the experimental example of the present invention;

[0056] Figure 16 This is a cross-sectional view of the epoxy resin mortar prepared in Example 1 after repair in the experimental example of the present invention;

[0057] Figure 17 This is a cross-sectional view after repair using the epoxy resin mortar prepared in Example 2 in the experimental example of the present invention;

[0058] Figure 18 Schematic diagram of casting the figure-eight bonded test block in the experimental example of the present invention;

[0059] Figure 19 Schematic diagram of compression testing performed using an MTS universal testing machine in an experimental example of the present invention;

[0060] Figure 20 Schematic diagram of the bonding strength test in the experimental example of the present invention;

[0061] Figure 21 The results of the compression test in the experimental example of the present invention;

[0062] Figure 22 The figures are the bonding strength test results in the experimental examples of the present invention.

[0063] Figure Number:

[0064] 1. Pile foundation to be repaired; 2. Hard rubber inner layer; 3. Hard rubber outer layer; 4. Soft rubber base layer; 5. Riverbed bottom; 6. Water; 7. Repair material. DETAILED DESCRIPTION

[0065] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0066] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0067] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0068] One embodiment of the present invention provides a method for preparing epoxy resin mortar, and the specific preparation method includes the following steps:

[0069] Step S00: Determine the optimal ratio between the components according to the calculation method;

[0070] Step S10: Weigh cement and river sand as dry materials according to the optimal ratio determined by calculation;

[0071] Step S20: adding the weighed dry material into the stirring pot and stirring for 3 minutes;

[0072] Step S30: adding epoxy resin and diluent into a stirring pot according to the optimal ratio determined by calculation, stirring and mixing for 5 minutes;

[0073] Step S40: Add the curing agent to the stirring pot according to the optimal ratio determined by calculation, and stir and mix for 3 minutes;

[0074] Step S50: According to the optimal ratio determined by calculation, the remaining dry materials are added to the stirring pot and stirred for 2 minutes to obtain epoxy resin mortar.

[0075] Preferably, the epoxy resin is a glycidyl ether epoxy resin.

[0076] Preferably, the glycidyl ether epoxy resin is bisphenol A glycidyl ether resin, including E44 epoxy resin and E51 epoxy resin.

[0077] Preferably, the diluent is a reactive diluent; the reactive diluent is selected from butyl glycidyl ether V501 diluent, or butyl glycidyl ether V501 diluent and benzyl glycidyl ether RX-692 diluent.

[0078] Preferably, the curing agent is a modified fatty amine epoxy resin curing agent; the modified fatty amine epoxy resin curing agent is selected from either W93 curing agent or TV7135 curing agent.

[0079] Preferably, the dosage of the curing agent is calculated as follows:

[0080]

[0081] Wherein, ω(α) is the mass fraction of amine curing agent required for 100 mass fractions of epoxy resin; ε is the molecular mass of amine; β is the number of active hydrogen atoms in the amine molecule; and δ is the epoxy value.

[0082] All raw materials used in the examples of the present invention were purchased from the market.

[0083] The epoxy resin mortar mix ratio in the embodiment of the present invention is as follows:

[0084] The epoxy resins selected are bisphenol A glycidyl ether resins E44 and E51.

[0085] As the diluent, two active diluents are selected: butyl glycidyl ether V501 diluent and benzyl glycidyl ether RX-692 diluent.

[0086] The curing agent is selected from two modified fatty amine curing agents: W93 curing agent and VT7135 curing agent.

[0087] The cement selected is P.O42.5R early strength cement.

[0088] The sand selected is natural river sand with medium specifications.

[0089] Among them, the amount of curing agent is calculated using the stoichiometric formula, which reduces the waste of curing agent and overcomes the problem of inaccurate curing agent dosage in traditional mix ratios, resulting in insufficient curing of epoxy resin.

[0090]

[0091] The following is an introduction through specific embodiments:

[0092] Example 1:

[0093] Step S00:

[0094] The orthogonal design method was used to determine the composition ratio of each group: epoxy resin (E44, E51): cement: river sand: diluent (butyl glycidyl ether V501): curing agent (TV7135) = 1:2:3:0.07:0.48395 (mass ratio). The curing agent dosage was calculated using a stoichiometric formula.

[0095] Step S10:

[0096] According to the determined ratio, 600g of cement and 900g of river sand were weighed as dry materials and divided into two equal parts.

[0097] Step S20:

[0098] Add the weighed first portion of dry material into the stirring pot and stir at 200 r / min for 3 minutes.

[0099] Step S30:

[0100] According to the determined ratio, 300 g of mixed epoxy resin (150 g each of E44 and E51) and 21 g of diluent (butyl glycidyl ether V501) were added and stirred at 200 r / min for 5 min.

[0101] Step S40:

[0102] According to the determined ratio, 145.2 g of curing agent (TV7135) was added and stirred at 200 r / min for 3 minutes.

[0103] For the calculation of curing agent dosage, according to the curing agent dosage formula:

[0104]

[0105] Setting parameters:

[0106] Epoxy value δ = 0.51 (mixed value of E44 and E51).

[0107] TV7135 curing agent parameters: amine molecular mass ε = 210, number of active hydrogen atoms β = 4.

[0108] Calculated:

[0109] ω(α)=210×0.51 / 4=26.78%.

[0110] That is, 26.78 parts of TV7135 curing agent are required for every 100 parts of epoxy resin. In this embodiment, the total amount of epoxy resin is 1.0 part, so the actual amount of curing agent used is 0.48395 part.

[0111] 300g×0.48395≈145.2g.

[0112] Step S50:

[0113] The remaining dry materials were added into the stirring pot and stirred at 200 r / min for 2 min before discharging to obtain epoxy resin mortar.

[0114] Example 2:

[0115] Step S00:

[0116] The orthogonal design method was used to determine the composition ratio of each group: epoxy resin (E44, E51): cement: river sand: diluent (butyl glycidyl ether V501 + benzyl glycidyl ether RX-692): curing agent (W93) = 1:2:3:0.07:0.314 (mass ratio). The curing agent dosage was calculated using a stoichiometric formula.

[0117] Step S10:

[0118] According to the determined ratio, 600g of cement and 900g of river sand were weighed as dry materials and divided into two equal parts.

[0119] Step S20:

[0120] Add the weighed first portion of dry material into the stirring pot and stir at 200 r / min for 3 minutes.

[0121] Step S30:

[0122] According to the determined ratio, 300 g of mixed epoxy resin (150 g each of E44 and E51) and 21 g of diluent (14.1 g of butyl glycidyl ether V501 diluent + 6.9 g of benzyl glycidyl ether RX-692 diluent) were added and stirred at 200 r / min for 5 min.

[0123] Step S40:

[0124] According to the determined ratio, 94.2 g of curing agent (W93) was added and stirred at 200 r / min for 3 minutes.

[0125] For the calculation of curing agent dosage, according to the curing agent dosage formula:

[0126]

[0127] Setting parameters:

[0128] Epoxy value δ = 0.51 (mixed value of E44 and E51).

[0129] W93 curing agent parameters: amine molecular weight ε = 180, number of active hydrogen atoms β = 4.

[0130] Calculated:

[0131] ω(α)=180×0.51 / 4=22.95%.

[0132] That is, 22.95 parts of W93 curing agent are required for every 100 parts of epoxy resin. In this embodiment, the total amount of epoxy resin is 1.0 part, so the actual amount of curing agent used is 0.314 part.

[0133] 300g×0.314=94.2g.

[0134] Step S50:

[0135] The remaining dry materials were added into the stirring pot and stirred at 200 r / min for 2 min before discharging to obtain epoxy resin mortar.

[0136] Comparative Example 1:

[0137] Ordinary cement mortar was prepared with a ratio of water: cement: river sand = 1:2:3.

[0138] Comparative Example 2:

[0139] The rapid-hardening cement mortar was prepared with a ratio of water: cement: river sand: curing agent: water reducing agent = 1.28:4:5.95:0.2:0.06.

[0140] (1)Reference Figures 1-4 The epoxy resin mortar prepared in Example 1 of the present invention has a strength test result (MPa) of:

[0141] 7d compressive strength is as high as 84.58MPa;

[0142] 7d flexural strength is as high as 32.27MPa;

[0143] 28d compressive strength is as high as 86.24MPa;

[0144] 28d flexural strength is as high as 32.54MPa;

[0145] The 7d wet bond strength to concrete substrate is as high as 3.21MPa;

[0146] The 28d wet bond strength of the mortar is as high as 3.78MPa;

[0147] The fluidity is 205mm;

[0148] The operating time is 262.5 minutes.

[0149] (2)Reference Figures 1-4 The epoxy resin mortar prepared in Example 2 of the present invention has a strength test result (MPa) of:

[0150] 7d compressive strength is as high as 90.37MPa;

[0151] 7d flexural strength is as high as 28.59MPa;

[0152] 28d compressive strength is as high as 81.83MPa;

[0153] 28d flexural strength is as high as 31.29MPa;

[0154] The 7d wet bond strength to concrete substrate is as high as 3.90MPa;

[0155] The 28d wet bond strength of the mortar is as high as 3.27MPa;

[0156] The fluidity is 210mm;

[0157] The operating time is 10.5 minutes.

[0158] (3) The strength test results (MPa) of the ordinary cement mortar prepared in Comparative Example 1 when naturally cured are as follows:

[0159] 7d flexural strength is 4.99MPa;

[0160] 28d flexural strength is 5.81MPa;

[0161] 7d compressive strength is 21.23MPa;

[0162] The 28d compressive strength is 30.44MPa;

[0163] 7d wet bond strength is 0.04MPa;

[0164] The 28d wet bond strength is 0.05MPa.

[0165] (4) The strength test results (MPa) of the rapid-hardening cement mortar prepared in Comparative Example 2 when naturally cured are as follows:

[0166] The 7d compressive strength is about 45MPa;

[0167] The 28d compressive strength is about 55MPa;

[0168] The 7d flexural strength is about 6MPa;

[0169] The 28d flexural strength is about 7MPa;

[0170] The 7d wet bond strength is about 2.5MPa;

[0171] The 28d wet bond strength is about 2.75MPa.

[0172] As can be seen from the above, the epoxy resin mortars prepared in the two different embodiments are suitable for construction scenarios with different repair volumes. Furthermore, they exhibit good underwater non-dispersion, causing minimal water pollution. Their compressive strength, flexural strength, and bond strength are far superior to those of ordinary cement mortar. At the same strength, their fluidity is far superior to that of ordinary cement mortar.

[0173] In Examples 1 and 2, by compounding E44 and E51 epoxy resins (0.5 parts each) and adjusting the viscosity with a diluent (692 / 501), a highly permeable slurry can be formed that can tightly bond to concrete surfaces (including wet surfaces).

[0174] In Example 1, TV7135 curing agent (0.48 parts) is used, and in Example 2, W93 curing agent (0.31 parts) is used. Both are compatible with the epoxy resin system and form a dense cross-linked structure after curing. The interfacial bonding strength can reach more than 3.2 MPa, which is significantly better than ordinary cement-based mortar (0.05-2.75 MPa).

[0175] In Example 1 and Example 2, by using cement (2 parts) and river sand (3 parts) as rigid aggregates and epoxy resin as a flexible bonding phase, the compressive strength can reach more than 80 MPa and the flexural strength can reach more than 28 MPa, with both rigidity and toughness.

[0176] Example 3:

[0177] Provided is an application of the epoxy resin mortar prepared by the above method in an underwater non-development pile foundation casting process, wherein the casting process comprises the following steps (refer to Figure 5-Figure 8 ):

[0178] Step 1: Clean and roughen the pile foundation to be repaired;

[0179] For example, the surface of the pile foundation can be cleaned and roughened by high-pressure water gun.

[0180] Step 2: Place the casting mold to form a casting space between the pile foundation and the casting mold and isolate the external water, such as Figure 5 As shown;

[0181] The casting mold consists of a hard rubber inner layer, a hard rubber outer layer, and a soft rubber bottom layer. The soft rubber bottom layer connects the hard rubber inner layer and the hard rubber outer layer, creating a space between the hard rubber outer layer and the hard rubber inner layer. This space is used to pour epoxy resin mortar to repair the pile foundation surface.

[0182] Step 3: Drain the casting space and drain the water into the casting mold so that the casting mold can keep the casting space sealed under the action of water gravity. Figure 6 As shown;

[0183] When draining, a water pump can be used to drain water into the mold's holding space in order to secure the mold. This is done by using the water's gravity to press the mold's bottom surface (soft rubber base) against the riverbed surface, keeping the resulting casting space sealed. The soft rubber base is designed to allow the mold to adapt to varying riverbed surface conditions, achieving a better seal (sealing the casting space).

[0184] When draining the casting space, drain the water into the mold's containment space. The water level inside the containment space must be higher than or even with the external water level. This is to prevent the mold from floating due to insufficient gravity, which could result in a leaky casting space.

[0185] Step 4: Pour the prepared epoxy resin mortar into the pouring space to repair the pile foundation surface, such as Figure 7 As stated;

[0186] When pouring the pouring space, the height of the poured epoxy resin mortar needs to be higher than the height of the hard rubber inner layer, that is, poured until it overflows. This is to avoid undrained moisture in the pouring space, which can achieve better repair results.

[0187] Step 5: After the epoxy resin mortar is cured, remove the formwork to complete the pile foundation repair. Figure 8 shown.

[0188] Experimental example (the verification test process of Example 3), taking the 110mm diameter pile foundation repair simulation as an example:

[0189] The difference between the verification test design and the casting process design is that the inner and outer hard rubber layers are replaced with hard PVC pipes. The process of the process verification test is as follows:

[0190] (1) Casting (making) concrete columns for repair.

[0191] A PVC mold with dimensions of 110 mm × 300 mm × 3.2 mm (outer diameter × height × thickness) is used. Figure 9 As shown, in order to facilitate demoulding, the mold is longitudinally grooved. Before pouring, the mold is sealed and fastened with waterproof tape and metal clamps.

[0192] After the concrete is evenly mixed, it is poured. The concrete curing method is natural curing. After curing for 7 days, it is demoulded and ready for use. Figure 10 .

[0193] Among them, in order to evaluate the bonding strength between epoxy repair mortar and concrete column, concrete slurry (without coarse and fine aggregates) was used to cast the eight-shaped mold, such as Figure 11 As shown, it is used for the subsequent casting of figure eight test blocks.

[0194] (2) Prefabricated grooving.

[0195] After the concrete column reaches 7 days old, the grooving treatment is carried out. The grooving arrangement is: thin shallow groove, thin deep groove, rough shallow groove and rough deep groove (the grooving dimensions refer to the "Technical Specification for Detection and Evaluation of Defects in Hydraulic Concrete Structures" (DL / T 5251-2010) and the "Technical Requirements for Repair and Reinforcement of Underwater Defects in Hydraulic Structures" (T / CDSA 600.2-2021) for the width standards of cracks above Class D and the depth standards of prefabricated grooves. The prefabricated groove dimensions are: thin groove width 3mm, rough groove width 1cm, shallow groove depth 4mm, deep groove depth 1.2cm). Figure 12 The figure shows the concrete column after cutting.

[0196] (3) Make a test casting mold.

[0197] A 140mm x 300mm x 4.0mm (outer diameter x height x thickness) PVC pipe was used to simulate the "inner hard rubber" in the casting mold. (The repair thickness was 4.3cm, which is less than 5cm, as specified in the Technical Requirements for Underwater Defect Repair and Reinforcement of Hydraulic Structures (T / CDSA 600.2-2021).

[0198] A PVC pipe of 250 mm × 300 mm × 5 mm (outer diameter × height × thickness) was used to simulate the “outer hard rubber” in the casting mold.

[0199] A soft rubber with a thickness of 10 mm was used to simulate the "soft rubber bottom layer" in the casting mold.

[0200] Acrylic plates are further used to fix and position the mold as a whole to prevent the mold from tilting when the repair material is poured;

[0201] The test casting mold made is as follows Figure 13 shown.

[0202] (4) Casting and repairing.

[0203] Use water tank to simulate underwater pouring repair, such as Figure 14 As shown, concrete columns are placed in the water tank, and coarse aggregate is laid on the bottom of the water tank to simulate the actual trenchless riverbed environment.

[0204] The specific steps are:

[0205] Step 1 (base surface treatment):

[0206] Use high-pressure water gun to clean the surface of concrete columns.

[0207] Step 2 (Mold Installation):

[0208] Connect the inner and outer PVC pipes through a soft rubber base to create a circular casting space. Secure the mold with acrylic sheet. Place the mold inside the water tank to fit the concrete column.

[0209] Step 3 (drainage sealing):

[0210] A water pump is used to drain the water in the casting space to the accommodation space between the inner and outer PVC pipes, and the water level is level with the outside of the mold.

[0211] Step 4 (pouring construction):

[0212] The epoxy resin mortar prepared in Example 1 or Example 2 is poured into the gap between the inner PVC pipe and the concrete column. During pouring, the height of the epoxy resin mortar needs to be higher than the height of the hard rubber inner layer, and then the mortar is compacted by its own weight.

[0213] Step 5 (mold removal and maintenance):

[0214] After 1 day, demoulding was carried out and leakage photos were recorded. Figure 15 ;

[0215] Use an electric cutting machine to cut the repair test block (concrete column repaired with epoxy resin mortar) into the same height, and then record the filling condition of the prefabricated cut groove. Figure 16 and Figure 17 The repaired areas of both epoxy resin mortars increased by 62.341%. The repaired specimens were then placed in water for curing for 28 days.

[0216] Among them, in step 4, the eight-shaped bonding test block is cast in the eight-shaped mold at the same time, such as Figure 18 As shown, and natural curing is carried out until 28 days.

[0217] When the repaired test block and the eight-shaped bonding test block are cured for 28 days, the compressive strength and bonding strength tests are carried out. Figure 19 and Figure 20 As shown, refer to Figure 21 and Figure 22 , which is the test result. Figure 21 In the test, the blank cement mortar is the figure-eight bonding test block.

[0218] Reference Figure 21 The failure loads of the two epoxy resin mortars increased by 95.536% and 68.126% respectively. Combined with the slice photos of the repaired concrete columns, it can be found that the bubbles in the material may weaken the reinforcement effect of the epoxy resin repair material.

[0219] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing epoxy resin mortar, characterized in that: The steps include: Step S00: Determine the optimal ratio between the components according to the calculation method; Step S10: Weigh cement and river sand as dry materials according to the optimal ratio determined by calculation; Step S20: adding the weighed dry material into the stirring pot and stirring for 3 minutes; Step S30: adding epoxy resin and diluent into a stirring pot according to the optimal ratio determined by calculation, stirring and mixing for 5 minutes; Step S40: Add the curing agent to the stirring pot according to the optimal ratio determined by calculation, and stir and mix for 3 minutes; Step S50: According to the optimal ratio determined by calculation, the remaining dry materials are added to a stirring pot and stirred for 2 minutes to obtain epoxy resin mortar.

2. The method for preparing the epoxy resin mortar according to claim 1, wherein: The epoxy resin is selected from glycidyl ether epoxy resin.

3. The method for preparing the epoxy resin mortar according to claim 2, wherein: The glycidyl ether epoxy resin is selected from bisphenol A glycidyl ether resin, including E44 epoxy resin and E51 epoxy resin.

4. The method for preparing the epoxy resin mortar according to claim 1, wherein: The diluent is a reactive diluent; The active diluent is selected from butyl glycidyl ether V501 diluent, or Two diluents, butyl glycidyl ether V501 and benzyl glycidyl ether RX-692, were selected.

5. The method for preparing the epoxy resin mortar according to claim 1, wherein: The curing agent is a modified fatty amine epoxy resin curing agent; The modified fatty amine epoxy resin curing agent is selected from either W93 curing agent or TV7135 curing agent.

6. The method for preparing the epoxy resin mortar according to claim 5, wherein: The calculation formula for the amount of the curing agent is: Wherein, ω(α) is the mass fraction of amine curing agent required for 100 mass fractions of epoxy resin; ε is the molecular mass of amine; β is the number of active hydrogen atoms in the amine molecule; and δ is the epoxy value.

7. An epoxy resin mortar, characterized in that: The method is prepared according to any one of claims 1 to 6.

8. An application of the epoxy resin mortar prepared by the method according to any one of claims 1 to 6 in an underwater non-development pile foundation casting process, characterized in that: The steps of the pouring process are: Step 1: Clean and roughen the pile foundation to be repaired; Step 2: Place the casting mold to form a casting space between the pile foundation and the casting mold and isolate external water; Step 3: Drain the casting space and drain the water into the casting mold so that the casting mold can keep the casting space sealed under the action of water gravity; Step 4: pouring the prepared epoxy resin mortar into the pouring space to repair the pile foundation surface; Step 5: After the epoxy resin mortar solidifies, remove the formwork to complete the pile foundation repair.

9. The pouring process according to claim 8, characterized in that: The casting mold comprises: a hard rubber inner layer, a hard rubber outer layer, and a soft rubber bottom layer; The soft rubber bottom layer connects the hard rubber inner layer and the hard rubber outer layer, so that an accommodating space is formed between the hard rubber outer layer and the hard rubber inner layer.

10. The pouring process according to claim 9, characterized in that: In the step 3, when draining the casting space, the water in the casting space is drained into the receiving space of the casting mold, and the water level inside the receiving space must be higher than the external water level or flush with the external water level; In the step 4, when pouring the pouring space, the height of the poured epoxy resin mortar needs to be higher than the height of the hard rubber inner layer.

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