Epoxy polymer modified cement mortar

Abstract

The invention discloses an epoxy polymer modified cement mortar, which belongs to the technical field of engineering materials, and comprises the following components: a defoamer, a water reducing agent, a thixotropic agent, cement, fine aggregate, an epoxy curing agent, an epoxy emulsion and water; the epoxy emulsion comprises the following components: an epoxy resin, a cationic emulsifier and water. The invention uses a cationic emulsifier to emulsify and modify the epoxy resin, so that the emulsified epoxy emulsion is alkaline, and the epoxy emulsion obtained by emulsification can maintain excellent stability in use, and while the cement mortar is easy to construct, the cement mortar can also have good adhesion to the outer wall of the steel pipe, and the cement mortar layer formed on the outer wall of the steel pipe can maintain good anti-corrosion performance for a long time, and the bonding strength between the cement mortar and the post-cast concrete can also be improved, so that the post-cast concrete can be tightly combined with the steel pipe through the cement mortar anti-corrosion layer.

Description

Technical Field

[0001] The invention relates to the technical field of engineering materials, and in particular to an epoxy polymer modified cement mortar. Background Art

[0002] In the planning and project establishment of modern cities, raw water pipelines, domestic water pipelines, tunnel lining steel pipes, buried pipelines and other pipelines (generally steel pipes) need to be cast with concrete and other materials and buried in the ground. However, after the pipeline is buried in the ground, when the pipeline is used for a long time, there will be poor interlayer adhesion, hollowing, stratification and other problems between the outer wall of the pipeline and the concrete. At this time, the outer wall of the steel pipe is easily corroded by air, moisture, soil, etc., causing the steel pipe to rust and oxidize, which will reduce the service life of the steel pipe.

[0003] In order to solve the above problems, the existing practice is usually to spray epoxy powder on the wall of the steel pipe in advance in the steel pipe production enterprise, so that the epoxy powder forms an anti-corrosion coating on the wall of the steel pipe. However, when the steel pipe sprayed with epoxy powder is installed in the tunnel, the gap between the tunnel wall and the outer wall of the steel pipe needs to be filled with concrete, but the bonding strength between the epoxy powder coating and the grouting concrete is poor, which will lead to poor bonding between the steel pipe and the grouting concrete, and the problems of hollowing and cracking will still occur, which cannot effectively solve the problem of rust and oxidation of the steel pipe.

[0004] There are also measures to make the steel pipe anti-corrosion by constructing cement mortar on the wall of the steel pipe. In order to improve the waterproof performance and anti-penetration ability of the cement mortar, emulsion is added to the cement mortar. However, the existing emulsions are mostly acrylic emulsions, and cement has a strong alkalinity, which can easily demulsify the acidic emulsion. The emulsion has poor stability during use, which makes it difficult to construct cement mortar and reduces the bonding strength between the steel pipe and concrete.

[0005] It can be seen that the existing technology still needs to be improved and enhanced. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide an epoxy polymer modified cement mortar, aiming to solve the problem of poor stability of the existing cement mortar emulsion in cement mortar and to improve the bonding ability between steel pipe and concrete.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] An epoxy polymer modified cement mortar comprises the following components in parts by weight:

[0009] 0.01-0.05 parts of defoamer, 0.1-0.5 parts of water reducer, 50-60 parts of water, 50-70 parts of cement, 100-140 parts of fine aggregate, and 100-120 parts of epoxy curing agent and epoxy emulsion in total;

[0010] The epoxy emulsion comprises the following components by weight:

[0011] 90-95 parts of epoxy resin, 5-10 parts of cationic emulsifier, and 40-50 parts of water.

[0012] Preferably, the cationic emulsifier is a propyltrimethylammonium chloride emulsifier.

[0013] Preferably, the propyltrimethylammonium chloride emulsifier is at least one of 2,3-epoxypropyltrimethylammonium chloride and methacryloylpropyltrimethylammonium chloride.

[0014] Preferably, the ratio of the epoxy curing agent to the epoxy emulsion in parts by weight is 1:(0.8-1.2).

[0015] Preferably, the epoxy polymer modified cement mortar further comprises the following components in parts by weight:

[0016] Thixotropic agent: 1.0 to 4.0 parts.

[0017] Preferably, the thixotropic agent comprises bentonite and fumed silica; the ratio of bentonite to fumed silica in parts by weight is 1:(1.0-2.0).

[0018] Preferably, the epoxy curing agent is at least one of aliphatic diamines, polyamines, and aromatic polyamines.

[0019] Preferably, the epoxy resin is at least one of epoxy resin E-51, epoxy resin E-44, and epoxy resin E-12.

[0020] Preferably, the water reducer is at least one of a polycarboxylate water reducer, a lignin sulfonate water reducer and an aminosulfonate water reducer.

[0021] The beneficial effects of the present invention are as follows: the present invention provides an epoxy polymer modified cement mortar, by using a cationic emulsifier to emulsify and modify the epoxy resin, so that the emulsified epoxy emulsion is alkaline, and the alkaline epoxy emulsion is introduced into the cement mortar system, the cationic emulsifier is not easy to fail, and the epoxy emulsion can maintain excellent stability in use, so that when the epoxy emulsion is introduced into the cement mortar system, the cement mortar will not have the problem of agglomeration, and while making the cement mortar easy to construct, the cement mortar can also have good adhesion to the outer wall of the steel pipe, the cement mortar layer formed on the outer wall of the steel pipe can maintain good anti-corrosion performance for a long time, and the bonding strength between the cement mortar and the later poured concrete can also be improved, so that the concrete can be tightly combined with the steel pipe through the cement mortar anti-corrosion layer, which can effectively reduce the tendency of concrete cracking and avoid the outer wall of the steel pipe from being corroded by air, moisture, soil, etc. DETAILED DESCRIPTION

[0022] The present invention provides an epoxy polymer modified cement mortar. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0023] The present invention provides an epoxy polymer modified cement mortar, comprising the following components in parts by weight:

[0024] 0.01-0.05 parts of defoamer, 0.1-0.5 parts of water reducer, 50-60 parts of water, 50-70 parts of cement, 100-140 parts of fine aggregate, and 100-120 parts of epoxy curing agent and epoxy emulsion in total;

[0025] The epoxy emulsion comprises the following components by weight:

[0026] 90-95 parts of epoxy resin, 5-10 parts of cationic emulsifier, and 40-50 parts of water.

[0027] Among the above components, cement and fine aggregate are the main components of cement mortar, among which cement can play a bonding role, which can combine fine aggregate and water to form a solid structure; while fine aggregate can fill the gap between cement and water, increase the volume of cement mortar, and thus reduce the cost of cement mortar. The main component of epoxy emulsion is epoxy resin, and epoxy resin is emulsified and modified by cationic emulsifier to obtain epoxy emulsion. Since cationic emulsifier has hydrophilic group and hydrophobic group that can combine with epoxy resin, and hydrophilic group is positively charged, after cationic emulsifier emulsifies epoxy resin, the epoxy emulsion obtained can be alkaline, and the pH value of epoxy emulsion is 8.0-9.5.

[0028] When alkaline epoxy emulsion is introduced into the cement mortar system, the cationic emulsifier is not easy to fail, and the epoxy emulsion can maintain excellent stability in use. Therefore, when the epoxy emulsion is introduced into the cement mortar system, the cement mortar will not have the problem of caking. While making the cement mortar easy to construct, it can also make the cement mortar have good adhesion to the outer wall of the steel pipe, and the waterproof performance and anti-penetration ability of the cement mortar can be maintained at a better level, so that the cement mortar layer formed on the outer wall of the steel pipe can maintain good anti-corrosion performance for a long time, and the bonding strength between the cement mortar and the post-poured concrete can also be improved, so that the concrete can be closely combined with the steel pipe through the cement mortar anti-corrosion layer, which can effectively reduce the tendency of concrete cracking and avoid the outer wall of the steel pipe from being corroded by air, moisture, soil, etc.

[0029] Among the above components, the epoxy curing agent reacts with the emulsified modified epoxy resin to form a dense network cross-linked structure, thereby improving the mechanical properties of the cement mortar and enhancing the anti-penetration ability of the cement mortar, and can effectively block the water from penetrating into the surface of the steel pipe after the tunnel seepage, so that the steel pipe is isolated from the external moisture, the anti-corrosion ability of the steel pipe can be improved, and the service life of the steel pipe can also be extended. The water reducer can reduce the viscosity of the cement mortar and improve the fluidity of the cement mortar. When the cement mortar with good fluidity is constructed on the wall of the steel pipe, the fine aggregate and cement in the cement mortar can be better arranged, and the gaps between the particles can be reduced, so that a denser structure can be formed after the cement mortar is cured, so that the waterproof performance and anti-penetration ability of the cement mortar are further enhanced.

[0030] Preferably, the cationic emulsifier is a propyltrimethylammonium chloride emulsifier. The hydrophilic part of the propyltrimethylammonium chloride emulsifier is a positively charged ammonium group. Compared with other positively charged groups, the ammonium group can more effectively electrostatically attract negatively charged oil droplets or solid surfaces. This electrostatic attraction enhances the stability of the oil droplets. The oil droplets are formed by the epoxy resin under the shear force of the high-speed disperser. Therefore, the ammonium group adsorbed on the epoxy resin oil droplets can wrap up the epoxy resin, so that the epoxy emulsion has long-term storage stability, and the emulsion is not prone to demulsification and stratification; when the epoxy emulsion is added to the cement mortar system, the epoxy emulsion can maintain excellent stability in use.

[0031] In addition, the positively charged ammonium groups can form hydrogen bonds and ionic bonds, which can increase the bonding strength of cement mortar.

[0032] The hydrophobic part of propyltrimethylammonium chloride emulsifier is a long-chain hydrocarbon group, which can form a more complex three-dimensional network structure during the cross-linking process with epoxy resin. This structure can effectively disperse the externally applied stress, thereby improving the bonding strength, compressive strength and other mechanical properties of cement mortar.

[0033] Preferably, the propyl trimethyl ammonium chloride emulsifier is at least one of 2,3-epoxypropyl trimethyl ammonium chloride and methacryloyl propyl trimethyl ammonium chloride. More preferably, the propyl trimethyl ammonium chloride emulsifier is 2,3-epoxypropyl trimethyl ammonium chloride. Since 2,3-epoxypropyl trimethyl ammonium chloride itself has epoxy groups, the epoxy groups can also undergo cross-linking reactions with epoxy resins during the emulsification modification process, forming a dense network cross-linking structure, thereby improving and enhancing the mechanical properties and anti-penetration ability of cement mortar.

[0034] Preferably, the ratio of the epoxy curing agent and the epoxy emulsion in parts by weight is 1: (0.8-1.2). When the amount of epoxy emulsion is too small, the epoxy group fails to completely react with the epoxy curing agent, and unreacted epoxy curing agent will remain in the cement mortar. The unreacted epoxy curing agent will affect the mechanical properties of the cement mortar and reduce the bonding strength between the cement mortar and the steel pipe and concrete. When the amount of epoxy emulsion is too large, the coating formed by the curing of the cement mortar is soft, and the mechanical properties of the cement mortar will also decrease. The present invention can effectively improve the mechanical properties and anti-corrosion properties of the cement mortar by controlling the dosage ratio of the epoxy curing agent and the epoxy emulsion within the above range.

[0035] Preferably, the epoxy polymer modified cement mortar further comprises the following components in parts by weight: 1.0 to 4.0 parts of thixotropic agent.

[0036] When cement mortar is sprayed on the outer wall of a steel pipe, the cement mortar usually needs to be sprayed to a thickness of 1000 to 1500 microns, and cement mortar at this thickness is prone to sagging. In order to solve the sagging problem of cement mortar during construction, the present invention introduces a thixotropic agent into the cement mortar so that the cement mortar has suitable thixotropy during the construction stage, and the sagging problem of cement mortar during construction can be improved.

[0037] Preferably, the thixotropic agent includes bentonite and fumed silica. When the cement mortar is just sprayed onto the (outer) wall of the steel pipe, the cement mortar has a high water content and a large polarity, and the bentonite provides the cement mortar with thixotropy; in the later stage of construction, the water content of the cement mortar decreases and the polarity is low, and the fumed silica provides the cement mortar with thixotropy. Therefore, the composite use of cement mortar and fumed silica can ensure that the sagging problem of cement mortar can be improved during the entire construction process.

[0038] The present invention has found through experiments that when the amount of thixotropic agent and the ratio of bentonite and fumed silica in parts by weight are within the above range, the cement mortar will not show obvious sagging during the construction process, and the cement mortar coating formed on the wall of the steel pipe can be evenly distributed, thereby ensuring that the bonding strength between the cement mortar and the steel pipe and concrete will not decrease.

[0039] Preferably, the epoxy curing agent may be at least one of aliphatic diamines, polyamines, and aromatic polyamines. The epoxy resin may be at least one of epoxy resin E-51, epoxy resin E-44, and epoxy resin E-12. The water reducer may be at least one of polycarboxylic acid water reducer, lignin sulfonate water reducer, and aminosulfonate water reducer.

[0040] The present invention provides a method for preparing epoxy polymer modified cement mortar, comprising the following steps:

[0041] S1: Weigh 0.01-0.05 parts of defoamer, 0.1-0.5 parts of water reducer, 1.0-4.0 parts of thixotropic agent, 50-60 parts of water, 50-70 parts of cement, 100-140 parts of fine aggregate, and 100-120 parts of epoxy curing agent and epoxy emulsion in total and place them in a mortar mixer;

[0042] S2: After the above raw materials are weighed, they are stirred at a speed of 25-35 r / min for 4 minutes to obtain epoxy polymer modified cement mortar.

[0043] The present invention also provides a method for preparing an epoxy emulsion, comprising the following steps:

[0044] R1: Weigh 90-95 parts of epoxy resin, 5-10 parts of cationic emulsifier, and 40-50 parts of water into a reaction vessel and heat to 50-60°C;

[0045] R2: Keep the temperature at 50-60℃ and use a high-speed disperser at a speed of 2000-8000r / min for 4-5min;

[0046] R3: After dispersion, the material is naturally cooled to room temperature and discharged to obtain the epoxy emulsion.

[0047] In order to further illustrate the epoxy polymer modified cement mortar provided by the present invention, the following examples and comparative examples are provided.

[0048] Example 1

[0049] This embodiment provides an epoxy polymer modified cement mortar, comprising the following components in parts by weight:

[0050] 0.01 parts of defoamer, 0.1 parts of polycarboxylate water reducer, 1.0 parts of bentonite, 1.0 parts of fumed silica, 50 parts of water, 50 parts of cement, 100 parts of fine aggregate, 56 parts of epoxy curing agent, 44 parts of epoxy emulsion;

[0051] The epoxy emulsion consists of the following components:

[0052] Epoxy resin E-51 90 parts, 2,3-epoxypropyltrimethylammonium chloride 5 parts, water 40 parts.

[0053] Example 2

[0054] This embodiment provides an epoxy polymer modified cement mortar, comprising the following components in parts by weight:

[0055] 0.05 parts of defoamer, 0.5 parts of lignin sulfonate water reducer, 0.5 parts of bentonite, 0.5 parts of fumed silica, 60 parts of water, 70 parts of cement, 140 parts of fine aggregate, 55 parts of epoxy curing agent, and 64 parts of epoxy emulsion;

[0056] The epoxy emulsion consists of the following components:

[0057] Epoxy resin E-44 95 parts, methacryloylpropyltrimethylammonium chloride 10 parts, water 50 parts.

[0058] Example 3

[0059] This embodiment provides an epoxy polymer modified cement mortar, comprising the following components in parts by weight:

[0060] 0.03 parts of defoamer, 0.3 parts of aminosulfonate water reducing agent, 2.0 parts of bentonite, 2.0 parts of fumed silica, 55 parts of water, 60 parts of cement, 120 parts of fine aggregate, 55 parts of epoxy curing agent, and 55 parts of epoxy emulsion;

[0061] The epoxy emulsion consists of the following components:

[0062] Epoxy resin E-12 92 parts, 2,3-epoxypropyltrimethylammonium chloride 8 parts, water 45 parts.

[0063] Comparative Example 1

[0064] This comparative example provides an epoxy polymer modified cement mortar, comprising the following components in parts by weight:

[0065] 0.01 parts of defoamer, 0.1 parts of polycarboxylate water reducer, 1.0 parts of bentonite, 1.0 parts of fumed silica, 50 parts of water, 50 parts of cement, 100 parts of fine aggregate, 56 parts of epoxy curing agent, 44 parts of epoxy emulsion;

[0066] The epoxy emulsion consists of the following components:

[0067] Epoxy resin E-51 80 parts, 2,3-epoxypropyltrimethylammonium chloride 5 parts, water 40 parts.

[0068] Comparative Example 2

[0069] This comparative example provides an epoxy polymer modified cement mortar, comprising the following components in parts by weight:

[0070] 0.01 parts of defoamer, 0.1 parts of polycarboxylate water reducer, 1.0 parts of bentonite, 1.0 parts of fumed silica, 50 parts of water, 50 parts of cement, 100 parts of fine aggregate, 56 parts of epoxy curing agent, 44 parts of epoxy emulsion;

[0071] The epoxy emulsion consists of the following components:

[0072] Epoxy resin E-51 90 parts, 2,3-epoxypropyltrimethylammonium chloride 3 parts, water 40 parts.

[0073] Comparative Example 3

[0074] This comparative example provides an epoxy polymer modified cement mortar, comprising the following components in parts by weight:

[0075] 0.01 parts of defoamer, 0.1 parts of polycarboxylate water reducer, 1.0 parts of bentonite, 1.0 parts of fumed silica, 50 parts of water, 50 parts of cement, 100 parts of fine aggregate, 56 parts of epoxy curing agent, 44 parts of epoxy emulsion;

[0076] The epoxy emulsion consists of the following components:

[0077] Epoxy resin E-51 90 parts, dodecyl ammonium chloride 5 parts, water 40 parts.

[0078] Comparative Example 4

[0079] This comparative example provides an epoxy polymer modified cement mortar, comprising the following components in parts by weight:

[0080] 0.01 parts of defoamer, 0.1 parts of polycarboxylate water reducer, 1.0 parts of bentonite, 1.0 parts of fumed silica, 50 parts of water, 50 parts of cement, 100 parts of fine aggregate, 63 parts of epoxy curing agent, and 37 parts of epoxy emulsion;

[0081] The epoxy emulsion consists of the following components:

[0082] Epoxy resin E-51 90 parts, 2,3-epoxypropyltrimethylammonium chloride 5 parts, water 40 parts.

[0083] Comparative Example 5

[0084] This comparative example provides an epoxy polymer modified cement mortar, comprising the following components in parts by weight:

[0085] 0.01 parts of defoamer, 0.1 parts of polycarboxylate water reducer, 1.0 parts of bentonite, 1.0 parts of fumed silica, 50 parts of water, 50 parts of cement, 100 parts of fine aggregate, 42 parts of epoxy curing agent, 58 parts of epoxy emulsion;

[0086] The epoxy emulsion consists of the following components:

[0087] Epoxy resin E-51 90 parts, 2,3-epoxypropyltrimethylammonium chloride 5 parts, water 40 parts.

[0088] Comparative Example 6

[0089] This comparative example provides an epoxy polymer modified cement mortar, comprising the following components in parts by weight:

[0090] 0.01 parts of defoamer, 0.1 parts of polycarboxylate water reducer, 0.6 parts of bentonite, 1.4 parts of fumed silica, 50 parts of water, 50 parts of cement, 100 parts of fine aggregate, 56 parts of epoxy curing agent, 44 parts of epoxy emulsion;

[0091] The epoxy emulsion consists of the following components:

[0092] Epoxy resin E-51 90 parts, 2,3-epoxypropyltrimethylammonium chloride 5 parts, water 40 parts.

[0093] Comparative Example 7

[0094] This comparative example provides an epoxy polymer modified cement mortar, comprising the following components in parts by weight:

[0095] 0.01 parts of defoamer, 0.1 parts of polycarboxylate water reducer, 1.3 parts of bentonite, 0.7 parts of fumed silica, 50 parts of water, 50 parts of cement, 100 parts of fine aggregate, 56 parts of epoxy curing agent, 44 parts of epoxy emulsion;

[0096] The epoxy emulsion consists of the following components:

[0097] Epoxy resin E-51 90 parts, 2,3-epoxypropyltrimethylammonium chloride 5 parts, water 40 parts.

[0098] Performance Testing

[0099] The epoxy polymer modified cement mortar provided in Examples 1 to 3 and Comparative Examples 1 to 7 was sprayed onto the outer wall of the steel pipe using a high-pressure sprayer. The spraying condition of the cement mortar and the appearance of the cement mortar coating formed on the outer wall of the steel pipe after curing were observed visually. The results are shown in Table 1.

[0100] The mechanical properties of the epoxy polymer modified cement mortars provided in Examples 1 to 3 and Comparative Examples 1 to 7 were tested, and the mechanical property test items included adhesion (7d), compressive strength (7d), and compressive strength (28d). The test results are shown in Table 2.

[0101] Among them, the standard for cement mortar adhesion test items is: GB / T5210-2006 "Pull-off adhesion test for paint and varnish";

[0102] The 7-day compressive strength test of cement mortar is based on the standard: GB / T 17671-2021 "Test method for strength of cement mortar";

[0103] The standard for the 28-day compressive strength test of cement mortar is: GB / T 17671-2021 "Test method for strength of cement mortar".

[0104] The epoxy polymer modified cement mortars provided in Examples 1 to 3 and Comparative Examples 1 to 7 were tested for their permeability coefficient (28d) and neutral salt spray resistance to characterize the anti-corrosion properties (waterproofness and anti-penetration ability) of the cement mortars. The test results are shown in Table 3.

[0105] Among them, the permeability coefficient (28d) test is based on the standard: DL / T 5150-2017 "Test Procedures for Hydraulic Concrete"

[0106] The neutral salt spray resistance test is based on the standard: GB / 1771-2007 "Determination of neutral salt spray resistance of paints and varnishes".

[0107] Performance test results analysis:

[0108] From the observation results in Table 1, it can be seen that the cement mortar provided in Comparative Example 2 has agglomeration phenomenon when used. This is because in the epoxy polymer modified cement mortar system provided in Comparative Example 2, the amount of cationic emulsifier in the epoxy emulsion is relatively small; when the amount of cationic emulsifier is relatively small, the epoxy resin cannot be emulsified and modified, resulting in poor storage stability of the epoxy emulsion and easy stratification. The introduction of such epoxy emulsion into the cement mortar system will make the cement mortar have poor stability in use and easy caking problems;

[0109] The cement mortar provided in Comparative Example 3 has a caking phenomenon when used. This is because in the epoxy polymer modified cement mortar system provided in Comparative Example 3, the cationic emulsifier in the epoxy emulsion is dodecyl ammonium chloride; the length of the hydrocarbon chain in the molecular structure of dodecyl ammonium chloride is longer than the hydrocarbon chain in the molecular structure of 2,3-epoxypropyltrimethylammonium chloride and methacryloylpropyltrimethylammonium chloride; and the presence of long-chain hydrocarbon groups will increase the viscosity of the epoxy emulsion, thereby affecting the storage stability and use stability of the epoxy emulsion;

[0110] The cement mortar provided in Comparative Examples 6 and 7 has sagging phenomenon during spraying, and the surface of the cement mortar coating is uneven and has slight cracks. This is because the dosage ratio of the two thixotropic agents, bentonite and fumed silica, is not optimal, so it is impossible to ensure that the sagging problem of the cement mortar can be improved during the entire construction process and that the cement mortar can be evenly sprayed onto the outer wall of the steel pipe;

[0111] However, there is a sagging problem during the construction of cement mortar. The surface of the cement mortar coating is uneven, cracked and has bubbles, which will further affect the mechanical properties and anti-corrosion ability of the cement mortar. From the test results of Table 2 and Table 3, it can be seen that the adhesion (7d), compressive strength (7d, 28d), permeability coefficient (28d) and neutral salt spray resistance of the cement mortars provided in Comparative Examples 2, 3, 6 and 7 are not as good as those provided in Examples 1 to 3.

[0112] From the test results in Table 2, it can be seen that the mechanical properties of the cement mortars prepared in Examples 1 to 3 all meet the requirements specified in various testing standards, wherein the (7-day) adhesion of the cement mortars prepared in Examples 1 to 3 to the steel is greater than 3 MPa, proving that the epoxy polymer-modified cement mortar has high bonding strength and can be tightly combined with the steel pipe and poured concrete, thereby effectively reducing the tendency of concrete cracking and preventing the outer wall of the steel pipe from being corroded by air, moisture, soil, etc., thereby helping to extend the service life of the steel pipe;

[0113] In the epoxy polymer modified cement mortar system provided in Comparative Example 1, the amount of epoxy resin in the epoxy emulsion is less than that in Example 1. After the cement mortar under this formula system is cured, the cement mortar coating is soft and has poor density. Therefore, the test results of various mechanical properties, permeability coefficient, and neutral salt spray resistance are not as good as the cement mortars provided in Examples 1 to 3.

[0114] The epoxy polymer modified cement mortar system provided in Comparative Example 4 has various mechanical property test results, permeability coefficient, and neutral salt spray resistance test results that are not as good as the cement mortars provided in Examples 1 to 3. This is because in the cement mortar formula system of Comparative Example 4, the amount of epoxy curing agent used is too large, resulting in unreacted epoxy curing agent remaining in the cement mortar;

[0115] However, the epoxy polymer modified cement mortar system provided in Comparative Example 5 has various mechanical property test results, as well as permeability coefficient and neutral salt spray resistance test results that are not as good as the cement mortars provided in Examples 1 to 3. This is because in the cement mortar formula system of Comparative Example 5, the amount of epoxy emulsion used is too large, which makes the coating formed by the curing of the cement mortar soft, and the mechanical properties and anti-corrosion properties of the cement mortar are reduced.

[0116] Table 1:

[0117] Cement mortar spraying Cement mortar coating appearance Example 1 Cement mortar has no caking and no sagging Smooth, no cracks, no bubbles Example 2 Cement mortar has no caking and no sagging Smooth, no cracks, no bubbles Example 3 Cement mortar has no caking and no sagging Smooth, no cracks, no bubbles Comparative Example 1 Cement mortar has no lumps and no sagging Smooth, no cracks, no bubbles Comparative Example 2 The cement mortar is agglomerated and there is no sagging when spraying. The surface is uneven, cracked, or has bubbles. Comparative Example 3 The cement mortar is agglomerated and there is no sagging when spraying. The surface is uneven, cracked, or has bubbles. Comparative Example 4 Cement mortar has no lumps and no sagging Smooth, no cracks, no bubbles Comparative Example 5 Cement mortar has no lumps and no sagging Smooth, no cracks, no bubbles Comparative Example 6 Cement mortar has no lumps and has sagging phenomenon when sprayed The surface is uneven, with slight cracks and no bubbles Comparative Example 7 Cement mortar has no lumps and has sagging phenomenon when sprayed The surface is uneven, with slight cracks and no bubbles

[0118] Table 2:

[0119] Adhesion 7d, pull-off method (steel) (MPa) Compressive strength 7d (MPa) Compressive strength 28d (MPa) Example 1 3.4 30.5 48.6 Example 2 3.2 30.2 48.5 Example 3 3.4 30.5 48.7 Comparative Example 1 2.9 27.2 46.5 Comparative Example 2 2.5 23 42.8 Comparative Example 3 2.7 24.8 43.5 Comparative Example 4 2.8 28.2 46.2 Comparative Example 5 2.9 28.6 46.2 Comparative Example 6 2.6 24.3 43.5 Comparative Example 7 2.9 24.5 44.2 Standard technical requirements ≥3 ≥25 ≥45

[0120] Table 3:

[0121] Permeability coefficient 28d (cm / s) Neutral salt spray resistance Example 1 <![CDATA[3.14x10 -13 ]]> Level 1 Example 2 <![CDATA[2.85x10 -13 ]]> Level 1 Example 3 <![CDATA[3.02x10 -13 ]]> Level 1 Comparative Example 1 <![CDATA[3.52x10 -13 ]]> Level 2 Comparative Example 2 <![CDATA[3.92x10 -13 ]]> Level 2 Comparative Example 3 <![CDATA[3.85x10 -13 ]]> Level 2 Comparative Example 4 <![CDATA[3.64x10 -13 ]]> Level 2 Comparative Example 5 <![CDATA[3.61x10 -13 ]]> Level 2 Comparative Example 6 <![CDATA[3.54x10 -13 ]]> Level 2 Comparative Example 7 <![CDATA[3.58x10 -13 ]]> Level 2 Standard technical requirements <![CDATA[≤3.3x10 -13 ]]> Level 1

[0122] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention, and all these changes or substitutions should fall within the protection scope of the claims attached to the present invention.

Claims

1. An epoxy polymer modified cement mortar, characterized in that: It includes the following components by weight: 0.01-0.05 parts of defoamer, 1.0-2.0 parts of water reducing agent, 1.0-4.0 parts of thixotropic agent, 50-60 parts of water, 50-70 parts of cement, 100-140 parts of fine aggregate, and a total of 100-120 parts of epoxy curing agent and epoxy emulsion; The epoxy emulsion comprises the following components by weight: 90-95 parts of epoxy resin, 5-10 parts of cationic emulsifier, 40-50 parts of water; The cationic emulsifier is a propyltrimethylammonium chloride emulsifier; The propyl trimethyl ammonium chloride emulsifier is at least one of 2,3-epoxypropyl trimethyl ammonium chloride and methacrylamide propyl trimethyl ammonium chloride; The thixotropic agent comprises bentonite and fumed silica; the ratio of bentonite to fumed silica is 1: (1.0-2.0) in parts by weight.

2. The epoxy polymer modified cement mortar according to claim 1, characterized in that: The ratio of the epoxy curing agent to the epoxy emulsion is 1: (0.8-1.2) by weight.

3. The epoxy polymer modified cement mortar according to claim 1, characterized in that: The epoxy curing agent is at least one of aliphatic diamines, polyamines, and aromatic polyamines.

4. The epoxy polymer modified cement mortar according to claim 1, characterized in that: The epoxy resin is at least one of epoxy resin E-51, epoxy resin E-44, and epoxy resin E-12.

5. The epoxy polymer modified cement mortar according to claim 1, characterized in that: The water reducer is at least one of a polycarboxylate water reducer, a lignin sulfonate water reducer and an aminosulfonate water reducer.