Multifunctional repair mortar and preparation method thereof

Abstract

The present application provides a multifunctional repair mortar, which belongs to the field of building materials technology. According to the mass fraction, the mortar includes: component A: 60-80 parts of epoxy resin, 5-20 parts of silicone resin, 1-2 parts of siloxane-epoxy block copolymer, and modified lithium-based penetrant, wherein the modified lithium-based penetrant is obtained by treating 1-5 parts of lithium-based penetrant with 0.5-1 parts of C10-C14 alkyl alcohol sulfate; component B: 1000-2000 parts of mortar base material, 1-2 parts of water reducer. The repair mortar provided in the present application has high adhesion and crack resistance, can effectively repair concrete cracks, improve the antifreeze performance, carbonization resistance and resistance to harmful chemical erosion of the repaired concrete, and extend the service life of the concrete.

Description

Technical Field

[0001] The invention belongs to the field of building materials, and in particular relates to a multifunctional repair mortar and a preparation method thereof. Background Art

[0002] As the most widely used and largest-volume building material, concrete is the foundation of my country's urbanization. In recent years, with the continuous advancement of my country's urbanization process, the large-scale construction of housing, bridges, shopping malls and various infrastructure has been basically completed. However, due to the increasing complexity of the occasions and environments where concrete materials are used, especially the harsh environmental conditions, concrete structures will be damaged and destroyed in various forms.

[0003] For example, in cold regions, concrete may experience multiple freeze-thaw cycles. When water enters the pores of concrete, it will freeze and expand when the temperature drops, causing stress inside the concrete. Long-term cycles may cause the concrete to be damaged. Carbon dioxide in the air also reacts with alkaline substances (such as calcium hydroxide) in concrete to carbonize. Carbonation reduces the alkalinity of concrete, weakens its protective effect on steel bars, and accelerates the corrosion of steel bars. Even due to industrial development, the burning of fossil fuels and emissions from human activities, the content of acidic substances in the atmosphere has increased significantly, resulting in frequent acid rain in various places. Acid rain corrodes concrete, and in severe cases, the entire structure becomes unstable and collapses.

[0004] Although demolition and reconstruction can solve the above problems, it will lead to huge waste of resources and carbon emissions. Extending the service life of concrete structures is the most effective way to reduce resource consumption and environmental pollution, and it is also an inevitable trend for cement-based composite materials to achieve sustainable development. Repair and protection materials can significantly extend the service life of existing infrastructure while reducing the cost of new construction. Therefore, the development of cement-based composite repair materials that can effectively repair buildings, roads and other infrastructure with a certain strength on concrete structure substrates and can also adapt to a variety of harsh environments or cold regions has broad application value and economic value.

[0005] At present, the prior art provides some materials that can be used for repairing roads and the like. For example, patent CN118026591A discloses a polymer repair mortar for quickly repairing roads, which has good bonding strength and shrinkage properties and can meet the performance requirements of concrete roads; patent CN118047584A discloses a polymer repair mortar that can be used under low temperature conditions; patent CN117682828A discloses a repair mortar containing a large amount of industrial additives, which is suitable for large temperature differences and salt freezing environments; patent CN 117361932 A and patent CN 111269025 A respectively provide a concrete surface enhancer and a lithium-based penetrant modified concrete surface enhancer, which are used to enhance the functionality of concrete.

[0006] However, the material functions of the above scheme are relatively single, and the multifunctional material components are very complex, which causes many inconveniences in actual operation. In addition, repair materials with simple components, ready-to-use, low requirements for the repair object, rapid effectiveness after use, and high initial strength are more practical for construction sites. Summary of the invention

[0007] In order to solve the above problems, this application proposes the following technical solutions:

[0008] On the one hand, the present application provides a repair mortar, which comprises, by weight:

[0009] Component A: 60-80 parts of epoxy resin, 5-20 parts of silicone resin, 1-2 parts of siloxane-epoxy block copolymer, and modified lithium-based penetrant, wherein the modified lithium-based penetrant is obtained by treating 1-5 parts of lithium-based penetrant with 0.5-1 parts of C10-C14 alkyl alcohol sulfate;

[0010] Component B: 1000~2000 parts of mortar base, 1~2 parts of water reducing agent.

[0011] In one embodiment, the treatment includes: mixing and stirring 1 to 5 parts of a lithium-based permeate with 0.5 to 1 part of a C10 to C14 alkyl alcohol sulfate.

[0012] Optionally, the mixing and stirring is to fully and evenly stir the lithium-based permeate and the C10-C14 alkyl alcohol sulfate, and the duration may be 2-20 minutes.

[0013] Optionally, the stirring method is not limited, for example, a constant speed stirrer may be used.

[0014] In one embodiment, the lithium-based infiltrating fluid comprises lithium silicate and silicon dioxide.

[0015] In one embodiment, the C10-C14 alkyl alcohol sulfate includes dodecyl alcohol sulfate, undecyl alcohol sulfate, dodecyl alcohol sulfate, tridecyl alcohol sulfate, and tetradecyl alcohol sulfate.

[0016] Preferably, the alkyl alcohol sulfate is dodecyl alcohol sulfate, also known as lauryl alcohol sulfate.

[0017] In one embodiment, the C10~C14 alkyl alcohol sulfate salt includes a sodium salt and / or a potassium salt of a C10~C14 alkyl alcohol sulfate.

[0018] In one embodiment, the epoxy resin comprises bisphenol A epoxy resin.

[0019] In one embodiment, the silicone resin includes methylphenyl silicone resin.

[0020] In one embodiment, the epoxy value of the siloxane-epoxy block copolymer is 2.0-3.0 wt %.

[0021] In one embodiment, the mortar base in component B includes water and one or more selected from cement, slag powder, and sand.

[0022] In one embodiment, the mortar base material includes: 220-300 parts of cement, 40-80 parts of slag powder, 900-1000 parts of sand, and 180-200 parts of water.

[0023] In one embodiment, the cement comprises P·O 42.5 cement.

[0024] In one embodiment, the slag powder is S95 slag powder that complies with the national standard "GB / T18046-2017 Granulated blast furnace slag powder for cement, mortar and concrete".

[0025] In one embodiment, the fineness modulus of the sand is 1.6 to 2.2.

[0026] In one embodiment, the water reducer comprises a polycarboxylate water reducer.

[0027] In one embodiment, the fluidity of the repair mortar is 200-230 mm, and the fluidity of the mortar is 140-160 mm.

[0028] On the other hand, the present application provides a method for preparing the repair mortar, comprising the following steps:

[0029] Step 1, weighing a lithium-based penetrant and a C10-C14 alkyl alcohol sulfate according to their mass fractions, mixing and stirring to obtain a modified lithium-based penetrant;

[0030] Step 2, weighing epoxy resin, silicone resin and siloxane-epoxy block copolymer in parts by mass and mixing them, adding the modified lithium-based permeate obtained in step 1 and stirring evenly to obtain a polymer dispersion;

[0031] Step 3: Weigh the cement base and the water reducing agent according to their mass fractions and mix them, add the polymer dispersion obtained in step 2, and stir evenly to obtain the repair mortar.

[0032] In one embodiment, the mixing and stirring time after adding the modified lithium-based permeate in step 2 is 5-10 minutes; the mixing and stirring time after adding the polymer dispersion in step 3 is 1-3 minutes.

[0033] On the other hand, the present application provides the use of the repair mortar, or the repair mortar prepared by the method, in preparing repair products and / or reinforcement products for cement, concrete, roads, and buildings.

[0034] Optionally, the roads include but are not limited to urban roads, highways, airport roads, etc.

[0035] Optionally, the repair product and / or reinforcement product can be used to improve the freeze-thaw resistance, carbonization resistance and erosion resistance of the target.

[0036] This application has at least the following beneficial effects:

[0037] The repair mortar provided by the present application has excellent freeze-thaw resistance, carbonization resistance and sulfate corrosion resistance. After the repair mortar provided by the present application is filled in the position to be repaired of the substrate with concrete as the main material, such as cement, roads, and buildings, the methylphenyl silicone resin in the repair mortar can form a layer of silicon oxide film on the surface of the capillary wall filling the gap. The film has the characteristics of air permeability and water-tightness, which can effectively reduce the water absorption rate of concrete and reduce the moisture content inside the concrete, thereby reducing the formation of ice during the freeze-thaw process and alleviating the concrete damage caused by the volume expansion of ice. In addition, since the debonding strength of bisphenol A epoxy resin with the surface of calcium carbonate is higher than the debonding strength with the surface of CSH, when the carbon dioxide in the air carbonizes the hydration product of the surface of the gap, the bisphenol A epoxy resin will quickly block the permeation channel of carbon dioxide gas; at the same time, bisphenol A epoxy resin also has high ductility on the surface of calcium carbonate. When subjected to external force, bisphenol A epoxy resin can reduce the formation of cracks by deformation, further improving the anti-carbonization ability. At the same time, the lithium-based penetrant in the repair mortar can react chemically with substances in the concrete to form silicates, thereby filling the pores in the concrete and establishing a strong, wear-resistant, impermeable dense layer on the surface, thereby improving resistance to sulfate erosion.

[0038] The repair mortar of the present application contains a large amount of cement-based materials, and the repair mortar prepared therefrom can be directly used to fill cracks and damaged parts of infrastructure such as roads that are waiting to be repaired, especially large areas of missing or damaged parts can be repaired, and there are no restrictions on the width and degree of loss of the repaired parts. In addition, the repair mortar provided by the present application has good fluidity and is also suitable for smaller gaps to be repaired. At the same time, the repair mortar provided by the present application has simple components, can be prepared and used immediately, and can show good bonding strength and impermeability after filling, which greatly improves the practicality of the repair mortar and its operability on the construction site.

[0039] 3. In the repair mortar provided by the present application, bisphenol A epoxy resin, methylphenyl silicone resin and lithium-based penetrant will undergo phase separation when directly mixed. The present application utilizes an appropriate amount of lauryl sulfate molecules to form micelles to encapsulate non-polar components, forming water-soluble micelles, thereby increasing the solubility of non-polar components in polar environments, and adopts an appropriate amount of siloxane-epoxy block copolymer to reduce the interfacial tension between epoxy resin and silicone resin without affecting the performance of lauryl sulfate, thereby improving the uniformity and dispersibility of the overall mixture and improving the state of the system after mixing, further improving its strength as well as freeze-thaw resistance, carbonization resistance and salt corrosion resistance, and realizing multifunctional composite. DETAILED DESCRIPTION

[0040] In order to more clearly explain the overall concept of the application, the following is described in detail by way of embodiment. In the following description, a large amount of specific details are provided so as to provide a more thorough understanding of the application. However, it is obvious to those skilled in the art that the application can be implemented without one or more of these details. In other examples, in order to avoid confusion with the application, some technical features well known in the art are not described.

[0041] Unless otherwise specified, the raw materials, reagents, instruments, equipment, etc. involved in the following examples can be obtained through commercial channels, and the use of each instrument and equipment can refer to its conventional operating method.

[0042] In the following embodiments: the epoxy resin adopts bisphenol A epoxy resin emulsion, which is commercially available in industrial grade, and the main chemical component is bisphenol A epoxy resin, and the solid content is 45%; the silicone resin adopts methylphenyl silicone resin emulsion, which is commercially available in industrial grade, and the main chemical components are methylphenylsilane and silicate, and the solid content is 50%; the lithium-based penetrant is commercially available in industrial grade, and the main chemical components are lithium silicate and nano-colloidal silica, and the solid content is 55%, wherein the lithium silicate content is 20%; the siloxane-epoxy block copolymer is commercially available in industrial grade, with a solid content of 98% and an epoxy value of 2.0-3.0wt%; the cement adopts P·O 42.5 cement, the slag powder adopts S95 slag powder in accordance with GB / T18046-2017 Granulated blast furnace slag powder for cement, mortar and concrete, and the sand adopts fine sand with a fineness modulus of 1.6~2.2.

[0043] Example 1

[0044] This embodiment provides a multifunctional repair mortar, and the raw materials for its preparation include, by weight:

[0045] 60 parts of bisphenol A epoxy resin emulsion, 20 parts of methylphenyl silicone resin emulsion, 5 parts of lithium-based penetrant, 1 part of sodium lauryl sulfate, 300 parts of cement, 40 parts of slag powder, 2 parts of siloxane-epoxy block copolymer (epoxy value 2wt%), 1000 parts of sand, 200 parts of water, and 2 parts of polycarboxylate water reducer.

[0046] The above raw materials in parts by mass are prepared according to the following method, including:

[0047] Step 1: Add 1 part of sodium lauryl sulfate to 5 parts of lithium-based penetrant, stir and mix thoroughly for 10 minutes to obtain a modified lithium-based penetrant for standby use;

[0048] Step 2: After the bisphenol A epoxy resin emulsion, the methyl phenyl silicone resin emulsion and the siloxane-epoxy block copolymer are fully mixed, the modified lithium-based penetrant is added into the polymer emulsion and stirred for 5 minutes to obtain a polymer dispersed emulsion;

[0049] Step 3: After evenly mixing the slag powder, cement, sand, water and polycarboxylic acid water reducer, add the polymer dispersion emulsion and stir again for 1 minute to obtain the multifunctional repair mortar.

[0050] Example 2

[0051] This embodiment provides a multifunctional repair mortar, and the raw materials for its preparation include, by weight:

[0052] 80 parts of bisphenol A epoxy resin emulsion, 5 parts of methylphenyl silicone resin emulsion, 1 part of lithium-based penetrant, 0.5 parts of potassium lauryl sulfate, 220 parts of cement, 80 parts of slag powder, 2 parts of siloxane-epoxy block copolymer (epoxy value is 3.0wt%), 900 parts of sand, 180 parts of water, and 1 part of polycarboxylic acid water reducer.

[0053] Wherein, 0.5 parts of potassium lauryl sulfate were added to 1 part of lithium-based penetrating liquid, and the mixture was stirred and mixed for 10 minutes to obtain a modified lithium-based penetrating liquid for use.

[0054] The above raw materials in parts by mass were used to prepare multifunctional repair mortar according to the method in Example 1.

[0055] Example 3

[0056] This embodiment provides a multifunctional repair mortar, and the raw materials for its preparation include, by weight:

[0057] 70 parts of bisphenol A epoxy resin emulsion, 14 parts of methylphenyl silicone resin emulsion, 3 parts of lithium-based penetrant, 0.8 parts of sodium lauryl sulfate, 270 parts of cement, 60 parts of slag powder, 1.5 parts of siloxane-epoxy block copolymer (epoxy value is 2.0wt%), 950 parts of sand, 190 parts of water, and 1.5 parts of polycarboxylic acid water reducer.

[0058] Among them, 0.8 parts of sodium lauryl sulfate were added to 3 parts of lithium-based penetration liquid, and the mixture was fully stirred and mixed for 10 minutes to obtain a modified lithium-based penetration liquid for use.

[0059] The above raw materials in parts by mass were used to prepare multifunctional repair mortar according to the method in Example 1.

[0060] Comparative Example 1

[0061] The preparation method of this example is roughly the same as that of Example 3, except that the raw materials are: 85 parts of bisphenol A epoxy resin emulsion, 300 parts of cement, 40 parts of slag powder, 950 parts of sand, 190 parts of water, and 2 parts of polycarboxylate water reducer. That is, it does not contain sodium lauryl sulfate-modified lithium-based penetrant, methylphenyl silicone resin, and siloxane-epoxy block copolymer.

[0062] Comparative Example 2

[0063] The preparation method of this example is substantially the same as that of Example 3, except that sodium lauryl sulfate is not used to modify the lithium-based permeate.

[0064] Effect experiment:

[0065] Component optimization based on product properties

[0066] The mortars prepared in Examples 1-3 were respectively recorded as 1# to 3#, and the mortars in Comparative Examples 1 and 2 were respectively recorded as D1# and D2#. Taking the mortar in Example 1 as an example, the dispersant and modifier therein were replaced and 4# to 13# were prepared by the same method. After the polymer dispersion prepared in step 2 of each example was left to stand for 1 minute, the texture of the obtained polymer dispersion was observed to see whether it was uniform. The results are shown in Table 1:

[0067]

[0068] From the results in Table 1, it can be seen that when the lithium-based penetrant is not modified, the mixture of bisphenol A epoxy resin, methyl phenyl silicone resin and lithium-based penetrant will show obvious phase separation, accompanied by the precipitation of a large number of emulsion droplets. However, using different dispersants to improve the interfacial tension of the resin phase cannot solve this problem (see 11#~13#, D2#). When exploring which modifier to use for treatment, different modifiers have obvious differences in the improvement of the uniformity of the above three components after mixing (4#~5#, 8#~10#). Among them, sodium lauryl sulfate has the best encapsulation ability for the non-polar molecular bundles of the mixture, but a small amount of resin emulsion droplets are still precipitated, and different dispersants also have a certain effect on the activity of sodium lauryl sulfate (see 6#~7#). In Examples 1 to 3 (see 1# to 3#), with the appropriate proportion of siloxane-epoxy block copolymer and sodium lauryl sulfate, the prepared polymer emulsion has a clear and uniform texture without stratification and no emulsion droplets precipitate, and is more suitable for preparation with mortar base materials to improve its performance as a repair mortar.

[0069] 2. Performance Test

[0070] Based on the component optimization results of the aforementioned product properties, the repair mortars prepared in Examples 1 to 3 and Comparative Examples 1 and 2 were tested for their initial mechanical strength and performance of anti-seepage, anti-freezing, anti-carbonization and anti-salt erosion capabilities. At the same time, taking the mortar of Example 3 as an example, sodium lauryl sulfate and siloxane-epoxy block copolymer were replaced with different mass parts to prepare Examples 14# (0.1 parts of sodium lauryl sulfate, 1.5 parts of siloxane-epoxy block copolymer (2wt%)), 15# (5 parts of sodium lauryl sulfate, 1.5 parts of siloxane-epoxy block copolymer (2wt%)), 16# (0.8 parts of sodium lauryl sulfate, 0.1 parts of siloxane-epoxy block copolymer (2wt%)), 17# (0.8 parts of sodium lauryl sulfate, 5 parts of siloxane-epoxy block copolymer (2wt%)), 18# (0.1 parts of sodium lauryl sulfate, 0.1 parts of siloxane-epoxy block copolymer (2wt%)), and 19# (5 parts of sodium lauryl sulfate, 5 parts of siloxane-epoxy block copolymer (2wt%)), and performance tests were carried out.

[0071] Among them, the test was carried out with reference to JC / T 984-2011 "Polymer Cement Waterproof Mortar" and GB / T 50082-2009 "Standard for Test Methods for Long-term Performance and Durability of Ordinary Concrete", and the test results are shown in Table 2.

[0072]

[0073] From the results in Table 2, it can be seen that the use of a single resin (see D1#) does not significantly improve the various properties of the mortar, while when multiple functional components are used to improve the performance of the mortar, the mixing uniformity between the mortar mixture components and the state of the system after mixing have an important influence on its performance (see D2# and 14#~19#). Among them, the mortars provided by Examples 1~3 (see 1#~3#) have significantly improved bonding strength, anti-freezing, anti-carbonization and anti-salt corrosion capabilities.

[0074] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A repair mortar, characterized in that: The mortar comprises, by mass: Component A: 60-80 parts of bisphenol A epoxy resin, 5-20 parts of methylphenyl silicone resin, 1-2 parts of siloxane-epoxy block copolymer, and modified lithium-based penetrant, wherein the modified lithium-based penetrant is obtained by mixing and stirring 1-5 parts of lithium-based penetrant with 0.5-1 part of C10-C14 alkyl alcohol sulfate; Component B: 1000-2000 parts of mortar base material, 1-2 parts of water reducing agent; The preparation method of the repair mortar comprises the following steps: Step 1, weighing a lithium-based penetrant and a C10-C14 alkyl alcohol sulfate according to their mass fractions, mixing and stirring to obtain a modified lithium-based penetrant; Step 2, weighing epoxy resin, silicone resin and siloxane-epoxy block copolymer in parts by mass and mixing them, adding the modified lithium-based permeate obtained in step 1 and stirring evenly to obtain a polymer dispersion; Step 3: Weigh the cement base and the water reducing agent according to their mass fractions and mix them, add the polymer dispersion obtained in step 2, and stir evenly to obtain the repair mortar.

2. The repair mortar according to claim 1, characterized in that: The lithium-based permeating fluid comprises lithium silicate and silicon dioxide; and / or the alkyl alcohol sulfate ester salt is dodecyl alcohol sulfate ester salt.

3. The repair mortar according to claim 1, characterized in that: The C10-C14 alkyl alcohol sulfate salt includes sodium salt and / or potassium salt of C10-C14 alkyl alcohol sulfate.

4. The repair mortar according to claim 1, characterized in that: The epoxy value of the siloxane-epoxy block copolymer is 2.0-3.0 wt %.

5. The repair mortar according to claim 1, characterized in that: In the component B, the mortar base material includes: 220-300 parts of cement, 40-80 parts of slag powder, 900-1000 parts of sand, and 180-200 parts of water.

6. The repair mortar according to claim 5, characterized in that: The cement is P·O 42.5 cement; And / or, the slag powder is S95 slag powder; And / or, the fineness modulus of the sand is 1.6 to 2.

2.

7. The repair mortar according to claim 1, characterized in that: The water reducer is a polycarboxylate water reducer.

8. Use of the repair mortar according to any one of claims 1 to 7 in preparing repair products and / or reinforcement products for cement, roads and buildings.

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