Composition for polymer mortar, polymer mortar, and method for preparing and use thereof

Abstract

The application relates to the technical field of building materials, and discloses a composition for polymer mortar, a polymer mortar, and a preparation method and application thereof. The composition contains cement, polymer emulsion, water-soluble polymer, sand, expanding agent, defoaming agent, retarder, water reducing agent, and water; the content of the polymer emulsion is 80-120 parts by weight, the content of the water-soluble polymer is 0.04-0.2 parts by weight, the content of the sand is 115-190 parts by weight, the content of the expanding agent is 2-8 parts by weight, the content of the defoaming agent is 0.1-0.6 parts by weight, the content of the retarder is 0.01-0.15 parts by weight, the content of the water reducing agent is 0.4-1.5 parts by weight, and the content of the water is 0-10 parts by weight, relative to 100 parts by weight of the cement; the polymer mortar prepared by using the composition has the repairing requirements of early strength and low elastic modulus, and meets the repairing requirements of the sky window period of a high-speed railway.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a polymer mortar composition, polymer mortar, its preparation method, and its application. Background Technology

[0002] Ballastless track technology is one of the key technologies for high-speed railway construction. It is a Chinese railway track system established based on my country's railway conditions through introduction, digestion, absorption, and reinnovation. The CRTS I type slab ballastless track is the earliest ballastless track structure suitable for high-speed railway development. The filling layer is the core component of the CRTS I type slab ballastless track structure, playing a crucial role in filling, supporting, bearing, and transmitting forces. The material used is cement emulsified asphalt mortar.

[0003] CRTS Type I slab track high-speed railway lines mainly operate in areas with complex climates. Under these complex conditions, coupled with the dynamic load impact from high-speed trains, the infill material experiences varying degrees of degradation, including rainwater erosion and interface delamination. Grouting is typically used to repair these structural defects. However, operational experience and on-site surveys show that the infill material in some CRTS Type I slab track sections has deteriorated severely, necessitating partial or even complete replacement of the track structure.

[0004] For the replacement of slabs, the use of traditional emulsified asphalt mortar as a filling layer material is limited by the restrictions on the use of asphalt materials. Therefore, the development of polymer cement mortar that meets the requirements of cement emulsified asphalt mortar and is suitable for construction during the track maintenance window of high-speed railway is of great engineering significance.

[0005] In recent years, polymer mortar has been widely used as a repair material in ballastless track concrete structures. For example, CN111517745A discloses a polymer repair mortar and its preparation method; however, this method cannot meet the repair needs during high-speed railway track maintenance windows. CN111620655A discloses a fast-hardening polymer mortar and its preparation method; however, this method is for repairing asphalt mortar repair slabs in CRTS II slab track filling layers, and the resulting polymer material does not meet the low elastic modulus performance requirements of the CRTS I type slab track filling layer.

[0006] CN109626897A discloses a grouting material for treating grout leakage in the subgrade of ballastless track for high-speed railways. However, the polymer grouting material prepared by this scheme cannot be used as a structural material on ballastless track, and the damping performance of the material is not considered. CN104150836A discloses a track slab sealing and anchoring mortar. However, this scheme does not consider the early strength performance of the prepared mortar, making it difficult to meet the repair needs during the "maintenance window" period of high-speed railways. CN111533517A discloses a rapid repair mortar for concrete track slabs of high-speed railways. The polymer mortar prepared by this scheme does not meet the low elastic modulus requirement of the filling layer of CRTS I type slab ballastless track.

[0007] In summary, there is an urgent need to develop a polymer mortar to address the performance standard requirements (Q / CR 659-2018 Repair Mortar for Concrete Structures of High-Speed ​​Railways) for CRTS Type I slab track filling material during slab replacement and the current ballastless track maintenance regulations (TG / GW 115-2012 Maintenance Rules for Ballastless Track Lines of High-Speed ​​Railways). Summary of the Invention

[0008] The purpose of this invention is to solve the problem that existing polymer mortars cannot meet the performance standard requirements of CRTS Type I slab track filling layer materials.

[0009] To achieve the above objectives, a first aspect of the present invention provides a composition for polymer mortar, the composition containing the following components, which may be stored individually or in combination:

[0010] Cement, polymer emulsion, water-soluble polymer, sand, expanding agent, defoamer, retarder, water-reducing agent, water;

[0011] Relative to 100 parts by weight of the cement, the content of the polymer emulsion is 80-120 parts by weight, the content of the water-soluble polymer is 0.04-0.2 parts by weight, the content of the sand is 115-190 parts by weight, the content of the expanding agent is 2-8 parts by weight, the content of the defoamer is 0.1-0.6 parts by weight, the content of the retarder is 0.01-0.15 parts by weight, the content of the water-reducing agent is 0.4-1.5 parts by weight, and the content of water is 0-10 parts by weight.

[0012] The cement is a combination of rapid-hardening sulfoaluminate cement and silicate cement with a strength grade of 42.5, with a content-to-mass ratio of 1:0.6-1.5.

[0013] The particle size distribution of the sand is 0.15-1.18 mm;

[0014] The polymer emulsion is selected from at least one of polystyrene-butadiene emulsion, styrene acrylate emulsion, and ethylene-vinyl acetate copolymer emulsion.

[0015] A second aspect of the present invention provides a method for preparing polymer mortar, the method being carried out using the composition described in the first aspect, comprising: mixing the polymer mortar with the components in the composition to obtain the polymer mortar.

[0016] A third aspect of the present invention provides a polymer mortar prepared by the method described in the second aspect.

[0017] The fourth aspect of the present invention provides the application of the polymer mortar described in the third aspect in railway construction.

[0018] This invention utilizes a specific ratio of rapid-hardening sulfoaluminate cement and silicate cement, combined with a specific polymer emulsion, and incorporates precisely proportioned water-soluble polymers, sand, expanding agents, defoamers, retarders, water-reducing agents, and water. The resulting polymer mortar can shorten the setting time of repair mortar materials, meeting the maintenance requirements for high-speed railway track maintenance during maintenance windows, thereby achieving early strength. Simultaneously, it can promote the later-stage strength growth of cement mortar and reduce strength loss caused by the rapid formation of ettringite.

[0019] Furthermore, the polymer mortar provided by this invention can form an organic-inorganic composite structure inside the hardened matrix; the continuous phase of the hardened matrix is ​​transformed from the cement phase to the polymer phase, which significantly reduces the elastic modulus of the repair polymer mortar, thus meeting the requirement of 100-300MPa elastic modulus in specification Q / CR 659-2018. At the same time, it can improve the workability of polymer cement mortar, increase the viscosity of the liquid phase, improve the stability of aggregates, and reduce segregation and bleeding. Attached Figure Description

[0020] Figure 1 This is a comparison diagram of the dynamic mechanical properties of Embodiment 1 and Comparative Example 6 provided by the present invention. Detailed Implementation

[0021] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0022] As previously described, a first aspect of the present invention provides a composition for polymer mortar, the composition containing the following components, which may be stored individually or in combination:

[0023] Cement, polymer emulsion, water-soluble polymer, sand, expanding agent, defoamer, retarder, water-reducing agent, water;

[0024] Relative to 100 parts by weight of the cement, the content of the polymer emulsion is 80-120 parts by weight, the content of the water-soluble polymer is 0.04-0.2 parts by weight, the content of the gravel is 115-190 parts by weight, the content of the expanding agent is 2-8 parts by weight, the content of the defoamer is 0.1-0.6 parts by weight, the content of the retarder is 0.01-0.15 parts by weight, the content of the water-reducing agent is 0.4-1.5 parts by weight, and the content of water is 0-10 parts by weight.

[0025] The cement is a combination of rapid-hardening sulfoaluminate cement and silicate cement with a strength grade of 42.5, with a content-to-mass ratio of 1:0.6-1.5.

[0026] The particle size distribution of the sand is 0.15-1.18 mm;

[0027] The polymer emulsion is selected from at least one of polystyrene-butadiene emulsion, styrene acrylate emulsion, and ethylene-vinyl acetate copolymer emulsion.

[0028] It should be noted that, in this invention, the particle size distribution of sand refers to the percentage of sand particles of different sizes in all sand particles.

[0029] Preferably, the silicate cement is selected from at least one of grade 42.5 silicate cement and grade 52.5 silicate cement.

[0030] In a preferred embodiment, the gravel is selected from at least one of manufactured sand and river sand.

[0031] Preferably, relative to 100 parts by weight of the cement, the content of the polymer emulsion is 90-100 parts by weight, the content of the water-soluble polymer is 0.045-0.12 parts by weight, the content of the gravel is 125-180 parts by weight, the content of the expanding agent is 2.5-6 parts by weight, the content of the defoamer is 0.15-0.45 parts by weight, the content of the retarder is 0.01-0.12 parts by weight, the content of the water-reducing agent is 0.45-1.2 parts by weight, and the content of water is 0-6 parts by weight. The inventors have found that, under this preferred embodiment, the polymer mortar prepared from the composition provided by the present invention has a lower elastic modulus and higher damping performance.

[0032] Preferably, the polymer emulsion is a polystyrene-butadiene emulsion.

[0033] More preferably, the polystyrene-butadiene emulsion has a viscosity of less than 200 mPa·s at 35°C, a solid content of 48-52 wt%, and a minimum film-forming temperature of no more than 10°C. The inventors have found that, under this preferred embodiment, the polymer mortar prepared from the composition provided by the present invention has a lower elastic modulus, a higher relative dynamic modulus of elasticity in antifreeze performance tests, and lower mass loss.

[0034] It should be noted that the solid content of the polystyrene-butadiene emulsion refers to the volume fraction of the dry film left after the emulsion has been cured or dried.

[0035] Preferably, the water-soluble polymer is selected from at least one of hydroxypropyl methylcellulose and polyacrylamide.

[0036] More preferably, the water-soluble polymer is polyacrylamide. The inventors have found that, under this preferred embodiment, the polymer mortar prepared from the composition provided by the present invention exhibits better anti-dispersion properties.

[0037] More preferably, the average molecular weight of the polyacrylamide does not exceed 10 million.

[0038] Preferably, the sand is selected from at least one of natural river sand and manufactured sand.

[0039] Preferably, the expanding agent is selected from at least one of magnesium oxide expanding agent and calcium sulfoaluminate expanding agent.

[0040] More preferably, the calcination temperature of the magnesium oxide expanding agent is 1100-1300℃, and the magnesium oxide content is 80-90wt%.

[0041] In a preferred embodiment, the retarder is selected from at least one of sodium gluconate, borax, and tartaric acid.

[0042] Preferably, the defoamer is selected from at least one of polyether defoamers, alcohol defoamers, and fatty acid defoamers.

[0043] Preferably, the water-reducing agent is selected from polycarboxylate powder water-reducing agents.

[0044] As previously stated, a second aspect of the present invention provides a method for preparing polymer mortar, the method being carried out using the composition described in the first aspect, comprising: mixing the polymer mortar with the components in the composition to obtain the polymer mortar.

[0045] Preferably, the mixing step includes:

[0046] (1) The polymer mortar is first mixed with the cement, expanding agent, retarder, gravel, and water-reducing agent in the composition to obtain a first material; and

[0047] A second mixture is formed by mixing a water-soluble polymer and a polymer emulsion, wherein the initial system of the second mixture optionally also contains water, to obtain a second material.

[0048] (2) The defoamer, the first material and the second material are mixed in a third mixture to obtain the polymer mortar.

[0049] Preferably, the conditions for the first mixing include: a temperature of 5-35°C and a time of 2-3 minutes.

[0050] Preferably, the conditions for the second mixing include: a temperature of 5-35°C and a time of 3-5 minutes.

[0051] Preferably, in step (2), the third mixing is carried out under stirring conditions, including a stirring speed of 170-180 rpm and a time of 2-4 min. The inventors have found that, under this preferred embodiment, the polymer mortar provided by the present invention exhibits higher homogeneity.

[0052] As previously stated, a third aspect of the present invention provides a polymer mortar prepared by the method described in the second aspect above.

[0053] Preferably, the ambient temperature for applying the polymer mortar is 5-35℃.

[0054] As previously stated, the fourth aspect of the present invention provides the application of the polymer mortar described in the third aspect in railway construction.

[0055] Preferably, the polymer mortar is used in the replacement of ballastless track slabs.

[0056] The present invention will be described in detail below through embodiments.

[0057] In the following examples, unless otherwise specified, all experimental instruments, reagents, and raw materials involved are commercially available products, and all reagents are analytical grade products.

[0058] In the following examples, unless otherwise specified, each part by weight represents 100g.

[0059] raw material

[0060] Rapid-hardening sulfoaluminate cement I: strength grade 42.5, purchased from Zhengzhou Jianwen Special Materials Technology Co., Ltd.;

[0061] Rapid-hardening sulfoaluminate cement II: strength grade 52.5, purchased from Zhengzhou Jianwen Special Materials Technology Co., Ltd.;

[0062] Silicate cement: Grade 42.5 silicate cement;

[0063] Polymer emulsion I: Polystyrene-butadiene emulsion, with a viscosity of 80 mPa·s at 35°C, a solid content of 50 wt%, and a minimum film-forming temperature of 10°C, purchased from Nanjing Chuhai New Materials Technology Co., Ltd.

[0064] Polymer Emulsion II: Styrene-acrylate emulsion, purchased from Beijing Ruishengte Building Materials Co., Ltd.;

[0065] Water-soluble polymer I: Polyacrylamide, brand (model): Anionic - 3 million, purchased from Sinopharm Chemical Reagent Co., Ltd.

[0066] Water-soluble polymer II: Hydroxypropyl methylcellulose, grade (model): 200,000 viscosity, purchased from Tianjin Zhonglian Chemical Reagent Co., Ltd.

[0067] Sand: Natural river sand, with a particle size distribution of 0.15-1.18 mm;

[0068] Expanding agent: Magnesium oxide expanding agent, brand (model) magnesium-based medium and high temperature expanding agent, purchased from Shandong Gaochuang Hengda New Building Materials Technology Co., Ltd.;

[0069] Defoamer: ZJ-D130, purchased from Jiangsu Zhaojia Building Materials Technology Co., Ltd.;

[0070] Retarding agent: Tartaric acid, purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0071] Water-reducing agent: Sika ViscoCrete-530P (polycarboxylate powder water-reducing agent), purchased from Shanghai Kaiyin Chemical Co., Ltd.

[0072] Example 1

[0073] This embodiment illustrates that the polymer mortar of the present invention is prepared according to the formula and process parameters in Table 1 and the method described below.

[0074] The method for preparing polymer mortar includes the following steps:

[0075] (1) The polymer mortar is first mixed with the cement, expanding agent, retarder, gravel, and water-reducing agent in the composition to obtain a first material; and

[0076] A second material is obtained by mixing water-soluble polymer, polymer emulsion and water in a second process.

[0077] The conditions for the first mixing are: a temperature of 15°C and a time of 3 minutes.

[0078] The conditions for the second mixing are: a temperature of 15°C and a time of 4 minutes.

[0079] (2) The defoamer, the first material and the second material are mixed in a third mixture to obtain the polymer mortar.

[0080] Unless otherwise specified, the remaining examples follow a similar process to Example 1. The difference is that the formulations and process parameters used in each example are different, as detailed in Table 1 (Note: Parameters not listed in Table 1 are the same as those in Example 1).

[0081] Table 1

[0082]

[0083]

[0084] Example 8

[0085] This embodiment follows a similar process to Embodiment 1, except that the conditions for the third mixing step in this embodiment are: a stirring speed of 108 rpm and a time of 4 min.

[0086] Everything else is the same as in Example 1.

[0087] Polymer mortar S8 was prepared.

[0088] Example 9

[0089] This embodiment follows a similar process to Embodiment 1, except that the conditions for the third mixing step in this embodiment are: a stirring speed of 172 rpm and a mixing time of 2 min.

[0090] Everything else is the same as in Example 1.

[0091] Polymer mortar S9 was prepared.

[0092] Example 10

[0093] This embodiment follows a similar process to Example 1, except that an equal mass of polymer emulsion II is used in this embodiment to replace polymer emulsion I in Example 1.

[0094] Everything else is the same as in Example 1.

[0095] Polymer mortar S10 was prepared.

[0096] Example 11

[0097] This embodiment follows a similar process to Example 1, except that an equal mass of water-soluble polymer II is used in this embodiment to replace water-soluble polymer I in Example 1.

[0098] Everything else is the same as in Example 1.

[0099] Polymer mortar S11 was prepared.

[0100] Example 12

[0101] This embodiment follows a similar process to Example 1, except that it uses 80 parts by weight of polymer emulsion I and 10 parts by weight of water.

[0102] Everything else is the same as in Example 1.

[0103] Polymer mortar S12 was prepared.

[0104] Example 13

[0105] This embodiment follows a similar process to Example 1, except that 120 parts by weight of polymer emulsion I are used in this embodiment.

[0106] Everything else is the same as in Example 1.

[0107] Polymer mortar S13 was prepared.

[0108] Comparative Example 1

[0109] This comparative example follows a similar process to Example 1, except that the mass ratio of rapid-hardening sulfoaluminate cement I to silicate cement is 1:2.

[0110] Everything else is the same as in Example 1.

[0111] Polymer mortar DS1 was prepared.

[0112] Comparative Example 2

[0113] This comparative example follows a similar process to Example 1, except that an equal mass of rapid-hardening sulfoaluminate cement I is used in this comparative example instead of the combination of rapid-hardening sulfoaluminate cement I and silicate cement in Example 1.

[0114] Everything else is the same as in Example 1.

[0115] Polymer mortar DS2 was prepared.

[0116] Comparative Example 3

[0117] This comparative example was carried out using a similar process to Example 1, except that 150 parts by weight of polymer emulsion I were used in this comparative example.

[0118] Everything else is the same as in Example 1.

[0119] Polymer mortar DS3 was prepared.

[0120] Comparative Example 4

[0121] This comparative example follows a similar process to Example 1, except that an equal mass of rapid-hardening sulfoaluminate cement II is used in this comparative example instead of rapid-hardening sulfoaluminate cement I in Example 1.

[0122] Everything else is the same as in Example 1.

[0123] Polymer mortar DS4 was prepared.

[0124] Comparative Example 5

[0125] This comparative example follows a similar process to Example 1, except that an equal mass of P.O42.5R (early-strength, fast-hardening cement, purchased from Wuxi Jianghuai Building Materials Technology Co., Ltd.) is used to replace the fast-hardening sulfoaluminate cement I in Example 1.

[0126] Everything else is the same as in Example 1.

[0127] Polymer mortar DS5 was prepared.

[0128] Comparative Example 6

[0129] This comparative example provides cement emulsified asphalt mortar (cationic emulsified asphalt produced by Shell (Tianjin) Company, wherein the mass fraction of asphalt is 60%) for comparison, to illustrate that the polymer mortar provided by the present invention has similar dynamic mechanical properties to cement emulsified asphalt mortar.

[0130] Test case

[0131] The performance of the polymer mortars prepared in the examples and comparative examples was tested using the same method.

[0132] The test standards and indicators for expansion, compressive strength, elastic modulus, expansion rate and frost resistance are: QCR 659-2018 "Repair Mortar for Concrete Structures of High-Speed ​​Railways", and the results are shown in Table 2;

[0133] The test standard (or method) for the agglomeration sieve residue rate is as follows: Weigh 250ml of freshly mixed mortar, pour it into a sieve with a diameter of Φ2mm and sieve it, and weigh the sieve residue mass. The results are shown in Table 3.

[0134] The testing standard (or method) for dynamic mechanical properties is as follows: frequency scanning is performed using a dynamic thermal analyzer, and the results are shown in [the table below]. Figure 1 .

[0135] Table 2

[0136]

[0137] Table 2 (continued)

[0138]

[0139] Table 2 (continued)

[0140]

[0141] Table 2 (continued)

[0142]

[0143]

[0144] Note: "-" in Table 2 indicates that compressive strength could not be measured.

[0145] Table 3

[0146]

[0147] As can be seen from the results in Table 2, the polymer mortar prepared using the polymer mortar composition provided by the present invention meets the requirements of QCR 659-2018 "Repair Mortar for High-Speed ​​Railway Concrete Structures".

[0148] The agglomeration sieve residue test values ​​of the polymer mortars prepared by the exemplary embodiments of the present invention, as shown in Table 3, indicate that the polymer mortars prepared under the preferred process conditions of the present invention (the third mixing conditions include: a stirring speed of 170-180 rpm and a time of 2-4 min) have higher homogeneity.

[0149] The present invention also provides, by way of example, a comparison diagram of the dynamic mechanical properties of Embodiment 1 and Comparative Example 6, as shown in the figure. Figure 1 As shown in the figure, the dynamic mechanical properties of the polymer mortar prepared by this invention are similar to those of cement emulsified asphalt mortar. The loss factor of the material is in the range of 0.2-0.4 at 1-100Hz, which shows good viscoelasticity and damping effect, meeting the performance standard requirements of CRTSI type slab track filling layer material.

[0150] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A composition for polymer mortar, characterized in that, The composition contains the following components, which may be stored individually or in combination: Cement, polymer emulsion, water-soluble polymer, sand, expanding agent, defoamer, retarder, water-reducing agent, water; Relative to 100 parts by weight of the cement, the content of the polymer emulsion is 80-120 parts by weight, the content of the water-soluble polymer is 0.04-0.2 parts by weight, the content of the sand is 115-190 parts by weight, the content of the expanding agent is 2-8 parts by weight, the content of the defoamer is 0.1-0.6 parts by weight, the content of the retarder is 0.01-0.15 parts by weight, the content of the water-reducing agent is 0.4-1.5 parts by weight, and the content of water is 0-10 parts by weight. The cement is a combination of rapid-hardening sulfoaluminate cement and silicate cement with a strength grade of 42.5, with a content-to-mass ratio of 1:0.6-1.

5. The particle size distribution of the sand is 0.15-1.18 mm; The polymer emulsion is a polystyrene-butadiene emulsion; the polystyrene-butadiene emulsion has a viscosity of less than 200 mPa·s at 35°C, a solid content of 48-52wt%, and a minimum film-forming temperature of no more than 10°C. The water-soluble polymer is polyacrylamide.

2. The composition according to claim 1, characterized in that, Relative to 100 parts by weight of the cement, the content of the polymer emulsion is 90-100 parts by weight, the content of the water-soluble polymer is 0.045-0.12 parts by weight, the content of the sand is 125-180 parts by weight, the content of the expanding agent is 2.5-6 parts by weight, the content of the defoamer is 0.15-0.45 parts by weight, the content of the retarder is 0.01-0.12 parts by weight, the content of the water-reducing agent is 0.45-1.2 parts by weight, and the content of water is 0-6 parts by weight.

3. The composition according to claim 1 or 2, characterized in that, The sand is selected from at least one of natural river sand and manufactured sand; And / or, the expanding agent is selected from at least one of magnesium oxide expanding agent and calcium sulfoaluminate expanding agent.

4. The composition according to claim 3, characterized in that, The retarder is selected from at least one of sodium gluconate, borax and tartaric acid.

5. A method for preparing polymer mortar, characterized in that, The method is carried out using the composition according to any one of claims 1-4, comprising: mixing the polymer mortar with the components in the composition to obtain the polymer mortar.

6. The method according to claim 5, characterized in that, The mixing step includes: (1) The polymer mortar is first mixed with the cement, expanding agent, retarder, sand and water-reducing agent in the composition to obtain the first material; and A second mixture is formed by mixing a water-soluble polymer and a polymer emulsion, wherein the initial system of the second mixture optionally also contains water, to obtain a second material. (2) The defoamer, the first material and the second material are mixed in a third mixture to obtain the polymer mortar.

7. The method according to claim 6, characterized in that, In step (2), the third mixing is carried out under stirring conditions, which include: stirring speed of 170-180 rpm and time of 2-4 min.

8. The polymer mortar prepared by the method according to any one of claims 5-7.

9. The application of the polymer mortar according to claim 8 in railway construction.

10. The application according to claim 9, characterized in that, The application in railway construction is its use in the replacement of ballastless track slabs.

Images