An anchoring mortar for precast concrete components and its preparation method

Abstract

This invention discloses a composition for sealing anchors in prestressed concrete precast components, comprising the following components in parts by weight: 100 parts cement, 50-250 parts fine aggregate, 3-25 parts mineral admixtures, 0.1-10 parts polymer, 0.1-5.0 parts modified super activated carbon, 0.1-1.0 parts dispersant, 0.1-2.0 parts expansion component, 0.1-1.0 parts plasticizer, 0-1.2 parts early-strength agent, 0.1-1.5 parts retarder, and 0.1-0.5 parts defoamer; wherein the modified super activated carbon is mainly prepared from petroleum coke, activator, and activation aid as raw materials. This invention also provides a mortar for sealing anchors in prestressed concrete precast components comprising the above composition and water, and its preparation method. The sealing mortar provided by this invention has advantages such as good interfacial adhesion and compatibility, high drying shrinkage and volume stability after hardening, and good resistance to seepage, frost, fatigue, and durability.

Description

Technical Field

[0001] This invention belongs to the technical field of concrete and railway construction materials, specifically relating to a sealing and anchoring mortar for precast concrete components and its preparation method. Background Technology

[0002] In railway construction, precast reinforced concrete components are widely used in structural parts such as bridges, track slabs, and sleepers. To ensure the service stability of these components under conditions of temperature changes, shrinkage and creep, structural system conversion, and train loads, prestressing is required during the fabrication process. This ensures the performance of the precast reinforced concrete components under flexural, shear, and tensile forces. After the reinforcement binding and prestressing are completed, concrete is poured. Once the concrete strength reaches 75% of the design value, the formwork can be removed. At this point, the anchorages formed during prestressing need to be sealed to protect the prestressed steel structure of the track slab from corrosion. Taking the widely used CRTSⅢ type track slab as an example, the diameter of the anchorage is approximately 20mm to 30mm. To ensure the construction quality and service performance of the track slab, relevant units and researchers have conducted extensive research on the sealing mortar.

[0003] The inventors had previously developed a cement mortar for sealing and anchoring concrete track slabs, comprising modified mesoporous zeolite powder, cationic surfactant-treated natural asphalt powder, and dispersible latex powder, and filed an invention patent application on February 27, 2024 (application number CN202410212876.6). Building upon this, the inventors continued their research and development of functional admixtures for the anchoring mortar, aiming to further improve its performance and ensure railway operation safety. Summary of the Invention

[0004] This invention provides a sealing mortar for prestressed concrete precast components and its preparation method. This sealing material has advantages such as simple construction, good interfacial adhesion and compatibility, high stability in volumetric shrinkage after hardening, and good resistance to seepage, frost damage, fatigue, and durability.

[0005] Therefore, the present invention adopts the following technical solution:

[0006] A composition for sealing anchors in prestressed concrete precast components, comprising the following components in parts by weight:

[0007] 100 parts cement, 50-250 parts fine aggregate, 3-25 parts mineral admixture, 0.1-10 parts polymer, 0.1-5.0 parts modified super activated carbon, 0.1-1.0 parts dispersant, 0.1-2.0 parts expanding component, 0.1-1.0 parts plasticizer, 0-1.2 parts early strength agent, 0.1-1.5 parts retarder, and 0.1-0.5 parts defoamer;

[0008] The modified super activated carbon is prepared by the following method:

[0009] 1) Take petroleum coke, crush it, and sieve it to obtain petroleum coke powder with a particle size of 100-300 mesh. Mix the petroleum coke powder with activator and activator powder evenly by mechanical mixing and transfer it to a heating furnace.

[0010] The activator is selected from one or more of sodium hydroxide, potassium hydroxide, and calcium hydroxide in any proportion; the activation aid is selected from one or more of potassium chloride, sodium chloride, calcium chloride, and magnesium chloride in any proportion; the mass ratio of petroleum coke, activator, and activation aid is:

[0011] 1∶2.5~4.5∶0.1~0.3;

[0012] 2) Under nitrogen protection, the temperature is increased in two stages. In the first stage, the temperature is increased to 350-450℃ and held for 1-3 hours. In the second stage, the temperature is increased to 700-800℃ and held for 0.5-2.5 hours. The heating rate of the first and second stages is 5.0±1.0℃ / min.

[0013] 3) Stop heating, allow to cool naturally to room temperature under nitrogen protection, remove the reactants, wash thoroughly with water until pH = 6.0-8.0, and then dry to obtain super activated carbon;

[0014] 4) The polycarboxylate superplasticizer mother liquor, cationic surfactant, shrinkage reducer, and fluorosilicate are premixed evenly, and then mixed with the super activated carbon obtained in step 3). The mixture is stirred thoroughly for 2 to 5 hours under a pressure of 0.3 to 0.5 MPa, filtered, and the filter cake is dried at 115±5℃ for 5 to 10 hours under nitrogen protection to obtain the modified super activated carbon.

[0015] The cationic surfactant is selected from one or more of hexadecyltrimethylammonium bromide, octadecyldimethylammonium chloride, and dodecyldipropylenetriamine in any proportion; the shrinkage reducing agent is selected from one or more of polyacryl alcohol, ethylene oxide-propylene oxide polymer, and dipropyl ethylene glycol monobutyl ether in any proportion; and the fluorosilicate is selected from one or more of sodium fluorosilicate, potassium fluorosilicate, and magnesium fluorosilicate in any proportion.

[0016] The mass ratio of the super activated carbon, cationic surfactant, shrinkage reducing agent, fluorosilicate, and polycarboxylate superplasticizer mother liquor obtained in step 3) is:

[0017] 500:30~60:25~55:15~40:35~66.

[0018] Preferably, in step 1), the particle size of the petroleum coke is 150-250 mesh.

[0019] Preferably, in step 1), the heating furnace is a tubular heating furnace.

[0020] Preferably, in step 1), the mass ratio of petroleum coke, activator, and activating aid is 1:2.8-4.0:0.15-0.25.

[0021] In step 2), the purpose of heating the petroleum coke powder, activator, and activating aid to 350–450°C in the first stage is to enhance the dehydration and carbonization effects. Preferably, the temperature in the first stage is raised to 400 ± 25°C.

[0022] Preferably, in step 2), the temperature is raised to 700±25℃ in the second stage.

[0023] Preferably, in step 3), the washing water is distilled water or deionized water.

[0024] Preferably, in step 3), the drying temperature is 100-110℃ and the drying time is 9-10h.

[0025] Preferably, the mass percentage concentration of the polycarboxylate shrinkage reducer mother liquor is 35% to 45%.

[0026] Preferably, the mass ratio of the super activated carbon, cationic surfactant, shrinkage reducing agent, fluorosilicate, and polycarboxylate superplasticizer mother liquor obtained in step 4) is:

[0027] 500:40~50:35~45:25~35:40~55.

[0028] As a preferred embodiment, the present invention provides a composition for sealing anchors in prestressed concrete precast components, comprising the following components in parts by weight:

[0029] 100 parts cement, 50-150 parts fine aggregate, 5-15 parts mineral admixture, 0.5-8.0 parts polymer, 0.2-4.0 parts modified super activated carbon, 0.1-0.8 parts dispersant, 0.1-1.2 parts expansion component, 0.1-0.6 parts plasticizer, 0.1-0.8 parts early strength agent, 0.2-1.4 parts retarder, and 0.1-0.4 parts defoamer;

[0030] The modified super activated carbon was prepared according to the above method.

[0031] As a more preferred embodiment, the present invention provides a composition for sealing anchors of prestressed concrete precast components, comprising the following components in parts by weight:

[0032] 100 parts cement, 80-140 parts fine aggregate, 5-10 parts mineral admixture, 2.0-8.0 parts polymer, 1.5-3.0 parts modified super activated carbon, 0.1-0.3 parts dispersant, 0.3-1.2 parts expansion component, 0.2-0.6 parts plasticizer, 0.1-0.6 parts early strength agent, 0.5-1.4 parts retarder, and 0.1-0.2 parts defoamer;

[0033] The modified super activated carbon was prepared according to the above method.

[0034] Preferably, the cement is selected from one or more of sulfoaluminate cement and silicate cement in any proportion.

[0035] More preferably, the sulfoaluminate cement is selected from one or more of grade 42.5 and grade 52.5 sulfoaluminate cements in any proportion.

[0036] Preferably, the silicate cement is selected from one or more of grade 42.5, grade 52.5 and grade 62.5 silicate cement in any proportion.

[0037] Preferably, the fine aggregate is selected from one or more of the following: quartz sand, river sand, and mountain sand with a continuous particle size distribution of 40-120 mesh and a moisture content of not more than 0.5%.

[0038] Preferably, the mineral admixture is selected from one or more of Grade I pulverized coal, Grade II fly ash, modified silica fume, and ground slag.

[0039] Preferably, the polymer is a soluble latex powder or a polymer emulsion; wherein the soluble latex powder is selected from one or more of vinyl acetate and ethylene copolymer powder, styrene and butadiene copolymer powder, and acrylate and styrene copolymer powder in any proportion; the polymer emulsion has a solid content of not less than 35% and is selected from one or more of modified acrylic emulsion, styrene-butadiene emulsion, styrene-acrylic emulsion, carboxylated styrene-butadiene emulsion, or vinyl acetate latex in any proportion.

[0040] Preferably, the dispersant is selected from one or more of aminocarboxylic acid water-reducing agents, polycarboxylic acid water-reducing agents, and naphthalene-based water-reducing agents in any proportion.

[0041] Preferably, the expansion component is selected from one or more of plastic expansion agents, UEA expansion components, CSA expansion components, calcium oxide expansion components, and magnesium oxide expansion components.

[0042] Preferably, the plasticizer is selected from one or more of bentonite, hydroxypropyl methylcellulose ether, carbomer resin and modified starch in any proportion.

[0043] Preferably, the early strength agent is selected from one or more of calcium formate, triethanolamine, lithium carbonate, lithium sulfate, and lithium hydroxide in any proportion.

[0044] Preferably, the retarding component is one or more of sodium gluconate, borax, aminated lignin, sodium citrate, boric acid, and tartaric acid in any proportion.

[0045] Preferably, the defoamer is selected from polyethers and organosilicones.

[0046] Another objective of this invention is to provide a sealing mortar for prestressed concrete precast components, comprising the above-mentioned composition and water, wherein the mass ratio of the composition to water is 100:4 to 15.

[0047] Preferably, the mass ratio of the composition to water is 100 parts: 6 to 14.

[0048] Furthermore, the present invention also provides a method for preparing the sealing and anchoring mortar for the prestressed concrete precast components, comprising the following steps:

[0049] S1. Prepare the composition and water for sealing prestressed concrete precast components according to the specified proportions;

[0050] S2. In an apparatus equipped with a stirring device, all solid components in the composition are mixed evenly at a stirring speed of 30 r / min to 90 r / min for a stirring time of not less than 30 s; then water and liquid components (if any) in the composition are added at a stirring speed of not less than 120 r / min for a stirring time of not less than 60 s to obtain the final product.

[0051] Step S2 above can be completed in one go at the construction site. In fact, this step can also be completed in stages: that is, all solid components in the composition of the present invention are mixed evenly in advance and set aside; then at the construction site, the evenly mixed solid mixture, the liquid components (if any) in the composition of the present invention, and water are mixed evenly in proportion to obtain the sealing mortar for prestressed concrete precast components.

[0052] This invention provides a high-performance sealing mortar for anchorages in prestressed concrete precast components, especially prestressed slab track concrete precast components. This sealing mortar utilizes a compounding technique involving cement, fine aggregate, mineral admixtures, polymers, modified super activated carbon, dispersants, expansion components, plasticizers, early-strength agents, retarder components, and defoamers. This results in an mortar with advantages such as easy construction, adjustable working time, good interfacial adhesion and compatibility, high stability of dry shrinkage volume after hardening, and excellent resistance to seepage, frost damage, fatigue, and durability.

[0053] Specifically, the modified super activated carbon of this invention has the following advantages: 1) The microcrystalline and capillary structure of the modified super activated carbon gives it well-developed pores, a large specific surface area, a large micro-mesopore volume, and a strong carrying capacity, enabling functional adsorption on the surface and inside the pore structure, which is conducive to the enrichment of effective components and thus promotes their function. 2) The functional admixture components such as polycarboxylate superplasticizer mother liquor, cationic surfactant, shrinkage reducer, and fluorosilicate adsorbed into the capillary of the super activated carbon can, on the one hand, continuously and for a long time reduce the surface tension of the residual liquid phase inside the pore structure, effectively reduce the drying shrinkage after curing, thereby maintaining volume stability and preventing the generation of cracks in the original concrete matrix; on the other hand, the slow release of functional admixtures adsorbed inside the pore structure can not only prevent and delay the corrosion of steel structural components inside the prestressed anchorage, ensuring the service performance of reinforced concrete precast components; but also, after the generation of micro-cracks, interact with external water to carry out self-repair of the cracks, thereby extending their service life. 3) Super activated carbon has excellent electrochemical performance and high capacity, which can capture free electrons, thereby slowing down the corrosion of reinforced concrete structures. 4) Super activated carbon also plays a role in adjusting the color of the prepared mortar mixture and the hardened product, so that the color of the sealing mortar is consistent with that of the concrete matrix.

[0054] This invention relates to a composition for sealing anchors in prestressed concrete precast components. The composition exhibits good adaptability to both dispersible powder and polymer emulsion, meeting the needs of single-component and two-component construction on-site. The added polymer enhances the adhesive properties of the mortar, improving the bond strength between the mortar and the interface. Furthermore, the simultaneous curing of the mortar and polymer film formation significantly improves the mortar's density, thereby enhancing its impermeability and freeze-thaw resistance. The combination of different expansive agents significantly improves the volume stability of the anchoring mortar at various stages of construction and hardening. The mortar's 28-day shrinkage rate is less than 0.01%, effectively reducing the interfacial stress between the mortar and the track slab substrate, thus ensuring the durability of the anchoring effect. The combination of plasticizers and dispersants effectively improves the workability of the mortar while enhancing its plasticity retention, effectively reducing construction difficulty and improving work efficiency. Detailed Implementation

[0055] The present invention will be described below with reference to specific embodiments. Those skilled in the art will understand that these embodiments are for illustrative purposes only and do not limit the scope of the invention in any way.

[0056] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, all raw materials and reagents used in the following examples are commercially available products. The purchase details of some reagents and raw materials are as follows:

[0057] Plastic expansion agent: Tangshan Polar Bear Building Materials Co., Ltd.;

[0058] UEA expansion component: Tangshan Polar Bear Building Materials Co., Ltd.;

[0059] Dispersible polymer powder: Wacker Chemie (China) Co., Ltd.;

[0060] Petroleum coke: Qilu Petrochemical Research Institute Co., Ltd.;

[0061] Polycarboxylate superplasticizer mother liquor: Jiangsu Subote New Material Co., Ltd.

[0062] The modified super activated carbon used in Examples 1-6 was prepared by the following method:

[0063] 1) Crush the petroleum coke and sieve it to obtain 200-mesh particles for later use. Mix the petroleum coke particles with the activator and activating aid in a mass ratio of 1:3.5:0.2 and place them evenly in a tubular heating furnace.

[0064] 2) Under N2 protection, the tubular heater is heated to 400℃ and held at that temperature for 2.5 hours to enhance dehydration and carbonization. Then, it is heated to 720℃ for activation for 1.0 hour. The heating rate for both stages is (5.0±1.0)℃.

[0065] / min.

[0066] 3) After activation, the sample was naturally cooled to room temperature under N2 protection, then washed thoroughly with deionized water until the pH reached 7.5, and dried in a 105℃ drying oven for 10 hours to obtain super activated carbon.

[0067] 4) Mix the super activated carbon obtained in step 3) with octadecyl dimethyl ammonium chloride, ethylene oxide-propylene oxide polymer, fluorosilicate, and polycarboxylate superplasticizer mother liquor at a mass percentage of 500:45:40:

[0068] Mix at a ratio of 30:45 and stir thoroughly for 3 hours under a pressure of 0.3 MPa. Filter the mixture and dry the filter cake at 110°C for 6 hours under N2 protection to obtain modified super activated carbon for later use.

[0069] Specifically, when the activator is potassium hydroxide, the activating aid is potassium chloride, and the fluorosilicate is potassium fluorosilicate, modified super activated carbon 1# is obtained; when the activator is sodium hydroxide, the activating aid is potassium chloride, and the fluorosilicate is magnesium fluorosilicate, modified super activated carbon 2# is obtained; and when the activator is potassium hydroxide, the activating aid is potassium chloride, and the fluorosilicate is magnesium fluorosilicate, modified super activated carbon 3# is obtained.

[0070] Example 1: A composition for sealing anchors in prestressed concrete precast components and a sealing mortar for prestressed concrete precast components.

[0071] The composition of the composition in this embodiment is shown in Table 1, where 1 part by mass = 50g; wherein:

[0072] The cement is grade 52.5 rapid-hardening sulfoaluminate cement;

[0073] The fine aggregate is manufactured sand with a continuous particle size distribution of 60 mesh to 120 mesh;

[0074] The mineral admixture consists of modified silica fume and Class I fly ash in a mass ratio of 2:3;

[0075] The polymer is a styrene-butadiene copolymer redispersible latex powder;

[0076] The modified super activated carbon is modified super activated carbon #1;

[0077] The expansion component consists of a plastic expansion agent and a UEA expansion component in a mass ratio of 1:10;

[0078] The plasticizer is hydroxypropyl methylcellulose ether;

[0079] The dispersant is a polycarboxylate superplasticizer;

[0080] The early strength agent is lithium carbonate;

[0081] The retarding components are tartaric acid and boric acid in a mass ratio of 1:1;

[0082] The defoamer is an organosilicon powder defoamer.

[0083] After weighing all the components of the above composition according to the proportion, add them to the mixer and stir at 60 r / min for 45 s to obtain the composition; then add an appropriate amount of mixing water according to the proportion and stir at 150 r / min for 90 s to finally obtain the sealing mortar for prestressed concrete precast components.

[0084] Example 2: A composition for sealing anchors in prestressed concrete precast components and a sealing mortar for prestressed concrete precast components.

[0085] The composition of the composition in this embodiment is shown in Table 1, where 1 part by mass = 50g; wherein:

[0086] The cement is grade 52.5 rapid-hardening sulfoaluminate cement and silicate cement in a mass ratio of 5:1;

[0087] The fine aggregate is river sand of 60-120 mesh with a moisture content of 0.1%;

[0088] The mineral admixture is Grade I fly ash;

[0089] The polymer is a redispersible latex powder copolymerized with acrylate and styrene;

[0090] The modified super activated carbon is modified super activated carbon #1;

[0091] The expansion components consist of 300-mesh flake aluminum powder, plastic expansion agent, and UEA expansion component in a mass ratio of 1:2:12.

[0092] The plasticizer is hydroxypropyl methylcellulose ether;

[0093] The dispersant is a polycarboxylate superplasticizer;

[0094] The early strength agent is lithium carbonate and calcium formate in a mass ratio of 1:10;

[0095] The retarding components are tartaric acid and citric acid in a mass ratio of 1:1;

[0096] The defoamer is an organosilicon powder defoamer.

[0097] The prestressed concrete precast component sealing mortar of this embodiment was prepared according to the same process steps as in Example 1.

[0098] Example 3: A composition for sealing anchors in prestressed concrete precast components and a sealing mortar for prestressed concrete precast components.

[0099] The composition of the composition described in this embodiment is shown in Table 1, where 1 part by mass = 50g; wherein:

[0100] The cement is 1 / 5 of grade 52.5 rapid-hardening sulfoaluminate cement and silicate cement;

[0101] The fine aggregate consists of machine-made silica sand and dried river sand in a mass ratio of 1:1, with a moisture content of no more than 0.1%.

[0102] The mineral admixture is modified silica fume;

[0103] The polymer is a redispersible latex powder copolymerized from vinyl acetate and ethylene;

[0104] The modified super activated carbon is modified super activated carbon #2;

[0105] The expansion components consist of 300-mesh granular aluminum powder, plastic expansion agent, and UEA expansion component in a mass ratio of 1:1:10.

[0106] The plasticizer is a mixture of bentonite and hydroxypropyl methylcellulose ether in a mass ratio of 3:1;

[0107] The dispersant is a polycarboxylate high-performance water-reducing agent;

[0108] The early strength agent is calcium formate and lithium hydroxide in a mass ratio of 5:1;

[0109] The retarding components are sodium gluconate and aminated lignin in a mass ratio of 4:1;

[0110] The defoamer is an organosilicon powder defoamer.

[0111] The prestressed concrete precast component sealing mortar of this embodiment was prepared according to the same process steps as in Example 1.

[0112] Example 4: A composition for sealing anchors in prestressed concrete precast components and a sealing mortar for prestressed concrete precast components.

[0113] The composition of the composition described in this embodiment is shown in Table 1, where 1 part by mass = 50g; wherein:

[0114] The cement is grade 52.5 rapid-hardening sulfoaluminate cement;

[0115] The fine aggregate is manufactured sand with a continuous particle size distribution of 60 mesh to 120 mesh;

[0116] The mineral admixture consists of modified silica fume and Class I fly ash in a mass ratio of 2:3;

[0117] The modified super activated carbon is modified super activated carbon #3;

[0118] The expansion component consists of a plastic expansion agent and a UEA expansion component in a mass ratio of 1:10;

[0119] The plasticizer is hydroxypropyl methylcellulose ether;

[0120] The dispersant is a polycarboxylate superplasticizer;

[0121] The early strength agent is lithium carbonate;

[0122] The retarding components are tartaric acid and boric acid in a mass ratio of 1:1;

[0123] The defoamer is an organosilicon powder defoamer;

[0124] The polymer emulsion is a copolymer emulsion of styrene and acrylic monomers with a mass concentration of 45%.

[0125] After weighing the solid components according to the proportion, add them to the mixer and stir at 60 r / min for 45 s until they are evenly mixed. Then add the polymer emulsion and mixing water according to the proportion and stir at 150 r / min for 90 s to finally obtain the sealing mortar for prestressed concrete precast components.

[0126] Example 5: A composition for sealing anchors in prestressed concrete precast components and a sealing mortar for prestressed concrete precast components.

[0127] The composition of the composition described in this embodiment is shown in Table 1, where 1 part by mass = 50g; wherein:

[0128] The cement is grade 52.5 silicate cement;

[0129] The fine aggregate consists of machine-made silica sand and dried river sand with a moisture content of no more than 0.1% in a mass ratio of 1:2;

[0130] The mineral admixture is modified silica fume;

[0131] The modified super activated carbon is modified super activated carbon #3;

[0132] The expansion components consist of aluminum powder, plastic expansion agent, and CSA expansion component in a mass ratio of 1:1:10.

[0133] The plasticizer is a mixture of bentonite and hydroxypropyl methylcellulose ether in a mass ratio of 10:1;

[0134] The dispersant is a polycarboxylate high-performance water-reducing agent;

[0135] The early-strength agent is calcium acetate;

[0136] The retarding components are lignin sulfonate amine and tartaric acid in a mass ratio of 1:1;

[0137] The polymer emulsion is an acrylic copolymer emulsion with a mass concentration of 45%.

[0138] The prestressed concrete precast component sealing mortar of this embodiment was prepared according to the same process steps as in Example 4.

[0139] Example 6: A composition for sealing anchors in prestressed concrete precast components and a sealing mortar for prestressed concrete precast components.

[0140] The types and compositions of cement, mineral admixtures, fine aggregates, super activated carbon, expansion components, plasticizers, dispersants, early strength agents, retarder components, defoamers, and polymer emulsions in this embodiment are the same as in Example 5. The difference is that when preparing the cement mortar, all components of the solid raw materials are first put into a high-speed mixer in proportion and mixed at high speed for 10 minutes to obtain a uniform dry powder, which is then sealed and set aside.

[0141] Then, when preparing the sealing mortar at the construction site, the pre-prepared dry powder, polymer emulsion, and mixing water are added to the mixer according to the mixing ratio and stirred at 120r / min for 150s to obtain the sealing mortar for prestressed concrete precast components.

[0142] Comparative Example 1: A type of cement mortar

[0143] The solid raw material composition of the cement mortar in this comparative example is shown in Table 1, where 1 part by mass = 50g; wherein:

[0144] The cement is a 1:5 ratio of 52.5 grade rapid-hardening sulfoaluminate cement and silicate cement;

[0145] The fine aggregate consists of machine-made silica sand and dried river sand in a mass ratio of 1:1, with a moisture content of no more than 0.1%.

[0146] The mineral admixture is modified silica fume;

[0147] The polymer is a redispersible latex powder of vinyl acetate and ethylene copolymer;

[0148] The expansion components consist of 300-mesh granular aluminum powder, plastic expansion agent, and UEA expansion component in a mass ratio of 1:1:10.

[0149] The plasticizer is a mixture of bentonite and hydroxypropyl methylcellulose ether in a mass ratio of 3:1;

[0150] The dispersant is a polycarboxylate high-performance water-reducing agent;

[0151] The early strength agent is calcium formate and lithium hydroxide in a mass ratio of 5:1;

[0152] The retarding components are sodium gluconate and aminated lignin in a mass ratio of 4:1;

[0153] The defoamer is an organosilicon powder defoamer.

[0154] The cement mortar of this comparative example was prepared using the same process steps as in Example 1.

[0155] Comparative Example 2: A type of cement mortar

[0156] The solid raw material composition of the cement mortar in this comparative example is shown in Table 1, where 1 part by mass = 50g; wherein:

[0157] The cement is a 1:5 ratio of 52.5 grade rapid-hardening sulfoaluminate cement and silicate cement;

[0158] The fine aggregate consists of machine-made silica sand and dried river sand in a mass ratio of 1:1, with a moisture content of no more than 0.1%.

[0159] The mineral admixture is modified silica fume;

[0160] The activated carbon used is commercially available 300-mesh activated carbon;

[0161] The polymer is a redispersible latex powder copolymerized from vinyl acetate and ethylene;

[0162] The expansion components consist of 300-mesh granular aluminum powder, plastic expansion agent, and UEA expansion component in a mass ratio of 1:1:10.

[0163] The plasticizer is a mixture of bentonite and hydroxypropyl methylcellulose ether in a mass ratio of 3:1;

[0164] The dispersant is a polycarboxylate high-performance water-reducing agent;

[0165] The early strength agent is calcium formate and lithium hydroxide in a mass ratio of 5:1;

[0166] The retarding components are sodium gluconate and aminated lignin in a mass ratio of 4:1;

[0167] The defoamer is an organosilicon powder defoamer.

[0168] The cement mortar of this comparative example was prepared using the same process steps as in Example 1.

[0169] Comparative Example 3: A type of cement mortar

[0170] The solid raw material composition of the cement mortar in this comparative example is shown in Table 1, where 1 part by mass = 50g; wherein:

[0171] The cement is a 1:5 ratio of 52.5 grade rapid-hardening sulfoaluminate cement and silicate cement;

[0172] The fine aggregate consists of machine-made silica sand and dried river sand in a mass ratio of 1:1, with a moisture content of no more than 0.1%.

[0173] The mineral admixture is modified silica fume;

[0174] The activated carbon was prepared using essentially the same process steps as the super activated carbon described in Example 1, with the difference being:

[0175] 1) The mass ratio of petroleum coke particles to potassium hydroxide and potassium chloride is 1:1:0.3;

[0176] 2) Octadecyl dimethyl ammonium chloride is replaced with tallow amine, ethylene oxide and propylene oxide polymer is replaced with glycerol, magnesium fluorosilicate is replaced with calcium acetate, and the mass percentage of super activated carbon to cationic surfactant, shrinkage reducer, fluorosilicate, and polycarboxylate superplasticizer mother liquor is 500:35:50:30:35.

[0177] The polymer is a redispersible latex powder of vinyl acetate and ethylene copolymer;

[0178] The expansion components consist of 300-mesh granular aluminum powder, plastic expansion agent, and UEA expansion component in a mass ratio of 1:1:10.

[0179] The plasticizer is a mixture of bentonite and hydroxypropyl methylcellulose ether in a mass ratio of 3:1;

[0180] The dispersant is a polycarboxylate high-performance water-reducing agent;

[0181] The early strength agent is calcium formate and lithium hydroxide in a mass ratio of 5:1;

[0182] The retarding components are sodium gluconate and aminated lignin in a mass ratio of 4:1;

[0183] The defoamer is an organosilicon powder defoamer.

[0184] The cement mortar of this comparative example was prepared using the same process steps as in Example 1.

[0185] Comparative Example 4: A type of cement mortar

[0186] The solid raw material composition of the cement mortar in this comparative example is shown in Table 1. Except for the amount of modified super activated carbon, the types and amounts of other raw materials are completely consistent with those in Example 3.

[0187] The cement mortar of this comparative example was prepared using the same process steps as in Example 1.

[0188] Table 1. Mass parts of cement mortar components in Examples 1-6 and Comparative Examples 1-4

[0189]

[0190] Mortar performance determination in various examples and comparative cases

[0191] According to the standards GB / T 17671-2021 "Test Method for Strength of Cement Mortar", DL / T5126-2001 "Test Procedure for Polymer Modified Cement Mortar", and GB / T50082-2009 "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete", the sealing mortars prepared in Examples 1 to 6 and the mortars prepared in Comparative Examples 1 to 4 were tested for performance. The test results are shown in Table 2.

[0192] Table 2 shows that the sealing and anchoring mortars described in Examples 1-6 all have a 1-day compressive strength greater than 50 MPa, a 7-day compressive strength greater than 60 MPa, a 28-day strength greater than 70 MPa, a 28-day shrinkage rate less than 0.01%, a push-out force greater than 10 kN, a bond strength greater than 3 MPa, a fatigue deformation of less than 0.02 mm after 3 million cycles, a relative dynamic modulus of elasticity greater than 95% for frost resistance, and a mass loss rate of less than 1.0%. These data all indicate that the sealing and anchoring mortar of the present invention has advantages such as good interfacial adhesion and compatibility, high drying shrinkage and volume stability after hardening, and good resistance to seepage, frost, fatigue, and durability.

[0193] The composition and dosage of mortar raw materials in Comparative Examples 1-4 are basically the same as those in Example 3. The differences are as follows: Comparative Example 1 omits modified super activated carbon; Comparative Example 2 uses commercially available activated carbon powder; the preparation process of the modified super activated carbon powder in Comparative Example 3 is different from that of this invention; and although Comparative Example 4 uses the modified super activated carbon of this invention, its dosage exceeds the range defined by this invention. Comparison of the test results with Example 3 shows that: because Comparative Example 1 did not add the modified super activated carbon involved in this invention, the performance of its mortar is significantly lower than that of the sealing and anchoring mortar in Example 3; while Comparative Example 4 added modified super activated carbon exceeding the range defined by this invention, and the performance of its sealing and anchoring mortar is close to that of the sealing and anchoring mortar in Example 3, but some indicators are slightly lower. However, because it used a relatively large amount of modified super activated carbon, the cost of the mortar is higher than that of Example 3, thus reducing its economic efficiency; the performance of the sealing and anchoring mortars prepared in Comparative Examples 2 and 4 is also significantly lower than that of the sealing and anchoring mortar prepared in Example 3. It is evident that the modified super activated carbon powder of this invention plays a particularly important role in various properties of mortar, especially volume stability, fatigue resistance, and freeze-thaw resistance.

[0194] Table 2. Mortar properties prepared in Examples 1-6 and Comparative Examples 1-4

[0195]

[0196] In summary, the above description of specific embodiments does not limit the present invention. The upper and lower limits and range values ​​of the sealing mortar raw materials involved in the present invention can realize the present invention. Those skilled in the art can make various changes or modifications based on the present invention. As long as they do not depart from the spirit of the present invention, they should all fall within the scope of the appended claims.

Claims

1. A composition for sealing anchors in prestressed concrete precast components, comprising the following components in parts by weight: 100 parts cement, 50-250 parts fine aggregate, 3-25 parts mineral admixture, 0.1-10 parts polymer, 0.1-5.0 parts modified super activated carbon, 0.1-1.0 parts dispersant, 0.1-2.0 parts expansion component, 0.1-1.0 parts plasticizer, 0-1.2 parts early strength agent, 0.1-1.5 parts retarder component, and 0.1-0.5 parts defoamer; in, The modified super activated carbon is prepared by the following method: 1) Take petroleum coke, crush it, and sieve it to obtain petroleum coke powder with a particle size of 100~300 mesh. Mix the petroleum coke powder with activator and activator powder evenly by mechanical mixing and transfer it to a heating furnace. The activator is selected from one or more of sodium hydroxide, potassium hydroxide, and calcium hydroxide in any proportion; the activation aid is selected from one or more of potassium chloride, sodium chloride, calcium chloride, and magnesium chloride in any proportion; the mass ratio of petroleum coke, activator, and activation aid is: 1∶2.5~4.5∶0.1~0.3； 2) Under nitrogen protection, the temperature is increased in two stages. In the first stage, the temperature is increased to 350~450℃ and held for 1h~3h. In the second stage, the temperature is increased to 700~800℃ and held for 0.5h~2.5h. The heating rate of the first and second stages is 5.0±1.0℃ / min. 3) Stop heating, allow to cool naturally to room temperature under nitrogen protection, remove the reactants, wash thoroughly with water until pH=6.0~8.0, and then dry to obtain super activated carbon; 4) The polycarboxylate superplasticizer mother liquor, cationic surfactant, shrinkage reducer, and fluorosilicate are premixed evenly, and then mixed with the super activated carbon obtained in step 3). The mixture is stirred thoroughly for 2 to 5 hours under a pressure of 0.3 to 0.5 MPa, filtered, and the filter cake is dried at 115±5℃ for 5 to 10 hours under nitrogen protection to obtain the modified super activated carbon. The cationic surfactant is selected from one or more of hexadecyltrimethylammonium bromide, octadecyldimethylammonium chloride, and dodecyldipropylenetriamine in any proportion; the shrinkage reducing agent is selected from one or more of polyacryl alcohol, ethylene oxide-propylene oxide polymer, and dipropyl ethylene glycol monobutyl ether in any proportion; and the fluorosilicate is selected from one or more of sodium fluorosilicate, potassium fluorosilicate, and magnesium fluorosilicate in any proportion. The mass ratio of the super activated carbon, cationic surfactant, shrinkage reducing agent, fluorosilicate, and polycarboxylate superplasticizer mother liquor obtained in step 3) is: 500∶30~60∶25~55∶15~40∶35~66。 2. The composition for sealing anchors of prestressed concrete precast components according to claim 1, characterized in that, In step 1), the particle size of the petroleum coke is 150-250 mesh.

3. The composition for sealing anchors of prestressed concrete precast components according to claim 1, characterized in that, In step 1), the heating furnace is a tubular heating furnace.

4. The composition for sealing anchors of prestressed concrete precast components according to claim 1 or 2, characterized in that, The mass ratio of the petroleum coke, activator, and activating aid is 1:2.8~4.0:0.15~0.

25.

5. The composition for sealing anchors of prestressed concrete precast components according to claim 1, characterized in that, In step 2), the temperature is raised to 400±25℃ in the first stage.

6. The composition for sealing anchors of prestressed concrete precast components according to claim 1, characterized in that, In step 3), the washing water is distilled water or deionized water.

7. The composition for sealing anchors of prestressed concrete precast components according to claim 1, characterized in that, In step 3), the drying temperature is 100~110℃ and the drying time is 9~10h.

8. The composition for sealing anchors of prestressed concrete precast components according to claim 1, characterized in that, The mass percentage concentration of the polycarboxylate superplasticizer mother liquor is 35%~45%.

9. The composition for sealing anchors of prestressed concrete precast components according to claim 1 or 8, characterized in that, The mass ratio of the super activated carbon, cationic surfactant, shrinkage reducing agent, fluorosilicate, and polycarboxylate superplasticizer mother liquor obtained in step 3) is: 500∶40~50∶35~45∶25~35∶40~55。 10. The composition for sealing anchors of prestressed concrete precast components according to claim 1, characterized in that, The composition comprises the following components in parts by weight: 100 parts cement, 50-150 parts fine aggregate, 5-15 parts mineral admixture, 0.5-8.0 parts polymer, 0.2-4.0 parts modified super activated carbon, 0.1-0.8 parts dispersant, 0.1-1.2 parts expansion component, 0.1-0.6 parts plasticizer, 0.1-0.8 parts early strength agent, 0.2-1.4 parts retarder, and 0.1-0.4 parts defoamer; The method for preparing the modified super activated carbon is as defined in any one of claims 1 to 9.

11. The composition for sealing anchors of prestressed concrete precast components according to claim 10, characterized in that, The composition for sealing anchors of prestressed concrete precast components comprises the following components in parts by weight: 100 parts cement, 80-140 parts fine aggregate, 5-10 parts mineral admixture, 2.0-8.0 parts polymer, 1.5-3.0 parts modified super activated carbon, 0.1-0.3 parts dispersant, 0.3-1.2 parts expansion component, 0.2-0.6 parts plasticizer, 0.1-0.6 parts early strength agent, 0.5-1.4 parts retarder, and 0.1-0.2 parts defoamer; The method for preparing the modified super activated carbon is as defined in any one of claims 1 to 9.

12. The composition for sealing anchors of prestressed concrete precast components according to claim 1, 10, or 11, characterized in that, The cement is selected from one or more of sulfoaluminate cement and silicate cement in any proportion.

13. The composition for sealing anchors of prestressed concrete precast components according to claim 12, characterized in that, The sulfoaluminate cement is selected from one or more of grade 42.5 and grade 52.5 sulfoaluminate cements in any proportion.

14. The composition for sealing anchors of prestressed concrete precast components according to claim 12, characterized in that, The silicate cement is selected from one or more of grade 42.5, 52.5 and 62.5 silicate cements in any proportion.

15. The composition for sealing anchors of prestressed concrete precast components according to claim 1, 10, or 11, characterized in that, The fine aggregate is selected from one or more of the following: quartz sand, river sand, and mountain sand with a continuous particle size distribution of 40-120 mesh and a moisture content of no more than 0.5%.

16. The composition for sealing anchors of prestressed concrete precast components according to claim 1, 10, or 11, characterized in that, The mineral admixture is selected from one or more of Grade I fly ash, Grade II fly ash, modified silica fume, and ground granulated slag.

17. The composition for sealing anchors of prestressed concrete precast components according to claim 1, 10, or 11, characterized in that, The polymer is a soluble latex powder or a polymer emulsion; wherein the soluble latex powder is selected from one or more of vinyl acetate and ethylene copolymer powder, styrene and butadiene copolymer powder, and acrylate and styrene copolymer powder in any proportion; the polymer emulsion has a solid content of not less than 35% and is selected from one or more of modified acrylic emulsion, styrene-butadiene emulsion, styrene-acrylic emulsion, carboxylated styrene-butadiene emulsion, or vinyl acetate latex in any proportion.

18. The composition for sealing anchors of prestressed concrete precast components according to claim 1, 10, or 11, characterized in that, The dispersant is selected from one or more of aminocarboxylic acid water-reducing agents, polycarboxylic acid water-reducing agents, and naphthalene-based water-reducing agents in any proportion.

19. The composition for sealing anchors of prestressed concrete precast components according to claim 1, 10, or 11, characterized in that, The expansion component is selected from one or more of the following: plastic expansion agent, UEA expansion component, CSA expansion component, calcium oxide expansion component, and magnesium oxide expansion component.

20. The composition for sealing anchors of prestressed concrete precast components according to claim 1, 10, or 11, characterized in that, The plasticizer is selected from one or more of bentonite, hydroxypropyl methylcellulose ether, carbomer resin and modified starch in any proportion.

21. The composition for sealing anchors of prestressed concrete precast components according to claim 1, 10, or 11, characterized in that, The early strength agent is selected from one or more of calcium formate, triethanolamine, lithium carbonate, lithium sulfate, and lithium hydroxide in any proportion.

22. The composition for sealing anchors of prestressed concrete precast components according to claim 1, 10, or 11, characterized in that, The retarding component is one or more of sodium gluconate, borax, aminated lignin, sodium citrate, boric acid, and tartaric acid in any proportion.

23. The composition for sealing anchors of prestressed concrete precast components according to claim 1, 10, or 11, characterized in that, The defoamer is selected from polyethers and organosilicones.

24. A sealing mortar for prestressed concrete precast components, comprising the composition of any one of claims 1 to 23 and water, wherein the mass ratio of the composition to water is 100:4 to 15.

25. The sealing mortar for prestressed concrete precast components according to claim 24, characterized in that, The mass ratio of the composition to water is 100:6~14.

26. The method for preparing sealing mortar for prestressed concrete precast components according to claim 24 or 25, comprising the following steps: S1. Prepare the composition and water for sealing prestressed concrete precast components according to the specified proportions; S2. In an apparatus equipped with a stirring device, all solid components in the composition are mixed evenly at a stirring speed of 30 r / min to 90 r / min for a stirring time of not less than 30 s; then water and the liquid components in the composition are added at a stirring speed of not less than 120 r / min for a stirring time of not less than 60 s to obtain the final product.

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