A set retarding agent for high fluidity cementitious materials and methods of making and using the same

Abstract

The application discloses a large-flow-state cement-based material anti-water bleeding agent and a preparation and use method thereof, and belongs to the technical field of building materials, and comprises the following raw materials in parts by weight: 20-30 parts of building solid waste regenerated powder, 5-10 parts of water-absorbing resin, 35-52 parts of water-retention suspension stabilizer, 1-6 parts of diethanolamine, 10-15 parts of malt dextrin, 1-2 parts of anhydrous cocoyl betaine, 2-5 parts of alpha-naphthyl sulfonic acid sodium and 1-5 parts of organic silicon defoaming agent. The large-flow-state cement-based material anti-water bleeding agent can effectively absorb the excess moisture in the cement-based material, improve the dispersibility, cohesiveness and fluidity of the cement-based material, has the advantages of quick effect, simple and convenient implementation operation and the ability to cope with different degrees of water bleeding.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of building materials, and particularly relates to a large-flow-state cement-based material anti-seepage agent and a preparation and use method thereof. BACKGROUND

[0002] Cement-based materials, including cement concrete, cement mortar and cement paste materials, are important application materials in the field of engineering construction, and have the characteristics of low cost, high strength and good durability. In order to improve the construction efficiency and facilitate the molding, cement concrete, mortar and paste materials mostly adopt a large flow state, including but not limited to: ①pumping concrete / mortar, which greatly facilitates the transportation and molding of concrete / mortar, and greatly improves the molding speed; ②self-leveling concrete / mortar, which relies on its good fluidity to achieve a smooth pouring surface without vibration after pouring, and has a slump requirement of ≥230mm, an extension requirement of ≥600mm, and an inverted slump cylinder extension time of ≤5s; ③vibration-free concrete, which can meet the strength requirements, impermeability and various durability requirements without vibration molding; ④self-compacting concrete, which can achieve high compactness without vibration, so that the concrete meets the strength and durability requirements; ⑤underwater pile concrete, which fully utilizes the fluidity of concrete to discharge in the underwater pile while ensuring the cohesiveness of the concrete under water to form high strength; and ⑥cement-based grouting / pressing / infusion material, which must achieve a large flow state and uniform dispersion without water seepage and stratification in order to fully fill the voids and play a role in bonding and fixing. From the above cement-based materials, the large fluidity not only facilitates the transportation of the materials, but also reduces the energy consumption in the material molding process, and maximizes the convenience of the construction process. However, a large flow state often requires a relatively large amount of water. Water is an important component in the hydration process of cement, which not only participates in the chemical reaction of cement strength increase process, but also provides the basis for the fluidity of cement-based materials. However, the density of water is much smaller than that of cement, so excessive water will easily cause different degrees of water seepage. Water seepage refers to the sinking of cementitious materials and sandstone and the floating of water from the surface of the mixture due to the much lower density of water relative to cementitious materials and sandstone. Therefore, due to the fluctuation of water content in each raw material, the different water demand and fluidity ratio, water seepage often occurs, only the degree is different.

[0003] Slight bleeding is very common in the application process of cement-based materials, and it has little adverse effect on the quality of concrete if the surface treatment and curing method are in place when forming, but if the bleeding rate exceeds a certain degree, it will have a great deteriorating effect on the material quality, the aggregate sinks, the surface water-cement ratio suddenly increases, which seriously affects the uniformity of the mixture, the strength and durability will be poor, and the difference in temperature change volume change caused by the difference in water-cement ratio is easy to cause serious cracking, and the sinking of the aggregate will also cause obvious settlement shrinkage and cracking, and if the bleeding degree increases, it will seriously affect the construction of the material, causing the blockage of the conveying equipment, and even if it is poured and formed, the material is prone to honeycomb and pitted surface, causing serious economic losses. Therefore, bleeding is an important indicator that needs to be strictly controlled in the production and construction process of cement-based materials.

[0004] At present, the bleeding of cement-based materials is generally treated by reprocessing and reprocessing, and there is no direct and effective material to improve it on site, which not only delays the construction time, but also affects the original proportion of the material, causing risks to quality control. In the production process of cement-based materials, ① the water consumption is different due to the different moisture contents of sand and stone, and the moisture content of the lower part is often higher than that of the upper part during the storage of sand and stone, and the water consumption cannot be adjusted in real time during the production process, causing fluctuations in the water content of the mixture; ② the different rock properties of sand and stone cause different saturated surface water absorption rates, even if the actual water consumption is unchanged, the difference in flowability of the mixture will also cause the bleeding rate to change accordingly; ③ the fluctuations in the water demand, flowability ratio of cement, fly ash, and mineral powder, and the changes in the fineness of these powders will greatly affect the bleeding rate of the final mixture. In addition to the above key factors, the sphericity of the aggregate, the sand and stone MB value, and excessive vibration during construction will also cause different degrees of bleeding in the final cement-based mixture material, increasing the risk of quality.

[0005] Therefore, how to provide an additive that can improve the bleeding problem of cement-based materials after stirring and effectively reduce the bleeding rate of the material is a technical problem that technicians in the field need to solve. SUMMARY

[0006] To solve the above technical problems, the present application provides a large-flow cement-based material anti-bleeding agent and its preparation and use method.

[0007] To achieve the above purpose, the present application provides the following technical solutions:

[0008] A large-flow cement-based material anti-bleeding agent, comprising the following raw materials by weight:

[0009] 20-30 parts of recycled construction solid waste powder, 5-10 parts of water-absorbing resin, 35-52 parts of water-retaining suspension stabilizer, 1-6 parts of diethanolamine, 10-15 parts of maltodextrin, 1-2 parts of anhydrous cocamidopropyl betaine, 2-5 parts of sodium α-alkenyl sulfonate, and 1-5 parts of organosilicon defoamer.

[0010] Preferably, the specific surface area of ​​the recycled construction waste powder is ≥500m². 2 / kg, is made from recycled sand powder from construction solid waste that meets the Class B technical requirements in standard JCT 2548-2019 "Recycled Sand Powder from Construction Solid Waste" through grinding.

[0011] Preferably, the water requirement ratio of the recycled sand powder from the construction solid waste is <2.0 and >1.8.

[0012] Beneficial effects: The recycled construction waste powder in this invention is made by grinding recycled construction waste sand powder that meets the Class B technical requirements of standard JCT 2548-2019 "Recycled Construction Waste Sand Powder". The water requirement ratio of the recycled construction waste sand powder must be <2.0 and >1.8, and the specific surface area after grinding is ≥500 m². 2 / kg. Because Class B construction solid waste recycled sand powder requires a relatively high water content, more water is needed to achieve the same fluidity requirements. Further grinding is then applied to increase the specific surface area to 500m². 2 At concentrations above / kg, it can effectively utilize excess exuded water, reducing bleeding while increasing the water retention of cement-based materials, thus ensuring their fluidity. Furthermore, recycled sand and powder from construction waste typically exhibit good compatibility with polycarboxylate superplasticizers, reducing bleeding caused by increased admixtures and also contributing to viscosity reduction.

[0013] Secondly, the water-absorbing resin in this invention has good adsorption properties, enabling it to adsorb excess water in cement-based materials. Diethanolamine mainly improves the hydration rate of cement and compensates for the delayed cement setting time caused by guar gum-modified polysaccharides, thus normalizing the setting time of cement-based materials that need adjustment. It also plays a role in early strength and accelerated setting. Excess exuded water increases the water-cement ratio of the material, which is detrimental to strength development; therefore, this component effectively solves this problem. Maltodextrin should meet the MD20 technical requirements in the national standard GB / T20884-2007 "Maltodexrin," mainly playing a role in adjusting the adhesion of cement-based materials. Exudation of water causes cement-based materials to easily separate, resulting in poor adhesion between cement-based materials and other materials; this component improves the bonding between the two materials. The colloidal material in this invention can improve the viscosity and dispersibility of cement paste, thus improving the performance of concrete. Uniformity; Sodium α-olefin sulfonate (AOS) is an anionic surfactant prepared by sulfonation and continuous neutralization of α-olefins in SO3 gas phase film. It can introduce a small number of fine bubbles, reduce the viscosity of the mixture, and reduce the problem of excessive viscosity caused by colloidal materials; Anhydrous cocamidopropyl betaine is a high-performance amphoteric surfactant. It is a powder prepared by drying coconut oil, N,N-dimethylpropylenediamine, and sodium chloroacetate. It can improve the foam stability of the above-mentioned AOS, ensuring that the microbubbles introduced into the system have good continuity before the initial setting time of cement, and the mixture can always maintain the characteristics of uniformity, high flowability, and low viscosity; Organosilicon defoamers should meet the technical requirements of ordinary solid type in the national standard GB / T26527-2024 "Organosilicon Defoamers", and can reduce the content of larger bubbles in the system and increase the density of cement-based materials.

[0014] Preferably, the water-retaining suspension stabilizer is a low molecular weight nonionic polysaccharide polymer, prepared by modification of guar gum, and the specific preparation method includes the following steps:

[0015] After removing the skin and germ from guar beans, the seeds are dried, pulverized, and then water is added. The mixture is then subjected to pressurized hydrolysis, precipitated with 20% ethanol, centrifuged, dried, and pulverized to obtain the water-retaining suspension stabilizer.

[0016] Beneficial effects: The water-retaining suspension stabilizer in this invention is mainly composed of galactose and mannose. Excessive water loss in bleed concrete leads to inconsistent viscosity of the mixture. The addition of modified guar gum polysaccharide can improve the cohesiveness of the cement paste and increase the viscosity of the mixture. Furthermore, its addition slightly prolongs the setting time of the cement paste.

[0017] Preferably, the water-absorbing resin is a starch-grafted acrylate polymer crosslinker and an acrylamide-acrylate copolymer crosslinker.

[0018] Preferably, the mass ratio of the starch-grafted acrylate polymer crosslinker to the acrylamide-acrylate copolymer crosslinker is (0.34-0.37):1.

[0019] Beneficial effects: The water-absorbing resin in this invention can absorb excess water to form a gel when added to the bleeding cement-based mixture, reducing the bleeding rate of the cement-based material. However, it also increases the viscosity of the mixture. Acrylamide-acrylate copolymer crosslinking has a good water absorption rate, but the viscosity increases and it reduces the coating of cement paste and aggregate, reducing the fluidity of the cement-based mixture. This is not conducive to the application of the high-fluidity material applicable to this invention. Therefore, adding some starch-grafted acrylate copolymer crosslinking ensures both water absorption rate and fluidity of the mixture.

[0020] A method for preparing an anti-bleeding agent for high-fluidity cement-based materials involves weighing the raw materials and mixing them evenly to obtain the anti-bleeding agent for high-fluidity cement-based materials.

[0021] A method for using an anti-bleeding agent for high-fluidity cement-based materials includes the following steps:

[0022] The bleeding rate of the cement-based material is tested, and the anti-bleeding agent is added to the cement-based material while stirring, depending on the severity of the bleeding, until the bleeding rate is reduced to within the range required for construction.

[0023] A method for detecting anti-bleeding agents for high-fluidity cement-based materials, corresponding to the reduction in bleeding rate, is provided by the following method: ΔB = 4% - Bc;

[0024] Where: ΔB is the decrease in the rate of water leakage;

[0025] 4% represents excessive water usage, resulting in a 4% bleeding rate;

[0026] Bc represents the water content exceeding the allowable level, resulting in a bleeding rate of 4%. After adding an anti-bleeding agent, the bleeding rate of the concrete is further reduced.

[0027] Preferably, the amount of anti-bleeding agent incorporated into Bc is 80 g / m³. 3 .

[0028] Preferably, ΔB is greater than 3.5%.

[0029] The test results are expressed as the average of the three batches of test measurements. If the difference between the maximum or minimum value and the median value in one of the three batches of tests exceeds 15% of the median value, then the maximum and minimum values ​​are discarded, and the median value is taken as the test result for that batch. If the difference between the measured values ​​and the median value in two batches both exceeds 15% of the median value, then the test results are invalid and should be repeated.

[0030] Beneficial effects: The bleeding rate of cement-based materials such as concrete and cement-based grouting materials was tested and calculated according to GBT50080. Under the conditions of ordinary concrete and cement-based grouting material mix proportions, the water content was excessive, specifically to achieve a bleeding rate of 4%. Then, the anti-bleeding agent provided by this invention was added, with the amount of anti-bleeding agent added ensuring ΔB > 3.5%. Within this range, the cement-based material achieved better uniformity and workability, reducing adverse phenomena such as uneven water-cement ratio, surface strength loss, and cracking caused by uneven volume changes due to surface bleeding.

[0031] Compared with the prior art, the present invention has the following advantages and technical effects:

[0032] The anti-bleeding agent for cement-based materials provided by this invention can effectively absorb excess water in cement-based materials, while improving the dispersibility, cohesiveness, and flowability of the materials. It reduces the strength loss caused by excess water, ensuring the durability of the cement-based materials. It has the advantages of rapid effect, simple and convenient implementation, and the ability to handle different degrees of bleeding. Furthermore, the product preparation method provided by this invention is simple, requiring only the mixing of raw materials, making it easy to apply on-site and greatly saving manpower and resources. Attached Figure Description

[0033] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0034] Figure 1 A photograph of the concrete mixing state before the addition of the anti-bleeding agent in Application Example 1;

[0035] Figure 2 This is a photograph of the concrete mixing state after adding an anti-bleeding agent in Application Example 1. Detailed Implementation

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to specific embodiments.

[0038] Unless otherwise specified, all raw materials used in the embodiments of this invention were purchased through commercial channels;

[0039] Among them, the recycled construction waste powder is a fine powder made by grinding recycled construction waste sand and powder, with a specific surface area ≥500m². 2 / kg, the recycled sand powder from solid waste is a Class B product that conforms to the standard JCT 2548-2019 Recycled Sand Powder from Construction Solid Waste, and the water requirement ratio must meet the requirements of <2.0 and >1.8;

[0040] The water-absorbing resin is obtained by mixing starch-grafted acrylate polymer crosslinker and acrylamide-acrylate copolymer crosslinker at a mass ratio of 0.34-0.37:1;

[0041] The water-retaining suspension stabilizer is a low molecular weight nonionic polysaccharide polymer, prepared by modification with guar gum. The specific preparation method includes the following steps:

[0042] After removing the skin and germ from guar beans, the seeds are dried, pulverized, and then water is added. The seeds are then subjected to pressure hydrolysis at 0.45 MPa and 35-45℃ for 3 hours. The seeds are then precipitated with 20% ethanol, centrifuged, dried, and pulverized to obtain the water-retaining suspension stabilizer.

[0043] The starch-grafted acrylate polymer crosslinking compound was purchased from Hubei Maidehao Biotechnology Co., Ltd.

[0044] Acrylamide-acrylate copolymer crosslinking material was purchased from Hangzhou Yuhao Chemical Technology Co., Ltd.

[0045] The silicone powder defoamer was purchased from Beijing Zhubao New Technology Co., Ltd.

[0046] In this embodiment of the invention, the reduction value of the bleeding rate of cement-based materials such as concrete, mortar, and neat cement paste is calculated according to formula (1):

[0047] ΔB = 4% - B C (1)

[0048] In the formula:

[0049] ΔB: Decrease in water exudation rate;

[0050] 4%: Excessive water usage resulted in a bleeding rate of 4%.

[0051] B C The bleeding rate after adding the recommended dosage of anti-bleeding agent after the water content is excessive and the bleeding rate reaches 4% is reached.

[0052] The test results are expressed as the average of the three batches of test measurements. If the difference between the maximum or minimum value and the median value in one of the three batches of tests exceeds 15% of the median value, then the maximum and minimum values ​​are discarded, and the median value is taken as the test result for that batch. If the difference between the measured values ​​and the median value in two batches both exceeds 15% of the median value, then the test results are invalid and need to be retested and recalculated.

[0053] The bleeding rate of cement-based materials was tested and calculated according to GB / T 50080. Under the mix design conditions of ordinary concrete and cement-based grouting materials, the water content was excessive. The specific dosage should be such that the bleeding rate of the concrete and cement-based grouting materials is 4%, and the amount of anti-bleeding agent added is 80 g / m³. 3 This makes ΔB > 3.5%.

[0054] Example 1

[0055] An anti-bleeding agent for high-fluidity cement-based materials comprises the following raw materials in parts by weight:

[0056] 25 parts of construction waste incineration recycled powder, 10 parts of water-absorbing resin, 39 parts of water-retaining suspension stabilizer, 4 parts of diethanolamine, 12 parts of maltodextrin, 2 parts of anhydrous cocamidopropyl betaine, 5 parts of sodium α-olefin sulfonate, and 3 parts of organosilicon defoamer.

[0057] The above raw materials are mixed evenly under dry conditions and sealed in a waterproof and moisture-proof packaging bag to obtain an anti-bleeding agent.

[0058] Using the formula ΔB=4%-B C The reduction in bleeding rate was calculated to determine whether the anti-bleeding agent was up to standard. The dosage of the anti-bleeding agent was 80 g / m³. 3 The final calculated value of ΔB is 3.8%.

[0059] Application Example 1

[0060] Pumped C30 concrete was used for construction. The pumped C30 concrete consisted of the following raw materials by weight: 270 parts cement, 90 parts fly ash, 160 parts water, 860 parts sand, 1040 parts crushed stone, and 5.6 parts admixture (HPWR-S type polycarboxylate high-performance water-reducing agent powder conforming to standard GB8076-2008 Concrete Admixtures). During construction, the concrete bleeding occurred. The causes included errors in the water weighing system, fluctuations in sand moisture content, and changes in the saturated surface dry water absorption rate of sand. According to standard GBT50080-2016, the test method for performance of ordinary concrete mixtures, the bleeding rate reached 4.2%. Slump, spread, and emptying time in the inverted slump cone could not be measured normally. The concrete bleeding was severe and could not be formed. See details below. Figure 1 .

[0061] Add 50g / m³ to the above-mentioned pumped C30 concrete 3After applying the anti-bleeding agent obtained in Example 1 (i.e., adding 50g per square meter of C30 concrete), the bleeding rate of the concrete was directly reduced to 0.1%, and the slump and spread recovered to 220mm and 550mm respectively. The emptying time of the inverted slump cone was 5.5s, indicating good fluidity and low viscosity, meeting the requirements for pumping construction. The final setting time was 9.5h, and the 7-day and 28-day compressive strengths reached 29.5MPa and 38.8MPa respectively. The impermeability also reached P10 grade, meeting the construction and acceptance requirements. The adjusted concrete mixture state is as follows: Figure 2 As shown.

[0062] Example 2

[0063] An anti-bleeding agent for high-fluidity cement-based materials comprises the following raw materials in parts by weight:

[0064] 30 parts of recycled construction solid waste powder, 10 parts of water-absorbing resin, 40 parts of water-retaining suspension stabilizer, 2 parts of diethanolamine, 10 parts of maltodextrin, 2 parts of anhydrous cocamidopropyl betaine, 3 parts of sodium α-alkenyl sulfonate, and 3 parts of organosilicon defoamer.

[0065] The above raw materials are mixed evenly under dry conditions and sealed in a waterproof and moisture-proof packaging bag to obtain an anti-bleeding agent.

[0066] Using the formula ΔB=4%-B C The reduction in bleeding rate was calculated to determine whether the anti-bleeding agent was up to standard. The dosage of the anti-bleeding agent was 80 g / m³. 3 The final calculated value of ΔB is 3.8%.

[0067] Application Example 2

[0068] The floor mortar used in the construction comprises the following raw materials by weight: 400 parts cement, 50 parts fly ash, 220 parts water, 1350 parts sand, and 6.0 parts admixture (HPWR-S type polycarboxylate high-performance water-reducing agent powder conforming to standard GB8076-2008 concrete admixtures). Upon delivery inspection, the mortar's bleeding rate reached 5.6%, with a noticeable layer of water seeping onto the surface, increasing the surface water-cement ratio and making this portion of the surface mortar highly susceptible to cracking, carbonization, and dusting. The consistency of the mortar could not be accurately measured according to the JGJ 70-2009 Basic Performance Test Method for Building Mortar, thus failing to meet the construction requirements.

[0069] Therefore, add 80g / m³ to the above-mentioned floor mortar. 3After applying the anti-bleeding agent obtained in Example 2, the mortar's bleeding rate was directly reduced to 0.2%, while the fluidity still met the construction requirements. The final setting time was 8.5 hours, and the consistency reached 145 mm, meeting the technical requirements for self-leveling. The 7-day and 28-day compressive strengths reached 39.7 MPa and 49.9 MPa, respectively.

[0070] Example 3

[0071] An anti-bleeding agent for high-fluidity cement-based materials comprises the following raw materials in parts by weight:

[0072] 20 parts of recycled construction solid waste powder, 10 parts of water-absorbing resin, 42 parts of water-retaining suspension stabilizer, 5 parts of diethanolamine, 15 parts of maltodextrin, 1 part of anhydrous cocamidopropyl betaine, 2 parts of sodium α-alkenyl sulfonate, and 4 parts of organosilicon defoamer.

[0073] The above raw materials are mixed evenly under dry conditions and sealed in a waterproof and moisture-proof packaging bag to obtain an anti-bleeding agent.

[0074] Using the formula ΔB=4%-B C The reduction in bleeding rate was calculated to determine whether the anti-bleeding agent was up to standard. The dosage of the anti-bleeding agent was 80 g / m³. 3 The final calculated value of ΔB is 3.9%.

[0075] Application Example 3

[0076] Cement grouting material was used for construction. This material comprises the following raw materials in parts by weight: 748 parts cement, 150 parts mineral powder, 150 parts fly ash, 99 parts silica fume, 153 parts steel fiber, 740 parts quartz powder, 170 parts water, and 25 parts admixture. Due to fluctuations in the water requirement ratio of the raw materials and the admixture, bleeding occurred, with a measured bleeding rate of 3.7%. The flowability of the material could not be measured according to the standard GB / T 50448-2015 Technical Specification for Application of Cement-Based Grouting Materials. The admixture was HPWR-S type polycarboxylate high-performance water-reducing agent powder conforming to the standard GB / T 8076-2008 Concrete Admixtures.

[0077] Add 130g / m to the above cement grouting material 3 After applying the anti-bleeding agent obtained in Example 3, the bleeding rate of the grout was directly reduced to 0%, meeting the construction requirements. Furthermore, the final setting time of the grout was 8 hours, the flow cone fluidity reached 15 seconds, and the 7-day compressive strength and 28-day compressive strength were 90.6 MPa and 116.3 MPa, respectively.

[0078] Comparative Example 1

[0079] An anti-bleeding agent, differing from Example 1 in that the specific surface area of ​​the recycled construction waste powder is only 320 m². 2 / kg, lower than the required 500m 2 / kg. Other raw materials, process steps and parameters are the same as in Example 1.

[0080] Using the formula ΔB=4%-B C The reduction in bleeding rate was calculated to determine whether the anti-bleeding agent was up to standard. The dosage of the anti-bleeding agent was 80 g / m³. 3 The final calculated ΔB is 3.2%, which is less than the required 3.5%.

[0081] Comparative Application Example 1

[0082] The difference from Application Example 1 is that the anti-bleeding agent obtained in Example 1 was replaced with an equal amount of the anti-bleeding agent obtained in Comparative Example 1. All other process steps and parameters were the same as in Example 1. The final concrete bleeding rate was reduced to 1.1%, and the slump and spread recovered to 160 mm and 360 mm, respectively. The emptying time of the inverted slump cone was 17.8 s. The fluidity improved somewhat but remained poor, with high viscosity, failing to meet the requirements for pumping construction. Furthermore, the final setting time was 14.0 h, and the 7-day and 28-day compressive strengths were 18.9 MPa and 27.6 MPa, respectively. The impermeability performance failed to reach P10 grade, thus failing to meet construction and acceptance requirements.

[0083] Comparative Example 2

[0084] An anti-bleeding agent, differing from Example 2 in that it does not include water-absorbing resin. All other raw materials, process steps, and parameters are the same as in Example 2.

[0085] Using the formula ΔB=4%-B C The reduction in bleeding rate was calculated to determine whether the anti-bleeding agent was up to standard. The dosage of the anti-bleeding agent was 80 g / m³. 3 The final calculated value of ΔB is 2.5%.

[0086] Comparative Application Example 2

[0087] The difference from Application Example 2 is that the anti-bleeding agent obtained in Example 2 was replaced with an equal amount of the anti-bleeding agent obtained in Comparative Example 2. All other process steps and parameters were the same as in Example 2. The final mortar bleeding rate was reduced to 1.7%, but the fluidity failed to meet construction requirements. Furthermore, the final setting time was 12.5 hours, and the consistency reached 75 mm, failing to meet the technical requirements for self-leveling. The 7-day and 28-day compressive strengths reached 31.5 MPa and 37.7 MPa, respectively.

[0088] Comparative Example 3

[0089] An anti-bleeding agent, which differs from Example 3 in that it does not include a water-retaining suspension stabilizer. All other raw materials, process steps, and parameters are the same as in Example 3.

[0090] Using the formula ΔB=4%-B C The reduction in bleeding rate was calculated to determine whether the anti-bleeding agent was up to standard. The dosage of the anti-bleeding agent was 80 g / m³. 3 The final calculated value of ΔB is 3.3%.

[0091] Comparative Application Example 3

[0092] The difference from Application Example 3 is that the anti-bleeding agent obtained in Example 3 was replaced with an equal amount of the anti-bleeding agent obtained in Comparative Example 3. All other process steps and parameters were the same as in Example 3. The bleeding rate of the grout was reduced to 0.8%, which failed to meet the construction requirements. Furthermore, the final setting time of the grout was 16 hours, the flow cone fluidity reached 32 seconds, and the 7-day compressive strength and 28-day compressive strength were 70.4 MPa and 85.7 MPa, respectively.

[0093] Comparative Example 4

[0094] An anti-bleeding agent, differing from Example 1 in that it does not include recycled construction waste powder and water-absorbing resin. All other raw materials, process steps, and parameters are the same as in Example 1.

[0095] Using the formula ΔB=4%-B C The reduction in bleeding rate was calculated to determine whether the anti-bleeding agent was up to standard. The dosage of the anti-bleeding agent was 80 g / m³. 3 The final calculated value of ΔB is 1.9%.

[0096] Comparative Application Example 4

[0097] The difference from Application Example 1 is that the anti-bleeding agent obtained in Example 1 was replaced with an equal amount of the anti-bleeding agent obtained in Comparative Example 4. All other process steps and parameters were the same as in Example 1. The final concrete bleeding rate was reduced to 2.1%, and the slump and spread recovered to 100 mm and 320 mm, respectively. The final setting time was 16.5 h, and the 7-day and 28-day compressive strengths were 15.4 MPa and 23.3 MPa, respectively. However, the impermeability performance failed to reach P10 grade, thus failing to meet the requirements for construction and factory inspection.

[0098] Comparative Example 5

[0099] An anti-bleeding agent, differing from Example 3 in that it does not include diethanolamine and sodium α-alkenylsulfonate. All other raw materials, process steps, and parameters are the same as in Example 3.

[0100] Using the formula ΔB=4%-B C The reduction in bleeding rate was calculated to determine whether the anti-bleeding agent was up to standard. The dosage of the anti-bleeding agent was 80 g / m³. 3 The final calculated value of ΔB is 3.3%.

[0101] Comparative Application Example 5

[0102] The difference from Application Example 3 is that the anti-bleeding agent obtained in Example 3 was replaced with an equal amount of the anti-bleeding agent obtained in Comparative Example 3. All other process steps and parameters were the same as in Example 3. The bleeding rate of the grout was reduced to 0.8%, meeting the construction requirements. Furthermore, the final setting time of the grout was 11.5 hours, the flow cone fluidity reached 26 seconds, and the 7-day compressive strength and 28-day compressive strength were 75.4 MPa and 99.7 MPa, respectively, showing a significant decrease in strength compared to Application Example 3.

[0103] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A high-fluidity cement-based material anti-bleeding agent, characterized in that, The ingredients include the following parts by weight: 20-30 parts of recycled construction solid waste powder, 5-10 parts of water-absorbing resin, 35-52 parts of water-retaining suspension stabilizer, 1-6 parts of diethanolamine, 10-15 parts of maltodextrin, 1-2 parts of anhydrous cocamidopropyl betaine, 2-5 parts of sodium α-alkenyl sulfonate, and 1-5 parts of organosilicon defoamer. The specific surface area of ​​the recycled construction solid waste powder is ≥500m². 2 / kg.

2. The anti-bleeding agent for high-fluidity cement-based materials according to claim 1, characterized in that, The recycled construction waste powder is made by grinding recycled construction waste sand powder that meets the Class B technical requirements of standard JCT 2548-2019 "Recycled Construction Waste Sand Powder".

3. The anti-bleeding agent for high-fluidity cement-based materials according to claim 2, characterized in that, The water requirement ratio of the recycled sand and powder from the construction solid waste is <2.0 and >1.

8.

4. The anti-bleeding agent for high-fluidity cement-based materials according to claim 1, characterized in that, The preparation method of the water-retaining suspension stabilizer includes the following steps: After removing the skin and germ from guar beans, the seeds are dried, pulverized, and then water is added. The mixture is then subjected to pressurized hydrolysis, precipitated with 20% ethanol, centrifuged, dried, and pulverized to obtain the water-retaining suspension stabilizer.

5. The anti-bleeding agent for high-fluidity cement-based materials according to claim 1, characterized in that, The water-absorbing resin is obtained by mixing starch-grafted acrylate polymer crosslinker and acrylamide-acrylate copolymer crosslinker in a mass ratio of (0.34-0.37):

1.

6. A method for preparing an anti-bleeding agent for high-fluidity cement-based materials as described in any one of claims 1-4, characterized in that, After weighing the raw materials, mix them evenly to obtain the anti-bleeding agent for the high-fluidity cement-based material.

7. The method of using the anti-bleeding agent for high-fluidity cementitious materials as described in any one of claims 1-4, characterized in that, Includes the following steps: The bleeding rate of the cement-based material is tested, and then the anti-bleeding agent is added to the cement-based material while stirring, depending on the severity of the bleeding, until the bleeding rate is reduced to within the range required for construction.

8. A method for detecting an anti-bleeding agent for high-fluidity cementitious materials as described in any one of claims 1-4, characterized in that, The corresponding decrease in the water exudation rate is determined using the following method: ΔB = 4% - Bc; Where: ΔB is the decrease in the rate of water leakage; 4% represents excessive water usage, resulting in a 4% bleeding rate; Bc represents the water content exceeding the allowable level, resulting in a bleeding rate of 4%. After adding an anti-bleeding agent, the bleeding rate of the concrete is further reduced.

9. The method for detecting an anti-bleeding agent for high-fluidity cementitious materials according to claim 8, characterized in that, In the Bc, the amount of anti-bleeding agent added is 80 g / m³. 3 .

10. The method for detecting an anti-bleeding agent for high-fluidity cementitious materials according to claim 8, characterized in that, The ΔB is greater than 3.5%.

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