Concrete super water-storing polymer type mineral admixture, its preparation method and application

Abstract

The application relates to the technical field of building materials, in particular to a concrete super water storage polymer type mineral admixture, a preparation method and application thereof. Technical points are as follows: a concrete super water storage polymer type mineral admixture comprises the following components in proportion by weight: 40-60 parts of regenerated micro powder, 25-30 parts of fly ash, 10-20 parts of a high water absorption resin composition and 5-10 parts of a chelating agent; wherein the high water absorption resin composition comprises sodium polyacrylate and polyacrylamide, and the weight ratio is 1-4. The concrete super water storage polymer type mineral admixture, the preparation method and the application thereof have strong water absorption and water storage capacity, and the super water storage polymer reaches a water absorption saturation state. The concrete super water storage polymer type mineral admixture can fill gaps after water absorption and expansion, and therefore can be made into a water sealing material to prevent water leakage.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and in particular to a concrete super-water-storage polymer type mineral admixture, a preparation method and application thereof. Background Art

[0002] Conventional concrete, one of the most common building materials, consumes a significant amount of water during its production, leading to water scarcity, especially in arid regions. Furthermore, the cement manufacturing process required for concrete production releases large amounts of carbon dioxide, contributing to the serious impacts of global warming and climate change.

[0003] Replacing some cement components with recycled materials has become an important strategy for reducing carbon emissions during concrete production. Low-carbon recycled concrete refers to the production of low-carbon recycled concrete by recycling resources such as waste concrete, construction waste, and industrial by-products, using recycled aggregates as components of the coarse and fine aggregates in concrete raw materials, and using CO2 to cure concrete. The low-carbon recycled concrete production process not only reduces the exploitation of natural resources, but also effectively reduces the demand for traditional cement, thereby reducing carbon dioxide emissions. In addition, the low energy consumption helps to increase the strength growth rate of concrete and improve the performance of concrete. It can effectively utilize CO2 gas emitted in factories, which has the effect of protecting the environment and reducing environmental pollution.

[0004] However, curing low-carbon recycled concrete in CO2 curing equipment accelerates the hydration rate of cement, and both the reaction degree and early compressive strength are improved. However, during the early curing of CO2 curing equipment, the temperature inside the CO2 curing instrument is high, which will cause the moisture inside the concrete specimen to evaporate, affecting the growth of concrete strength during the later room temperature curing. Summary of the Invention

[0005] The purpose of the present invention is to develop a super-water-storage polymer-type mineral admixture for concrete, and its preparation method and application, which has strong water absorption and water storage capabilities and can bring the super-water-storage polymer to a water-saturated state. The super-water-storage polymer-type mineral admixture for concrete absorbs water and expands to fill gaps, and can therefore also be made into a water-sealing material to prevent water leakage. Different super-water-storage polymers have different water absorption and release capabilities. When used as raw materials to prepare concrete mixtures, during the cement hydration process, when the moisture content within the concrete is low and a humidity difference occurs within the concrete, the super-water-storage polymer slowly releases its own moisture, providing moisture for the later hydration of the cement clinker, ensuring the later strength of the concrete, improving the plastic shrinkage cracking performance, and reducing and delaying the generation and expansion of microcracks.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions:

[0007] The application provides a concrete super water storage polymer type mineral admixture, which comprises the following components in parts by weight: recycled micro powder 40-60 parts, fly ash 25-30 parts, high water absorption resin composition 10-20 parts and chelating agent 5-10 parts.

[0008] The high water absorption resin composition comprises sodium polyacrylate and polyacrylamide, and the weight ratio of sodium polyacrylate to polyacrylamide is 1-4.

[0009] The recycled micro powder is obtained by gradually crushing and grinding construction waste such as waste concrete and waste clay bricks, and has a small fineness.

[0010] The preparation process of the recycled micro powder is as follows: large construction waste is preliminarily crushed into small pieces by using a large crusher; the steel bars, wood blocks and plastics in the construction waste pieces are preliminarily removed by using air separation and magnetic separation methods; the impurities in the preliminarily screened pieces are secondarily sorted by manual screening, and the residual soil on the surface of the pieces is removed by using a water washing process. The clean construction waste pieces are sent into a secondary crusher, and then the coarse and fine aggregates of different sizes are screened by a screening system; finally, the screened aggregates are ground into powder by using a special grinding machine, so that the recycled construction waste micro powder is obtained.

[0011] The high water absorption resin composition has multiple hydrophilic groups, can interact with water molecules, has excellent water aggregation capacity, can stably keep the absorbed water, and forms a structure similar to a gel. The high water absorption resin composition can react with the recycled micro powder, so as to change the properties and performance of the super water storage polymer, increase the water absorption capacity and water retention of the super water storage polymer.

[0012] The admixture further comprises fly ash, the fly ash has an active effect and a filling effect, has an activation effect on the recycled micro powder, can effectively improve the structural density of the concrete, and has a certain active effect, so as to shorten the gap between the cement and the fly ash.

[0013] Further, the mass ratio of sodium polyacrylate to polyacrylamide is determined by the mixing amount of the recycled micro powder, the fly ash and the high water absorption resin composition.

[0014] Further, when 1≤N / A≤1.5.

[0015] W is the weight fraction of the recycled micro powder.

[0016] F is the weight percentage of fly ash;

[0017] G is the weight percentage of the super absorbent resin composition;

[0018] N is the weight percentage of sodium polyacrylate;

[0019] A is the weight percentage of polyacrylamide.

[0020] In a superabsorbent resin composition, if the sodium polyacrylate dosage is too low and the polyacrylamide dosage is too high, and the recycled micropowder dosage is too high, excessive water absorption can occur, causing the composition to become too gelled and lose fluidity, hindering construction and processing. If the sodium polyacrylate dosage is too high, the stability of the mixture can be reduced, leading to phase separation or precipitation, affecting the uniformity and consistency of the material. Under these conditions, the recycled micropowder dosage is much greater than the combined dosage of fly ash and superabsorbent resin. Therefore, the ratio of sodium polyacrylate to polyacrylamide should be appropriately reduced to ensure smooth hydration of the concrete.

[0021] Furthermore, when When , then 1.5<N / A≤4;

[0022] Wherein, W is the weight percentage of the regenerated micro powder;

[0023] F is the weight percentage of fly ash;

[0024] G is the weight percentage of the super absorbent resin composition;

[0025] N is the weight percentage of sodium polyacrylate;

[0026] A is the weight percentage of polyacrylamide.

[0027] When the above situation occurs, due to the increase in the content of fly ash relative to recycled micro-wax, it is easy to cause accelerated hydration of concrete, excessive local heat release, and early cracking of concrete. Therefore, increasing the content of polyacrylamide in the super absorbent resin composition can delay the hydration time of concrete and avoid excessive local heat release.

[0028] Furthermore, the superabsorbent resin composition also includes a surfactant, a crosslinking agent, a stabilizer, and a pH stabilizer. The auxiliary agents used in the present invention, including surfactants, stabilizers, and pH adjusters, are used to adjust the particle size, dispersibility, and stability of the polymer to suit different application requirements. The weight percentages of the other components in the superabsorbent resin composition are as follows: superabsorbent resin: 60-90 parts; surfactant: 0.1-5 parts; crosslinking agent: 0.1-5 parts; stabilizer: 0.01-2 parts; pH stabilizer: 0.01-1 part.

[0029] Furthermore, the chelating agent is EDTA.

[0030] EDTA can form stable complexes with a variety of metal ions. During the reaction, the carboxyl and amino groups of EDTA form complexes with the metal ions, encapsulating the metal ions within the EDTA molecules. The balance and extent of the reaction can be adjusted based on the reaction conditions and metal ion concentration. After the metal ions are complexed with EDTA, their activity is weakened, affecting their properties and behavior in the reaction system. In the combined application of recycled micropowder, fly ash, and superabsorbent resin compositions, EDTA can adjust the water absorption and water retention properties of the superabsorbent resin composition by complexing the metal ions. EDTA can also improve the stability of the reaction system, increasing the stability and sustainability of the reaction products.

[0031] The present invention also provides a method for preparing a super water-storage polymer type mineral admixture for concrete, comprising the following steps:

[0032] Regenerated micro powder, fly ash, a highly absorbent resin composition and a chelating agent are added into water, mixed, and heated for reaction to obtain a reaction liquid; and the reaction liquid is dried to obtain a super water-storage polymer mineral admixture for concrete.

[0033] Furthermore, the reaction liquid is dried, including standing the reaction liquid for stratification to obtain an upper clear liquid and a lower material; the upper clear liquid and the lower material are dried separately to obtain material 1 and material 2; and material 1 and material 2 are mixed and ground to obtain a concrete super water storage polymer type mineral admixture.

[0034] Separating the supernatant from the bottom layer and drying the bottom layer has the following advantages:

[0035] Fine control of composition: By separating and drying the supernatant and bottom materials, the composition and ratio of each component can be more precisely controlled. This makes subsequent reactions easier to control and ensures that the various components in the reaction solution are recombined as needed to meet the specific performance and quality requirements of the product. Maximum resource utilization: Both the supernatant and bottom materials are used in subsequent reactions, maximizing the utilization of raw materials.

[0036] Reducing waste generation helps reduce production costs and resource waste, thereby improving the economic and sustainable nature of production. Consistency and stability: Because the supernatant and bottom materials are more consistent in composition after separation and drying, subsequent reactions are easier to control, resulting in product consistency and stability. This is crucial for producing high-quality products. Reduced waste disposal: Drying the supernatant and bottom materials separately reduces the complexity and cost of waste disposal. Waste disposal typically requires additional resources and environmental costs, so reducing waste generation helps alleviate the environmental burden. In summary, drying the supernatant and bottom materials separately and using them both for subsequent reactions improves the efficiency and quality of the production process and reduces production costs. This helps ensure optimal product performance, consistency, and sustainability.

[0037] The material components after drying the supernatant and the bottom material are mainly composed of the following ingredients:

[0038] The supernatant liquid includes unreacted or unnecessary soluble materials, such as unreacted chelating agent, undissolved super absorbent resin residue, etc. The bottom layer material includes reacted or solid components, such as regenerated micropowder, fly ash, super absorbent resin composition, etc. These components have different particle sizes and properties and need to be dried and treated to ensure that they are suitable for application in super water-storage polymer type mineral admixtures for concrete. In general, separating and drying the supernatant liquid and the bottom layer material is a key process step, which helps to improve the quality, performance and economy of super water-storage polymer type mineral admixtures for concrete, while reducing waste of resources. In the present invention, static stratification can cause the regenerated micropowder and the super absorbent resin composition to react, thereby improving the water absorption performance of the regenerated micropowder while improving the stability and mechanical strength of the super water-storage polymer and reducing the breakage and decomposition of the polymer particles.

[0039] Furthermore, the temperature of the heating reaction is 60-75°C.

[0040] Furthermore, the reaction time is 4 to 5 hours.

[0041] Furthermore, the standing stratification time is 3 to 5 hours.

[0042] The third object of the present invention is to provide an application method of concrete super water storage polymer type mineral admixture, which has the same technical effect.

[0043] The technical solution is as follows:

[0044] The invention discloses an application of a concrete super water storage polymer type mineral admixture, which comprises adding the concrete super water storage polymer type mineral admixture into concrete, with the admixture amount being 5% to 10% of the mass of the concrete.

[0045] In summary, the present invention has the following beneficial effects:

[0046] The present invention provides a super-water-storage polymer-based mineral admixture for concrete, which has strong water absorption and storage capabilities, allowing the super-water-storage polymer to reach a saturated state. The super-water-storage polymer-based mineral admixture for concrete absorbs water and expands to fill gaps, thus also being used as a water-sealing material to prevent water leakage. DETAILED DESCRIPTION

[0047] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, a concrete super-water-storage polymer mineral admixture and its preparation method and application proposed in accordance with the present invention, its specific implementation method, characteristics and effects are described in detail as follows.

[0048] This specific embodiment provides a concrete super water storage polymer type mineral admixture, which includes the following components, calculated by weight: 40-60 parts of recycled micropowder, 25-30 parts of fly ash, 10-20 parts of super absorbent resin composition and 5-10 parts of chelating agent;

[0049] The super absorbent resin composition comprises sodium polyacrylate and polyacrylamide in a weight ratio of 1 to 4.

[0050] In this embodiment, the mass ratio of sodium polyacrylate and polyacrylamide is determined by the amount of regenerated micropowder, fly ash and super absorbent resin composition, as follows: When , then 1≤N / A≤1.5; when When , then 1.5<N / A≤4;

[0051] Wherein, W is the weight percentage of the regenerated micro powder;

[0052] F is the weight percentage of fly ash;

[0053] G is the weight percentage of the super absorbent resin composition;

[0054] N is the weight percentage of sodium polyacrylate;

[0055] A is the weight percentage of polyacrylamide.

[0056] The super absorbent resin composition provided in this embodiment further includes a surfactant, a cross-linking agent, a stabilizer and a pH stabilizer.

[0057] This specific embodiment also provides a method for preparing a super water-storage polymer type mineral admixture for concrete, comprising the following steps:

[0058] Regenerated micro powder, fly ash, a highly absorbent resin composition and a chelating agent are added into water, mixed, and heated for reaction to obtain a reaction liquid; and the reaction liquid is dried to obtain a super water-storage polymer mineral admixture for concrete.

[0059] The process of drying the reaction liquid also includes allowing the reaction liquid to stand and separate into layers to obtain an upper clear liquid and a lower material; drying the upper clear liquid and the lower material separately to obtain material 1 and material 2; and mixing and grinding material 1 and material 2 to obtain a super-water-storage polymer mineral admixture for concrete.

[0060] This specific embodiment also provides an application of a super water-storage polymer type mineral admixture for concrete, specifically, adding the super water-storage polymer type mineral admixture for concrete to a content of 5% to 10% of the mass of the concrete.

[0061] Example 1: A concrete super-water-storage polymer mineral admixture and its preparation method and application

[0062] The concrete super water-storage polymer mineral admixture provided in this embodiment comprises the following components, calculated by weight: 40 parts of recycled micropowder, 30 parts of fly ash, 20 parts of a super absorbent resin composition, and 10 parts of EDTA;

[0063] In this embodiment, W+F=70 parts, F+G=50 parts; therefore, Furthermore, in the super absorbent resin composition, the value range of N / A is 1.5 to 4; in this embodiment, 4 is selected; that is, sodium polyacrylate is 16 parts and polyacrylamide is 4 parts.

[0064] Wherein, W is the weight percentage of the regenerated micro powder;

[0065] F is the weight percentage of fly ash;

[0066] G is the weight percentage of the super absorbent resin composition;

[0067] N is the weight percentage of sodium polyacrylate;

[0068] A is the weight percentage of polyacrylamide.

[0069] The preparation method of the concrete super water storage polymer type mineral admixture provided in this embodiment is as follows:

[0070] Regenerated micropowder, fly ash, a super absorbent resin composition and a chelating agent are added into water, mixed, heated to 60° C., and reacted for 5 hours to obtain a reaction liquid; the reaction liquid is dried, allowed to stand for 3 hours to separate into layers, and an upper clear liquid and a lower layer of material are obtained; the upper clear liquid and the lower layer of material are dried separately to obtain material 1 and material 2; material 1 and material 2 are mixed and ground to obtain a super water-storage polymer mineral admixture for concrete.

[0071] Example 2: A concrete super-water-storage polymer mineral admixture and its preparation method and application

[0072] The concrete super water storage polymer mineral admixture provided in this embodiment comprises the following components, calculated by weight: 50 parts of recycled micropowder, 27 parts of fly ash, 20 parts of a super absorbent resin composition, and 10 parts of EDTA;

[0073] In this embodiment, W+F=77 parts, F+G=47 parts; therefore, Furthermore, in the super absorbent resin composition, the value range of N / A is 1.5 to 4; in this embodiment, 7:3 is selected; that is, sodium polyacrylate is 14 parts and polyacrylamide is 6 parts.

[0074] Wherein, W is the weight percentage of the regenerated micro powder;

[0075] F is the weight percentage of fly ash;

[0076] G is the weight percentage of the super absorbent resin composition;

[0077] N is the weight percentage of sodium polyacrylate;

[0078] A is the weight percentage of polyacrylamide.

[0079] The preparation method of the concrete super water storage polymer type mineral admixture provided in this embodiment is as follows:

[0080] Regenerated micropowder, fly ash, a super absorbent resin composition and a chelating agent are added into water, mixed, heated to 70° C., and reacted for 4 hours to obtain a reaction liquid; the reaction liquid is dried, allowed to stand for 3 hours to separate into layers, and an upper clear liquid and a lower layer of material are obtained; the upper clear liquid and the lower layer of material are dried separately to obtain material 1 and material 2; material 1 and material 2 are mixed and ground to obtain a super water-storage polymer mineral admixture for concrete.

[0081] Example 3: A concrete super-water-storage polymer mineral admixture and its preparation method and application

[0082] The concrete super water-storage polymer mineral admixture provided in this embodiment comprises the following components, calculated by weight: 60 parts of recycled micropowder, 25 parts of fly ash, 10 parts of a super absorbent resin composition, and 5 parts of EDTA;

[0083] In this embodiment, W+F=85 parts, F+G=35 parts; therefore, Furthermore, in the super absorbent resin composition, the value range of N / A is 1 to 1.5; in this embodiment, 6:4 is selected; that is, sodium polyacrylate is 12 parts and polyacrylamide is 8 parts.

[0084] Wherein, W is the weight percentage of the regenerated micro powder;

[0085] F is the weight percentage of fly ash;

[0086] G is the weight fraction of the superabsorbent resin composition;

[0087] N is the weight fraction of sodium polyacrylate;

[0088] A is the weight fraction of polyacrylamide.

[0089] The preparation method of the concrete super water storage polymer type mineral admixture provided in the embodiment is as follows:

[0090] The recycled micro powder, fly ash, superabsorbent resin composition and chelating agent are added to water and mixed, heated to 75 DEG C, and reacted for 4 hours to obtain a reaction liquid; the reaction liquid is dried and layered for 3 hours to obtain an upper clear liquid and a lower material; the upper clear liquid and the lower material are dried respectively to obtain material 1 and material 2; the material 1 and the material 2 are mixed and ground to obtain the concrete super water storage polymer type mineral admixture.

[0091] Embodiment 4: a concrete super water storage polymer type mineral admixture and a preparation method and application thereof

[0092] The concrete super water storage polymer type mineral admixture provided in the embodiment comprises the following components in terms of weight fraction: 45 parts of recycled micro powder, 30 parts of fly ash, 20 parts of superabsorbent resin composition and 5 parts of EDTA;

[0093] In the embodiment, W+F=75 parts, and F+G=50 parts; therefore, Further, in the superabsorbent resin composition, the value range of N / A is 1.5-4; in the embodiment, 4:1 is selected; that is, 16 parts of sodium polyacrylate and 4 parts of polyacrylamide.

[0094] W is the weight fraction of the recycled micro powder;

[0095] F is the weight fraction of the fly ash;

[0096] G is the weight fraction of the superabsorbent resin composition;

[0097] N is the weight fraction of sodium polyacrylate;

[0098] A is the weight fraction of polyacrylamide.

[0099] The preparation method of the concrete super water storage polymer type mineral admixture provided in the embodiment is as follows:

[0100] The recycled micro powder, fly ash, superabsorbent resin composition and chelating agent are added to water and mixed, heated to 70 DEG C, and reacted for 5 hours to obtain a reaction liquid; the reaction liquid is dried and layered for 3 hours to obtain an upper clear liquid and a lower material; the upper clear liquid and the lower material are dried respectively to obtain material 1 and material 2; the material 1 and the material 2 are mixed and ground to obtain the concrete super water storage polymer type mineral admixture.

[0101] Embodiment 5: a concrete super water-storing polymer type mineral admixture and a preparation method and application thereof

[0102] The concrete super water-storing polymer type mineral admixture provided in the embodiment includes the following components according to weight fractions: 55 parts of recycled micro powder, 25 parts of fly ash, 10 parts of a super water-absorbing resin composition, and 10 parts of EDTA;

[0103] In the embodiment, W+F=80 parts, and F+G=35 parts; therefore, Further, in the super water-absorbing resin composition, the value range of N / A is 1-1.5; in the embodiment, 6:4 is selected; that is, 12 parts of sodium polyacrylate and 4 parts of polyacrylamide.

[0104] W is the weight fraction of the recycled micro powder;

[0105] F is the weight fraction of the fly ash;

[0106] G is the weight fraction of the super water-absorbing resin composition;

[0107] N is the weight fraction of the sodium polyacrylate;

[0108] A is the weight fraction of the polyacrylamide.

[0109] The preparation method of the concrete super water-storing polymer type mineral admixture provided in the embodiment is as follows:

[0110] The recycled micro powder, the fly ash, the super water-absorbing resin composition, and the chelating agent are added into water for mixing, heated to 60°C, and reacted for 4.5 hours to obtain a reaction liquid; the reaction liquid is dried and left to stand for 3 hours to obtain upper clear liquid and lower material; the upper clear liquid and the lower material are dried respectively to obtain material 1 and material 2; the material 1 and the material 2 are mixed and ground to obtain the concrete super water-storing polymer type mineral admixture.

[0111] Comparative Embodiment 1: a concrete super water-storing polymer type mineral admixture and a preparation method and application thereof

[0112] The concrete super water-storing polymer type mineral admixture provided in the embodiment includes the following components according to weight fractions: 40 parts of recycled micro powder, 30 parts of fly ash, 20 parts of a super water-absorbing resin composition, and 10 parts of EDTA;

[0113] In the super water-absorbing resin composition in the embodiment, N / A is selected as 9:1; that is, 18 parts of sodium polyacrylate and 2 parts of polyacrylamide.

[0114] N is the weight fraction of the sodium polyacrylate;

[0115] A is the weight fraction of the polyacrylamide.

[0116] The preparation method of the concrete super water storage polymer type mineral admixture provided in this embodiment is as follows:

[0117] Regenerated micropowder, fly ash, a super absorbent resin composition and a chelating agent are added into water, mixed, heated to 60° C., and reacted for 5 hours to obtain a reaction liquid; the reaction liquid is dried, allowed to stand for 3 hours to separate into layers, and an upper clear liquid and a lower layer of material are obtained; the upper clear liquid and the lower layer of material are dried separately to obtain material 1 and material 2; material 1 and material 2 are mixed and ground to obtain a super water-storage polymer mineral admixture for concrete.

[0118] Comparative Example 2: A concrete super-water-storage polymer mineral admixture and its preparation method and application

[0119] The concrete super water-storage polymer mineral admixture provided in this embodiment comprises the following components, calculated by weight: 40 parts of recycled micropowder, 30 parts of fly ash, 20 parts of a super absorbent resin composition, and 10 parts of EDTA;

[0120] In this embodiment, the ratio of N / A in the super absorbent resin composition is 5:5; that is, sodium polyacrylate is 10 parts and polyacrylamide is 10 parts.

[0121] Wherein, N is the weight percentage of sodium polyacrylate;

[0122] A is the weight percentage of polyacrylamide.

[0123] The preparation method of the concrete super water storage polymer type mineral admixture provided in this embodiment is as follows:

[0124] Regenerated micropowder, fly ash, a super absorbent resin composition and a chelating agent are added into water, mixed, heated to 60° C., and reacted for 5 hours to obtain a reaction liquid; the reaction liquid is dried, allowed to stand for 3 hours to separate into layers, and an upper clear liquid and a lower layer of material are obtained; the upper clear liquid and the lower layer of material are dried separately to obtain material 1 and material 2; material 1 and material 2 are mixed and ground to obtain a super water-storage polymer mineral admixture for concrete.

[0125] Comparative Example 3: A concrete super-water-storage polymer mineral admixture and its preparation method and application

[0126] The concrete super water storage polymer mineral admixture provided in this embodiment comprises the following components, calculated by weight: 40 parts of recycled micropowder, 30 parts of fly ash, 16 parts of a super absorbent resin composition, and 10 parts of EDTA;

[0127] In this embodiment, the amount of sodium polyacrylate in the super absorbent resin composition is 16 parts.

[0128] The preparation method of the concrete super water storage polymer type mineral admixture provided in this embodiment is as follows:

[0129] Regenerated micropowder, fly ash, a super absorbent resin composition and a chelating agent are added into water, mixed, heated to 60° C., and reacted for 5 hours to obtain a reaction liquid; the reaction liquid is dried, allowed to stand for 3 hours to separate into layers, and an upper clear liquid and a lower layer of material are obtained; the upper clear liquid and the lower layer of material are dried separately to obtain material 1 and material 2; material 1 and material 2 are mixed and ground to obtain a super water-storage polymer mineral admixture for concrete.

[0130] Comparative Example 4: A concrete super-water-storage polymer mineral admixture and its preparation method and application

[0131] The concrete super water-storage polymer mineral admixture provided in this embodiment comprises the following components, calculated by weight: 40 parts of recycled micropowder, 30 parts of fly ash, 4 parts of a super absorbent resin composition, and 10 parts of EDTA;

[0132] In this embodiment, the polyacrylamide in the super absorbent resin composition is 4 parts.

[0133] The preparation method of the concrete super water storage polymer type mineral admixture provided in this embodiment is as follows:

[0134] Regenerated micropowder, fly ash, a super absorbent resin composition and a chelating agent are added into water, mixed, heated to 60° C., and reacted for 5 hours to obtain a reaction liquid; the reaction liquid is dried, allowed to stand for 3 hours to separate into layers, and an upper clear liquid and a lower layer of material are obtained; the upper clear liquid and the lower layer of material are dried separately to obtain material 1 and material 2; material 1 and material 2 are mixed and ground to obtain a super water-storage polymer mineral admixture for concrete.

[0135] Performance Verification

[0136] The concrete super water-storage polymer mineral admixtures prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were added to concrete in corresponding proportions for performance testing. Preparation of concrete with super water-storage polymer mineral admixture: cement, sand, gravel, water, mineral admixture and admixture are mixed in a mass ratio of 53.23:139.73:216:31.27:13.32:1, and the super water-storage polymer mineral admixture prepared in Examples 1 to 5 is added, and the admixture amount is 25% of the cementitious material; wherein the cement is P.O42.5 cement produced by Beijing Jinyu Cement Economic and Trade Co., Ltd.; the fly ash is the third-grade fly ash produced by Hebei Zongrun Mineral Products Co., Ltd.; the gravel is 5-25 mm continuously graded gravel, its mud content is 0.9%, and the crushing value index is 7.6; the sand is medium sand, its mud content is 0.9%, and the fineness modulus is 2.5; the admixture is a polycarboxylate water reducer produced by Hebei Shengtong Building Materials Technology Co., Ltd., its solid content is 19.6%, and the water reduction rate is 30%.

[0137] After the above concrete mixture is evenly mixed, it is poured into a forming mold of a cubic specimen with a side length of 150mm. The compressive strength of the concrete sample is measured using a measuring instrument. After the mortar is evenly mixed, it is poured into a flat thin plate specimen of 800mm×600mm×100mm for early crack resistance test, and tested using a crack width and depth comprehensive tester. The "Code for Design of Concrete Structures" (GB 50180-2017) stipulates that on the concrete surface, crack width less than 0.3mm, crack depth less than 1.5mm, crack depth less than 3mm, and concrete block crack width less than 0.5mm are all within the allowable range. The classification of crack visibility is shown in Table 1.

[0138] The concrete was demoulded 24 hours after forming, and the compressive strength and early crack resistance tests were carried out after reaching the age of 3d and 28d. The test results are shown in Table 2.

[0139] Table 1. Crack visibility classification

[0140]

[0141] Table 2. Performance test results

[0142]

[0143] According to the comparison of the test results of Comparative Example 1 and Example 1, it can be seen that when the dosage of the regenerated micropowder is increased and the weight ratio of sodium polyacrylate to polyacrylamide is greater than 4, the 3d strength and 28d strength decrease significantly, and at the same time, more microcracks and a certain amount of fine cracks appear. The reason for this is that when the dosage of the regenerated micropowder is high, if the proportion of sodium polyacrylate is too high, it will lead to insufficient water when the regenerated micropowder is hydrated.

[0144] According to the comparison of the test results of Comparative Example 2 and Example 1, when the dosage of recycled micropowder is increased, if the dosage of sodium polyacrylate is too small, the 3d strength and 28d strength will also decrease significantly, and more microcracks and fine cracks will also appear. The reason for this is that the dosage of sodium polyacrylate is too small and the water retention performance is insufficient, resulting in water shortage in the late stage of concrete hydration and excessive water in the early stage.

[0145] According to the comparison of the test results of Comparative Example 3 and Example 1, it can be seen that when sodium polyacrylate exists alone, the 3d strength and 28d strength of the concrete are obviously insufficient, and large cracks and medium cracks also appear. The reason for this is that.

[0146] According to the comparison of the test results of Comparative Example 3 and Example 1, when sodium polyacrylate exists alone, the 3d strength and 28d strength of the concrete are obviously insufficient, and large cracks and medium cracks also appear. The reason for this is that sodium polyacrylate generally has a fast water absorption speed because it is a relatively strong water-absorbing resin. This leads to the formation of areas with too fast water absorption speed in the concrete, resulting in uneven distribution of water in the concrete. Uneven water distribution can cause cracks on the surface of the concrete. The high water absorption of sodium polyacrylate can cause the formation of a large number of small pores in the concrete, which can weaken the cohesiveness of the concrete. This can lead to problems with the stability and durability of the concrete structure. Sodium polyacrylate swells after absorbing water, which can introduce microscopic voids in the concrete, reducing the compressive strength of the concrete.

[0147] According to the comparison of the test results of Comparative Example 4 and Example 1, when polyacrylamide exists alone, the 3d strength and 28d strength of the concrete are obviously insufficient, and large cracks and medium cracks also appear. The reason for this is that the water absorption speed of polyacrylamide is greatly affected by temperature. At low temperatures, the water absorption speed of polyacrylamide is generally slow. At high temperatures, the water absorption speed of polyacrylamide generally increases. In specific applications, temperature factors need to be considered, and appropriate types of polyacrylamide and temperature conditions need to be selected according to the required water absorption speed and performance. Due to the slow water absorption speed of polyacrylamide, it may not be able to quickly absorb all the water in the concrete. This can result in some unabsorbed water in the concrete, which is distributed locally in the concrete, with some areas containing more water and some areas being relatively dry, leading to local differences in humidity within the concrete, which causes local differences in the compressive strength of the concrete, affecting the performance of the concrete.

[0148] In summary, the sodium polyacrylate and polyacrylamide used in the super water-storing polymer provided by the present application have a synergistic effect, and different formula proportions are given for different amounts of recycled micro-powder.

[0149] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been shown by the preferred embodiment as above, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the technical solution of the present application, and any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present application are still within the scope of the technical solution of the present application.

Claims

1. A super water-storage polymer mineral admixture for concrete, characterized in that: The composition comprises the following components, calculated by weight: 40 to 60 parts of regenerated micropowder, 25 to 30 parts of fly ash, 10 to 20 parts of a super absorbent resin composition, and 5 to 10 parts of a chelating agent; wherein the super absorbent resin composition comprises sodium polyacrylate and polyacrylamide, with a weight ratio of 1 to 4; The mass ratio of the sodium polyacrylate and the polyacrylamide is determined by the dosage of the regenerated micropowder, fly ash and the super absorbent resin composition; when ≥ (F+G), then 1≤N / A≤1.5; when < (F+G), then 1.5 < N / A ≤ 4; Wherein, W is the weight percentage of the regenerated micro powder; F is the weight percentage of fly ash; G is the weight percentage of the super absorbent resin composition; N is the weight percentage of sodium polyacrylate; A is the weight percentage of polyacrylamide; The super absorbent resin composition further comprises a surfactant, a cross-linking agent, a stabilizer and a pH stabilizer; The chelating agent is EDTA.

2. The method for preparing the super water-storage polymer type mineral admixture for concrete according to claim 1, wherein: The method comprises the following steps: adding regenerated micro powder, fly ash, a highly absorbent resin composition and a chelating agent into water, mixing the mixture, heating the mixture for reaction, and obtaining a reaction liquid; and drying the reaction liquid to obtain a concrete super-water storage polymer mineral admixture.

3. The method for preparing the super water-storage polymer type mineral admixture for concrete according to claim 2, characterized in that: The reaction liquid is dried, including standing the reaction liquid for stratification to obtain an upper clear liquid and a lower material; the upper clear liquid and the lower material are dried separately to obtain material 1 and material 2; and material 1 and material 2 are mixed and ground to obtain a concrete super water storage polymer type mineral admixture.

4. The method for preparing the super water-storage polymer type mineral admixture for concrete according to any one of claims 2 or 3, characterized in that: The temperature of the heating reaction is 60-75°C.

5. The use of the super water-storage polymer type mineral admixture for concrete according to claim 1, characterized in that: The concrete super water storage polymer type mineral admixture is added into the concrete, and the adding amount is 5% to 10% of the mass of the concrete.

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