Mildew-resistant water-resistant beta type building phosphogypsum self-leveling mortar and preparation method thereof

Abstract

The present application relates to a kind of anti-mildew water-resistant beta type building phosphogypsum self-leveling mortar and its preparation method, belong to the technical field of gypsum-based mortar and building material.The mortar is composed of the following components by weight: antifungal waterproof component 1-7 parts, beta type building phosphogypsum 100 parts, retarding water reducing agent 1-4 parts, water retaining agent 0.05-0.2 parts, close-packed aggregate 10-20 parts, composite powder 1-30 parts, water 25-50 parts;The present application prepares water-resistant self-leveling mortar with beta type building phosphogypsum as the main raw material, effectively improves the water resistance of phosphogypsum through the synergistic effect of waterproof component and composite powder;Through the grading technology of retarding water reducing agent and close-packed aggregate sand, the high fluidity and high strength of self-leveling gypsum mortar are guaranteed;The softening coefficient of the mortar is above 0.85, the saturated water absorption is below 6%, the compressive strength / bending strength is 25-45 / 6-14 MPa, the shrinkage is low, the operation is simple, and the construction efficiency is high.

Description

Technical Field

[0001] This invention relates to a mildew-resistant and water-resistant β-type building phosphogypsum self-leveling mortar and its preparation method, belonging to the technical field of gypsum-based mortar and building materials. Background Technology

[0002] Gypsum-based self-leveling mortar is a floor leveling material made with gypsum as the base material, supplemented with aggregates, other cementing materials, and admixtures. It has advantages such as fast construction speed, short construction period, simple process, good thermal insulation and fire resistance, and a warm and comfortable feel underfoot. However, it also has disadvantages such as poor water resistance, susceptibility to mold, and low strength. The gypsum base materials used in gypsum-based self-leveling mortar mainly include α-high-strength gypsum and β-type gypsum. β-type gypsum is rapidly formed under superheated unsaturated vapor pressure, exhibiting acidity with a pH value between 3 and 6. Its main component is β-type calcium sulfate hemihydrate. It hardens quickly, with initial setting / final setting times of 3–5 and 7–9 minutes respectively. It has low strength, with a compressive strength of 5–8 MPa at standard consistency water content. It also has a low softening coefficient, typically 0.3–0.5, and a high saturated water absorption rate of 25–40%. Its crystal surface is rough with numerous cracks. Compared to α-type gypsum, it requires more water and has lower strength, making it more difficult to prepare self-leveling mortars with excellent water resistance and mechanical properties. Furthermore, as a type of phosphogypsum, β-type gypsum has even lower mechanical properties due to its high impurity content, failing to meet the typical compressive strength requirement of over 20 MPa for self-leveling mortars. Therefore, improving the mold resistance, water resistance, and strength of β-type architectural phosphogypsum self-leveling mortar is crucial for the widespread application of β-type architectural phosphogypsum and for optimizing the performance and reducing the cost of self-leveling mortars. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, one of the objectives of this invention is to provide a mildew-resistant and water-resistant β-type building phosphogypsum self-leveling mortar, which has high compressive strength and high flexural strength, as well as good water resistance and mildew resistance.

[0004] The second objective of this invention is to provide a method for preparing anti-mildew and water-resistant β-type building phosphogypsum self-leveling mortar.

[0005] To achieve the objectives of this invention, the following technical solutions are provided.

[0006] A mildew-resistant and water-resistant β-type building phosphogypsum self-leveling mortar, the mortar being composed of the following components in parts by weight:

[0007]

[0008] The anti-mildew and waterproof component, by weight, is a compound of 5-10 parts of anti-mildew component and 5-10 parts of waterproof component; the waterproof component, by weight, is a compound of 1-2 parts of organosilicon polymer, 1-5 parts of emulsion, and 0.05-0.22 parts of surfactant; the organosilicon polymer is sodium methylsiloxane, potassium methylsiloxane, hydrogen-containing silicone oil, or silicone resin; the emulsion is at least one of silicone-acrylic emulsion, ethylene-vinyl acetate copolymer (EVA) emulsion, and styrene-acrylic emulsion; the surfactant is triethylhexyl phosphate, cellulose derivative, or polyacrylamide; the anti-mildew component, by weight, is a compound of 1-2 parts of nano zinc oxide, 2-4 parts of zirconium phosphate, 1-5 parts of polyquaternary ammonium salt, 3-6 parts of nano titanium dioxide, 10-15 parts of polydimethylsiloxane, and 75-85 parts of montmorillonite.

[0009] Preferably, in the waterproofing component, the organosilicon polymer is sodium methylsiloxane, the emulsion is silicone-acrylic emulsion, and the surfactant is polyacrylamide;

[0010] The retarding water-reducing agent is a compound water-reducing agent, which, by weight, consists of 80-90 parts water-reducing component, 1-4.5 parts retarding component, 2-3.4 parts defoaming component, and 80-90 parts water; wherein, the water-reducing component is compounded from 40-50 parts polycarboxylate water-reducing agent and 40-50 parts melamine water-reducing agent, and the retarding component is compounded from 1-4 parts organic retarder and 0-0.5 parts inorganic retarder; the retarding water-reducing agent can adjust the setting time of β-type building phosphogypsum self-leveling mortar to 1-48 hours and the water-cement ratio to 0.25-0.5 by adjusting the dosage, thus preparing a high-strength, high-flowability gypsum self-leveling mortar.

[0011] Preferably, in the retarding water-reducing agent, the organic retarder is a protein-based retarder, a sugar, or a sugar derivative; the inorganic retarder is a borate, borax, or citric acid-based retarder; and the defoaming component is a polysiloxane, a polyether, or a polyether-modified siloxane.

[0012] More preferably, the organic retarder is a protein-based retarder, the inorganic retarder is a citric acid-based retarder, and the defoaming component is a polysiloxane.

[0013] The composite powder, by weight, comprises 15-25 parts of inorganic cementitious material and 1.5-2.5 parts of alkaline activator; wherein the inorganic cementitious material is at least one selected from silicate cement, cement clinker, mineral powder, and fly ash; the alkaline activator is calcium oxide, sodium carbonate, calcium hydroxide, or potassium silicate; the alkaline activator can promote the hydration reaction of the inorganic cementitious material, increasing the amount of hydraulic hydration products such as calcium silicate (aluminate) hydrate and ettringite, thereby improving the strength of gypsum and giving it a better waterproof effect. Furthermore, the composite powder can improve the pH value of the gypsum system, making it alkaline, allowing the waterproofing components and water-retaining agents to exert their optimal effects.

[0014] Preferably, in the composite powder, the inorganic cementitious materials are silicate cement and mineral powder, and the alkaline activator is sodium carbonate. Choosing sodium carbonate as the alkaline activator promotes the hydration reaction of the inorganic cementitious materials, while its hydration products, such as calcium carbonate and hydrated sodium aluminosilicate gel, have good volume stability and will not cause shrinkage cracking in gypsum products.

[0015] The densely packed aggregate, by weight, consists of 1-2 parts of aggregate with a particle size of 0.1-0.2 mm and 1-2 parts of aggregate with a particle size of 0.2-0.4 mm in a continuous gradation; the aggregate is natural sand or manufactured sand; the gradation can reduce the porosity in the self-leveling mortar, making the overlap between the dihydrate gypsum crystals and the hydration products of sand and inorganic cementitious materials more compact, significantly improving the mortar strength. Furthermore, a good gradation will further increase the workability of the self-leveling mortar.

[0016] The water-retaining agent, by weight, consists of 0-0.1 parts of adhesive powder and 0-0.2 parts of cellulose ether, and the weight of the adhesive powder and the cellulose ether cannot both be 0; wherein the adhesive powder is a styrene-butadiene copolymer, a tert-carbonate copolymer, or an ethylene-vinyl acetate copolymer; the cellulose ether is one or two of methylcellulose, hydroxypropyl methylcellulose, and hydroxyethyl methylcellulose, and the viscosity of the cellulose ether is 5W-20W;

[0017] Preferably, in the water-retaining agent, the cellulose ether is hydroxypropyl methylcellulose and the adhesive powder is a styrene-butadiene copolymer.

[0018] The working principle of the anti-mildew and waterproof component is as follows: the addition of organosilicon polymers to the waterproof component forms a hydrophobic film, giving the self-leveling mortar excellent water resistance. The emulsion can form a film or fill the pores of the matrix, further improving the water resistance of the gypsum. In addition, the emulsion acts as a lubricant, which is beneficial to the formation of the organosilicon polymer hydrophobic film. While improving the water resistance of the gypsum, the emulsion also has a significant toughening effect, which can greatly improve the flexural strength of the self-leveling gypsum mortar without the addition of fibers. The surfactant is an interfacial dispersant with both oleophilic and hydrophilic properties within its molecule, enabling uniform dispersion of the organosilicon polymer and emulsion, resulting in a well-compatible mixture. Furthermore, it also facilitates the dispersion of retarding water-reducing agents and water-retaining agents in the gypsum, preventing the sedimentation and aggregation of gypsum particles and improving the mechanical properties of the self-leveling gypsum mortar.

[0019] The main active ingredients in the antifungal component are polydimethylsiloxane and montmorillonite. These ingredients can react with sulfhydryl or hydroxyl groups at the active site of enzymes, directly attacking the enzyme's active components, causing inactivation, and leading to microbial death. The auxiliary ingredients are nano-zinc oxide, zirconium phosphate, polyquaternary ammonium salt, and nano-titanium dioxide. These auxiliary ingredients can destroy and prevent the formation of pathogen cell membranes, leading to pathogen death. The synergistic effect of the main active ingredients and auxiliary ingredients results in a broader spectrum of bactericidal activity, especially with a strong inhibitory effect on molds, yeasts, and algae.

[0020] Preferably, a mildew-resistant and water-resistant β-type building phosphogypsum self-leveling mortar is composed of the following components in parts by weight: 100 parts of β-type building phosphogypsum, 2-7 parts of mildew-resistant and waterproof component, 1-4 parts of retarding water-reducing agent, 0.07-0.20 parts of water-retaining agent, 10-20 parts of densely packed aggregate, 10-30 parts of composite powder, and 25-40 parts of water.

[0021] A method for preparing the anti-mildew and water-resistant β-type building phosphogypsum self-leveling mortar of the present invention includes the following steps:

[0022] Step 1: Add the retarding water-reducing agent and the anti-mildew and waterproofing component to the water, stir well, and obtain solution A;

[0023] Step 2: Dry mix β-type building phosphogypsum, water-retaining agent, densely packed aggregate, and composite powder for 1.5–2.5 min to obtain powder B;

[0024] Step 3: Slowly add solution A to powder B and stir for 2-3 minutes to obtain β-type building phosphogypsum self-leveling mortar.

[0025] Preferably, the anti-mildew and waterproof component mentioned in step one is prepared using the following method:

[0026] (1) Add organosilicon polymer and acetic acid to deionized water at the same time, and stir at 20-25°C for 15-30 min to allow the two to react fully and obtain organosilicon solution; wherein acetic acid is a catalyst and the amount added is 25%-40% of the mass of organosilicon polymer;

[0027] (2) Add the emulsion to the organosilicon solution obtained in step (1) and stir until homogeneous to obtain a mixed solution;

[0028] (3) Add surfactant to the mixed solution obtained in step (2) while stirring, and stir for 30 to 45 minutes to obtain a well-adapted mixed solution, namely a waterproof component solution;

[0029] (4) Add the anti-mildew components nano zinc oxide, zirconium phosphate, polyquaternary ammonium salt, nano titanium dioxide, polydimethylsiloxane and montmorillonite to the waterproof component solution in sequence, and stir for 10 to 15 minutes in a stirrer at 20 to 25°C and 3000 to 4000 r / min to obtain a well-adapted anti-mildew and waterproof component mixture.

[0030] Preferably, the modification process includes the following steps for β-type building phosphogypsum: drying β-type building phosphogypsum at 100-120℃ for 2-3 hours, neutralizing it with alkali at a mass concentration of 4%-9%, aging it for 48-72 hours, and grinding it to a fineness of 40-80 μm to produce β-type hemihydrate phosphogypsum, thus completing the modification; the β-type hemihydrate phosphogypsum contains ≥85% hemihydrate gypsum and ≤4% dihydrate gypsum. The drying, neutralization, and aging processes in the modification process can reduce the content of harmful impurities such as soluble phosphorus, soluble fluorine, and organic matter in the phosphogypsum, ensuring the quality of the prepared gypsum products.

[0031] An application of the anti-mildew and water-resistant β-type building phosphogypsum self-leveling mortar of the present invention, wherein the mortar is suitable for fine leveling of concrete floors;

[0032] Specifically, the construction is carried out using automated machinery, and after the mortar is fully dried, a leveling layer with waterproof and mildew-resistant properties is obtained.

[0033] Beneficial effects

[0034] (1) This invention provides a mildew-resistant and water-resistant β-type building phosphogypsum self-leveling mortar. The mortar effectively improves the water resistance of gypsum through the synergistic effect of waterproof components and composite powder. The continuous gradation technology of sand in the retarding water-reducing agent and compacted aggregate ensures the high fluidity and high strength of the self-leveling gypsum mortar, solving the problems of low strength, water resistance and easy mold in phosphogypsum. Under the synergistic effect of multiple components, a self-leveling mortar with high strength, high flexural strength and water resistance and mildew resistance is obtained. The softening coefficient of the mortar is above 0.85, the saturated water absorption rate is below 6%, the compressive / flexural strength is 25-45 / 6-14MPa, the shrinkage is low and the construction efficiency is high. It overcomes the shortcomings of β-type building phosphogypsum self-leveling mortar and promotes the development of building materials.

[0035] (2) This invention provides a mold-resistant and water-resistant β-type building phosphogypsum self-leveling mortar. The mortar is mainly composed of mold-resistant and waterproof components. Through the synergistic effect of multiple components, the water resistance and antibacterial properties of the self-leveling mortar are effectively improved: the addition of organosilicon polymers in the waterproof components can form a hydrophobic film, giving the self-leveling mortar excellent water resistance. The emulsion can form a film or fill the pores of the matrix, further improving the water resistance of the gypsum. In addition, the composite powder can improve the pH value of the gypsum system, making it alkaline, so that the waterproof components and water-retaining agents can play a better role. The main effective components and auxiliary components in the mold-resistant components can coordinate with each other to have a broader spectrum of bactericidal activity, especially a strong inhibitory effect on mold, yeast and algae. At the same time, the good waterproof properties keep the interior of the gypsum specimens at low humidity, which has a positive effect on its mold resistance.

[0036] (3) This invention provides a mildew-resistant and water-resistant β-type building phosphogypsum self-leveling mortar. The mortar effectively improves the compressive strength and mechanical properties of the β-type building phosphogypsum self-leveling mortar through the synergistic effect of a retarding water-reducing agent, densely packed aggregate, composite powder, and mildew-resistant and waterproofing components. The emulsion in the waterproofing component significantly enhances the water resistance of the gypsum while also providing a toughening effect, substantially increasing the flexural strength of the self-leveling gypsum mortar without the addition of fibers. The surfactant also facilitates the application of the retarding water-reducing agent and water-retaining agent in the gypsum. Dispersion prevents the settling and aggregation of gypsum particles, improving the mechanical properties of self-leveling gypsum mortar; tightly packed aggregates, under the continuous gradation conditions, can reduce the porosity of self-leveling mortar and increase its strength; in the composite powder, alkaline activators can promote the hydration reaction of inorganic cementitious materials, increasing the amount of hydraulic hydration products such as calcium silicate (aluminate) hydrate and ettringite. These hydration products have good volume stability and will not cause shrinkage and cracking of gypsum products, thus improving the strength of gypsum while giving it a better waterproof effect.

[0037] (4) This invention provides a mildew-resistant and water-resistant β-type building phosphogypsum self-leveling mortar. The retarding water-reducing agent added to the mortar is a compound water-reducing agent, which can fill the gaps between β-type gypsum, improve the density, and adjust the setting time to the range of 1 to 48 hours by adjusting the dosage, and adjust the water-cement ratio to 0.25 to 0.5 to prepare a high-strength and highly fluid gypsum self-leveling mortar. At the same time, an antifoaming component is compounded in the retarding water-reducing agent, which can reduce internal defects of gypsum mortar and make the matrix more compact.

[0038] (5) This invention provides a method for preparing anti-mildew and water-resistant β-type building phosphogypsum self-leveling mortar. The method reduces the content of harmful impurities such as soluble phosphorus, soluble fluorine, and organic matter in phosphogypsum by modifying β-type building phosphogypsum powder, thereby ensuring the quality of the prepared gypsum products. The water resistance of gypsum is effectively improved by the synergistic effect of waterproof components and composite powder. The high fluidity and high strength of self-leveling gypsum mortar are ensured by the continuous gradation technology of sand in the retarding water-reducing agent and composite aggregate.

[0039] (6) The present invention provides an application of anti-mildew and water-resistant β-type building phosphogypsum self-leveling mortar, which is easy to construct using automated machinery, and is simple to operate and highly efficient. Attached Figure Description

[0040] Figure 1 The image shows the initial flowability of Comparative Example 3;

[0041] Figure 2 Image showing the initial flowability of Example 3;

[0042] Figure 3 Here is an image of water dripping from the cross-section of specimen 3 (Comparative Example 3);

[0043] Figure 4 Image showing water dripping from the cross-section of specimen 3 in Example 3;

[0044] Figure 5 This is a diagram showing the anti-mildew test results of specimen 1 in Comparative Example 1;

[0045] Figure 6 This is a diagram showing the anti-mildew test results of the specimen in Example 1;

[0046] Figure 7 This is a diagram showing the anti-mildew test results of specimen 2 in Comparative Example 2;

[0047] Figure 8 This is a diagram showing the anti-mildew test results of the specimen in Example 2;

[0048] Figure 9 This is a diagram showing the anti-mildew test results of specimen 3 in Comparative Example 3;

[0049] Figure 10 This is a diagram showing the anti-mildew test results of the specimen in Example 3. Detailed Implementation

[0050] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention. Unless otherwise specified, the methods described are conventional methods, and the raw materials are all available from publicly available commercial sources.

[0051] Example 1

[0052] A mildew-resistant and water-resistant β-type building phosphogypsum self-leveling mortar, the mortar being composed of the following raw material components in parts by weight: 2 parts mildew-resistant and waterproof component, 100 parts β-type building phosphogypsum, 1 part retarding water-reducing agent, 0.07 parts water-retaining agent, 10 parts densely packed aggregate, 10 parts composite powder, and 40 parts water.

[0053] The anti-mildew and waterproof component, by weight, comprises the following components and proportions: hydrogen-containing silicone oil: styrene-acrylic emulsion: polyacrylamide: nano zinc oxide: zirconium phosphate: polyquaternium salt: nano titanium dioxide: polydimethylsiloxane: montmorillonite compounded in the proportion of 5:10:0.2:1:0.4:0.5:0.6:1.5:11.2;

[0054] The components of the retarding water-reducing agent, by weight, are as follows: polycarboxylate superplasticizer: melamine superplasticizer: protein retarder: polyether-modified siloxane: water = 1:1:0.05:0.06:2.2;

[0055] The densely packed aggregate, by weight, comprises the following components and proportions: manufactured sand with a particle size of 0.1–0.2 mm : natural sand with a particle size of 0.2–0.4 mm = 1:2;

[0056] The composite powder, by weight, comprises the following components and proportions: ordinary silicate cement: fly ash: sodium carbonate = 5:5:0.6;

[0057] The water-retaining agent, by weight, comprises the following components and proportions: styrene-butadiene copolymer: hydroxyethyl methylcellulose = 0.08:0.10.

[0058] A method for preparing the anti-mildew and water-resistant β-type building phosphogypsum self-leveling mortar described in this embodiment includes the following steps:

[0059] Step 1: Add the retarding water-reducing agent and the anti-mildew and waterproofing component to the water, stir well, and obtain solution A;

[0060] (1) Add organosilicon polymer and acetic acid to deionized water at the same time, and stir at 22°C for 30 min to allow them to react fully and obtain organosilicon solution; wherein acetic acid is a catalyst and the amount added is 25% of the mass of organosilicon polymer;

[0061] (2) Add the emulsion to the organosilicon solution obtained in step (1) and stir until homogeneous to obtain a mixed solution;

[0062] (3) Add surfactant to the mixed solution obtained in step (2) while stirring, and stir for 45 minutes to obtain a well-adapted mixed solution, namely a waterproof component solution;

[0063] (4) Add the anti-mildew components nano zinc oxide, zirconium phosphate, polyquaternary ammonium salt, nano titanium dioxide, polydimethylsiloxane and montmorillonite to the waterproof component solution in sequence, and stir for 15 min in a stirrer at 22℃ and 4000r / min to obtain an anti-mildew and waterproof component mixture with good adaptability.

[0064] Step 2: Dry mix β-type building phosphogypsum, water-retaining agent, densely packed aggregate, and composite powder for 2 minutes to obtain powder B;

[0065] Step 3: Slowly add solution A to powder B and stir for 3 minutes to obtain β-type building phosphogypsum self-leveling mortar.

[0066] Comparative Example 1

[0067] Comparative Example 1 was based solely on Example 1, except that the "anti-mildew and waterproof component" was removed, while all other conditions remained unchanged, resulting in a β-type building phosphogypsum self-leveling mortar.

[0068] Example 2

[0069] Example 2 is based solely on Example 1, except that the weight of the anti-mildew and waterproof component is changed from "2 parts" to "4 parts", while all other conditions remain unchanged, to obtain an anti-mildew and water-resistant β-type building phosphogypsum self-leveling mortar.

[0070] Comparative Example 2

[0071] Comparative Example 2 was based solely on Example 2, except that the "retarding water-reducing agent" was replaced with "ordinary gypsum water-reducing agent" while all other conditions remained unchanged, resulting in a β-type building phosphogypsum self-leveling mortar.

[0072] Example 3

[0073] A mildew-resistant and water-resistant β-type building phosphogypsum self-leveling mortar is provided, comprising the following raw material components in parts by weight: 7 parts mildew-resistant and waterproof component, 100 parts β-type building phosphogypsum, 4 parts retarding water-reducing agent, 0.2 parts water-retaining agent, 20 parts densely packed aggregate, 30 parts composite powder, and 25 parts water; other conditions are the same as in Example 1, to obtain a mildew-resistant and water-resistant β-type building phosphogypsum self-leveling mortar.

[0074] Comparative Example 3

[0075] Comparative Example 3, based solely on Example 3, removes the "closely packed aggregate" to obtain a β-type building phosphogypsum self-leveling mortar.

[0076] The tests were conducted according to standards GB / T 9776-2008 Building Gypsum and JC / T 1023-2007 Gypsum-Based Self-Leveling Mortar. Performance tests were performed on the self-leveling mortars prepared in Examples 1-3 and Comparative Examples 1-3, and the results are shown in Table 1. Initial flowability is shown in [Table data missing]. Figures 1-2 See the image of the water dripping section of the specimen (specimen size: 40×40×160mm). Figures 3-4 .

[0077] Table 1. Performance test results of the gypsum self-leveling mortars described in Examples 1-3 and Comparative Examples 1-3

[0078]

[0079] As shown in Table 1, the test results of Comparative Example 1 and Example 1, Comparative Example 2 and Example 2, and Comparative Example 3 and Example 3 indicate that the anti-mildew waterproofing component, the retarding water-reducing agent, and the densely packed aggregate can all effectively improve the strength, saturated strength, softening coefficient, and contact angle of β-type building phosphogypsum self-leveling mortar, and reduce the saturated water absorption rate. This demonstrates that the anti-mildew waterproofing component, the retarding water-reducing agent, and the densely packed aggregate used in this invention can effectively improve the strength and softening coefficient of β-type building phosphogypsum self-leveling mortar, reduce the water absorption rate of the system, and improve water resistance. Furthermore, the test results show that using different formulations of the waterproofing component, retarding water-reducing agent, water-retaining agent, densely packed aggregate, and composite powder of this invention can all produce a positive gain on the strength and water resistance of β-type building phosphogypsum self-leveling mortar.

[0080] According to the standard ASTM G21 "Determination of Fungal Resistance of Synthetic Polymer Materials", antifungal resistance tests were conducted. The antifungal resistance level was determined by visually observing the area of ​​fungal growth (Level 0: No fungal growth, extremely strong antifungal resistance; Level 1: Fungal growth and spore formation traces, area <10%, relatively strong antifungal resistance; Level 2: Small amount of fungal growth and spore formation, 10% < area < 30%, no antifungal resistance; Level 3: Small amount of fungal growth and spore formation, 30% < area < 60%, no antifungal resistance; Level 4: Small amount of fungal growth and spore formation, 60% < area < 100%, no antifungal resistance). The selected fungal species were: *Aspergillus niger* (ATCC 16404); *Penicillium pineophilum* (ATCC 11797); *Chaetoceros globosum* (ATCC 6205); *Cladosporium brevichorum* (ATCC 9645); and *Cladosporium buddingii* (ATCC 16404). 15233), the results are shown in Table 1. Anti-mildew and waterproof components can effectively improve the anti-mildew grade, retarding water-reducing agent can extend the setting time by 20 times, and densely packed aggregate can improve the initial fluidity of β-type building phosphogypsum self-leveling mortar.

[0081] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A mildew-resistant and water-resistant β-type building phosphogypsum self-leveling mortar, characterized in that: It is composed of the following components in parts by weight: 100 parts of β-type building phosphogypsum, 1-7 parts of anti-mildew and waterproof component, 1-4 parts of retarding water-reducing agent, 0.05-0.20 parts of water-retaining agent, 10-20 parts of compacted aggregate, 1-30 parts of composite powder, and 25-50 parts of water. The anti-mildew and waterproof component, by weight, consists of 5-10 parts of anti-mildew component and 5-10 parts of waterproof component; wherein, the waterproof component consists of 1-2 parts of organosilicon polymer, 1-5 parts of emulsion and 0.05-0.22 parts of surfactant; the anti-mildew component consists of 1-2 parts of nano zinc oxide, 2-4 parts of zirconium phosphate, 1-5 parts of polyquaternary ammonium salt, 3-6 parts of nano titanium dioxide, 10-15 parts of polydimethylsiloxane and 75-85 parts of montmorillonite; The retarding water-reducing agent comprises, by weight, 80-90 parts water-reducing component, 1-4.5 parts retarding component, 2-3.4 parts defoaming component, and 80-90 parts water; wherein the water-reducing component consists of 40-50 parts polycarboxylate-based water-reducing agent and 40-50 parts melamine-based water-reducing agent, and the retarding component consists of 1-4 parts organic retarder and 0-0.5 parts inorganic retarder; The composite powder, by weight, comprises 15-25 parts of inorganic cementitious material and 1.5-2.5 parts of alkaline activator; The densely packed aggregate, by weight, consists of 1-2 parts of aggregate with a particle size of 0.1-0.2 mm and 1-2 parts of aggregate with a particle size of 0.2-0.4 mm in continuous gradation, wherein the aggregate is natural sand or manufactured sand; In the waterproofing component, the organosilicon polymer is sodium methylsiloxane, the emulsion is silicone-acrylic emulsion, and the surfactant is polyacrylamide.

2. The anti-mildew and water-resistant β-type building phosphogypsum self-leveling mortar according to claim 1, characterized in that: The water-retaining agent, by weight, consists of 0-0.1 parts of adhesive powder and 0-0.2 parts of cellulose ether, wherein the weight parts of the adhesive powder and the cellulose ether are not both 0; wherein the adhesive powder is a styrene-butadiene copolymer, a tert-carbonate copolymer, or an ethylene-vinyl acetate copolymer; and the cellulose ether is one or two of methylcellulose, hydroxypropyl methylcellulose, and hydroxyethyl methylcellulose, with a viscosity of 5W-20W.

3. The anti-mildew and water-resistant β-type building phosphogypsum self-leveling mortar according to claim 2, characterized in that: In the retarding water-reducing agent, the organic retarder is a protein-based retarder, a sugar, or a sugar derivative; the inorganic retarder is a borate, borax, or citric acid-based retarder; and the defoaming component is a polysiloxane, a polyether, or a polyether-modified siloxane. In the composite powder, the inorganic cementing material is at least one of silicate cement, cement clinker, mineral powder and fly ash; the alkaline activator is calcium oxide, sodium carbonate, calcium hydroxide or potassium silicate. In the water-retaining agent, the cellulose ether is hydroxypropyl methylcellulose, and the adhesive powder is a styrene-butadiene copolymer.

4. The anti-mildew and water-resistant β-type building phosphogypsum self-leveling mortar according to claim 3, characterized in that: In the aforementioned retarding water-reducing agent, the organic retarder is a protein-based retarder, the inorganic retarder is a citric acid-based retarder, and the defoaming component is polysiloxane.

5. The anti-mildew and water-resistant β-type building phosphogypsum self-leveling mortar according to claim 3, characterized in that: In the composite powder, the inorganic cementing materials are silicate cement and mineral powder, and the alkaline activator is sodium carbonate.

6. The anti-mildew and water-resistant β-type building phosphogypsum self-leveling mortar according to any one of claims 1 to 5, characterized in that: The mortar is composed of the following components in parts by weight: 100 parts of β-type building phosphogypsum, 2-7 parts of anti-mildew and waterproof component, 1-4 parts of retarding water-reducing agent, 0.07-0.20 parts of water-retaining agent, 10-20 parts of compacted aggregate, 10-30 parts of composite powder, and 25-40 parts of water.

7. A method for preparing the anti-mildew and water-resistant β-type building phosphogypsum self-leveling mortar as described in any one of claims 1 to 6, characterized in that: Includes the following steps: Step 1: Add the retarding water-reducing agent and the anti-mildew and waterproofing component to the water, stir well, and obtain solution A; Step 2: Dry mix β-type building phosphogypsum, water-retaining agent, densely packed aggregate, and composite powder for 1.5–2.5 min to obtain powder B; Step 3: Slowly add solution A to powder B and stir for 2-3 minutes to obtain β-type building phosphogypsum self-leveling mortar.

8. The method for preparing a mildew-resistant and water-resistant β-type building phosphogypsum self-leveling mortar according to claim 7, characterized in that: The anti-mildew and waterproof component is prepared using the following method: (1) Add organosilicon polymer and acetic acid to deionized water at the same time, and stir at 20-25°C for 15-30 min to allow the two to react fully and obtain organosilicon solution; wherein acetic acid is a catalyst and the amount added is 25%-40% of the mass of organosilicon polymer; (2) Add the emulsion to the organosilicon solution and stir until homogeneous to obtain a mixed solution; (3) Add the surfactant to the mixed solution while stirring, and stir for 30-45 minutes to obtain a waterproof component solution; (4) Add the anti-mildew components nano zinc oxide, zirconium phosphate, polyquaternary ammonium salt, nano titanium dioxide, polydimethylsiloxane and montmorillonite to the waterproof component solution in sequence, and stir at 20-25℃ and 3000-4000r / min for 10-15min to obtain the anti-mildew and waterproof component mixture.

9. The method for preparing a mildew-resistant and water-resistant β-type building phosphogypsum self-leveling mortar according to claim 7, characterized in that: The method also includes a modification process for β-type building phosphogypsum: drying β-type building phosphogypsum at 100-120℃ for 2-3 hours, neutralizing it with alkali at a mass concentration of 4%-9%, aging it for 48-72 hours, and grinding it to a fineness of 40-80μm to produce β-type hemihydrate phosphogypsum, thus completing the modification.

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