Impermeable concrete foaming agent and preparation method thereof

Abstract

The invention discloses an impermeable concrete foaming agent and a preparation method thereof. The impermeable concrete foaming agent comprises modified siloxane, sodium alpha-olefin sulfonate, silica fume micro powder, polyvinyl alcohol, sulfonated melamine formaldehyde resin, polypropylene fibers, acrylic ester, an air entraining agent, a retarder, a water reducing agent and an antifreeze agent. According to the anti-permeability concrete foaming agent, by adding the modified siloxane and the silica fume micro powder, a compact microstructure is formed, pores and cracks in concrete are remarkably reduced, and the anti-permeability performance is improved; excellent hydrophobicity is provided through modified siloxane, and water is further prevented from entering the concrete. Due to the use of the sodium alpha-olefin sulfonate and the sulfonated melamine formaldehyde resin, the sulfate corrosion resistance of the concrete is improved, and the durability of the concrete is improved. The concrete anti-seepage agent has obvious effects in the aspects of improving the anti-seepage performance, the freeze-thaw resistance, the durability and the working performance of concrete, and meanwhile, has good environmental protection performance and economic benefits.

Description

Technical Field

[0001] The invention relates to the field of concrete materials, and in particular to an anti-seepage concrete foaming agent and a preparation method thereof. Background Art

[0002] Concrete is one of the most commonly used materials in construction projects, with good mechanical properties and durability. However, ordinary concrete has certain permeability problems, especially when exposed to water or other liquid environments for a long time, the permeability will cause the internal structure of the concrete to be damaged, thus affecting its service life. This permeability problem is particularly prominent in projects such as underground projects, bridges, tunnels, etc. that are in long-term contact with water.

[0003] To solve this problem, traditional methods usually improve the anti-seepage performance of concrete by adding waterproofing agents or using waterproof coatings. However, these methods have the following limitations:

[0004] 1. Limitations of waterproofing agents: Waterproofing agents are easily affected by the concrete mix ratio and construction process, and their effectiveness is difficult to guarantee. Moreover, waterproofing agents may decompose or become ineffective during long-term use, resulting in a decrease in the concrete's impermeability.

[0005] 2. Defects of waterproof coating: Waterproof coating is easily damaged by external mechanical means. Once the coating is damaged, the waterproof effect will be greatly reduced. Moreover, the coating construction is complicated, which increases the construction cost and time.

[0006] In addition, although the existing foamed concrete technology can improve the lightweight and thermal insulation properties of concrete by introducing bubbles, the instability of the bubble structure often leads to a decrease in the strength and durability of the concrete, and fails to significantly improve its anti-permeability properties.

[0007] In recent years, researchers have tried to develop new concrete foaming agents to ensure the lightweight performance of concrete while significantly improving its impermeability. Concrete foaming agents can form evenly distributed tiny bubbles in concrete, thereby improving the performance of concrete. However, existing foaming agents still have shortcomings in improving the impermeability of concrete, which are specifically manifested in the following aspects:

[0008] 1. Poor bubble stability: Many foaming agents have bubbles that easily burst during the mixing and pouring of concrete, resulting in an unstable bubble structure in the final concrete, affecting its performance.

[0009] 2. Limited anti-seepage effect: Existing foaming agents have limited effect in improving the anti-seepage performance of concrete and cannot meet the needs of some special engineering projects that require high anti-seepage performance.

[0010] 3. Poor overall performance: Many foaming agents, while improving a certain property, often affect other properties of concrete, such as strength, early strength development, etc. Summary of the invention

[0011] In order to overcome the problems of poor concrete impermeability and unstable bubbles in the existing foaming agent in improving the concrete impermeability, the present invention aims to provide an impermeable concrete foaming agent, which can not only effectively improve the concrete impermeability, but also significantly improve the strength and durability of the concrete. The present invention also provides a method for preparing an impermeable concrete foaming agent, so that the prepared impermeable concrete foaming agent forms a stable bubble structure in the concrete, significantly improves the concrete impermeability, and takes into account the strength and durability of the concrete, so as to meet the demand of modern engineering for high-performance concrete.

[0012] To achieve the above object, the present invention provides the following technical solutions:

[0013] An anti-seepage concrete foaming agent comprises the following raw materials in parts by weight:

[0014] 4-16 parts of modified siloxane; 10-30 parts of sodium α-olefin sulfonate; 10-20 parts of silica fume powder, 2-10 parts of polyvinyl alcohol; 1-3 parts of sulfonated melamine formaldehyde resin; 0.2-1 parts of polypropylene fiber; 2-8 parts of acrylate; 1-6 parts of air entraining agent; 1-6 parts of retarder; 1-4 parts of water reducer; 2-6 parts of antifreeze agent.

[0015] As a further solution of the present invention, the impermeable concrete foaming agent includes the following raw materials in parts by weight: 10 parts of modified siloxane; 20 parts of sodium α-olefin sulfonate; 15 parts of silica fume powder, 6 parts of polyvinyl alcohol; 2 parts of sulfonated melamine formaldehyde resin; 0.6 parts of polypropylene fiber; 5 parts of acrylate; 3.5 parts of air entraining agent; 3.5 parts of retarder; 2.5 parts of water reducer; and 4 parts of antifreeze agent.

[0016] As a further solution of the present invention, the modified siloxane is an organic siloxane monomer and a methyl methacrylate (MMA) monomer, and a peroxide is used as an initiator to generate free radicals, and the free radicals react with the organic siloxane monomer and the methyl methacrylate monomer to form a copolymer; wherein the organic siloxane monomer is one of methyltrimethoxysilane (MTMS), vinyltrimethoxysilane (VTMS), and γ-glycidoxypropyltrimethoxysilane (GPTMS).

[0017] As a further solution of the present invention, when vinyltrimethoxysilane (VTMS) is copolymerized with methyl methacrylate (MMA), benzoyl peroxide is used as the initiator, and the vinyl group in the vinyltrimethoxysilane reacts with methyl methacrylate through free radical polymerization to form a polymer containing siloxy groups, thereby obtaining a modified siloxane.

[0018] As a further scheme of the present invention, when copolymerizing methyltrimethoxysilane (MTMS) and methyl methacrylate (MMA), benzoyl peroxide is used as the initiator, and methyltrimethoxysilane undergoes free radical copolymerization with methyl methacrylate via a methoxy group to obtain a modified siloxane; the epoxy group in γ-glycidyloxypropyltrimethoxysilane is ring-opened under alkaline conditions, and benzoyl peroxide is used as the initiator to introduce an epoxy group into the siloxane molecule, and the methyl methacrylate undergoes copolymerization to obtain a modified siloxane.

[0019] In the anti-seepage concrete foaming agent, modified siloxane plays the role of filling pores in concrete and improving the anti-seepage performance. By adding modified siloxane, the micropores and fine cracks inside the concrete can be effectively filled, the penetration of the penetrating medium can be reduced, and the density and anti-seepage of the concrete can be improved.

[0020] As a further solution of the present invention, the silica fume powder is obtained by crushing silica ore with a particle size of 0.1-1 micron and a specific surface area of ​​15-30m 2 / g and silica fume with SiO2 content not less than 85%. In the anti-seepage concrete foaming agent, silica fume powder plays a role in refining pores and enhancing the density of concrete. By adding silica fume powder and using it with modified siloxane, the microscopic pores in the concrete can be filled, the density and anti-seepage of the concrete can be improved, and the mechanical properties of the concrete can be enhanced. Combined with the use of sodium α-olefin sulfonate in the anti-seepage concrete foaming agent, it helps to improve the fluidity and water-reducing effect of the concrete, effectively disperse cement particles, reduce the viscosity of the concrete, improve fluidity and workability, and reduce the water-cement ratio of the concrete and increase the compressive strength.

[0021] As a further embodiment of the present invention, the air entraining agent is one or more of rosin resin, alkyl sulfonate, and alkylbenzene sulfonate, wherein the alkyl sulfonate is sodium dodecyl sulfonate, and the alkylbenzene sulfonate is sodium dodecylbenzene sulfonate.

[0022] As a further embodiment of the present invention, the retarder is one or more of sodium borate, sodium gluconate, citric acid, and lignin sulfonate.

[0023] As a further embodiment of the present invention, the water reducer is one or more of a naphthalene-based water reducer, a polycarboxylate water reducer, and a wood calcium water reducer; wherein the naphthalene-based water reducer is a naphthalenesulfonate formaldehyde condensate; the polycarboxylate water reducer is a polycarboxylate ether superplasticizer (PCE); and the wood calcium water reducer is calcium lignin sulfonate.

[0024] As a further embodiment of the present invention, the antifreeze agent is one or more of calcium chloride, sodium sulfate and urea.

[0025] In the anti-seepage concrete foaming agent, polyvinyl alcohol is used as a thickener and binder. The addition of polyvinyl alcohol can increase the cohesiveness of concrete, improve the crack resistance of concrete, and enhance the bonding strength of concrete with other materials; sulfonated melamine formaldehyde resin is used as a reinforcing agent and curing agent. Sulfonated melamine formaldehyde resin can react with cement to form a gel, enhance the mechanical properties and durability of concrete, and improve its anti-seepage and weather resistance; the addition of polypropylene fiber can effectively control the shrinkage cracks of concrete, improve its tensile strength and toughness, and delay the development of cracks in concrete; the addition of acrylic acid ester can improve the durability and anti-freeze and thaw properties of concrete, increase the flexibility of concrete, and reduce the occurrence of cracks; air entraining agent, retarder, water reducer and antifreeze agent are used to adjust the pore structure of concrete, slow down the setting speed of cement, control the fluidity of concrete and enhance the anti-freeze performance of concrete, respectively, which can comprehensively improve the performance of concrete and make the concrete foaming agent have good fluidity, durability and anti-seepage.

[0026] A preparation method based on an impermeable concrete foaming agent, the steps are as follows:

[0027] 1) Weigh modified siloxane, sodium α-olefin sulfonate, silica fume powder, polyvinyl alcohol, sulfonated melamine formaldehyde resin, polypropylene fiber, acrylate, air entraining agent, retarder, water reducing agent and antifreeze agent according to weight parts and set aside;

[0028] 2) premixing the modified siloxane and sodium α-olefin sulfonate, adding the weighed modified siloxane and sodium α-olefin sulfonate into a mixing container, stirring at a speed of 200-250 r / min, stirring for 10-15 minutes, and controlling the temperature at 25° C. to obtain a liquid mixture;

[0029] 3) Pretreatment of dry powder: dry-mix the silica fume powder and polyvinyl alcohol at a stirring speed of 150-200 r / min for 5-10 minutes to obtain a dry powder mixture;

[0030] 4) Mixing the dry powder with the liquid: adding the liquid mixture of step 2) to the dry powder mixture of step 3), and stirring at a speed of 300-350 r / min, a stirring time of 15-20 minutes, and a temperature controlled at 30° C.;

[0031] 5) Adding auxiliary agents and ultrasonic treatment: adding sulfonated melamine formaldehyde resin, polypropylene fiber, acrylate, air entraining agent, retarder, water reducer and antifreeze agent in sequence, stirring at a speed of 250-300 r / min after each addition, stirring for 5 minutes, and a total stirring time of 35 minutes; transferring the mixture to an ultrasonic treatment device for ultrasonic treatment, with an ultrasonic frequency of 25 kHz, an ultrasonic time of 15-20 minutes, and a treatment temperature of 40°C.

[0032] 6) High shear mixing and vacuum degassing: the mixture after ultrasonic treatment is placed in a high shear mixer for high shear mixing, the shear rate is 4000-4500r / min, and the mixing time is 20 minutes; the mixture after high shear mixing is transferred to a vacuum degassing device for degassing, wherein the vacuum degree is -0.09MPa, and the degassing time is 20 minutes, the degassed mixture is cooled to room temperature, and the cooled mixture is placed in a stable container and allowed to stand for 24 hours. After quality inspection, the qualified anti-permeability concrete foaming agent is obtained and stored in a sealed container.

[0033] Compared with the prior art, the anti-seepage concrete foaming agent and the preparation method thereof of the present invention have the following beneficial effects:

[0034] 1. Significantly improved the impermeability of concrete: by adding modified siloxane and silica fume powder, a dense microstructure is formed, which significantly reduces the pores and cracks inside the concrete and improves the impermeability; modified siloxane provides excellent hydrophobicity, further preventing moisture from entering the concrete.

[0035] 2. Enhanced the freeze-thaw resistance of concrete: The addition of antifreeze agent enables the concrete to maintain good toughness and stability in low temperature environment, preventing the damage of freeze-thaw cycle to the concrete; the use of polypropylene fiber increases the toughness of concrete and reduces cracks caused by temperature changes.

[0036] 3. Improved the working performance of concrete: The use of water reducer improves the fluidity and operability of concrete mixture, reduces water consumption, and makes concrete easier to construct and shape. The addition of retarder prolongs the initial setting time of concrete, making it easier to operate under complex construction conditions.

[0037] 4. Increased durability of concrete: The use of sodium α-olefin sulfonate and sulfonated melamine formaldehyde resin improves the concrete's resistance to sulfate erosion and durability. The addition of acrylate provides additional bonding strength and enhances the overall strength and wear resistance of concrete.

[0038] 5. Improved the foaming effect of concrete: The proportion of air entraining agent can make the concrete produce an appropriate amount of uniform bubbles during the hardening process, reduce the density of concrete, and improve the thermal insulation and sound insulation performance. Ultrasonic treatment and high shear mixing steps ensure that the bubbles in the mixture are evenly dispersed, improving the foaming effect and stability of the foaming agent.

[0039] 6. Improved stability and environmental performance: The addition of polyvinyl alcohol and other chemical additives makes the foaming agent have good chemical stability, and it is not easy to decompose or fail during long-term storage. All raw materials meet environmental protection requirements, and there is no harmful gas emission during the preparation process, which meets the standards of green building materials. Moreover, the preparation method of the present invention simplifies the process flow and reduces production costs by strictly controlling the parameters of each step. The coordination and connection of each step ensures the high-quality output of the foaming agent and improves production efficiency.

[0040] In summary, the present invention provides a high-performance anti-seepage concrete foaming agent and a preparation method thereof, which exhibits significant effects in improving the anti-seepage, freeze-thaw resistance, durability and working performance of concrete, and also has good environmental performance and economic benefits.

[0041] In order to more clearly illustrate the structural features and effects of the present invention, the present invention is described in detail below in conjunction with specific embodiments. DETAILED DESCRIPTION

[0042] The technical solution of the present invention is further described in detail below in conjunction with specific implementation methods.

[0043] Example 1

[0044] The present embodiment provides an anti-seepage concrete foaming agent, comprising the following raw materials in parts by weight:

[0045] 16 parts of modified siloxane; 30 parts of sodium α-olefin sulfonate; 20 parts of silica fume powder, 10 parts of polyvinyl alcohol; 3 parts of sulfonated melamine formaldehyde resin; 1 part of polypropylene fiber; 8 parts of acrylate; 6 parts of air entraining agent; 6 parts of retarder; 4 parts of water reducer; 6 parts of antifreeze agent.

[0046] In this embodiment, the modified siloxane is a copolymer of vinyltrimethoxysilane (VTMS) and methyl methacrylate (MMA), which is initiated by benzoyl peroxide. The vinyl group in the vinyltrimethoxysilane reacts with methyl methacrylate through free radical polymerization to form a polymer containing siloxy groups, thereby obtaining a modified siloxane.

[0047] The silica fume powder is made by crushing silica ore with a particle size of 0.5-0.8 microns and a specific surface area of ​​20m 2 / g and silica fume with SiO2 content not less than 85%; the air entraining agent is sodium dodecyl sulfonate; the retarder is sodium borate; the water reducer is naphthalene sulfonate formaldehyde condensate; and the antifreeze agent is calcium chloride.

[0048] The preparation method of the anti-seepage concrete foaming agent in this embodiment comprises the following steps:

[0049] 1) Weigh modified siloxane, sodium α-olefin sulfonate, silica fume powder, polyvinyl alcohol, sulfonated melamine formaldehyde resin, polypropylene fiber, acrylate, air entraining agent, retarder, water reducing agent and antifreeze agent according to weight parts and set aside;

[0050] 2) premixing the modified siloxane and sodium α-olefin sulfonate, adding the weighed modified siloxane and sodium α-olefin sulfonate into a mixing container, stirring at a speed of 200 r / min, stirring for 15 minutes, and controlling the temperature at 25° C. to obtain a liquid mixture;

[0051] 3) Pretreatment of dry powder: dry-mix the silica fume powder and polyvinyl alcohol at a stirring speed of 150 r / min for 10 minutes to obtain a dry powder mixture;

[0052] 4) Mixing the dry powder with the liquid: Add the liquid mixture of step 2) to the dry powder mixture of step 3), and stir at a speed of 350 r / min, a stirring time of 15 minutes, and a temperature of 30° C.;

[0053] 5) Adding auxiliary agents and ultrasonic treatment: adding sulfonated melamine formaldehyde resin, polypropylene fiber, acrylate, air entraining agent, retarder, water reducer and antifreeze agent in sequence, stirring at a speed of 300 r / min after each addition, stirring for 5 minutes, and a total stirring time of 35 minutes; transferring the mixture to an ultrasonic treatment equipment for ultrasonic treatment, with an ultrasonic frequency of 25 kHz, an ultrasonic time of 20 minutes, and a treatment temperature of 40°C.

[0054] 6) High shear mixing and vacuum degassing: the mixture after ultrasonic treatment is placed in a high shear mixer for high shear mixing, the shear rate is 4000r / min, and the mixing time is 20 minutes; the mixture after high shear mixing is transferred to a vacuum degassing device for degassing, wherein the vacuum degree is -0.09MPa, and the degassing time is 20 minutes, the degassed mixture is cooled to room temperature, and the cooled mixture is placed in a stable container and allowed to stand for 24 hours. After quality inspection, the qualified anti-permeability concrete foaming agent is obtained and stored in a sealed container.

[0055] Example 2

[0056] The present embodiment provides an anti-seepage concrete foaming agent, comprising the following raw materials in parts by weight:

[0057] 12 parts of modified siloxane; 25 parts of sodium α-olefin sulfonate; 18 parts of silica fume powder, 8 parts of polyvinyl alcohol; 2.5 parts of sulfonated melamine formaldehyde resin; 0.8 parts of polypropylene fiber; 6 parts of acrylate; 5 parts of air entraining agent; 5 parts of retarder; 3 parts of water reducer; 5 parts of antifreeze agent.

[0058] In this embodiment, the modified siloxane is a copolymer of vinyltrimethoxysilane (VTMS) and methyl methacrylate (MMA), which is initiated by benzoyl peroxide. The vinyl group in the vinyltrimethoxysilane reacts with methyl methacrylate through free radical polymerization to form a polymer containing siloxy groups, thereby obtaining a modified siloxane.

[0059] The silica fume powder is made by crushing silicon ore, with a particle size of 0.1-1 micron and a specific surface area of ​​15-30m 2 / g and the SiO2 content is not less than 85% of silica fume; the air entraining agent is rosin resin; the retarder is sodium gluconate; the water reducer is polycarboxylic acid high-efficiency water reducer; the antifreeze agent is sodium sulfate.

[0060] The preparation method of the anti-seepage concrete foaming agent in this embodiment comprises the following steps:

[0061] 1) Weigh modified siloxane, sodium α-olefin sulfonate, silica fume powder, polyvinyl alcohol, sulfonated melamine formaldehyde resin, polypropylene fiber, acrylate, air entraining agent, retarder, water reducing agent and antifreeze agent according to weight parts and set aside;

[0062] 2) premixing the modified siloxane and sodium α-olefin sulfonate, adding the weighed modified siloxane and sodium α-olefin sulfonate into a mixing container, stirring at a speed of 250 r / min, stirring for 10 minutes, and controlling the temperature at 25° C. to obtain a liquid mixture;

[0063] 3) Pretreatment of dry powder: dry-mix silica fume powder and polyvinyl alcohol at a stirring speed of 200 r / min for minutes to obtain a dry powder mixture;

[0064] 4) Mixing the dry powder with the liquid: adding the liquid mixture of step 2) to the dry powder mixture of step 3), and stirring at a stirring speed of 300 r / min, a stirring time of 20 minutes, and a temperature controlled at 30° C.;

[0065] 5) Adding auxiliary agents and ultrasonic treatment: adding sulfonated melamine formaldehyde resin, polypropylene fiber, acrylate, air entraining agent, retarder, water reducer and antifreeze agent in sequence, stirring at a speed of 300 r / min after each addition, stirring for 5 minutes, and a total stirring time of 35 minutes; transferring the mixture to an ultrasonic treatment equipment for ultrasonic treatment, with an ultrasonic frequency of 25 kHz, an ultrasonic time of 20 minutes, and a treatment temperature of 40°C.

[0066] 6) High shear mixing and vacuum degassing: the mixture after ultrasonic treatment is placed in a high shear mixer for high shear mixing, the shear rate is 4000r / min, and the mixing time is 20 minutes; the mixture after high shear mixing is transferred to a vacuum degassing device for degassing, wherein the vacuum degree is -0.09MPa, and the degassing time is 20 minutes, the degassed mixture is cooled to room temperature, and the cooled mixture is placed in a stable container and allowed to stand for 24 hours. After quality inspection, the qualified anti-permeability concrete foaming agent is obtained and stored in a sealed container.

[0067] Example 3

[0068] The present embodiment provides an anti-seepage concrete foaming agent, comprising the following raw materials in parts by weight:

[0069] 10 parts of modified siloxane; 20 parts of sodium α-olefin sulfonate; 15 parts of silica fume powder, 6 parts of polyvinyl alcohol; 2 parts of sulfonated melamine formaldehyde resin; 0.6 parts of polypropylene fiber; 5 parts of acrylate; 3.5 parts of air entraining agent; 3.5 parts of retarder; 2.5 parts of water reducer; 4 parts of antifreeze agent.

[0070] In this embodiment, the modified siloxane is a copolymer of vinyltrimethoxysilane (VTMS) and methyl methacrylate (MMA), which is initiated by benzoyl peroxide. The vinyl group in the vinyltrimethoxysilane reacts with methyl methacrylate through free radical polymerization to form a polymer containing siloxy groups, thereby obtaining a modified siloxane.

[0071] The silica fume powder is made by crushing silicon ore, with a particle size of 0.1-1 micron and a specific surface area of ​​15-30m 2 / g and silica fume with SiO2 content not less than 85%; the air entraining agent is rosin resin; the retarder is citric acid; the water reducing agent is calcium lignin sulfonate; and the antifreeze agent is urea.

[0072] The preparation method of the anti-seepage concrete foaming agent in this embodiment comprises the following steps:

[0073] 1) Weigh modified siloxane, sodium α-olefin sulfonate, silica fume powder, polyvinyl alcohol, sulfonated melamine formaldehyde resin, polypropylene fiber, acrylate, air entraining agent, retarder, water reducing agent and antifreeze agent according to weight parts and set aside;

[0074] 2) premixing the modified siloxane and sodium α-olefin sulfonate, adding the weighed modified siloxane and sodium α-olefin sulfonate into a mixing container, stirring at a speed of 230 r / min, stirring for 13 minutes, and controlling the temperature at 25° C. to obtain a liquid mixture;

[0075] 3) Pretreatment of dry powder: dry-mix the silica fume powder and polyvinyl alcohol at a stirring speed of 180 r / min for 8 minutes to obtain a dry powder mixture;

[0076] 4) Mixing the dry powder with the liquid: adding the liquid mixture of step 2) to the dry powder mixture of step 3), and stirring at a stirring speed of 320 r / min, a stirring time of 18 minutes, and a temperature controlled at 30° C.;

[0077] 5) Adding auxiliary agents and ultrasonic treatment: adding sulfonated melamine formaldehyde resin, polypropylene fiber, acrylate, air entraining agent, retarder, water reducer and antifreeze agent in sequence, stirring at a speed of 280 r / min after each addition, stirring for 5 minutes, and a total stirring time of 35 minutes; transferring the mixture to an ultrasonic treatment equipment for ultrasonic treatment, with an ultrasonic frequency of 25 kHz, an ultrasonic time of 18 minutes, and a treatment temperature of 40°C.

[0078] 6) High shear mixing and vacuum degassing: the mixture after ultrasonic treatment is placed in a high shear mixer for high shear mixing, the shear rate is 4300r / min, and the mixing time is 20 minutes; the mixture after high shear mixing is transferred to a vacuum degassing device for degassing, wherein the vacuum degree is -0.09MPa, and the degassing time is 20 minutes, the degassed mixture is cooled to room temperature, and the cooled mixture is placed in a stable container and allowed to stand for 24 hours. After quality inspection, the qualified anti-permeability concrete foaming agent is obtained and stored in a sealed container.

[0079] Example 4

[0080] The present embodiment provides an anti-seepage concrete foaming agent, comprising the following raw materials in parts by weight:

[0081] 4 parts of modified siloxane; 10 parts of sodium α-olefin sulfonate; 10 parts of silica fume powder, 2 parts of polyvinyl alcohol; 1 part of sulfonated melamine formaldehyde resin; 0.2 parts of polypropylene fiber; 2 parts of acrylate; 1 part of air entraining agent; 1 part of retarder; 1 part of water reducing agent; 2 parts of antifreeze agent.

[0082] In this embodiment, the modified siloxane is a copolymer of vinyltrimethoxysilane (VTMS) and methyl methacrylate (MMA), which is initiated by benzoyl peroxide. The vinyl group in the vinyltrimethoxysilane reacts with methyl methacrylate through free radical polymerization to form a polymer containing siloxy groups, thereby obtaining a modified siloxane.

[0083] The silica fume powder is made by crushing silicon ore, with a particle size of 0.1-1 micron and a specific surface area of ​​15-30m 2 / g and silica fume with SiO2 content not less than 85%; the air entraining agent is sodium dodecyl sulfonate; the retarder is lignin sulfonate; the water reducer is naphthalene sulfonate formaldehyde condensate; and the antifreeze agent is urea.

[0084] The preparation method of the anti-seepage concrete foaming agent in this embodiment comprises the following steps:

[0085] 1) Weigh modified siloxane, sodium α-olefin sulfonate, silica fume powder, polyvinyl alcohol, sulfonated melamine formaldehyde resin, polypropylene fiber, acrylate, air entraining agent, retarder, water reducing agent and antifreeze agent according to weight parts and set aside;

[0086] 2) premixing the modified siloxane and sodium α-olefin sulfonate, adding the weighed modified siloxane and sodium α-olefin sulfonate into a mixing container, stirring at a speed of 200 r / min, stirring for 15 minutes, and controlling the temperature at 25° C. to obtain a liquid mixture;

[0087] 3) Pretreatment of dry powder: dry-mix the silica fume powder and polyvinyl alcohol at a stirring speed of 150 r / min for 10 minutes to obtain a dry powder mixture;

[0088] 4) Mixing the dry powder with the liquid: Add the liquid mixture of step 2) to the dry powder mixture of step 3), and stir at a speed of 350 r / min, a stirring time of 15 minutes, and a temperature of 30° C.;

[0089] 5) Adding auxiliary agents and ultrasonic treatment: adding sulfonated melamine formaldehyde resin, polypropylene fiber, acrylate, air entraining agent, retarder, water reducer and antifreeze agent in sequence, stirring at a speed of 250 r / min after each addition, stirring for 5 minutes, and a total stirring time of 35 minutes; transferring the mixture to an ultrasonic treatment equipment for ultrasonic treatment, with an ultrasonic frequency of 25 kHz, an ultrasonic time of 15 minutes, and a treatment temperature of 40°C.

[0090] 6) High shear mixing and vacuum degassing: the mixture after ultrasonic treatment is placed in a high shear mixer for high shear mixing, the shear rate is 4000r / min, and the mixing time is 20 minutes; the mixture after high shear mixing is transferred to a vacuum degassing device for degassing, wherein the vacuum degree is -0.09MPa, and the degassing time is 20 minutes, the degassed mixture is cooled to room temperature, and the cooled mixture is placed in a stable container and allowed to stand for 24 hours. After quality inspection, the qualified anti-permeability concrete foaming agent is obtained and stored in a sealed container.

[0091] Example 5

[0092] The present embodiment provides an anti-seepage concrete foaming agent, comprising the following raw materials in parts by weight:

[0093] 6 parts of modified siloxane; 12 parts of sodium α-olefin sulfonate; 12 parts of silica fume powder, 4 parts of polyvinyl alcohol; 2 parts of sulfonated melamine formaldehyde resin; 0.4 parts of polypropylene fiber; 4 parts of acrylate; 2 parts of air entraining agent; 2 parts of retarder; 2 parts of water reducer; 3 parts of antifreeze agent.

[0094] In this embodiment, the modified siloxane is a copolymer of vinyltrimethoxysilane (VTMS) and methyl methacrylate (MMA), which is initiated by benzoyl peroxide. The vinyl group in the vinyltrimethoxysilane reacts with methyl methacrylate through free radical polymerization to form a polymer containing siloxy groups, thereby obtaining a modified siloxane.

[0095] The silica fume powder is made by crushing silicon ore, with a particle size of 0.1-1 micron and a specific surface area of ​​15-30m 2 / g and silica fume with SiO2 content not less than 85%; the air entraining agent is sodium dodecylbenzene sulfonate; the retarder is sodium borate; the water reducer is polycarboxylic acid high-efficiency water reducer; and the antifreeze agent is calcium chloride.

[0096] The preparation method of the anti-seepage concrete foaming agent in this embodiment comprises the following steps:

[0097] 1) Weigh modified siloxane, sodium α-olefin sulfonate, silica fume powder, polyvinyl alcohol, sulfonated melamine formaldehyde resin, polypropylene fiber, acrylate, air entraining agent, retarder, water reducing agent and antifreeze agent according to weight parts and set aside;

[0098] 2) pre-mixing the modified siloxane and sodium α-olefin sulfonate, adding the weighed modified siloxane and sodium α-olefin sulfonate into a mixing container, stirring at a speed of 220 r / min, stirring for 13 minutes, and controlling the temperature at 25° C. to obtain a liquid mixture;

[0099] 3) Pretreatment of dry powder: dry-mix the silica fume powder and polyvinyl alcohol at a stirring speed of 180 r / min for 8 minutes to obtain a dry powder mixture;

[0100] 4) Mixing the dry powder with the liquid: Add the liquid mixture of step 2) to the dry powder mixture of step 3), and stir at a speed of 320 r / min, a stirring time of 17 minutes, and a temperature of 30° C.

[0101] 5) Adding auxiliary agents and ultrasonic treatment: adding sulfonated melamine formaldehyde resin, polypropylene fiber, acrylate, air entraining agent, retarder, water reducer and antifreeze agent in sequence, stirring at a speed of 280 r / min after each addition, stirring for 5 minutes, and a total stirring time of 35 minutes; transferring the mixture to an ultrasonic treatment equipment for ultrasonic treatment, with an ultrasonic frequency of 25 kHz, an ultrasonic time of 18 minutes, and a treatment temperature of 40°C.

[0102] 6) High shear mixing and vacuum degassing: the mixture after ultrasonic treatment is placed in a high shear mixer for high shear mixing, the shear rate is 4300r / min, and the mixing time is 20 minutes; the mixture after high shear mixing is transferred to a vacuum degassing device for degassing, wherein the vacuum degree is -0.09MPa, and the degassing time is 20 minutes, the degassed mixture is cooled to room temperature, and the cooled mixture is placed in a stable container and allowed to stand for 24 hours. After quality inspection, the qualified anti-permeability concrete foaming agent is obtained and stored in a sealed container.

[0103] Comparative Example 1

[0104] An anti-seepage concrete foaming agent comprises the following raw materials in parts by weight:

[0105] 30 parts of sodium α-olefin sulfonate; 20 parts of silica fume powder, 10 parts of polyvinyl alcohol; 3 parts of sulfonated melamine formaldehyde resin; 1 part of polypropylene fiber; 8 parts of acrylate; 6 parts of air entraining agent; 6 parts of retarder; 4 parts of water reducing agent; 6 parts of antifreeze agent. Among them, the anti-seepage concrete foaming agent does not contain modified siloxane.

[0106] Comparative Example 2

[0107] An anti-seepage concrete foaming agent comprises the following raw materials in parts by weight:

[0108] 16 parts of modified siloxane; 20 parts of silica fume powder, 10 parts of polyvinyl alcohol; 3 parts of sulfonated melamine formaldehyde resin; 1 part of polypropylene fiber; 8 parts of acrylate; 6 parts of air entraining agent; 6 parts of retarder; 4 parts of water reducing agent; 6 parts of antifreeze agent. Among them, the anti-permeability concrete foaming agent does not contain sodium α-olefin sulfonate.

[0109] Comparative Example 3

[0110] An anti-seepage concrete foaming agent comprises the following raw materials in parts by weight:

[0111] 16 parts of modified siloxane; 30 parts of sodium α-olefin sulfonate; 20 parts of silica fume powder, 10 parts of polyvinyl alcohol; 1 part of polypropylene fiber; 8 parts of acrylate; 6 parts of air entraining agent; 6 parts of retarder; 4 parts of water reducing agent; 6 parts of antifreeze agent. Among them, the anti-seepage concrete foaming agent does not contain sulfonated melamine formaldehyde resin.

[0112] The preparation processes of Comparative Examples 1-3 are the same as those of Example 1.

[0113] Effect verification:

[0114] The anti-seepage type concrete foaming agent prepared in Examples 1-5 and the anti-seepage type concrete foaming agent prepared in Comparative Examples 1-3 were subjected to the following tests:

[0115] (1) Anti-seepage performance test

[0116] Test item: anti-seepage pressure.

[0117] Test method: The anti-permeability test method specified in GB / T 50082 "Test method for long-term performance and durability of ordinary concrete" was adopted. After the concrete specimens were cured under standard curing conditions for 28 days, they were tested using an anti-permeability instrument and the maximum water pressure on the specimens was recorded. The test results are shown in Table 1.

[0118] (2) Freeze-thaw resistance test

[0119] Test items: relative dynamic elastic modulus and mass loss rate.

[0120] Test method: The rapid freeze-thaw cycle test was carried out in accordance with GB / T 50082. The relative dynamic elastic modulus and mass loss rate of the specimens were measured after 100 freeze-thaw cycles. The test results are shown in Table 1.

[0121] (3) Working performance test

[0122] Test items: slump and workable time.

[0123] Test method: Carry out slump test according to GB / T 50080 and record the slump value of concrete mixture. Measure the time from mixing to initial setting of concrete at standard room temperature and record the operable time. The test result data is shown in Table 1.

[0124] (4) Durability test

[0125] Test items: Sulfate resistance and alkali-aggregate reaction.

[0126] Test method: Sulfate corrosion resistance test was carried out in accordance with GB / T 50082. The concrete specimens were immersed in sodium sulfate solution. After 28 days, the mass change and strength loss of the specimens were measured. Alkali-aggregate reaction test was carried out to measure the expansion rate of concrete specimens in alkaline environment. The test results are shown in Table 2.

[0127] (5) Foaming effect test

[0128] Test items: Bubble uniformity and bubble stability.

[0129] Test method: Observe the distribution of bubbles in the concrete specimens under a microscope to evaluate the uniformity of the bubbles. Measure the bubble retention rate of the concrete specimens after 28 days of curing to evaluate the stability of the bubbles. The test results are shown in Table 2.

[0130] Table 1 Test results of anti-seepage concrete foaming agent

[0131]

[0132]

[0133] Table 2 Test results of anti-seepage concrete foaming agent

[0134]

[0135] Through the above multiple tests, the impermeable concrete foaming agents prepared in Examples 1-5 show excellent performance in terms of impermeability, freeze-thaw resistance, working performance, durability and foaming effect, especially in Examples 4 and 5, whose various performance indicators are at a high level, showing good application prospects and practical use value.

[0136] The anti-seepage concrete foaming agent of the present invention can not only effectively improve the anti-seepage performance of concrete, but also significantly improve the strength and durability of concrete. The preparation method of the anti-seepage concrete foaming agent of the present invention enables the prepared anti-seepage concrete foaming agent to form a stable bubble structure in concrete, significantly improve the anti-seepage performance of concrete, while taking into account the strength and durability of concrete, and meet the needs of modern engineering for high-performance concrete.

[0137] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. An anti-seepage concrete foaming agent, characterized in that: The invention comprises the following raw materials in parts by weight: 4-16 parts of modified siloxane; 10-30 parts of sodium α-olefin sulfonate; 10-20 parts of silica fume powder, 2-10 parts of polyvinyl alcohol; 1-3 parts of sulfonated melamine formaldehyde resin; 0.2-1 parts of polypropylene fiber; Acrylate 2-8 parts; air entraining agent 1-6 parts; retarder 1-6 parts; water reducer 1-4 parts; 2-6 parts of antifreeze.

2. The anti-seepage concrete foaming agent according to claim 1, characterized in that: The anti-seepage concrete foaming agent comprises the following raw materials in parts by weight: 10 parts of modified siloxane; 20 parts of sodium α-olefin sulfonate; 15 parts of silica fume powder, and 6 parts of polyvinyl alcohol; 2 parts of sulfonated melamine formaldehyde resin; 0.6 parts of polypropylene fiber; 5 parts of acrylate; 3.5 parts of air entraining agent; 3.5 parts of retarder; 2.5 parts of water reducing agent; 4 parts of antifreeze agent.

3. The anti-seepage concrete foaming agent according to claim 2, characterized in that: The modified siloxane is an organic siloxane monomer and a methyl methacrylate monomer, with peroxide as an initiator, generating free radicals, and the free radicals undergo a free radical polymerization reaction with the organic siloxane monomer and the methyl methacrylate monomer to form a copolymer; wherein the organic siloxane monomer is one of methyltrimethoxysilane, vinyltrimethoxysilane, and γ-glycidyloxypropyltrimethoxysilane.

4. The anti-seepage concrete foaming agent according to claim 3, characterized in that: When vinyltrimethoxysilane is copolymerized with methyl methacrylate, benzoyl peroxide is used as the initiator, and the vinyl group in the vinyltrimethoxysilane reacts with methyl methacrylate through free radical polymerization to form a polymer containing siloxy groups, thereby obtaining a modified siloxane.

5. The anti-seepage concrete foaming agent according to claim 3, characterized in that: When methyltrimethoxysilane and methyl methacrylate are copolymerized, benzoyl peroxide is used as the initiator, and methyltrimethoxysilane undergoes free radical copolymerization with methyl methacrylate via the methoxy group to obtain modified siloxane; the epoxy group in γ-glycidyloxypropyltrimethoxysilane is ring-opened under alkaline conditions, and benzoyl peroxide is used as the initiator to introduce the epoxy group into the siloxane molecule, and copolymerization reaction is carried out with methyl methacrylate to obtain modified siloxane.

6. The anti-seepage concrete foaming agent according to claim 2, characterized in that: The silica fume powder is made by crushing silicon ore, with a particle size of 0.1-1 micron and a specific surface area of ​​15-30m 2 / g and silica fume with SiO2 content not less than 85%.

7. The anti-seepage concrete foaming agent according to claim 2, characterized in that: The air entraining agent is one or more of rosin resin, alkyl sulfonate, and alkylbenzene sulfonate, wherein the alkyl sulfonate is sodium dodecyl sulfonate, and the alkylbenzene sulfonate is sodium dodecylbenzene sulfonate.

8. The anti-seepage concrete foaming agent according to claim 2, characterized in that: The retarder is one or more of sodium borate, sodium gluconate, citric acid and lignin sulfonate.

9. The anti-seepage concrete foaming agent according to claim 2, characterized in that: The water reducer is one or more of naphthalene-based water reducer, polycarboxylic acid water reducer, and wood calcium water reducer; the antifreeze agent is one or more of calcium chloride, sodium sulfate, and urea.

10. A method for preparing an anti-seepage concrete foaming agent as claimed in any one of claims 1 to 9, characterized in that: Here are the steps: 1) Weigh modified siloxane, sodium α-olefin sulfonate, silica fume powder, polyvinyl alcohol, sulfonated melamine formaldehyde resin, polypropylene fiber, acrylate, air entraining agent, retarder, water reducing agent and antifreeze agent according to weight parts and set aside; 2) premixing the modified siloxane and sodium α-olefin sulfonate, adding the weighed modified siloxane and sodium α-olefin sulfonate into a mixing container, stirring at a speed of 200-250 r / min, stirring for 10-15 minutes, and controlling the temperature at 25° C. to obtain a liquid mixture; 3) Pretreatment of dry powder: dry-mix the silica fume powder and polyvinyl alcohol at a stirring speed of 150-200 r / min for 5-10 minutes to obtain a dry powder mixture; 4) Mixing the dry powder with the liquid: adding the liquid mixture of step 2) to the dry powder mixture of step 3), and stirring at a speed of 300-350 r / min, a stirring time of 15-20 minutes, and a temperature controlled at 30° C.; 5) Adding additives and ultrasonic treatment: adding sulfonated melamine formaldehyde resin, polypropylene fiber, acrylate, air entraining agent, retarder, water reducer and antifreeze agent in sequence, stirring at a speed of 250-300 r / min after each addition, stirring for 5 minutes, and a total stirring time of 35 minutes; transferring the mixture to an ultrasonic treatment device for ultrasonic treatment, with an ultrasonic frequency of 25 kHz, an ultrasonic time of 15-20 minutes, and a treatment temperature of 40°C; 6) High shear mixing and vacuum degassing: the mixture after ultrasonic treatment is placed in a high shear mixer for high shear mixing, the shear rate is 4000-4500r / min, and the mixing time is 20 minutes; the mixture after high shear mixing is transferred to a vacuum degassing device for degassing, wherein the vacuum degree is -0.09MPa, and the degassing time is 20 minutes, the degassed mixture is cooled to room temperature, and the cooled mixture is placed in a stable container and allowed to stand for 24 hours. After quality inspection, the qualified anti-permeability concrete foaming agent is obtained and stored in a sealed container.

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