Magnesium-calcium-based joint protection agent, preparation method thereof and waterproof cement mortar

Abstract

The application discloses a magnesium-calcium anti-joint agent, a preparation method thereof and waterproof cement mortar. The anti-joint agent comprises a mixture of magnesium oxide and calcium oxide to which graphene oxide is attached. The preparation method comprises the following steps: (1) mixing magnesium oxide and calcium oxide to obtain a magnesium-calcium powder, and then fluidizing the powder; (2) applying a dispersion liquid formed by atomized graphene oxide and a volatile non-aqueous dispersion medium to the fluidized powder. After completion, the obtained mixture is mechanically ground to obtain the magnesium-calcium anti-joint agent. The waterproof cement mortar comprises the following raw materials: 100 parts by weight of cementing material, 2-10 parts by weight of the magnesium-calcium anti-joint agent, 120-350 parts by weight of fine aggregate and 30-60 parts by weight of mixing water. The anti-joint agent effectively realizes real-time compensation of internal volume change of the cement mortar, prevents development of microcracks and realizes efficient waterproofing of the cement mortar.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of anti-cracking agent preparation, and particularly relates to a magnesium-calcium anti-cracking agent, a preparation method thereof and waterproof cement mortar. BACKGROUND

[0002] The information disclosed in this Background section is for the purpose of generally presenting the context of the application. The information disclosed in this Background section is not to be taken as an acknowledgement or any form of suggestion that this information forms prior art that is already known to a person skilled in the art.

[0003] Cement mortar is widely used in buildings and infrastructure, such as building walls, building floors, ground leveling layers, urban drainage pipes, building facility reinforcement and repair, etc. Cement mortar itself has a certain waterproof property, but in humid, high water pressure and other scenarios, the waterproof effect is not ideal, and water leakage and seepage often occur. At present, waterproof agents or sealing layers are usually used to improve the waterproof and anti-permeability of mortar, and waterproof agents are always the key materials to ensure the smooth progress of construction programs of building engineering projects.

[0004] At present, mortar waterproofing agents are mainly divided into organic waterproofing agents, inorganic waterproofing agents, and organic-inorganic composite waterproofing agents. Among them, organic waterproofing agents (such as organic silicon waterproofing agents, polymer waterproofing agents, etc.) can improve the waterproof effect of mortar and improve the toughness of mortar. However, the incorporation of organic matter will significantly delay the cement hydration and reduce the mechanical strength of the mortar, affect the work performance and setting time, and require higher construction technology. Inorganic waterproofing agents include chloride metal salt, sodium silicate, and aluminum salt. Among them, chloride metal salt waterproofing agents contain a lot of chloride ions, which are easy to cause steel corrosion, and are less used at present. Sodium silicate waterproofing agents have fast reaction speed and are suitable for quick plugging and short-term engineering, but are not suitable for long-term high-pressure humid application scenarios. The mechanism of aluminum salt waterproofing agents is to complex with hydration products, so there are certain requirements for the type and mineral components of cement, and they are only suitable for Portland cement systems. Organic-inorganic composite waterproofing agents combine the characteristics of organic and inorganic components, can optimize the pore structure of mortar, improve the density, and improve the waterproof performance and mechanical properties of mortar. However, the currently developed organic-inorganic composite waterproofing agents have high cost, require professional construction technology, and may need regular maintenance, which has certain resistance in popularization. Therefore, waterproofing agents and waterproof mortar still need further research and development to meet the application requirements of green safety, stable performance, and high applicability.

[0005] In the hydration process of cement-based binder, due to self-shrinkage, chemical shrinkage, drying shrinkage and other factors, the internal structure of the mortar is loose and porous. When the pore structure is poor, such as the porosity is too large and the proportion of harmful pores is too large, stress concentration is easy to occur around the pores, leading to the formation of micro-cracks, and further development into cracks and leakage channels, eventually leading to water penetration and seepage of the test piece. Therefore, one of the fundamental measures for mortar waterproofing is to compensate for the volume change of the mortar in real time, to regulate the internal pore structure, and to prevent the formation and development of micro-cracks. At present, volume control agents such as shrinkage reducing agents and expanding agents can effectively optimize the pore structure of cement concrete materials and improve the waterproofing and crack resistance. However, the inventors have found that due to their volume control effect, they cannot be well matched with the shrinkage of the binder at each hydration stage, and the volume control agent cannot achieve mortar waterproofing. SUMMARY

[0006] In order to adapt the volume control agent to the volume time domain change of the mortar, the present application provides a magnesium-calcium-based crack prevention agent, a preparation method thereof and a waterproof cement mortar, which effectively realizes real-time compensation of the internal volume change of the cement mortar, prevents the development of micro-cracks, and realizes efficient waterproofing of the cement mortar. Specifically, the present application discloses the technical solutions shown below.

[0007] Firstly, the present application discloses a magnesium-calcium-based crack prevention agent, which comprises a mixture of magnesium oxide and calcium oxide to which graphene oxide is attached.

[0008] Further, the mass ratio of the magnesium oxide and the calcium oxide is 100:20-100.

[0009] Further, the total mass ratio of the graphene oxide and the magnesium oxide and the calcium oxide is 0.01-1:100. Preferably, the lateral size of the graphene oxide is 0.05-20 μm. Increasing the lateral size of the graphene oxide is conducive to playing the role of nucleation site, which can promote the volume expansion of the magnesium oxide and effectively alleviate its inhibitory effect on the calcium oxide.

[0010] Secondly, the present application discloses a preparation method of a magnesium-calcium-based crack prevention agent, comprising the following steps:

[0011] (1) mixing magnesium oxide and calcium oxide to obtain a magnesium-calcium-based powder, and then fluidizing the powder.

[0012] (2) applying a dispersion liquid formed by atomized graphene oxide and a volatile non-aqueous dispersion medium to the fluidized powder. After completion, the obtained mixture is mechanically ground to obtain the magnesium-calcium-based crack prevention agent.

[0013] Further, in step (1), the mass ratio of the magnesium oxide and the calcium oxide is 100:20-100.

[0014] Further, in step (2), the dispersion is applied at a mass ratio of 100:0.01~1 of the powder to the graphene oxide in the dispersion.

[0015] Further, in step (2), the content of graphene oxide in the dispersion is 0.1~10 mg / mL. Optionally, the volatile non-aqueous dispersion medium includes one of anhydrous methanol, anhydrous ethanol, anhydrous propanol, tetrachloromethane, etc.

[0016] Further, in step (2), the movement mode of the atomized dispersion and the fluidized powder is convective collision, so as to utilize the phase change of the non-aqueous dispersion medium to make graphene oxide uniformly adhere to the surface of the magnesium-calcium powder particles. Optionally, the initial relative velocity of the convection is 20~200 m / s, and the temperature of the convection environment is 50~200℃.

[0017] Furthermore, in step (2), the grinding time is 10~120 min. During this process, the squeezing-impact effect of the rigid grinding balls is used to increase the bonding force between graphene oxide and magnesium-calcium powder particles, so that graphene oxide is uniformly and firmly attached to magnesium-calcium powder particles.

[0018] Furthermore, this invention discloses a waterproof cement mortar, comprising the following raw materials: 100 parts by weight of cementitious material, 2-10 parts by weight of the magnesium-calcium anti-crack agent of this invention, 120-350 parts by weight of fine aggregate, and 30-60 parts by weight of mixing water.

[0019] Furthermore, the waterproof cement mortar also includes admixtures. Optionally, the admixtures include at least one of water-reducing agents, early-strength agents, and thickeners. Optionally, the water-reducing agent is 0.5 to 2 parts by weight, the early-strength agent is 0.02 to 0.05 parts by weight, and the thickener is 0.2 to 1 part by weight.

[0020] Further, the cementitious material includes at least one of cement, fly ash, silica fume, and mineral powder. Optionally, the cement is selected from any one of silicate cement, sulfoaluminate cement, aluminate cement, ferroaluminate cement, and geopolymer cement.

[0021] Furthermore, the fine aggregate includes at least one of quartz sand, manufactured sand, etc.

[0022] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0023] The magnesium-calcium anti-joint agent prepared by the application avoids the problems of steel bar corrosion, accelerated setting, instability, low cement variety adaptation, and the like caused by traditional inorganic salt waterproof agents, avoids the problems of volume control agents such as shrinkage reducing agents and expansion agents mismatching the shrinkage process of cementitious materials, and avoids the problems of strength loss and poor durability caused by organic waterproof agents. This is because: the application utilizes the protonation effect of graphene oxide to promote the dissolution of magnesium oxide, and utilizes the activation nucleation effect of graphene oxide to promote the crystallization growth of magnesium oxide hydration products, promotes the hydration of magnesium oxide, increases the volume increment and volume increase rate of magnesium oxide within 28 days, effectively compensates the volume shrinkage of cementitious materials, and at the same time, since the hydration reaction of magnesium oxide is promoted to end early, the adverse effects caused by the volume expansion of delayed hydration of magnesium oxide are avoided. On the other hand, the application utilizes the complexation effect of graphene oxide on fast-hydrating calcium oxide to reduce the volume increment and volume increase rate of calcium oxide in the slurry in the initial hydration stage, so that the volume expansion of calcium oxide mainly occurs in the volume shrinkage stage after the formation of hardened body, and on the other hand, the hydration process of calcium oxide is delayed, which helps to reduce the concentrated heat release in the early hydration stage and reduce the temperature shrinkage of cementitious materials. The expansion of the magnesium-calcium anti-joint agent of the application and the volume shrinkage of cement mortar are matched throughout the process, the volume change of the mortar is timely compensated, the internal pores of the mortar are filled, the formation and development of microcracks are prevented, the waterproof and impermeable effect is achieved, and at the same time, the mechanical strength of the cement mortar can be improved. At the same time, the anti-joint agent of the application has the technical advantages of green safety, stable performance, wide application environment, high efficiency and economy, and the like. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings, which form a part of the present description, are included to provide a further understanding of the application and are incorporated in and constitute a part of this application. The drawings illustrate embodiments of the present application and, together with their description, serve to explain the application.

[0025] Figure 1 The sample graph of the magnesium-calcium anti-joint agent prepared for the following Example 1.

[0026] Figure 2 The scanning electron microscope (SEM) graph of the magnesium-calcium anti-joint agent prepared for the following Example 1. DETAILED DESCRIPTION

[0027] The application will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the application and not to limit the scope of the application. The experimental methods not specified in the following examples are usually carried out according to the conventional conditions or according to the conditions recommended by the manufacturers.

[0028] Unless otherwise defined, all technical and scientific terms used in the present disclosure have the same meaning as commonly understood by one of ordinary skill in the art. The reagents or materials used in the present disclosure can be purchased through conventional routes, and are used according to the conventional methods or according to the product instructions, unless otherwise specified.

[0029] In addition, any method and material similar or equivalent to the described content can be applied to the method of the present disclosure. The technical solutions of the present disclosure are further described in conjunction with the drawings and specific embodiments of the present disclosure.

[0030] Example 1

[0031] 1. A preparation method of a magnesium-calcium-based joint prevention agent, comprising the following steps:

[0032] (1) uniformly mixing magnesium oxide powder and calcium oxide powder with fineness of 200 mesh in a mass ratio of 100:20 to obtain a magnesium-calcium-based powder, for standby.

[0033] (2) ultrasonically dispersing graphene oxide with a lateral size of 0.5 μm in anhydrous ethanol to form a dispersion liquid, wherein the content of graphene oxide is 1 mg / mL, for standby.

[0034] (3) fluidizing the magnesium-calcium-based powder by using pneumatic dispersion technology, and atomizing the local dispersion liquid. Then, the fluidized magnesium-calcium-based powder and the atomized dispersion liquid are countercurrently mixed in a mass ratio of graphene oxide to magnesium-calcium-based powder of 0.1:100, and the initial relative speed of the two fluids is 70 m / s, and the environmental temperature is 100°C, to obtain a mixed powder after completion.

[0035] (4) putting the mixed powder into a planetary vertical homogenizer for mechanical grinding, wherein corundum balls are used as the grinding medium, the planetary vertical homogenizer is operated at a speed of 300 r / min, and the grinding time is 60 min, to obtain a magnesium-calcium-based joint prevention agent after completion, as shown in Figure 1 , and the micro-morphology of the joint prevention agent is shown in Figure 2 .

[0036] 2. A preparation method of a waterproof cement mortar, comprising the following steps:

[0037] (i) taking the following raw materials: 100 parts by weight of P•O 425 type ordinary portland cement, 4 parts by weight of the magnesium-calcium-based joint prevention agent of the present embodiment, 300 parts by weight of quartz sand with a particle size distribution of 1-3 mm, 50 parts by weight of mixing water, and 1 part by weight of polycarboxylic acid water reducer.

[0038] (ii) After mixing the above raw materials, stirring for 3 min, then pouring the obtained cement mortar into a mold, demolding after molding, and curing in a curing box with a temperature of 20±2℃ and a relative humidity of not less than 95% for 28 days, a waterproof mortar test piece is obtained.

[0039] The waterproof mortar test piece is tested for water permeation pressure according to "Waterproofing Agent for Mortar and Concrete" (JC 474-2008). The waterproof mortar test piece is tested for shrinkage according to "Polymer Cement Waterproofing Mortar" (C / T 984-2005). The waterproof mortar test piece is tested for compressive strength and flexural strength according to "Cement and Concrete Mortar Strength Test Method (ISO Method)" (GB / T 17671-1999), and the results are shown in the following table:

[0040] .

[0041] Example 2

[0042] 1. A preparation method of a magnesium-calcium-based joint protection agent, comprising the following steps:

[0043] (1) uniformly mixing magnesium oxide powder and calcium oxide powder with a fineness of 300 mesh at a mass ratio of 100:50 to obtain a magnesium-calcium-based powder, for standby use.

[0044] (2) ultrasonically dispersing graphene oxide with a lateral size of 1 μm in anhydrous propyl alcohol to form a dispersion liquid, wherein the content of graphene oxide is 3 mg / mL, for standby use.

[0045] (3) fluidizing the magnesium-calcium-based powder by using pneumatic dispersion technology, and atomizing the local dispersion liquid. Then, the fluidized magnesium-calcium-based powder and the atomized dispersion liquid are countercurrently mixed at a mass ratio of graphene oxide to magnesium-calcium-based powder of 0.3:100, and the initial relative speed of the two fluids is 50 m / s, and the environmental temperature is 60℃, to obtain a mixed powder.

[0046] (4) putting the mixed powder into a planetary vertical homogenizer for mechanical grinding, wherein corundum balls are used as grinding medium, the planetary vertical homogenizer is operated at a speed of 200 r / min, and the grinding time is 100 min, to obtain a magnesium-calcium-based joint protection agent.

[0047] 2. A preparation method of a waterproof cement mortar, comprising the following steps:

[0048] (i) taking the following raw materials: 100 parts by weight of P•O 425 type ordinary Portland cement, 6 parts by weight of the magnesium-calcium-based joint protection agent of the present embodiment, 250 parts by weight of machine-made sand with a particle size distribution of 1-3 mm, 45 parts by weight of mixing water, and 1 part by weight of polycarboxylic acid water reducing agent.

[0049] (ii) After mixing the above raw materials, stirring for 3 min, then pouring the obtained cement mortar into a mold, demolding after molding, and curing in a curing box with a temperature of 20±2℃ and a relative humidity of not less than 95% for 28 days, a waterproof mortar test piece is obtained.

[0050] The waterproof mortar test piece is tested for water permeation pressure according to "Waterproofing Agent for Mortar and Concrete" (JC 474-2008). The waterproof mortar test piece is tested for shrinkage according to "Polymer-modified Cement Waterproofing Mortar" (C / T 984-2005). The waterproof mortar test piece is tested for compressive strength and flexural strength according to "Method for Testing Strength of Cement Mortar (ISO Method)" (GB / T 17671-1999), and the results are shown in the following table:

[0051] .

[0052] Example 3

[0053] 1. A preparation method of a magnesium-calcium joint protection agent, comprising the following steps:

[0054] (1) Magnesium oxide powder and calcium oxide powder with a fineness of 350 mesh are mixed uniformly at a mass ratio of 100:80 to obtain a magnesium-calcium powder, which is used for standby.

[0055] (2) Graphene oxide with a lateral size of 0.1 μm is ultrasonically dispersed in tetrachloromethane to form a dispersion liquid, wherein the content of graphene oxide is 0.5 mg / mL, which is used for standby.

[0056] (3) The magnesium-calcium powder is fluidized by using pneumatic dispersion technology, and the local dispersion liquid is atomized. Then, the fluidized magnesium-calcium powder and the atomized dispersion liquid are countercurrently mixed at a mass ratio of graphene oxide to magnesium-calcium powder of 0.05:100, and the initial relative speed of the two fluids is 120 m / s, and the environmental temperature is 100℃, to obtain a mixed powder.

[0057] (4) The mixed powder is put into a planetary vertical homogenizer for mechanical grinding, and corundum balls are used as the grinding medium, the planetary vertical homogenizer is operated at a speed of 350 r / min, and the grinding time is 20 min, to obtain a magnesium-calcium joint protection agent.

[0058] 2. A preparation method of a waterproof cement mortar, comprising the following steps:

[0059] (i) The following raw materials are taken: 100 parts by weight of P•O 425 type ordinary Portland cement, 3 parts by weight of the magnesium-calcium joint protection agent of the present embodiment, 150 parts by weight of machine-made sand with a particle size distribution of 1-3 mm, 30 parts by weight of mixing water, 1.5 parts by weight of polycarboxylic acid water reducing agent, and 0.02 parts by weight of triethanolamine early strength agent.

[0060] (ii) Mix the above raw materials and stir for 3 minutes. Then pour the resulting cement mortar into the mold, demold after molding, and cure in a curing box at a temperature of 20±2℃ and a relative humidity of not less than 95% for 28 days to obtain the waterproof mortar specimen.

[0061] The water permeability pressure of the waterproof mortar specimen was tested according to "Mortar and Concrete Waterproofing Agent" (JC 474-2008). The shrinkage rate of the waterproof mortar specimen was tested according to "Polymer Cement Waterproof Mortar" (C / T 984-2005). The compressive strength and flexural strength of the waterproof mortar specimen were tested according to "Test Method for Strength of Cement Mortar (ISO Method)" (GB / T 17671-1999). The results are shown in the table below:

[0062] .

[0063] Example 4

[0064] 1. A method for preparing a magnesium-calcium based sealant, comprising the following steps:

[0065] (1) Mix magnesium oxide powder and calcium oxide powder, both with a fineness of 400 mesh, at a mass ratio of 100:100 to obtain magnesium-calcium powder for later use.

[0066] (2) Graphene oxide with a transverse dimension of 15 μm was ultrasonically dispersed in tetrachloromethane to form a dispersion with a graphene oxide content of 5 mg / mL, for later use.

[0067] (3) The magnesium-calcium powder is fluidized using pneumatic dispersion technology, and the local dispersion is atomized. Then, the fluidized magnesium-calcium powder and the atomized dispersion are convectively mixed at a mass ratio of graphene oxide to magnesium-calcium powder of 0.5:100, with an initial relative velocity of 140 m / s and an ambient temperature of 120°C. After completion, a mixed powder is obtained.

[0068] (4) The mixed powder is put into a planetary vertical homogenizer for mechanical grinding. Corundum balls are used as the grinding medium. The planetary vertical homogenizer operates at a speed of 200 r / min and the grinding time is 40 min. After the grinding is completed, a magnesium-calcium anti-crack agent is obtained.

[0069] 2. A method for preparing waterproof cement mortar, comprising the following steps:

[0070] (i) Take the following raw materials: Portland cement P•O 425 type 100 parts by weight, the magnesium-calcium based jointing preventive of the present embodiment 5 parts by weight, quartz sand with particle size distribution between 1 and 3 mm 350 parts by weight, mixed water 60 parts by weight, polycarboxylic acid water reducing agent 0.9 parts by weight, and hydroxymethyl cellulose thickening agent 0.5 parts by weight.

[0071] (ii) After mixing the above raw materials, stir for 3 min, then pour the obtained cement mortar into a mold, demold after molding, and cure in a curing box with temperature of 20±2℃ and relative humidity not less than 95% for 28 days to obtain a waterproof mortar test piece.

[0072] Test the water permeation pressure of the waterproof mortar test piece according to "Waterproofing agent for mortar and concrete" (JC 474-2008). Test the shrinkage of the waterproof mortar test piece according to "Polymer cement waterproof mortar" (C / T 984-2005). Test the compressive strength and flexural strength of the waterproof mortar test piece according to "Method of testing strength of cement mortar (ISO method)" (GB / T 17671-1999), and the results are shown in the following table:

[0073] .

[0074] Example 5

[0075] 1. A preparation method of a magnesium-calcium based jointing preventive, comprising the following steps:

[0076] (1) Mix magnesium oxide powder and calcium oxide powder with fineness of 400 mesh at a mass ratio of 100:50 to obtain magnesium-calcium based powder, for standby use.

[0077] (2) Ultrasonically disperse graphene oxide with transverse size of 8 μm in anhydrous propyl alcohol to form a dispersion liquid, wherein the content of graphene oxide is 0.5 mg / mL, for standby use.

[0078] (3) Fluidize the magnesium-calcium based powder by using pneumatic dispersion technology, and atomize the local dispersion liquid. Then, mix the fluidized magnesium-calcium based powder and the atomized dispersion liquid in a counter flow manner at a mass ratio of graphene oxide to magnesium-calcium based powder of 0.05:100, and the initial relative speed of the two fluids is 20 m / s, and the environmental temperature is 50℃, to obtain a mixed powder after completion.

[0079] (4) Put the mixed powder into a planetary vertical homogenizer for mechanical grinding, wherein corundum balls are used as grinding medium, the rotation rate of the planetary vertical homogenizer is 500 r / min, and the grinding time is 30 min, to obtain the magnesium-calcium based jointing preventive after completion.

[0080] 2. A preparation method of waterproof cement mortar, comprising the following steps:

[0081] (i) Take the following raw materials: 100 parts by weight of P•F 425 type fly ash Portland cement, 6 parts by weight of the magnesium-calcium based joint prevention agent of the present embodiment, 200 parts by weight of quartz sand with a particle size distribution between 1 and 3 mm, 35 parts by weight of water, and 1.1 parts by weight of polycarboxylic acid water reducing agent.

[0082] (ii) After mixing the above raw materials, stir for 3 min, then pour the obtained cement mortar into a mold, demold after molding, and cure in a curing box with a temperature of 20±2℃ and a relative humidity of not less than 95% for 28 days to obtain a waterproof mortar test piece.

[0083] Test the water permeation pressure of the waterproof mortar test piece according to "Waterproofing agent for mortar and concrete" (JC 474-2008). Test the shrinkage of the waterproof mortar test piece according to "Polymer cement waterproof mortar" (C / T 984-2005). Test the compressive strength and flexural strength of the waterproof mortar test piece according to "Method for testing strength of cement mortar (ISO method)" (GB / T 17671-1999), and the results are shown in the following table:

[0084] .

[0085] Example 6

[0086] 1. A preparation method of a magnesium-calcium based joint prevention agent, comprising the following steps:

[0087] (1) Mix magnesium oxide powder and calcium oxide powder with a fineness of 220 mesh in a mass ratio of 100:30 to obtain a magnesium-calcium based powder, for standby use.

[0088] (2) Ultrasonically disperse graphene oxide with a lateral size of 20 μm in tetrachloromethane to form a dispersion liquid, wherein the content of graphene oxide is 0.1 mg / mL, for standby use.

[0089] (3) Fluidize the magnesium-calcium based powder by using pneumatic dispersion technology, and atomize the local dispersion liquid. Then, mix the fluidized magnesium-calcium based powder and the atomized dispersion liquid in a proportion of 0.01:100 of the mass ratio of graphene oxide to magnesium-calcium based powder, and the initial relative speed of the two fluids is 100 m / s, and the environmental temperature is 120℃, to obtain a mixed powder after completion.

[0090] (4) Put the mixed powder into a planetary vertical homogenizer for mechanical grinding, and use corundum balls as the grinding medium, and the operating speed of the planetary vertical homogenizer is 600 r / min, and the grinding time is 15 min, to obtain a magnesium-calcium based joint prevention agent after completion.

[0091] 2. A method for preparing a waterproof cement mortar, comprising the following steps:

[0092] (i) taking the following raw materials: 100 parts by weight of P•C 425 type composite portland cement, 2 parts by weight of the magnesium-calcium jointing agent of the present embodiment, 350 parts by weight of machine-made sand with a particle size distribution of 1-3 mm, 40 parts by weight of mixing water, and 1.5 parts by weight of polycarboxylic acid water reducing agent.

[0093] (ii) mixing the above raw materials and stirring for 3 min, then pouring the obtained cement mortar into a mold, demolding after molding, and curing in a curing box with a temperature of 20±2℃ and a relative humidity of not less than 95% for 28 days to obtain a waterproof mortar test piece.

[0094] The waterproof mortar test piece is tested for water permeation pressure according to "Waterproofing agent for mortar and concrete" (JC 474-2008), for shrinkage according to "Polymer cement waterproof mortar" (C / T 984-2005), and for compressive strength and flexural strength according to "Method for testing strength of cement mortar (ISO method)" (GB / T 17671-1999), with the results shown in the following table:

[0095] .

[0096] Example 7

[0097] 1. A method for preparing a magnesium-calcium jointing agent, comprising the following steps:

[0098] (1) uniformly mixing magnesium oxide powder and calcium oxide powder with a fineness of 350 mesh at a mass ratio of 100:80 to obtain a magnesium-calcium powder, for standby use.

[0099] (2) ultrasonically dispersing graphene oxide with a lateral size of 0.5 μm in anhydrous propanol to form a dispersion liquid, wherein the content of graphene oxide is 5 mg / mL, for standby use.

[0100] (3) fluidizing the magnesium-calcium powder by using pneumatic dispersion technology, and atomizing the local dispersion liquid. Then, the fluidized magnesium-calcium powder and the atomized dispersion liquid are countercurrently mixed at a mass ratio of graphene oxide to magnesium-calcium powder of 0.5:100, with an initial relative speed of the two fluids of 200 m / s and an environmental temperature of 180℃, to obtain a mixed powder.

[0101] (4) putting the mixed powder into a planetary vertical homogenizer for mechanical grinding, with corundum balls as the grinding medium, at a running speed of the planetary vertical homogenizer of 250 r / min and a grinding time of 120 min, to obtain the magnesium-calcium jointing agent.

[0102] 2. A method for preparing a waterproof cement mortar, comprising the following steps:

[0103] (i) taking the following raw materials: 100 parts by weight of P•F 425 type fly ash portland cement, 5 parts by weight of the magnesium-calcium jointing agent of the present embodiment, 120 parts by weight of machine-made sand with a particle size distribution of 1-3 mm, 30 parts by weight of mixing water, 2 parts by weight of polycarboxylic acid water reducing agent, and 0.05 parts by weight of triethanolamine early strength agent.

[0104] (ii) mixing the above raw materials and stirring for 3 min, then pouring the obtained cement mortar into a mold, demolding after molding, and curing in a curing box with a temperature of 20±2℃ and a relative humidity of not less than 95% for 28 days to obtain a waterproof mortar test piece.

[0105] The waterproof mortar test piece is tested for water permeation pressure according to "Waterproofing agent for mortar and concrete" (JC 474-2008). The waterproof mortar test piece is tested for shrinkage according to "Polymer cement waterproof mortar" (C / T 984-2005). The waterproof mortar test piece is tested for compressive strength and flexural strength according to "Method for testing strength of cement mortar (ISO method)" (GB / T 17671-1999), and the results are shown in the following table:

[0106] .

[0107] Example 8

[0108] 1. A method for preparing a magnesium-calcium jointing agent, comprising the following steps:

[0109] (1) uniformly mixing magnesium oxide powder and calcium oxide powder with a fineness of 400 mesh in a mass ratio of 100:75 to obtain a magnesium-calcium powder, for standby use.

[0110] (2) ultrasonically dispersing graphene oxide with a lateral size of 0.05 μm in anhydrous methanol to form a dispersion liquid, wherein the content of graphene oxide is 10 mg / mL, for standby use.

[0111] (3) fluidizing the magnesium-calcium powder by using pneumatic dispersion technology, and atomizing the dispersion liquid. Then, the fluidized magnesium-calcium powder and the atomized dispersion liquid are countercurrently mixed in a mass ratio of graphene oxide to magnesium-calcium powder of 1:100, and the initial relative speed of the two fluids is 175 m / s, and the environmental temperature is 160℃, to obtain a mixed powder after completion.

[0112] (4) The mixed powder is put into a planetary vertical homogenizer for mechanical grinding, the planetary vertical homogenizer uses corundum balls as grinding medium, the running speed of the planetary vertical homogenizer is 400 r / min, and the grinding time is 35 min, and the magnesium-calcium-based joint prevention agent is obtained after completion.

[0113] 2. A preparation method of waterproof cement mortar, comprising the following steps:

[0114] (i) the following raw materials are taken: 100 parts by weight of P•C 425 type composite portland cement, 8 parts by weight of the magnesium-calcium-based joint prevention agent of the embodiment, 300 parts by weight of machine-made sand with a particle size distribution of 1-3 mm, 60 parts by weight of mixing water, 1.4 parts by weight of polycarboxylic acid water reducing agent, and 1 part by weight of hydroxymethyl cellulose thickening agent.

[0115] (ii) the above raw materials are mixed and stirred for 3 min, then the obtained cement mortar is cast into a mold, demolded after molding, and cured in a curing box with a temperature of 20±2℃ and a relative humidity of not less than 95% for 28 days, and a waterproof mortar test piece is obtained.

[0116] The waterproof mortar test piece is tested for water permeation pressure according to "Waterproofing agent for mortar and concrete" (JC 474-2008), for shrinkage rate according to "Polymer cement waterproof mortar" (C / T 984-2005), and for compressive strength and flexural strength according to "Method for testing strength of cement mortar (ISO method)" (GB / T 17671-1999), and the results are shown in the following table:

[0117] .

[0118] Example 9

[0119] 1. A preparation method of magnesium-calcium-based joint prevention agent, comprising the following steps:

[0120] (1) magnesium oxide powder and calcium oxide powder with a fineness of 300 mesh are uniformly mixed according to a mass ratio of 100:35 to obtain magnesium-calcium-based powder, which is used for standby.

[0121] (2) graphene oxide with a lateral size of 5 μm is ultrasonically dispersed in tetrachloromethane to form a dispersion liquid, wherein the content of graphene oxide is 0.3 mg / mL, which is used for standby.

[0122] (3) the magnesium-calcium-based powder is fluidized by using pneumatic dispersion technology, and the dispersion liquid is atomized. Then, the fluidized magnesium-calcium-based powder and the atomized dispersion liquid are countercurrently mixed according to a mass ratio of graphene oxide to magnesium-calcium-based powder of 0.03:100, the initial relative speed of the two fluids is 70 m / s, and the environmental temperature is 100℃, and a mixed powder is obtained after completion.

[0123] (4) The mixed powder is put into a planetary vertical homogenizer for mechanical grinding, the planetary vertical homogenizer uses corundum balls as grinding medium, the operating speed of the planetary vertical homogenizer is 450 r / min, and the grinding time is 10 min, and the magnesium-calcium-based joint prevention agent is obtained after completion.

[0124] 2. A preparation method of waterproof cement mortar, comprising the following steps:

[0125] (i) the following raw materials are taken: 100 parts by weight of fast-hardening 425 type sulphoaluminate cement, 5 parts by weight of the magnesium-calcium-based joint prevention agent of the embodiment, 280 parts by weight of quartz sand with a particle size distribution of 1-3 mm, 45 parts by weight of mixing water, and 1.2 parts by weight of polycarboxylic acid water reducing agent.

[0126] (ii) the above raw materials are mixed and stirred for 3 min, then the obtained cement mortar is cast into a mold, demolded after molding, and cured in a curing box with a temperature of 20±2℃ and a relative humidity of not less than 95% for 28 days, and a waterproof mortar test piece is obtained.

[0127] The waterproof mortar test piece is tested for water permeation pressure according to "Waterproofing agent for mortar and concrete" (JC 474-2008), for shrinkage rate according to "Polymer cement waterproof mortar" (C / T 984-2005), and for compressive strength and flexural strength according to "Method for testing strength of cement mortar (ISO method)" (GB / T 17671-1999), and the results are shown in the following table:

[0128] .

[0129] Example 10

[0130] 1. A preparation method of a magnesium-calcium-based joint prevention agent, comprising the following steps:

[0131] (1) magnesium oxide powder and calcium oxide powder with a fineness of 300 mesh are uniformly mixed according to a mass ratio of 100:60 to obtain magnesium-calcium-based powder, which is used for standby.

[0132] (2) graphene oxide with a transverse size of 10 μm is ultrasonically dispersed in anhydrous propyl alcohol to form a dispersion liquid, wherein the content of graphene oxide is 2 mg / mL, which is used for standby.

[0133] (3) the magnesium-calcium-based powder is fluidized by using pneumatic dispersion technology, and the local dispersion liquid is atomized. Then, the fluidized magnesium-calcium-based powder and the atomized dispersion liquid are countercurrently mixed according to a mass ratio of graphene oxide to magnesium-calcium-based powder of 0.2:100, the initial relative speed of the two fluids is 150 m / s, and the environmental temperature is 200℃, and a mixed powder is obtained after completion.

[0134] (4) The mixed powder is put into a planetary vertical homogenizer for mechanical grinding, the planetary vertical homogenizer uses corundum balls as grinding medium, the operating speed of the planetary vertical homogenizer is 250 r / min, and the grinding time is 100 min, and the magnesium-calcium-based joint prevention agent is obtained after completion.

[0135] 2. A preparation method of waterproof cement mortar, comprising the following steps:

[0136] (i) taking the following raw materials: 100 parts by weight of CA50 type aluminate cement, 6 parts by weight of the magnesium-calcium-based joint prevention agent of the embodiment, 220 parts by weight of quartz sand with a particle size distribution of 1-3 mm, 45 parts by weight of mixing water, and 0.5 parts by weight of polycarboxylic acid water reducing agent.

[0137] (ii) After mixing the above raw materials, stirring for 3 min, the obtained cement mortar is poured into a mold, demolded after molding, and cured in a curing box with a temperature of 20±2℃ and a relative humidity of not less than 95% for 28 days, and a waterproof mortar test piece is obtained.

[0138] The waterproof mortar test piece is tested for water permeation pressure according to "Waterproofing agent for mortar and concrete" (JC 474-2008). The shrinkage rate of the waterproof mortar test piece is tested according to "Polymer cement waterproof mortar" (C / T 984-2005). The compressive strength and flexural strength of the waterproof mortar test piece are tested according to "Cement mortar strength test method (ISO method)" (GB / T17671-1999), and the results are shown in the following table:

[0139] .

[0140] Example 11

[0141] 1. A preparation method of a magnesium-calcium-based joint prevention agent, comprising the following steps:

[0142] (1) Magnesium oxide powder and calcium oxide powder with a fineness of 300 mesh are uniformly mixed according to a mass ratio of 100:100 to obtain magnesium-calcium-based powder, which is used as needed.

[0143] (2) Graphene oxide with a lateral size of 6 μm is ultrasonically dispersed in anhydrous ethanol to form a dispersion liquid, wherein the content of graphene oxide is 1 mg / mL, which is used as needed.

[0144] (3) The magnesium-calcium-based powder is fluidized by using pneumatic dispersion technology, and the dispersion liquid is atomized. Then, the fluidized magnesium-calcium-based powder and the atomized dispersion liquid are countercurrently mixed according to a mass ratio of graphene oxide to magnesium-calcium-based powder of 0.1:100, the initial relative speed of the two fluids is 80 m / s, and the environmental temperature is 90℃, and a mixed powder is obtained after completion.

[0145] (4) The mixed powder is put into a planetary vertical homogenizer for mechanical grinding, the planetary vertical homogenizer uses corundum balls as grinding medium, the running speed of the planetary vertical homogenizer is 300 r / min, and the grinding time is 30 min, so that the magnesium-calcium anti-cracking agent is obtained.

[0146] 2. A preparation method of waterproof cement mortar, comprising the following steps:

[0147] (i) the following raw materials are taken: 85 parts by weight of P•1 425 type Portland cement, 5 parts by weight of class I fly ash, 10 parts by weight of S95 grade mineral powder, 10 parts by weight of the magnesium-calcium anti-cracking agent of the embodiment, 170 parts by weight of quartz sand with a particle size distribution of 1-3 mm, 55 parts by weight of mixing water, 1 part by weight of polycarboxylic acid water reducing agent, 0.02 parts by weight of triethanolamine early strength agent, and 0.4 parts by weight of hydroxymethyl cellulose thickening agent.

[0148] (ii) the above raw materials are mixed and stirred for 3 min, then the obtained cement mortar is cast into a mold, demolded after molding, and cured in a curing box with a temperature of 20±2℃ and a relative humidity of not less than 95% for 28 days, so that a waterproof mortar test piece is obtained.

[0149] The waterproof mortar test piece is tested for water permeation pressure according to "Waterproofing agent for mortar and concrete" (JC 474-2008), for shrinkage rate according to "Polymer cement waterproofing mortar" (C / T 984-2005), and for compressive strength and flexural strength according to "Method for testing strength of cement mortar (ISO method)" (GB / T 17671-1999), and the results are shown in the following table:

[0150] .

[0151] Example 12

[0152] A preparation method of waterproof cement mortar, comprising the following steps:

[0153] (i) the following raw materials are taken: 100 parts by weight of P•O 425 type ordinary Portland cement, 4 parts by weight of magnesium oxide powder with a fineness of 200 mesh, 300 parts by weight of quartz sand with a particle size distribution of 1-3 mm, and 50 parts by weight of mixing water, and 1 part by weight of polycarboxylic acid water reducing agent.

[0154] (ii) the above raw materials are mixed and stirred for 3 min, then the obtained cement mortar is cast into a mold, demolded after molding, and cured in a curing box with a temperature of 20±2℃ and a relative humidity of not less than 95% for 28 days, so that a waterproof mortar test piece is obtained.

[0155] The waterproof mortar test piece is tested for water permeation pressure according to "Waterproofing agent for mortar and concrete" (JC 474-2008). The waterproof mortar test piece is tested for shrinkage according to "Polymer cement waterproofing mortar" (C / T 984-2005). The waterproof mortar test piece is tested for compressive strength and flexural strength according to "Cement mortar strength test method (ISO method)" (GB / T 17671-1999), and the results are shown in the following table:

[0156] .

[0157] Example 13

[0158] A preparation method of a waterproof cement mortar, comprising the following steps:

[0159] (i) taking the following raw materials: 100 parts by weight of P•O 425 type ordinary Portland cement, 6 parts by weight of calcium oxide powder with a fineness of 300 mesh, 250 parts by weight of machine-made sand with a particle size distribution of 1-3 mm, 45 parts by weight of mixing water, and 1 part by weight of polycarboxylic acid water reducer.

[0160] (ii) mixing the above raw materials and stirring for 3 min, then pouring the obtained cement mortar into a mold, demolding after molding, and curing in a curing box with a temperature of 20±2℃ and a relative humidity of not less than 95% for 28 days to obtain a waterproof mortar test piece.

[0161] The waterproof mortar test piece is tested for water permeation pressure according to "Waterproofing agent for mortar and concrete" (JC 474-2008). The waterproof mortar test piece is tested for shrinkage according to "Polymer cement waterproofing mortar" (C / T 984-2005). The waterproof mortar test piece is tested for compressive strength and flexural strength according to "Cement mortar strength test method (ISO method)" (GB / T 17671-1999), and the results are shown in the following table:

[0162] .

[0163] Example 14

[0164] 1. A preparation method of a magnesium-calcium joint sealant, comprising the following steps:

[0165] (1) ultrasonically dispersing graphene oxide with a lateral size of 8 μm in anhydrous propyl alcohol to form a dispersion liquid, wherein the content of graphene oxide is 0.5 mg / mL, for standby use.

[0166] (2) The magnesium oxide powder with fineness of 400 mesh is fluidized by using pneumatic dispersion technology, and the local dispersion liquid is atomized. Then the fluidized magnesium oxide powder and the atomized dispersion liquid are mixed in a ratio of 0.05:100 of the mass ratio of graphene oxide to the magnesium oxide powder, and the initial relative speed of the two fluids is 20 m / s, and the ambient temperature is 50°C, to obtain the mixed powder after completion.

[0167] (3) The mixed powder is put into a planetary vertical homogenizer for mechanical grinding, and corundum balls are used as the grinding medium, and the running speed of the planetary vertical homizer is 500 r / min, and the grinding time is 30 min, to obtain the magnesium-based joint prevention agent after completion.

[0168] 2. A preparation method of waterproof cement mortar, comprising the following steps:

[0169] (i) The following raw materials are taken: P•F 425 type fly ash portland cement 100 parts by weight, the magnesium-based joint prevention agent of the embodiment 6 parts by weight, quartz sand with particle size distribution of 1-3 mm 200 parts by weight, mixing water 35 parts by weight, and polycarboxylic acid water reducing agent 1.1 parts by weight.

[0170] (ii) After mixing the above raw materials, stirring is carried out for 3 min, and then the obtained cement mortar is cast into a mold, demolded after molding, and cured in a curing box with a temperature of 20±2°C and a relative humidity of not less than 95% for 28 days, to obtain a waterproof mortar test piece.

[0171] The waterproof mortar test piece is tested for water permeation pressure according to "Waterproofing agent for mortar and concrete" (JC 474-2008). The waterproof mortar test piece is tested for shrinkage rate according to "Polymer cement waterproof mortar" (C / T 984-2005). The waterproof mortar test piece is tested for compressive strength and flexural strength according to "Cement mortar strength test method (ISO method)" (GB / T 17671-1999), and the results are shown in the following table:

[0172] .

[0173] Example 15

[0174] 1. A preparation method of a magnesium-calcium-based joint prevention agent, comprising the following steps:

[0175] (1) Graphene oxide with a lateral size of 0.05 μm is ultrasonically dispersed in anhydrous methanol to form a dispersion liquid, wherein the content of graphene oxide is 10 mg / mL, and the dispersion liquid is prepared for use.

[0176] (2) The calcium oxide powder with fineness of 400 mesh is fluidized by using pneumatic dispersion technology, and the local dispersion liquid is atomized. Then the fluidized calcium oxide powder and the atomized dispersion liquid are mixed in a counter flow with a mass ratio of 1:100, and the initial relative speed of the two fluids is 175 m / s, and the ambient temperature is 160°C, and the mixed powder is obtained after completion.

[0177] (3) The mixed powder is put into a planetary vertical homogenizer for mechanical grinding, and corundum balls are used as the grinding medium, and the operating speed of the planetary vertical homizer is 400 r / min, and the grinding time is 35 min, and the calcium-based joint prevention agent is obtained after completion.

[0178] 2. A preparation method of waterproof cement mortar, comprising the following steps:

[0179] (i) The following raw materials are taken: P•C 425 type composite portland cement 100 parts by weight, the calcium-based joint prevention agent of the present embodiment 8 parts by weight, machine-made sand with particle size distribution of 1-3 mm 300 parts by weight, mixing water 60 parts by weight, polycarboxylic acid water reducing agent 1.4 parts by weight, and hydroxymethyl cellulose thickening agent 0.7 parts by weight.

[0180] (ii) After mixing the above raw materials, stirring is carried out for 3 min, and then the obtained cement mortar is cast into a mold, demolded after molding, and cured in a curing box with a temperature of 20±2°C and a relative humidity of not less than 95% for 28 days, and a waterproof mortar test piece is obtained.

[0181] The waterproof mortar test piece is tested for water permeation pressure according to "Waterproofing agent for mortar and concrete" (JC 474-2008). The shrinkage rate of the waterproof mortar test piece is tested according to "Polymer cement waterproof mortar" (C / T 984-2005). The compressive strength and the flexural strength of the waterproof mortar test piece are tested according to "Cement mortar strength test method (ISO method)" (GB / T 17671-1999), and the results are shown in the following table:

[0182] .

[0183] From the test results of the above embodiments, it can be seen that the water permeation pressure of the cement mortar containing the anti-joint agent prepared in embodiments 1-11 reaches 1.2 MPa or above, i.e. the waterproof performance reaches P12 or above, achieving good waterproof performance, improved mechanical properties, and reduced shrinkage. In addition, the improvement in the flexural strength also indicates good toughness of the cement mortar. It can be seen that the anti-joint agent described above can enable the cement mortar to simultaneously have good waterproof performance, low shrinkage, good mechanical strength, and toughness. This is because the expansion of the magnesium-calcium anti-joint agent of embodiments 1-11 and the volume shrinkage of the cement mortar are fully matched, which can timely offset the volume change of the mortar, fill the internal pores of the mortar, prevent the formation and development of micro-cracks, achieve waterproof and impermeable effects, and also improve the mechanical strength of the cement mortar. In addition, it can be seen from embodiments 1-11 that the magnesium-calcium anti-joint agent of the present application can be applied to various types of cementitious materials.

[0184] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can modify the technical solutions described in the foregoing embodiments or make equivalent replacements to some technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A magnesium-calcium based seam inhibitor, characterized by, The mixture formed by the magnesium oxide and the calcium oxide to which graphene oxide is attached; wherein: the mass ratio of the magnesium oxide and the calcium oxide is 100:20-100; the total mass ratio of the graphene oxide to the magnesium oxide and the calcium oxide is 0.01-1:100; and the lateral size of the graphene oxide is 0.05-20 μm.

2. The method for producing the magnesium-calcium-based joint preventive agent according to claim 1, characterized by, The method comprises the following steps: (1) mixing magnesium oxide and calcium oxide in a proportion to obtain a magnesium-calcium powder, and then fluidizing the powder; (2) applying a dispersion formed by atomized graphene oxide and a volatile non-aqueous dispersion medium to the fluidized powder; and after completion, mechanically grinding the obtained mixture to obtain the magnesium-calcium joint prevention agent; In step (2), the mass ratio of the powder to the graphene oxide in the dispersion is 100:0.01-1, and the content of the graphene oxide in the dispersion is 0.1-10 mg / mL.

3. The method for producing a magnesium-calcium-based joint corrosion preventive according to claim 2, characterized by, The volatile non-aqueous dispersion medium comprises one of anhydrous methanol, anhydrous ethanol, anhydrous propanol, and tetrachloromethane.

4. The method for producing a magnesium-calcium-based joint-preventing agent according to claim 2 or 3, characterized by, In step (2), the movement mode of the atomized dispersion and the fluidized powder is convection collision.

5. The method for producing a magnesium-calcium-based joint inhibitor according to claim 4, characterized by, The initial relative speed of the convection is 20-200 m / s.

6. The method for producing a magnesium-calcium-based joint-preventing agent according to claim 4, characterized by, The ambient temperature of the convection is 50-200 °C.

7. The method for producing a magnesium-calcium-based joint inhibitor according to claim 2 or 3, characterized by, In step (2), the grinding time is 10-120 min.

8. A waterproof cement mortar, characterized by, The waterproof cement mortar comprises the following raw materials: 100 parts by weight of a cementitious material, 2-10 parts by weight of the magnesium-calcium joint prevention agent of claim 1 or the magnesium-calcium joint prevention agent prepared by the method of any one of claims 2-7, 120-350 parts by weight of fine aggregate, and 30-60 parts by weight of mixing water.

9. The waterproofing cement mortar according to claim 8, characterized in that, The waterproof cement mortar further comprises an admixture.

10. The waterproofing cement mortar according to claim 9, characterized in that, The admixture comprises at least one of a water reducing agent, an early strength agent, and a thickening agent.

11. The waterproofing cement mortar according to claim 10, characterized in that, The water reducing agent is 0.5-2 parts by weight, the early strength agent is 0.02-0.05 parts by weight, and the thickening agent is 0.2-1 parts by weight.

12. The waterproof cement mortar according to any one of claims 9 to 11, characterized in that, The cementitious material comprises at least one of cement, fly ash, silica fume, and mineral powder.

13. The waterproofing cement mortar according to claim 12, characterized in that, The cement is selected from any one of Portland cement, sulphoaluminate cement, aluminate cement, ferro-aluminate cement, and geopolymer cement.

14. The waterproof cement mortar according to any one of claims 9 to 11, characterized in that, The fine aggregate comprises at least one of quartz sand and machine-made sand.

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