Super retarder as well as preparation method and application thereof

Abstract

The invention relates to a super retarder as well as a preparation method and application thereof. The super retarder is prepared from the following raw materials in percentage by mass: 25 to 35 percent of a phosphino-acrylic acid copolymer, 15 to 25 percent of a phosphino-carboxylic acid copolymer, 10 to 20 percent of sodium gluconate, 5 to 10 percent of a sediment dispersing agent, 5 to 10 percent of an olefine acid-2-acrylamide-2-methylpropanesulfonic acid copolymer and 5 to 10 percent of ammonium polyphosphate. The technical problem to be solved is how to provide the super retarder which can delay the condensation of concrete waste slurry, purify harmful ions in the concrete waste slurry and repeatedly utilize the concrete waste slurry to prepare concrete, and the obtained concrete is good in strength.

Description

Technical Field

[0001] The present invention belongs to the field of retarders, and particularly relates to an ultra-retarder and its preparation method and application. Background Art

[0002] Concrete is often used in the fields of construction and civil engineering and is a widely used material. However, during the production and use of concrete, water needs to be added to the concrete raw materials at the concrete mixing plant to hydrate the cement in the concrete raw materials and mix it with other raw materials. During the production process, a large amount of waste slurry water, also known as concrete waste slurry water, will be generated during the processing of concrete raw materials at the mixing plant. Since the concrete waste slurry water not only contains residues of solid particle components such as cement particles, but also contains a large amount of harmful ions (such as SO4 2- 、OH - etc.), and under the action of these harmful ions, the solid particles in the waste slurry water are prone to chemical reactions, and thus the waste slurry water is prone to coagulation; in addition, the coagulation of the concrete waste slurry water not only hinders the recycling of the waste slurry water, but also accelerates the loss of the equipment at the concrete mixing plant.

[0003] Some literatures have proposed to dry and grind the concrete waste slurry water to make concrete waste slurry dry powder in order to improve the reuse of the gelling components in the waste slurry water, save cement, and improve the resource utilization rate. However, during the preparation of concrete by incorporating the concrete waste slurry dry powder prepared by the foregoing scheme, the early rheology is poor, and the mechanical strength of the prepared concrete usually decreases significantly with the increase of the content of the concrete waste slurry powder; in addition, during the process of preparing the concrete waste slurry dry powder by drying and grinding in the foregoing scheme, a relatively large amount of expensive mechanical equipment and a large amount of fuel need to be invested, and the production cost is high.

[0004] Therefore, how to delay the coagulation of the concrete waste slurry water, purify the harmful ions in the concrete waste slurry water, reuse the concrete waste slurry water to prepare concrete, and retain the strength of the prepared concrete while reducing the input cost is one of the key points and difficulties in this field of research. Summary of the Invention

[0005] The main object of the present invention is to provide an ultra-retarder and its preparation method and application. The technical problem to be solved is how to provide an ultra-retarder that can delay the coagulation of the concrete waste slurry water, purify the harmful ions in the concrete waste slurry water, reuse the concrete waste slurry water to prepare concrete, and obtain good concrete strength.

[0006] The object of the present invention and the solution to its technical problem are achieved by the following technical solutions. An ultra-retarder according to the present invention, calculated by mass percentage, its raw materials include:

[0007] 25 - 40% phosphonoacrylic acid copolymer, 15 - 25% phosphonyl carboxylic acid copolymer, 10 - 20% sodium gluconate, 5 - 10% sediment dispersant, 5 - 10% acrylic acid-2-acrylamido-2-methylpropane sulfonic acid copolymer, 5 - 10% polyphosphoric acid amine.

[0008] The object of the present invention and the technical problems to be solved can also be further realized by the following technical measures.

[0009] Preferably, in the aforementioned super retarder, the mass ratio of the sediment dispersant to the acrylic acid-2-acrylamido-2-methylpropane sulfonic acid copolymer in the super retarder is 1:0.8 - 1.5.

[0010] Preferably, in the aforementioned super retarder, its raw materials further include: 5 - 15% sodium salt containing a phosphoric acid group.

[0011] Preferably, in the aforementioned super retarder, the sodium salt of the phosphoric acid group is selected from at least one of sodium ethylene diamine tetramethylene phosphonate, tetrasodium ethylenediaminetetraacetate, and tetrasodium hydroxyethylidene diphosphonate.

[0012] Preferably, in the aforementioned super retarder, its raw materials further include: 5 - 10% 2-phosphono-1,2,4-tricarboxylic acid butane.

[0013] Preferably, in the aforementioned super retarder, its raw materials further include: 5 - 10% polyamino polyether methylene phosphonic acid.

[0014] Preferably, in the aforementioned super retarder, the content of the phosphonoacrylic acid copolymer is 25 - 30%, and the content of the phosphonyl carboxylic acid copolymer is 20 - 25%.

[0015] Preferably, in the aforementioned super retarder, the polymerization degree of the phosphonoacrylic acid copolymer ≥2, the polymerization degree of the phosphonyl carboxylic acid copolymer is 10 - 1000, and the polymerization degree of the acrylic acid-2-acrylamido-2-methylpropane sulfonic acid copolymer is 50 - 500.

[0016] The object of the present invention and the technical problems to be solved are also achieved by the following technical solutions. A preparation method of a super retarder according to the present invention includes the following steps:

[0017] S1 Mix the phosphonoacrylic acid copolymer, phosphonyl carboxylic acid copolymer, and sodium gluconate, dissolve them in water, and stir evenly at 30 - 45°C to form a mixed solution A;

[0018] S2 Add the sediment dispersant, acrylic acid-2-acrylamido-2-methylpropane sulfonic acid copolymer, and polyphosphoric acid amine to the mixed solution A, and continue to stir evenly under the conditions of S1 to form a mixed solution B;

[0019] S3 cools the mixture B to room temperature and filters out impurities to obtain the super retarder.

[0020] In terms of mass percentage, the raw materials of the super retarder include: 25-40% phosphonoacrylic acid copolymer, 15-25% phosphonyl carboxylic acid copolymer, 10-20% sodium gluconate, 5-10% sediment dispersant, 5-10% acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, and 5-10% polyphosphoric acid amide.

[0021] The application of the super retarder described in the foregoing solution in concrete waste slurry water, wherein the addition amount of the super retarder is 1.0-2.0% of the total mass of the concrete waste slurry water; the mass percentage of total solids in the concrete waste slurry water ≤ 10%.

[0022] By means of the above technical solution, a super retarder, its preparation method and application proposed by the present invention have at least the following advantages:

[0023] A super retarder provided by the present invention, through a large number of experimental studies, selects multiple components and limits the content of multiple components, so that various raw material components in the super retarder act synergistically, can effectively delay the setting time of waste slurry water, the prepared concrete has good strength, reduces slump loss, and uses this super retarder in concrete production, the process is simple, the input cost is low, and significant economic benefits can be achieved.

[0024] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly and implement it in accordance with the content of the specification, the following takes the preferred embodiments of the present invention and combines with the drawings to describe in detail as follows. Description of the Drawings

[0025] Figure 1 It is a comparison diagram of XRD patterns of hydration products of waste slurry water with super retarder added for 5 minutes in Example 8 and waste slurry water in Comparative Example 1.

[0026] Figure 2 It is a comparison diagram of XRD patterns of hydration products of waste slurry water with super retarder added for 6 hours in Example 8 and waste slurry water in Comparative Example 1.

[0027] Figure 3 It is a comparison diagram of XRD patterns of hydration products of waste slurry water with super retarder added for 12 hours in Example 8 and waste slurry water in Comparative Example 1. Detailed Embodiments

[0028] To further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following will, in conjunction with preferred embodiments, describe a superplasticizer and its preparation method and application proposed according to the present invention. Its specific implementation manner, structure, features and effects will be described in detail as follows.

[0029] The inventor studied the properties of the dry powder of concrete waste slurry prepared by the prior art and found that a relatively large amount of harmful ions and the hydration products of the gelling components were retained in the dry powder of concrete waste slurry prepared by the prior art. Therefore, it is easy to affect the strength of concrete. In view of the research progress of the prior art, the present invention designs and develops a superplasticizer for waste slurry water, which can not only delay the setting time of the waste slurry water (hereinafter referred to as "waste slurry water" for short) generated by the concrete mixing plant, but also purify the harmful ions contained in the waste slurry water, reduce the content of harmful ions in the waste slurry water, and then enable the waste slurry water to be recycled for the hydration and mixing of concrete raw materials without affecting the various properties of the formed concrete (including the workability, mechanical properties, etc. of the concrete).

[0030] Based on this, the present invention provides a superplasticizer, and in terms of mass percentage content, its raw materials include:

[0031] 25 - 40% phosphonoacrylic acid copolymer, 15 - 25% phosphonocarboxylic acid copolymer, 10 - 20% sodium gluconate, 5 - 10% sediment dispersant, 5 - 10% acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, 5 - 10% polyphosphoric acid amide.

[0032] For the superplasticizer obtained by the present invention adopting this technical solution, on the one hand, after adding the superplasticizer of the present invention to the waste slurry water, the polymer in the superplasticizer can adsorb on the surface of solid substances such as residual cement particles in the waste slurry water to form an adsorption layer. This can not only hinder the contact between the residual cement particles and water, thereby delaying the hydration reaction of the residual cement in the waste slurry water, but also further help to avoid the aggregation adsorption precipitation between the residual solid particles in the waste slurry water, so as to effectively extend the setting time of the waste slurry water and avoid the rapid setting of the waste slurry water; on the other hand, sodium gluconate can form a stable chelate with calcium ions in the waste slurry water. This is not only conducive to reducing the content of calcium ions in the waste slurry water, and then reducing or even avoiding the formation of calcium sulfate or calcium carbonate precipitation, but also the formed chelate can further adsorb and coat the harmful ions in the waste slurry water, reducing the content of harmful ions in the waste slurry water to reduce or even avoid the erosion of harmful ions on the equipment and the impact on the durability of concrete. In view of this, the present invention not only helps to delay the setting time of the waste slurry water, but also helps to reduce or even avoid the harmful effects of the waste slurry water on the components of concrete raw materials during the recycling process; therefore, the waste slurry water treated by the superplasticizer provided by the present invention can be recycled, and the strength of the prepared concrete is good.

[0033] The present invention strictly limits the content of the phosphonoacrylic acid copolymer in the super retarder to achieve the design purpose of the present invention. During the research process, the inventor found that if the content of the phosphonoacrylic acid copolymer is too high, it will inhibit the hydration of C3S to a certain extent. When the waste slurry water is treated with the super retarder under this condition and concrete is prepared, compared with the comparative reference, the isothermal calorimetry shows that the heat of hydration released in 24 hours is reduced by 35-40%. The 3-day compressive strength of the concrete prepared by this scheme decreases by 20-25% (comparison), and it will also cause excessive retardation, hindering the construction progress. The inventor also found that if the content of the phosphonoacrylic acid copolymer is too low, it may cause the out-of-control of impurity ions, such as SO4 2- oversaturation, which may further affect the mechanical properties of the prepared concrete.

[0034] The comparative reference in the present invention is to replace the waste slurry water with tap water and prepare concrete under the same process parameters and operation methods as those for preparing concrete with the waste slurry water treated by adding the super retarder.

[0035] The present invention strictly limits the content of the phosphonyl carboxylate copolymer to achieve the design purpose of the present invention. The inventor found that if the content of the phosphonyl carboxylate copolymer is too high, the phosphonyl carboxylate copolymer may be overly adsorbed on the surface of cement particles, resulting in a sudden increase in the viscosity of the slurry. When the waste slurry water is treated with the super retarder under this condition and concrete is prepared, compared with the comparative reference, the slump loss rate increases by 40-60%. If the content of the phosphonyl carboxylate copolymer is too low, it may cause the peak value of the hydration heat release rate to shift forward, and the internal temperature difference of mass concrete exceeds the cracking risk threshold of 25°C.

[0036] The present invention strictly limits the content of sodium gluconate to achieve the design purpose of the present invention. If the content of sodium gluconate is too high, it may cause excessive inhibition of the hydration process and deterioration of the pore structure. If the content of sodium gluconate is too low, there may be a risk of out-of-control temperature rise and an accelerated loss of workability.

[0037] The present invention strictly limits the content of the sediment dispersant to achieve the design purpose. If the content of the sediment dispersant is too high, it may compete for adsorption with the polycarboxylate water reducer, resulting in a 30-40% reduction in the dispersion efficiency. If the content of the sediment dispersant is too low, it may increase the pore connectivity and sharply increase the alkali-aggregate reaction activity.

[0038] The present invention strictly limits the content of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer to achieve the design purpose. If the content of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is too high, it may cause excessive dispersion, resulting in a decrease in the viscosity of the slurry, and then may cause segregation and bleeding; too many sulfonic acid groups may excessively chelate calcium ions, delaying the hydration reaction and affecting the strength development; if the content of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is too low, it may affect the dispersion effect of concrete raw materials, cause cement particle flocculation, and the workability becomes poor, and the slump loss of the prepared concrete test block accelerates.

[0039] The present invention strictly limits the content of the polyphosphoric acid amine to achieve the design purpose. If the content of the polyphosphoric acid amine is too high, it may deteriorate the physical properties, resulting in an increase in the brittleness of the material and a decrease in flexibility, affecting the mechanical properties of the concrete; if the content of the polyphosphoric acid amine is too low, the raw material utility cannot be achieved.

[0040] In the foregoing solution, in some embodiments, the degree of polymerization of the phosphonoacrylic acid copolymer is ≥2, that is, the phosphonoacrylic acid copolymer contains at least 2 repeating units; the degree of polymerization of the phosphonyl carboxylic acid copolymer is 10-1000, that is, the repeating units of the phosphonyl carboxylic acid copolymer are 10-1000; the degree of polymerization of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is 50-500, that is, the repeating units of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer are 50-500. The present invention optimizes the degree of polymerization of each copolymer to maximize the functionality of each component raw material, improve the balance between components, and further make the synergistic effect between components better. The superplasticizer formed is incorporated into the waste slurry water, and the adsorption layer formed on the surface of solid particles is more stable, which helps to improve the purification effect on harmful ions in the waste slurry water. In view of this, the quality of the concrete prepared with the superplasticizer obtained under this condition is better.

[0041] In the foregoing solution, in order to further extend the setting time of the waste slurry water, preferably, in some embodiments, the mass ratio of the sediment dispersant to the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer in the superplasticizer raw material is 1:0.8-1.5; in some other embodiments, the mass ratio of the sediment dispersant to the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is preferably 1:0.8-1.2; in some other embodiments, the mass ratio of the sediment dispersant to the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is preferably 1:1.

[0042] In some embodiments of the foregoing solution, 5-15% of sodium salt containing phosphate group is further included in the super retarder raw material to further delay the setting time of the waste slurry water and reduce or even avoid the poisoning effect of harmful ions in the waste slurry water on the components in the concrete. Preferably, in some embodiments, 10-15% of sodium ethylene diamine tetra (methylene phosphonate) is added to the super retarder; preferably, in some other embodiments, 10-15% of tetrasodium ethylenediaminetetraacetate is added to the super retarder; preferably, in some other embodiments, 5-10% of tetrasodium hydroxyethane diphosphonate is added to the super retarder of the present invention. The sodium salt raw material containing phosphate group added in the foregoing solution can form stable chelates with calcium ions in the waste slurry water, which helps to delay the setting time of the waste slurry water and reduce or even avoid the poisoning effect of harmful ions in the waste slurry water on the components in the concrete.

[0043] In the foregoing solution, in order to further extend the setting of the waste slurry water, preferably, in some embodiments, 5-10% of 2-phosphono-1,2,4-tricarboxylic acid butane (abbreviation "PBTCA") is added. The PBTCA molecule contains phosphonic acid group and carboxylic acid group, and these groups can form stable chelates with metal ions such as calcium ions and magnesium ions in the cement. This chelation restricts the participation of metal ions in the cement hydration reaction, thereby delaying the cement hydration process.

[0044] In the foregoing solution, in order to further extend the setting time of the waste slurry water and maintain or even increase the compressive strength of the prepared concrete, preferably, in some embodiments, 5-10% of polyamino polyether methylene phosphonic acid (abbreviation "PAPEMP") is added; PAPEMP can chelate metal ions, has a high calcium tolerance, disperse cement particles, adsorb on the cement surface, and can interfere with the formation of hydration products, and thus can effectively delay the hydration rate of the cement and extend the setting time, so as to achieve a retardation effect.

[0045] In the foregoing solution, preferably, in some embodiments, the content of the phosphonoacrylic acid copolymer is 25-30%, and the content of the phosphonocarboxylic acid copolymer is 20-25%. Under this condition, the phosphonic acid group and carboxylic acid group in the phosphonoacrylic acid copolymer can better chelate metal ions such as calcium ions and disperse cement particles, delaying cement hydration. Under alkaline conditions, it will not precipitate with zinc ions, so it can be compounded with other corrosion inhibitors (such as zinc salts) to enhance the corrosion inhibition effect.

[0046] Some embodiments of the present invention also provide a preparation method of the super retarder, which is specifically as follows:

[0047] S1 Mix the phosphonoacrylic acid copolymer, phosphonocarboxylic acid copolymer, and sodium gluconate, dissolve them in water, and stir evenly at 30-45°C to form a mixed solution A. Under this condition, each raw material is not only evenly mixed but also has good performance. Preferably, in some embodiments, the mass percentage of water in the formed mixed solution A is 50-60%. Under this condition, each component of the coagulant is completely dissolved in water, the mixing is more uniform, and it is beneficial to save water resources;

[0048] S2 Add the sediment dispersant, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, and polyphosphoric acid amine to the above-mentioned mixed solution A, and continue to stir evenly under the condition described in S1 to form a mixed solution B;

[0049] S3 Cool the mixed solution B to room temperature, filter to remove impurities, and obtain the super retarder;

[0050] The raw materials of the super retarder by mass percentage include: 25-40% phosphonoacrylic acid copolymer, 15-25% phosphonocarboxylic acid copolymer, 10-20% sodium gluconate, 5-10% sediment dispersant, 5-10% acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, 5-10% polyphosphoric acid amine.

[0051] Some embodiments of the present invention also provide an application method of the super retarder in the treatment process of waste slurry water, which is as follows:

[0052] The super retarder described in the above scheme is added to the waste slurry, and the mass percentage of the total solids in the waste slurry is ≤10%, and the mass percentage of the total solids in the total solid waste slurry is the total mass percentage of the solutes and insoluble solid particles in the waste slurry; the amount of the super retarder added is 1.0-2.0% of the total mass of the waste slurry. In some embodiments, the amount of the super retarder added is 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8% of the total mass of the waste slurry. %, 1.9%, 2.0% and any value between these process parameters. Under these conditions, the super retarder acts on the waste slurry water, which can not only effectively delay the setting time of the waste slurry water, but also the prepared concrete has good compressive strength. The reason may be that the super retarder prepared by the present invention delays the early hydration reaction of cement, makes the cement hydration more sufficient and uniform, reduces the weak points in the cement stone, and thus improves the later strength of the concrete; further, after the concrete mixing is completed, it is found that the tricalcium silicate content is increased, which helps to improve the strength of the concrete. In addition, the super retarder provided by the present invention can also reduce the slump loss. The reason may be that the water-reducing component in the super retarder synergistically acts with the admixture in the concrete raw materials, such as the polycarboxylate water-reducing agent, to effectively reduce the water consumption of the concrete while maintaining good fluidity. It synergizes with other components. In the process of delaying the setting time, the slowdown of the cement hydration reaction also reduces the consumption of water, thereby reducing the slump loss.

[0053] The waste slurry water mentioned in the present invention includes wastewater and waste slurry generated by cleaning concrete production mixing equipment, concrete transport vehicles, and concrete pumping equipment; wastewater and waste slurry generated by separating waste concrete, and wastewater generated by flushing concrete production sites.

[0054] In summary, the super retarder prepared by the present invention can effectively delay the setting time of waste slurry water through the synergistic effect of multiple components, and the prepared concrete has good strength and reduces slump loss. The use of super retarder in concrete production can achieve significant economic benefits, among which the improved economic benefits are mainly reflected in the following aspects:

[0055] Resource recycling: By extending the setting time of waste slurry water, it can be reused in concrete production, reducing the use of fresh water resources and lowering production costs.

[0056] Improve construction efficiency: Super retarder prolongs the operable time of waste slurry water, giving construction workers more time to mix, transport and pour concrete, reducing construction problems caused by too rapid setting and improving construction efficiency.

[0057] Reduce material waste: Since super retarder can effectively control the setting time of waste slurry water and control the strength development of concrete, it reduces material waste caused by early setting or insufficient strength.

[0058] The present invention will be further described below in conjunction with specific embodiments, but it should not be construed as a limitation on the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art to the present invention based on the above content of the present invention still fall within the protection scope of the present invention.

[0059] Unless otherwise specified, the materials, reagents, etc. involved below are all commercially available products well-known to those skilled in the art; unless otherwise specified, the methods are all well-known methods in the art. Unless otherwise defined, the technical terms or scientific terms used shall have the ordinary meaning as understood by those of ordinary skill in the art to which the present invention pertains.

[0060] The concrete raw materials involved in the following examples and comparative examples are:

[0061] Cement (P·I 42.5 Portland cement);

[0062] Fly ash (Class II fly ash);

[0063] Ground granulated blast-furnace slag (S95 grade);

[0064] Sand (machine-made medium sand in Zone II);

[0065] Stone (5-25 continuous gradation gravel);

[0066] Waste slurry water (obtained from the production line of Beijing Tiejian Yongtai New Building Materials Co., Ltd.);

[0067] Water-reducing agent (polycarboxylate water-reducing agent).

[0068] Regarding the detection of the total solid content, harmful ions (SO4 2- , OH - ) content, and the compressive strength of concrete, as well as the detection method for the slump loss of concrete in each example and comparative example are as follows:

[0069] Detection of the total solid content in concrete waste slurry water: drying method;

[0070] Detection of harmful ion content: titration method and ICP method;

[0071] Compressive strength detection: detected according to the "Standard for Test Methods of Mechanical Properties of Ordinary Concrete" (GB / T50081-2019);

[0072] Detection of the slump loss of concrete: detected according to the "Standard for Test Methods of Mechanical Properties of Ordinary Concrete" (GB / T 50081-2019).

[0073] The mass percentage content of the total solids in the concrete waste slurry water used in the following examples and comparative examples is ≤10%.

[0074] Example 1

[0075] This example provides a super-retarding agent for recycled water (hereinafter referred to as "RWA") and its preparation method and application, which are specifically as follows:

[0076] Preparation of RWA

[0077] S1: Mix phosphonoacrylic acid copolymer, phosphonocarboxylic acid copolymer, and sodium gluconate in the proportions shown in Table 1, add water, and stir evenly at a temperature of 40°C.

[0078] S2: Add sediment dispersant, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, and ammonium polyphosphate to the above mixture, and continue to stir for 45 minutes under the above conditions until evenly mixed.

[0079] Step 3: Cool the mixture obtained in Step 2 to room temperature, filter to remove impurities, obtain an RWA solution, and store it sealed.

[0080] Application of RWA

[0081] Add the RWA prepared in this example to the recycled water (the total solid content in the recycled water is shown in Table 2) at 1.5% of the total mass of the recycled water, and shake well.

[0082] Weigh the concrete raw materials as follows by mass:

[0083] 3.8 parts of cement, 1.2 parts of fly ash, 0.8 part of slag powder, 14.8 parts of sand, 14.2 parts of stone, 1.4 parts of recycled water treated with RWA, and the addition amount of polycarboxylate water reducer is 2.2% of the total mass of the cementitious materials (including cement, fly ash, and slag powder).

[0084] Using the above concrete raw materials, add the concrete recycled water treated with the RWA prepared in this example, stir evenly, mold, and cure the concrete blocks for 28 days under the curing conditions of a temperature of 20 ± 2°C and a relative humidity of 95%.

[0085] Index detection

[0086] Detect the content of harmful ions (SO4 2- , OH - ) in the concrete recycled water treated in this example; detect the compressive strength of the prepared concrete cured for 7 days and 28 days, as well as the 1h slump loss of the concrete. The detection method is the same as described above.

[0087] The detection results of each index are shown in Table 2.

[0088] Example 2

[0089] This example provides a super-retarding agent for waste pulp water (RWA) and its preparation method and application, which are basically the same as the preparation process and method of Example 1, except that the content of the raw material components of RWA is different, as shown in Table 1 specifically.

[0090] The index detection and detection method are the same as those in Example 1, and the detection results are shown in Table 2.

[0091] Example 3

[0092] This example provides a super-retarding agent for waste pulp water (RWA) and its preparation method and application, which are basically the same as the preparation process and method of Example 1, except that the content of the raw material components of RWA is different, as shown in Table 1 specifically.

[0093] The index detection and detection method are the same as those in Example 1, and the detection results are shown in Table 2.

[0094] Example 4

[0095] This example provides a super-retarding agent for waste pulp water (RWA) and its preparation method and application, which are basically the same as the preparation process and method of Example 1, except that sodium ethylene diamine tetra (methylene phosphonate) is added to the raw materials of RWA, and the content of each component of the raw materials of RWA is shown in Table 1 specifically.

[0096] The index detection and detection method are the same as those in Example 1, and the detection results are shown in Table 2.

[0097] Example 5

[0098] This example provides a super-retarding agent for waste pulp water (RWA) and its preparation method and application, which are basically the same as the preparation process and method of Example 1, except that tetrasodium ethylenediaminetetraacetate is added to the raw materials of RWA, and the content of each component of the raw materials of RWA is shown in Table 1 specifically.

[0099] The index detection and detection method are the same as those in Example 1, and the detection results are shown in Table 2.

[0100] Example 6

[0101] This example provides a super-retarding agent for waste pulp water (RWA) and its preparation method and application, which are basically the same as the preparation process and method of Example 1, except that tetrasodium ethylenediaminetetraacetate and tetrasodium hydroxyethylidene diphosphonate are added to the raw materials of RWA, and the content of each component of the raw materials of RWA is shown in Table 1 specifically.

[0102] The index detection and detection method are the same as those in Example 1, and the detection results are shown in Table 2.

[0103] Example 7

[0104] This embodiment provides a super retarder for waste pulp water (RWA) and its preparation method and application. The preparation process and method are basically the same as those in Embodiment 1, except that sodium ethylenediaminetetraacetate, tetrasodium hydroxyethylethylenediphosphonate, and 2-phosphono-1,2,4-tricarboxylic acid butane are added to the raw materials of RWA. The specific content of each component of the raw materials of RWA is shown in Table 1.

[0105] The index detection and detection method are the same as those in Embodiment 1, and the detection results are shown in Table 2.

[0106] Embodiment 8

[0107] This embodiment provides a super retarder for waste pulp water (RWA) and its preparation method and application. The preparation process and method are basically the same as those in Embodiment 1, except that sodium ethylenediaminetetraacetate, tetrasodium hydroxyethylethylenediphosphonate, 2-phosphono-1,2,4-tricarboxylic acid butane, and polyamino polyether methylene phosphonic acid are added to the raw materials of RWA. The specific content of each component of the raw materials of RWA is shown in Table 1.

[0108] The index detection and detection method are the same as those in Embodiment 1, and the detection results are shown in Table 2; further, the hydration products in the waste pulp water after adding the super retarder for waste pulp water in this embodiment are detected by XRD and the attached drawings are drawn, as shown in the attachment Figures 1 - 3 .

[0109] Comparative Example 1

[0110] It is basically the same as the preparation process and method in Embodiment 1, except that no measures are taken to treat the concrete waste pulp water.

[0111] The detection indexes and detection methods are the same as those in Embodiment 1.

[0112] The detection results are shown in Table 2. The hydration products in this comparative waste pulp water are detected and the attached drawings are drawn Figures 1 - 3 .

[0113] Comparative Example 2

[0114] This embodiment provides a super retarder for waste pulp water (RWA) and its preparation method and application. The preparation process and method are basically the same as those in Embodiment 1, except that the mass percentage content of the phosphonoacrylic acid copolymer is reduced to 20%, and the mass percentage content of sodium gluconate is increased to 30%. The specific content of the raw material components of RWA is shown in Table 1.

[0115] The index detection and detection method are the same as those in Embodiment 1, and the detection results are shown in Table 2.

[0116] Comparative Example 3

[0117] This embodiment provides a super retarder (RWA) and its preparation method and application, which are basically the same as the preparation process and method of Embodiment 1, except that the mass percentage content of sodium gluconate is reduced to 5%, and the mass percentage content of phosphono carboxylic acid copolymer is increased to 31%. The specific content of the raw material components of RWA is shown in Table 1.

[0118] The index detection and detection method are the same as those in Embodiment 1, and the detection results are shown in Table 2.

[0119] Comparative Example 4

[0120] This embodiment provides a super retarder (RWA) and its preparation method and application, which are basically the same as the preparation process and method of Embodiment 1, except that the mass percentage content of acrylic acid-2-acrylamide-2-methylpropane sulfonic acid copolymer is reduced to 2%, and the mass percentage content of polyphosphoric acid amine is increased to 16%. The specific content of the raw material components of RWA is shown in Table 1.

[0121] The index detection and detection method are the same as those in Embodiment 1, and the detection results are shown in Table 2.

[0122] Table 1 Mass percentage content (%) of raw material components of super retarder (RWA) for waste slurry water in each embodiment

[0123]

[0124] In Table 1, the ratio of the mass percentage content of the sediment dispersant to the acrylic acid-2-acrylamide-2-methylpropane sulfonic acid copolymer is expressed as m1:m2.

[0125] Table 2 Detection results of each embodiment and comparative example

[0126]

[0127]

[0128] As can be seen from Table 2, the concrete prepared by recycling the concrete waste slurry treated with the super retarder (RWA) for waste slurry water prepared by the technical solution of the present invention has good strength and small slump loss; further, compared with the comparative examples in Table 2, the content of OH - ions decreases, and the content of SO4 2- ions decreases. It can be seen that the RWA provided by the present invention helps to purify the harmful ions in the concrete waste slurry.

[0129] Compared with other embodiments, the concrete compressive strength and durability of Embodiment 7 are better. The reason may be that: the added raw material 2-phosphono-1,2,4-tricarboxylic acid butane in the RWA of Embodiment 7 can improve the hydration process of cement, improve the compressive strength and durability; and it also regulates the hydration rate of cement to form a denser structure during the setting and hardening process of cement.

[0130] Example 8 has less slump loss compared with other examples. The reason is that the molecular structure of the polyamino polyether methylene phosphonic acid, which is the increased raw material in Example 8, has a chelating effect, and it has a high calcium tolerance, scale inhibition and dispersion performance, and the ability to stabilize metal oxides.

[0131] As shown in the Figures 1 - 3 attached figures, in which, part a in each figure represents the waste slurry water described in Comparative Example 1, and part b in each figure represents the waste slurry water treated with the RWA described in Example 8 of the present invention. Figure 1 It can be seen that for the untreated waste slurry water of Comparative Example 1, its residual hydration products are mainly calcium hydroxide (CH), calcium carbonate (CaCO3), tricalcium silicate (C3S) and ettringite (AFt); for the waste slurry water treated with the RWA described in Example 8 of the present invention, the types of hydration products have not changed, and the content of hydration products in the waste slurry water treated with the RWA described in the present invention at 5 min is equivalent to that in the waste slurry water of Comparative Example 1. By Figure 2 knowing, the untreated waste slurry water has an obvious CH peak intensity after 6 h, and the CH peak of the waste slurry water treated with the RWA described in Example 8 of the present invention is extremely weak after 6 h. It can be seen that the RWA described in the present invention can significantly prolong the setting time of the waste slurry water. The reason may be that after adding the RWA, it reacts with Ca(OH)2 on the surface of the formed clinker phase to form "insoluble" calcium phosphate, thus hindering the normal hydration and delaying the setting time of the waste slurry water. By Figure 3 knowing, the CH peak of the untreated waste slurry water is further significantly enhanced after 12 h, and the CH peak of the waste slurry water treated with the RWA described in Example 8 is stronger than the Figure 2 CH peak therein after 12 h. This shows that the RWA described in the present invention has an inhibitory effect on the cement hydration in the waste slurry water within 12 h after being added to the waste slurry water, and the waste slurry water doped with the RWA can further hydrate after 12 h, which is beneficial to delaying the setting of the waste slurry water; in addition, the C3S of the waste slurry water treated with the RWA described in Example 8 of the present invention is significantly increased, which is beneficial to improving the strength of the concrete.

[0132] In Comparative Examples 2-4, since the raw material components of the prepared RWA are not within the scope required by the present invention, when it is used for waste slurry water treatment and further for the preparation of concrete, the performance of the prepared concrete fails to meet the design purpose of the present invention or the project is blocked.

[0133] The technical features in the claims and / or the description of the present invention can be combined, and the combination method is not limited to the combination obtained through the citation relationship in the claims. The technical solutions obtained by combining the technical features in the claims and / or the description are also within the protection scope of the present invention.

[0134] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A super retarder, characterized in that, In terms of mass percentage, its raw materials include: 25 - 40% phosphonoacrylic acid copolymer, 15 - 25% phosphonocarboxylic acid copolymer, 10 - 20% sodium gluconate, 5 - 10% sediment dispersant, 5 - 10% acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, and 5 - 10% polyphosphoric acid amide.

2. The super retarder according to claim 1, characterized in that, In the super retarder, the mass ratio of the sediment dispersant to the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is 1:0.8 - 1.

5.

3. The super retarder according to claim 1, wherein Its raw materials also include: 5 - 15% sodium salt containing a phosphate group.

4. The super retarder according to claim 3, wherein The sodium salt of the phosphate group is selected from at least one of sodium ethylene diamine tetra(methylene phosphonate), tetrasodium ethylenediaminetetraacetate, and tetrasodium hydroxyethylidene diphosphonate.

5. The super retarder according to claim 3, characterized in that, Its raw materials also include: 5 - 10% 2-phosphono-1,2,4-tricarboxylic acid butane.

6. The super retarder according to claim 5, characterized in that, Its raw materials also include: 5 - 10% polyamino polyether methylene phosphonic acid.

7. The super retarder according to claim 1, characterized in that, The content of the phosphonoacrylic acid copolymer is 25 - 30%, and the content of the phosphonocarboxylic acid copolymer is 20 - 25%.

8. The super retarder according to any one of claims 1 to 7, characterized in that, The polymerization degree of the phosphonoacrylic acid copolymer is ≥2, the polymerization degree of the phosphonocarboxylic acid copolymer is 10 - 1000, and the polymerization degree of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is 50 - 500.

9. A preparation method of a super retarder, characterized in that, It includes the following steps: S1 Mix the phosphonoacrylic acid copolymer, phosphonocarboxylic acid copolymer, and sodium gluconate, add water to dissolve, and stir evenly under the condition of 30 - 45°C to form a mixed solution A; S2 Add the sediment dispersant, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, and polyphosphoric acid amide to the mixed solution A, and continue to stir evenly under the condition of S1 to form a mixed solution B; S3 Cool the mixed solution B to room temperature, filter to remove impurities, and thus obtain the super retarder; In terms of mass percentage, the raw materials of the super retarder include: 25 - 40% phosphonoacrylic acid copolymer, 15 - 25% phosphonocarboxylic acid copolymer, 10 - 20% sodium gluconate, 5 - 10% sediment dispersant, 5 - 10% acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, and 5 - 10% polyphosphoric acid amide.

10. Use of a super-retarding agent according to any one of claims 1 to 8 in concrete waste water, characterized in that, The addition amount of the super retarder is 1.0 - 2.0% of the total mass of the concrete waste slurry water; the mass percentage of the total solids in the concrete waste slurry water ≤10%.

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