A deflocculant for concrete washed sand and its preparation method

Abstract

The invention discloses a kind of concrete water-washed sand deflocculant and preparation method thereof, the deflocculant includes 0.5 1 parts of air entraining agent, 0.1 0.2 parts of sodium lauryl sulfoacetate, 15 30 parts of sodium metabisulfite, 20 32 parts of sodium thiosulfate, 0.5 1 parts of triethanolamine, 35 49 parts of dimethicone, 2 5 parts of maltodextrin, 0.4 1 parts of cellulose, 0.5 1 parts of glyceryl monostearate.The deflocculant of the present invention can play the role of suspension stability, prevent the undesirable phenomenon that the system is unstable and fluidity is reduced due to particle aggregation, can effectively solve the concrete viscosity brought by flocculant, slump retention performance is insufficient, easy to separate the bad problems such as bleeding, and effectively reduce concrete viscosity, ensure construction performance and the quality of concrete after hardening.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and in particular to a deflocculant and a preparation method thereof for solving the problem of residual flocculant in washed sand. Background Art

[0002] The mud, mica, light materials, chloride ions, salts, etc. in sand will have an adverse effect on the quality of concrete, greatly weakening the durability of concrete, thereby endangering the life of concrete buildings. In particular, chloride ions and inorganic salts will cause steel bars to rust, greatly endangering the life of buildings. Therefore, concrete sand generally adopts a water washing process in the production process to wash away harmful components in the sand and purify it to meet relevant standards. Due to the limitation of water resources and cost control, coupled with low water washing efficiency, flocculants are widely used in sand production, which not only improves water washing efficiency, but also reduces environmental pressure. The main function of flocculants is to promote the sedimentation and aggregation of suspended matter such as light materials, mud, mica, etc. in the sand during the water washing process, so as to facilitate their separation, thereby achieving the effect of purifying the sand.

[0003] In the existing concrete water-washed sand process, it has become normal for flocculants to remain in the concrete sand. Although flocculants can bring positive significance to the quality of concrete sand, the residual flocculants in the concrete sand have a significant adverse effect on the construction performance of concrete. For example: first, the viscosity of the freshly mixed concrete increases, which increases the difficulty of pumping the mixture and brings certain risks of pipe blockage; second, under the action of the flocculant, the cement in the concrete mixture is very easy to separate from the aggregate and sink, affecting the collapse resistance and uniformity of the concrete; third, a large amount of flocculant residue will cause the mixture to segregate or even bleed, which is not conducive to the construction of concrete and even the quality after hardening; even after being pumped into the mold, the uniformity of the concrete deteriorates, the cement slurry sinks, the aggregate is exposed, and the surface even bleeds, affecting the appearance quality. Flocculant residues bring many disadvantages in terms of concrete setting time, early strength, slump resistance, and production uniformity control. Especially in Guangdong, more than 80% of the concrete is made of granite, which is more sensitive to slump resistance. Small amounts of flocculant residues will increase the viscosity of the concrete and reduce the fluidity of the concrete; large amounts of residues will cause the concrete to segregate or even bleed, causing great obstacles to concrete construction and ultimately posing a major hidden danger to the performance of the concrete after hardening. Summary of the Invention

[0004] In order to address the shortcomings and deficiencies in the above-mentioned prior art, the object of the present invention is to provide a deflocculant and a preparation method thereof that solves the problem of concrete bleeding, can effectively improve the control level of the workability of fresh concrete, reduce the occurrence of undesirable phenomena such as insufficient workability and return of materials, and improve the efficiency of concrete construction.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] In one aspect, the present invention provides a deflocculant for concrete washed sand, the deflocculant comprising the following components in parts by weight:

[0007]

[0008] Furthermore, the deflocculant comprises the following components in parts by weight:

[0009]

[0010] Furthermore, the air entraining agent includes any one of polyether phosphate, sodium dodecyl sulfate, and sodium dodecylbenzene sulfonate.

[0011] Furthermore, the water-retaining agent includes any one of maltodextrin, hydroxypropyl methylcellulose, and starch ether.

[0012] On the other hand, the present invention also provides a method for preparing a deflocculant for concrete washed sand, the preparation method comprising the following steps:

[0013] Step 1) Weigh the following components by weight: 0.5-1 part of air entraining agent, 0.1-0.2 part of sodium lauryl sulfoacetate, 15-30 parts of sodium metabisulfite, 20-30 parts of sodium thiosulfate, 0.5-1 part of triethanolamine, 35-49 parts of diutan gum, 2-5 parts of maltodextrin, 0.4-1 part of cellulose, and 0.5-1 part of glyceryl monostearate;

[0014] Step 2) placing the sodium lauryl sulfoacetate, sodium metabisulfite, sodium thiosulfate, triethanolamine, diutan gum, maltodextrin, cellulose, and glyceryl monostearate weighed in step 1) into a blender and mixing to obtain a mixture;

[0015] Step 3) The mixture is stirred uniformly by a stirring rod inside the stirrer, and an air entraining agent is added during the stirring process. The stirring is continued at a stirring speed of 90-120 r / min until uniform, and the stirring time is 150-360 minutes to obtain a deflocculant.

[0016] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0017] 1) The deflocculant of the present invention comprises 0.5-1 parts of an air entraining agent, 0.1-0.2 parts of sodium lauryl sulfoacetate, 15-30 parts of sodium metabisulfite, 20-32 parts of sodium thiosulfate, 0.5-1 parts of triethanolamine, 35-49 parts of diutan gum, 2-5 parts of maltodextrin, 0.4-1 parts of cellulose, and 0.5-1 parts of glyceryl monostearate. The deflocculant of the present invention can play a role in suspension stability, prevent the undesirable phenomena of system instability and reduced fluidity caused by particle aggregation, and can effectively solve the undesirable problems of high concrete viscosity, insufficient slump retention performance, easy segregation and exudation caused by flocculants, and effectively reduce the viscosity of concrete, ensuring the construction performance and the quality of the hardened concrete.

[0018] 2) The preparation method of the present invention can fully exert the efficacy of each component by subjecting the components to reasonable mixing, stirring and other reactions, so that the deflocculant obtained after preparation of the present invention can reduce the MB value, mud content, chloride ion, salt, mica, soluble matter and other indicators in the sand, thereby solving the technical problem that residual flocculant in concrete sand has an adverse effect on the construction performance of concrete. DETAILED DESCRIPTION

[0019] To better illustrate the objectives, technical solutions, and advantages of the present invention, the present invention is further described by the following examples. Obviously, the following examples are only a portion of the embodiments of the present invention, rather than all of them; it should be understood that the embodiments of the present invention are only used to illustrate the technical effects of the present invention, and are not intended to limit the scope of protection of the present invention.

[0020] On the one hand, the present invention provides a deflocculant for concrete washed sand, the deflocculant comprising the following components by weight: 0.5-1 part of air entraining agent, 0.1-0.2 part of sodium lauryl sulfoacetate, 15-30 parts of sodium metabisulfite, 20-30 parts of sodium thiosulfate, 0.5-1 part of triethanolamine, 35-49 parts of diutan gum, 2-5 parts of maltodextrin, 0.4-1 part of cellulose, and 0.5-1 part of glyceryl monostearate. The deflocculant provided by the present invention can well exert the anti-flocculation effect, improve the dispersibility of the various components of concrete, improve the uniformity of the mixture, reduce the viscosity of concrete, improve the workability of concrete, and ensure the quality of concrete.

[0021] The air-entraining agent added in the present invention can entrain air, increase concrete fluidity, and reduce the high viscosity of concrete caused by water bleeding. When used in conjunction with hydroxypropyl methylcellulose ether, it improves the fluidity of concrete while ensuring that the air content meets the requirements and does not damage the strength, allowing the mixture to resume normal construction.

[0022] In a specific implementation, the deflocculant of the present invention includes the following components in parts by weight: 0.8 parts of air entraining agent, 0.2 parts of sodium lauryl sulfoacetate, 25 parts of sodium metabisulfite, 25 parts of sodium thiosulfate, 1 part of triethanolamine, 43 parts of diutan gum, 4 parts of maltodextrin, 1 part of cellulose, and 1 part of glyceryl monostearate. The sodium lauryl sulfoacetate in the deflocculant of the present invention is an effective foam stabilizer, which improves the stability and persistence of bubbles in the mud system and reduces the viscosity, dispersibility and 2-hour slump retention performance of the cement slurry; the added sodium metabisulfite improves the early strength of the concrete and alleviates the delayed effect of the flocculant on the setting time and early strength of the cement slurry; the added sodium thiosulfate helps solubilize diutan gum maltodextrin and improves the encapsulation of the concrete; the added triethanolamine improves the early strength and delays the adverse effects of the flocculant on the setting time of the concrete, insufficient slump retention of the mixture and the like; the diutan gum has the effects of dispersion, emulsification and suspension; the cellulose has the functions of defoaming, thickening and improving the encapsulation of the concrete; and the glyceryl monostearate has the effects of lubrication and emulsification, thereby improving the workability and pumpability of the concrete.

[0023] In a specific implementation, the air-entraining agent of the present invention includes any one of polyether phosphate, sodium lauryl sulfate, and sodium dodecylbenzene sulfonate; the water-retaining agent includes any one of maltodextrin, hydroxypropyl methylcellulose, hydroxyethyl cellulose, and starch ether; the sodium lauryl sulfate added in the present invention can reduce the viscosity and dispersion of the cement slurry, and improve the slump and expansion of the concrete; the added maltodextrin can further improve the anti-precipitation, consistency, and water-retaining effects of the cement slurry.

[0024] Regarding the usage principle of the deflocculant of the present invention: the deflocculant of the present invention has strong functionality, but the addition amount is small, and it needs to be mixed into the concrete water reducer for use. The addition amount of different types of concrete water reducers is 3-15kg per cubic meter of concrete; the addition amount of the deflocculant of the present invention is 2%-12% of the amount of concrete water reducer, and is adjusted according to the residual degree of flocculant. It is added to the concrete water reducer and mixed thoroughly, and it is uniformly dissolved without precipitation.

[0025] Compared with the current technology of merely increasing the amount of water reducing agent and water consumption, the deflocculant provided by the present invention can not only alleviate the adverse effects of the flocculant on the setting time without affecting the early and late strengths of concrete, but also improve the encapsulation of concrete, reduce the emptying time of the inverted slump cone of concrete mixtures leaving the factory, increase the slump, expansion, 1-hour slump retention performance of concrete, etc., and the deflocculant can be added in a relatively small amount, has obvious effects, is simple to operate, and has good practicality.

[0026] On the other hand, the present invention also provides a method for preparing a deflocculant for concrete washed sand, the preparation method comprising the following steps:

[0027] Step 1) Weigh the following components by weight: 0.5-1 part of air entraining agent, 0.1-0.2 part of sodium lauryl sulfoacetate, 15-30 parts of sodium metabisulfite, 20-30 parts of sodium thiosulfate, 0.5-1 part of triethanolamine, 35-49 parts of diutan gum, 2-5 parts of maltodextrin, 0.4-1 part of cellulose, and 0.5-1 part of glyceryl monostearate;

[0028] Step 2) placing the sodium lauryl sulfoacetate, sodium metabisulfite, sodium thiosulfate, triethanolamine, diutan gum, maltodextrin, cellulose, and glyceryl monostearate weighed in step 1) into a blender and mixing to obtain a mixture;

[0029] Step 3) The mixture is stirred uniformly by a stirring rod inside the stirrer, and an air entraining agent is added during the stirring process. The stirring is continued at a stirring speed of 90-120 r / min until uniform, and the stirring time is 150-360 minutes to obtain a deflocculant.

[0030] On the other hand, the present invention also provides a method for preparing a deflocculant for concrete washed sand, the preparation method comprising the following steps:

[0031] 1. The present invention is further described below with reference to three specific embodiments provided by the present invention:

[0032] In a specific embodiment of the present invention, the deflocculant of the present invention can be prepared using the following components (unit: parts by weight), as shown in the following Table 1:

[0033] Sodium lauryl sulfate, sodium lauryl sulfoacetate, sodium metabisulfite, sodium thiosulfate, triethanolamine, diutan gum, maltodextrin, cellulose, glyceryl monostearate.

[0034] Raw material components Example 1 Example 2 Sodium lauryl sulfate 0.8 servings 1 serving Sodium lauryl sulfoacetate 0.2 servings 0.2 servings Sodium metabisulfite 25 servings 25 servings Sodium thiosulfate 30 servings 30 servings triethanolamine 1 serving 0.5 serving Diuta 37 servings 39.5 servings maltodextrin 4 servings 2 servings cellulose 1 serving 1 serving Glyceryl Monostearate 1 serving 0.5 serving

[0035] Table 1

[0036] According to the weight of each component provided in Example 1 to Example 2 in Table 1 above, a deflocculant was prepared according to the following steps. The preparation method specifically includes the following steps:

[0037] Step 1) weighing the raw materials of each component of the deflocculant according to the ratios described in Examples 1 and 2;

[0038] Step 2) placing the sodium lauryl sulfoacetate, sodium metabisulfite, sodium thiosulfate, triethanolamine, diutan gum, maltodextrin, cellulose, and glyceryl monostearate weighed in step 1) into a blender and mixing to obtain a mixture;

[0039] Step 3) The mixture is stirred uniformly by a stirring rod inside the stirrer, and an air entraining agent is added during the stirring process. The stirring is continued at a stirring speed of 90-120 r / min until uniform, and the stirring time is 150-360 minutes to obtain a deflocculant.

[0040] 2. The deflocculants prepared in the above examples were used in concrete mixtures containing residual flocculants, and the properties of the concrete were tested. The test results are as follows:

[0041] (Test 1) Test on the produced pumped C30 concrete mixture

[0042] 1. Take the produced pumped C30 concrete mixture. The formulation of C30 concrete mixture is shown in Table 1-1 below:

[0043] cement fly ash water sand gravel admixtures 270 80 168 855 1040 6.0

[0044] Table 1-1

[0045] 2. The concrete mixture is tested before leaving the factory. The performance is shown in Table 1-2 below:

[0046] Table 1-2

[0047] 3. After testing, the residual flocculant in the sand of the C30 concrete mixture was about 10g / ton of sand. The flocculant type was polyacrylamide. The viscosity of the concrete was relatively high, and undesirable conditions such as concrete cement slurry sinking and exposed stones occurred. The deflocculant prepared in Example 1 was added to the concrete water reducer. The concrete water reducer containing the deflocculant prepared in Example 1 of the present invention was dissolved in the C30 concrete mixture, stirred evenly, and used. The amount of the deflocculant was 8% of the amount of the concrete water reducer.

[0048] 4. The performance of the C30 concrete mixture after dissolving the deflocculant was tested. The test results are shown in Table 1-3 below:

[0049]

[0050] Table 1-3

[0051] 5. Test conclusion: Combining Tables 1-2 and 1-3, it can be seen that after adding the deflocculant configured in Example 1 of the present invention, the viscosity of the concrete mixture is reduced, especially in terms of flow rate, which is significantly improved, and the setting time and strength properties are partially improved.

[0052] (Test 2) Test on the produced pumped C50 concrete mixture

[0053] 1. Take the produced pumped C50 concrete mixture. The formula of C50 concrete mixture is shown in Table 2-1 below:

[0054] cement fly ash water sand gravel admixtures 360 80 162 760 1060 7.8

[0055] Table 2-1

[0056] 2. The concrete mixture is tested before leaving the factory. The performance is shown in Table 2-2 below:

[0057]

[0058] Table 2-2

[0059] 3. Testing of the C50 concrete mix revealed a flocculant residue of approximately 7g / ton of sand, using alum as the flocculant. Factory inspection revealed a slow concrete flow rate, with a collapse time of 15.9 seconds, making it difficult to pump concrete. Pumping at higher speeds would result in high pump pressure and loss due to high viscosity, making pipe blockage highly likely. The deflocculant prepared in Example 2 was added to the concrete water reducer. A concrete water reducer containing the deflocculant prepared in Example 2 was added to the C50 concrete mix, stirred evenly, and then used. The amount of deflocculant used in Example 2 was 12% of the amount of the concrete water reducer.

[0060] 4. The performance of the C50 concrete mixture after dissolving the deflocculant was tested. The test results are shown in Table 2-3 below:

[0061]

[0062] Table 2-3

[0063] 6. Test conclusion: Combining Table 2-2 and Table 2-3, it can be seen that after adding the deflocculant configured in Example 2 of the present invention to the C50 concrete mixture, the viscosity of the concrete is reduced, the workability and pumpability are significantly improved, and the delay in setting time is alleviated.

[0064] Based on the above embodiments and test results, it can be seen that the use of the deflocculants of Examples 1 and 2 of the present invention can reduce the viscosity reduction of concrete, can well exert the anti-flocculation effect, improve the dispersibility of the various components of concrete, improve the uniformity of the mixture, improve the workability of concrete, and ensure the quality of concrete.

[0065] The implementation methods of the present invention are not limited to the above-mentioned embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A deflocculant for concrete washed sand, characterized by: The deflocculant comprises the following components in parts by weight: The air entraining agent includes any one of polyether phosphate, sodium lauryl sulfate, and sodium dodecylbenzene sulfonate; the water retaining agent includes any one of maltodextrin, hydroxypropyl methylcellulose, and starch ether.

2. The deflocculant for concrete washed sand according to claim 1, characterized in that: The deflocculant comprises the following components in parts by weight:

3. A method for preparing a deflocculant for concrete washed sand, characterized by: The preparation method comprises the following steps: Step 1) Weigh the following components by weight: 0.5-1 part of air entraining agent, 0.1-0.2 part of sodium lauryl sulfoacetate, 15-30 parts of sodium metabisulfite, 20-30 parts of sodium thiosulfate, 0.5-1 part of triethanolamine, 35-49 parts of diutan gum, 2-5 parts of maltodextrin, 0.4-1 part of cellulose, and 0.5-1 part of glyceryl monostearate; Step 2) placing the sodium lauryl sulfoacetate, sodium metabisulfite, sodium thiosulfate, triethanolamine, diutan gum, maltodextrin, cellulose, and glyceryl monostearate weighed in step 1) into a blender and mixing to obtain a mixture; Step 3) The mixture is stirred uniformly by a stirring rod inside the stirrer, and an air entraining agent is added during the stirring process. The stirring is continued at a stirring speed of 90-120 r / min until uniform, and the stirring time is 150-360 minutes to obtain a deflocculant.

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