Retarder for hydraulic concrete and preparation method thereof

Abstract

The invention provides a retarder for hydraulic concrete and a preparation method thereof, and belongs to the technical field of water conservancy and hydropower engineering. The invention discloses a concrete retarder which is prepared from the following raw materials in parts by mass: 10-15 parts of chitosan, 8-12 parts of cane sugar, 1-3 parts of citric acid, 10-15 parts of ethyoxyl diglycol ether, 4-8 parts of ammonium bicarbonate, 1-3 parts of sodium gluconate and 20-40 parts of mixed water, and the used concrete has the advantages of proper setting speed, long retarding time, low hydration heat, excellent later strength and durability, good workability, good water retention property, good water retention property and the like. The device adapts to different climates and construction requirements, facilitates site construction, is good in comprehensive performance and high in practicability, and has certain popularization value.

Description

Technical Field

[0001] The invention relates to the technical field of water conservancy and hydropower engineering, and in particular to a retarder for hydraulic concrete and a preparation method thereof. Background Art

[0002] Concrete retarder is a chemical substance added to concrete paste or concrete mixture, and its main function is to delay the setting and hardening process of concrete. Usually, concrete needs a certain amount of time for pouring, vibrating, shaping and other processes during construction. During these processes, if the concrete sets or hardens too early, it may affect the quality of the project and the normal progress of construction. Concrete retarder affects the hydration reaction of cement in concrete and delays the chemical bonding between cement particles, thereby extending the initial setting time and final setting time of concrete. The use of concrete retarder can adjust the setting speed of concrete to adapt to different climates and construction requirements. However, the existing ordinary retarders cannot adjust the setting speed of concrete well, which is not conducive to on-site construction and may even affect the later strength of concrete. Summary of the invention

[0003] The purpose of the present invention is to provide a retarder for hydraulic concrete and a preparation method thereof, which can well adjust the setting speed of concrete, make the hydraulic concrete have longer controllability during construction, and make it easier to carry out various construction operations, which has great practical significance for concrete construction.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] On the one hand, a retarder for hydraulic concrete is made of the following raw materials in parts by weight: 10 to 15 parts of chitosan, 8 to 12 parts of sucrose, 1 to 3 parts of citric acid, 10 to 15 parts of ethoxydiethylene glycol ether, 4 to 8 parts of ammonium bicarbonate, 1 to 3 parts of sodium gluconate, and 20 to 40 parts of mixing water.

[0006] In a second aspect, the present invention provides a method for preparing a retarder for hydraulic concrete, comprising the following steps:

[0007] Step S1: selecting retarder raw materials: chitosan, sucrose, citric acid, ethoxydiethylene glycol ether, ammonium bicarbonate, sodium gluconate, and mixing water;

[0008] Step S2: After selecting the retarder raw materials, weigh them according to the following mass parts: 10 to 15 parts of chitosan, 8 to 12 parts of sucrose, 1 to 3 parts of citric acid, 10 to 15 parts of ethoxydiethylene glycol ether, 4 to 8 parts of ammonium bicarbonate, 1 to 3 parts of sodium gluconate, and 20 to 40 parts of mixing water;

[0009] S3: Add 20-40 parts of mixed water into the reactor and heat to 30°C;

[0010] S4: adding 10 to 15 parts of chitosan into a reaction kettle and stirring;

[0011] S5: adding 8 to 12 parts of sucrose into a reaction kettle and stirring;

[0012] S6: Add 1 to 3 parts of citric acid into the reaction kettle and stir;

[0013] S7: heating the solution to 70° C. and adding 10 to 15 parts of ethoxydiethylene glycol ether into a reaction kettle and stirring;

[0014] S8: Add 4 to 8 parts of ammonium bicarbonate into the reaction kettle and stir;

[0015] S9: Add 1 to 3 parts of sodium gluconate into a reaction kettle and stir;

[0016] S10: After the stirring is completed, cooling treatment is performed to obtain the finished product;

[0017] Preferably, in S4, the stirring time is 10 minutes.

[0018] Preferably, in S5, the stirring time is 5 minutes.

[0019] Preferably, in S6, the stirring time is 2 minutes.

[0020] Preferably, in S7, the stirring time is 20 minutes.

[0021] Preferably, in S8, the stirring time is 40 minutes.

[0022] Preferably, in S9, the stirring time is 10 minutes.

[0023] Beneficial effects of the present invention:

[0024] (1) By adding chitosan, tricalcium silicate that has not yet been hydrated is destroyed and forms hydrated calcium silicate crystals, thereby preventing the formation of crystals and prolonging the setting time of concrete. Chitosan has a retarding effect on cement slurry, which can reduce the fluidity of cement slurry and reduce surface cracks.

[0025] (2) By adding sucrose, it is adsorbed onto the surface of cement particles, making it difficult for the particles to expand and interweave, delaying the cement setting time, enhancing the concrete's impermeability and reducing the concrete's fluidity.

[0026] (3) By adding sodium gluconate, citric acid, and ammonium bicarbonate, the workability of concrete is improved while the later strength of concrete is increased, tiny pores are filled, the permeability and cracking risk are reduced, and the corrosion and aging of concrete are reduced.

[0027] (4) The present invention has a significant retarding effect, an initial setting time of ≥24 hours, and has high efficiency and stability. It not only improves the comprehensive performance of the retarder, but also has very important economic and social benefits.

[0028] Additional advantages of the present invention will be more clearly given in the following description or learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0030] Figure 1 The present invention is a flowchart of a retarder for hydraulic concrete and a preparation method thereof according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below by the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0032] It should be understood by those skilled in the art that unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which this invention belongs.

[0033] It should also be understood that terms, such as those defined in commonly used dictionaries, should be understood to have a meaning consistent with that in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless as defined herein.

[0034] Those skilled in the art will appreciate that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements and / or groups thereof.

[0035] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0036] To facilitate understanding of the present invention, the present invention is further explained below with reference to specific embodiments in conjunction with the accompanying drawings, and the specific embodiments do not constitute a limitation on the embodiments of the present invention.

[0037] Those skilled in the art should understand that the drawings are merely schematic diagrams of embodiments, and the components in the drawings are not necessarily necessary for implementing the present invention.

[0038] The embodiment of the present invention provides a retarder for hydraulic concrete and a preparation method thereof, which is made of the following raw materials in parts by mass: 10 to 15 parts of chitosan, 8 to 12 parts of sucrose, 1 to 3 parts of citric acid, 10 to 15 parts of ethoxydiethylene glycol ether, 4 to 8 parts of ammonium bicarbonate, 1 to 3 parts of sodium gluconate, and 20 to 40 parts of mixing water.

[0039] The following is the experimental test part of the present invention:

[0040] Inspection and testing basis: "Classification, Nomenclature and Definition of Concrete Admixtures" GB / T 8075-2005, "Test Method for Stability of Standard Water Content and Setting Time of Cement" GB / T 1346-2011, "Test Method for Strength of Cement Mortar (ISO Method)" GB / T 17671-2021, "Test Method for Homogeneity of Concrete Admixtures" GB / T 8077-2012, and "Retarder for Concrete Admixtures for Construction" GB8076-2008.

[0041] Main inspection and testing equipment and numbers: LT5001 electronic balance (GL01040001-3), NJ-160A cement slurry mixer (GL01040009), Vicat instrument (GL01040008-1), JJ-5 cement mortar mixer (GL01040013), ZS-15 cement mortar vibrating table (GL01040014), CDT1305-2 microcomputer-controlled electronic pressure testing machine (GL01040015), JS-306 stopwatch (GL01040007), etc.

[0042] The inspection and testing report is shown in Table 1.

[0043] Table 1. Inspection and testing report

[0044]

[0045] After testing, the sample's indicators meet the relevant technical requirements.

[0046] Embodiment 1: clean the reactor, select raw materials after cleaning, and after selecting the retarder raw materials, weigh the following raw materials in parts by mass: 10 parts of chitosan, 8 parts of sucrose, 1 part of citric acid, 10 parts of ethoxydiethylene glycol ether, 4 parts of ammonium bicarbonate, 1 part of sodium gluconate, and 20 parts of mixing water; add 20 parts of mixing water into the reactor and heat it to 30°C, then add 10 parts of chitosan into the reactor and stir for 10 minutes, then add 8 parts of sucrose into the reactor and stir for 5 minutes, then add 1 part of citric acid into the reactor and stir for 2 minutes. After the stirring is completed, the solution is heated to 70°C and 10 parts of ethoxydiethylene glycol ether are added to the reactor and stirred for 20 minutes, then 4 parts of ammonium bicarbonate are added to the reactor and stirred for 40 minutes, then 1 part of sodium gluconate is added to the reactor and stirred for 10 minutes. After the stirring is completed, it is cooled to obtain the finished product.

[0047] Embodiment 2: clean the reactor, select raw materials after cleaning, and after selecting the retarder raw materials, weigh the following raw materials in parts by mass: 12 parts of chitosan, 10 parts of sucrose, 2 parts of citric acid, 12 parts of ethoxydiethylene glycol ether, 6 parts of ammonium bicarbonate, 2 parts of sodium gluconate, and 30 parts of mixing water; add 30 parts of mixing water into the reactor and heat it to 30°C, then add 12 parts of chitosan into the reactor and stir for 10 minutes, then add 10 parts of sucrose into the reactor and stir for 5 minutes, then add 2 parts of citric acid into the reactor and stir for 2 minutes. After the stirring is completed, the solution is heated to 70°C and 12 parts of ethoxydiethylene glycol ether are added to the reactor and stirred for 20 minutes, then 6 parts of ammonium bicarbonate are added to the reactor and stirred for 40 minutes, then 2 parts of sodium gluconate are added to the reactor and stirred for 10 minutes. After the stirring is completed, cool the solution to obtain the finished product.

[0048] Embodiment 3: clean the reactor, select raw materials after cleaning, and after selecting the retarder raw materials, weigh the following raw materials in parts by mass: 15 parts of chitosan, 12 parts of sucrose, 3 parts of citric acid, 15 parts of ethoxydiethylene glycol ether, 8 parts of ammonium bicarbonate, 3 parts of sodium gluconate, and 40 parts of mixing water; add 40 parts of mixing water into the reactor and heat it to 30°C, then add 15 parts of chitosan into the reactor and stir for 10 minutes, then add 12 parts of sucrose into the reactor and stir for 5 minutes, then add 3 parts of citric acid into the reactor and stir for 2 minutes. After the stirring is completed, heat the solution to 70°C and add 15 parts of ethoxydiethylene glycol ether into the reactor and stir for 20 minutes, then add 8 parts of ammonium bicarbonate into the reactor and stir for 40 minutes, then add 3 parts of sodium gluconate into the reactor and stir for 10 minutes. After the stirring is completed, cool the solution to obtain the finished product.

[0049] Embodiment 4: clean the reactor, select raw materials after cleaning, and after selecting the retarder raw materials, weigh the following raw materials in parts by mass: 10 parts of chitosan, 9 parts of sucrose, 2 parts of citric acid, 13 parts of ethoxydiethylene glycol ether, 8 parts of ammonium bicarbonate, 3 parts of sodium gluconate, and 25 parts of mixing water; add 25 parts of mixing water into the reactor and heat it to 30°C, then add 10 parts of chitosan into the reactor and stir for 10 minutes, then add 9 parts of sucrose into the reactor and stir for 5 minutes, then add 2 parts of citric acid into the reactor and stir for 2 minutes. After the stirring is completed, the solution is heated to 70°C and 13 parts of ethoxydiethylene glycol ether is added to the reactor and stirred for 20 minutes, then 8 parts of ammonium bicarbonate is added to the reactor and stirred for 40 minutes, then 3 parts of sodium gluconate is added to the reactor and stirred for 10 minutes. After the stirring is completed, it is cooled to obtain the finished product.

[0050] The effect of the retarder in the embodiment of the present invention is characterized by cement setting time and mechanical properties. The test method of the material setting time and compressive strength complies with the national standard "Concrete Admixture Homogeneity Test Method" GB / T8077-2012 and "Concrete Admixture Retarder for Construction" GB8076-2008. The specific test results are shown in Table 2 and Table 3.

[0051] Table 2. Mechanical properties comparison test

[0052] 8h compressive strength / Mpa 24h compressive strength / Mpa 28d compressive strength Mpa Example 1 3.1 18.0 33.3 Example 2 3.3 20.6 34.9 Example 3 2.8 17.4 29.6 Example 4 2.7 18.2 30.8

[0053] Table 3. Coagulation time comparison test

[0054] Initial setting time / h Final setting time / h Example 1 50 58 Example 2 66 70 Example 3 58 62 Example 4 53 60

[0055] Through experiments and comparisons of the retarders formed by the proportions of Examples 1, 2, 3, and 4, it is found that the retarder of Example 2 has the best comprehensive performance. After use, it effectively alleviates the coagulation of concrete, and enables the concrete to have appropriate rapid setting time, excellent late strength and durability.

[0056] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative labor on the basis of the technical solution disclosed in the present invention should be included in the scope of protection of the present invention.

Claims

1. A retarder for hydraulic concrete, characterized in that: The invention is prepared from the following raw materials in parts by weight: 10 to 15 parts of chitosan, 8 to 12 parts of sucrose, 1 to 3 parts of citric acid, 10 to 15 parts of ethoxydiethylene glycol ether, 4 to 8 parts of ammonium bicarbonate, 1 to 3 parts of sodium gluconate and 20 to 40 parts of mixing water.

2. A method for preparing a retarder for hydraulic concrete, characterized in that: The following steps are involved: Step S1: selecting retarder raw materials: chitosan, sucrose, citric acid, ethoxydiethylene glycol ether, ammonium bicarbonate, sodium gluconate, and mixing water; Step S2: After selecting the retarder raw materials, weigh them according to the following mass parts: 10 to 15 parts of chitosan, 8 to 12 parts of sucrose, 1 to 3 parts of citric acid, 10 to 15 parts of ethoxydiethylene glycol ether, 4 to 8 parts of ammonium bicarbonate, 1 to 3 parts of sodium gluconate, and 20 to 40 parts of mixing water; Step S3: Add 20 to 40 parts of mixed water into the reactor and heat to 30° C.; Step S4: adding 10 to 15 parts of chitosan into a reaction kettle and stirring; Step S5: adding 8 to 12 parts of sucrose into a reaction kettle and stirring; Step S6: adding 1 to 3 parts of citric acid into a reaction kettle and stirring; Step S7: heating the solution to 70° C. and adding 10 to 15 parts of ethoxydiethylene glycol ether into a reaction kettle and stirring; Step S8: adding 4 to 8 parts of ammonium bicarbonate into a reaction kettle and stirring; Step S9: adding 1 to 3 parts of sodium gluconate into a reaction kettle and stirring; Step S10: After the stirring is completed, cooling treatment is performed to obtain a finished product.

3. The method for preparing a retarder for hydraulic concrete according to claim 2, characterized in that: In step S4, the stirring time is 10 minutes.

4. The method for preparing a retarder for hydraulic concrete according to claim 2, characterized in that: In step S5, the stirring time is 5 minutes.

5. The method for preparing a retarder for hydraulic concrete according to claim 2, characterized in that: In step S6, the stirring time is 2 minutes.

6. The method for preparing a retarder for hydraulic concrete according to claim 2, characterized in that: In step S7, the stirring time is 20 minutes.

7. The method for preparing a retarder for hydraulic concrete according to claim 2, characterized in that: In step S8, the stirring time is 40 minutes.

8. The method for preparing a retarder for hydraulic concrete according to claim 2, characterized in that: In step S9, the stirring time is 10 minutes.

Images