A hydration heat inhibitor for concrete, its preparation method and usage method

Abstract

This application relates to the field of concrete additives, and specifically discloses a heat of hydration inhibitor for concrete, its preparation method and usage method. The heat of hydration inhibitor for concrete is prepared from a starch hydrolyzate and an additive. The weight ratio of the starch hydrolyzate to the additive is 100:(1-3). The starch hydrolyzate is prepared from the following raw materials: starch, water, a hydrolase and a purifying agent. The weight ratio of the starch, water and hydrolase is 100:(250-500):(0.02-0.08). The volume ratio of the water to the purifying agent is 4:1. The heat of hydration inhibitor for concrete of this application can be used in concrete projects, and has the advantages of effectively controlling the heat release rate of cement hydration and reducing the influence on the strength and setting time of concrete.

Description

Technical Field

[0001] This application relates to the field of concrete additives. More specifically, it relates to a heat of hydration inhibitor for concrete, its preparation method and usage method. Background Art

[0002] A large amount of heat is released during the hydration process of cement. Coupled with the poor thermal conductivity of concrete itself, a large temperature difference between the inside and outside will be formed during the temperature rise of concrete. During the temperature drop stage, large shrinkage is likely to occur, resulting in concrete cracking. Especially in mass concrete, it is very common for the temperature difference between the inside and outside to reach more than 40°C. To prevent cracking, low-heat cement or pre-buried cooling water pipes are often used in on-site construction to control the cracking problem caused by temperature.

[0003] To solve the problem of temperature cracking in concrete caused by excessive temperature rise, it is necessary to improve the concentrated heat release of cement and regulate the hydration process of cement, so that the heat generated by hydration has enough time to be released to the outside.

[0004] In recent years, researchers at home and abroad have proposed to regulate the hydration of concrete through heat of hydration inhibitor materials to reduce the temperature rise of concrete, so as to reduce or even avoid the risk of temperature shrinkage cracking of concrete. Among them, the most widely used heat of hydration inhibitor is prepared by hydrolyzing starch-based materials.

[0005] Currently, commercially available heat of hydration inhibitors generally cause an excessive prolongation of the setting time of concrete, which has a negative impact on the development of concrete strength. Summary of the Invention

[0006] In order to reduce the adverse effect of the prolongation of the setting time of concrete caused by adding a heat of hydration inhibitor, this application provides a heat of hydration inhibitor for concrete, its preparation method and usage method.

[0007] In the first aspect, this application provides a heat of hydration inhibitor for concrete, adopting the following technical solution:

[0008] A heat of hydration inhibitor for concrete is prepared from a starch hydrolyzate and an additive. The weight ratio of the starch hydrolyzate to the additive is 100:(1 - 3). The starch hydrolyzate is prepared from the following raw materials: starch, water, a hydrolase, and a purification agent. The weight ratio of the starch, water, and hydrolase is 100:(250 - 500):(0.02 - 0.08), and the volume ratio of the water to the purification agent is 4:1.

[0009] By adopting the above technical solution, starch is hydrolyzed to form small molecular chains, effectively reducing the gelatinization temperature. The starch is hydrolyzed by hydrolase so that the molecular chains are not too short, and the small molecular substances are purified by a purifying agent. The hydrolyzed molecular chains act with the additive to further reduce the temperature, thereby reducing the hydration heat of concrete while minimizing the impact on the strength and setting time of concrete.

[0010] Preferably, the starch is corn starch.

[0011] By adopting the above technical solution, corn starch has the widest source, relatively low price and large application amount. Selecting corn starch can control the production cost and ensure the output.

[0012] Preferably, the hydrolase is one of medium-temperature α-amylase or low-temperature α-amylase, preferably medium-temperature α-amylase.

[0013] By adopting the above technical solution, medium-temperature α-amylase is an endoamylase with starch as the substrate and is relatively stable below 60°C, and the optimal action temperature is 60-70°C. Therefore, when using medium-temperature α-amylase to hydrolyze starch, high reaction conditions are not required, effectively reducing the production difficulty.

[0014] Preferably, the purifying agent is ethanol.

[0015] By adopting the above technical solution, ethanol is used as the purifying agent to dissolve the possible small molecules, further purifying the product, and effectively reducing the short molecular chains.

[0016] Preferably, the additive includes alkaline substances such as sodium hydroxide, urea, ammonia water, or salt substances such as magnesium sulfate, sodium sulfate, calcium nitrate.

[0017] By adopting the above technical solution, the addition of the additive effectively changes the gelatinization temperature of the product, thereby improving the hydration heat regulation performance of the product while ensuring that the mechanical properties and workability of the product on concrete are not affected.

[0018] In the second aspect, the present application provides a preparation method of a hydration heat inhibitor for concrete, adopting the following technical solution:

[0019] A preparation method of a hydration heat inhibitor for concrete includes the following steps:

[0020] S1. Adjust the starch into a slurry with a mass concentration of 20% - 40% with water; add hydrolase, with an addition amount of 0.02% - 0.08% of the starch mass, hydrolyze at 30 - 60°C for 2 - 4 h, adjust the pH to 3 to inactivate the enzyme for 30 min, and then adjust the pH to neutral to obtain a hydrolyzed product;

[0021] S2. Add a purification agent to the hydrolysis product in S1. The volume ratio of the added amount of the purification agent to the water consumption in S1 is 1:4. Stir for 30 min, filter out the product, and then dry and grind it at 105 °C to obtain a purified product. The residue on a 1.18-mm sieve of the purified product is ≤0.4%.

[0022] S3. Add an additive with a mass fraction of 1% - 3% to the purified product in S2, mix evenly, and prepare a hydration heat inhibitor.

[0023] By adopting the above technical solution, S1 hydrolyzes starch to a certain extent, but it is not necessary to hydrolyze it into shorter-chain products with very high temperature and long reaction time. Generally speaking, the shorter the molecular chain, the lower the gelatinization temperature, and the better the effect when used in concrete. However, if the molecular chain is too short, it is very likely to affect the setting time and strength of concrete. S2 purifies the small-molecule substances that may exist in the first-step reaction; S3 reduces the products with a slightly higher gelatinization temperature in the first-step reaction by adding an external additive, so that when used in concrete, it can not only not affect the strength and setting time, but also ensure the effect of reducing temperature.

[0024] Preferably, the substance used to adjust the pH to 3 in S1 is one of hydrochloric acid or sulfuric acid.

[0025] By adopting the above technical solution, hydrochloric acid or sulfuric acid is used to inactivate the medium-temperature α-amylase, thereby interrupting the continuous hydrolysis of starch, with quick effect and easily available raw materials.

[0026] Preferably, the substance used to adjust the pH to neutral in S1 is a saturated sodium hydroxide solution.

[0027] By adopting the above technical solution, hydrochloric acid or sulfuric acid is neutralized, so that the prepared product is neutral, reducing the influence of acids and alkalis on the performance of concrete.

[0028] In the third aspect, the present application provides a method for using a hydration heat inhibitor for concrete, adopting the following technical solution:

[0029] Preferably, the hydration heat inhibitor and the gelling material are mixed evenly and then added to the concrete. The dosage is 0.55% of the gelling material.

[0030] By adopting the above technical solution, it can be added along with the gelling material during the concrete mixing process, with simple and convenient operation.

[0031] In summary, the present application has the following beneficial effects:

[0032] 1. Since the temperature for synthesizing the hydration heat inhibitor in this application is generally low, the reaction is mild, the time is short, and the quality of the synthesized product is more stable. Finally, the gelatinization property of the product can be improved by adding additives to the product after the reaction, so as to achieve stable and controllable performance of the hydration heat inhibitor.

[0033] 2. The preparation method of the hydration heat inhibition material provided by this application is simple and easy to implement, facilitating large-scale industrial production.

[0034] 3. The hydration heat inhibitor material prepared by the method of this application can significantly reduce the adiabatic temperature rise of concrete, and has no negative impact on the setting time and strength development of concrete.

[0035] 4. Compared with the traditional method, the method for preparing the hydration heat inhibitor material in this application has a simple preparation process, avoids the large-scale use of acids, and has significant progress in terms of operation simplicity and environmental protection. Detailed implementation mode

[0036] The following further elaborates on this application in conjunction with examples.

[0037] Preparation example

[0038] Preparation example 1

[0039] This preparation example provides a hydration heat inhibitor, which is prepared by the following steps:

[0040] S1. Adjust corn starch with water to form a slurry with a mass concentration of 20%; add medium-temperature α-amylase with a dosage of 0.04% of the starch mass, hydrolyze at 30 °C for 2 h, adjust the pH to 3 to inactivate the enzyme for 30 min, and then adjust the pH to neutral to obtain a hydrolysis product;

[0041] S2. Add ethanol to the hydrolysis product in S1. The volume ratio of the added ethanol to the water consumption in S1 is 1:4, stir for 30 min, filter out the product, and then dry and grind it at 105 °C to obtain a purified product. The residue on a 1.18 mm sieve of the purified product is ≤ 0.4%;

[0042] S3. Add sodium hydroxide with a mass fraction of 1% to the purified product in S2, mix evenly to obtain a hydration heat inhibitor.

[0043] Preparation example 2

[0044] This preparation example provides a hydration heat inhibitor, which is prepared by the following steps:

[0045] S1. Adjust corn starch with water to form a slurry with a mass concentration of 30%; add medium-temperature α-amylase with a dosage of 0.06% of the starch mass, hydrolyze at 30 °C for 2 h, adjust the pH to 3 to inactivate the enzyme for 30 min, and then adjust the pH to neutral to obtain a hydrolysis product;

[0046] S2. Add ethanol to the hydrolysis product in S1. The volume ratio of the added ethanol to the water consumption in S1 is 1:4. Stir for 30 min, filter out the product, and then dry and grind it at 105 °C to obtain a purified product. The residue on a 1.18-mm sieve of the purified product is ≤0.4%;

[0047] S3. Add sodium hydroxide with a mass fraction of 1% to the purified product in S2, mix evenly to obtain a hydration heat inhibitor.

[0048] Preparation Example 3

[0049] This preparation example provides a hydration heat inhibitor, which is prepared by the following steps:

[0050] S1. Adjust corn starch into a slurry with a mass concentration of 40% with water; add medium-temperature α-amylase with a dosage of 0.08% of the starch mass, hydrolyze at 30 °C for 2 h, adjust the pH to 3 to inactivate the enzyme for 30 min, and then adjust the pH to neutral to obtain a hydrolysis product;

[0051] S2. Add ethanol to the hydrolysis product in S1. The volume ratio of the added ethanol to the water consumption in S1 is 1:4. Stir for 30 min, filter out the product, and then dry and grind it at 105 °C to obtain a purified product. The residue on a 1.18-mm sieve of the purified product is ≤0.4%;

[0052] S3. Add sodium hydroxide with a mass fraction of 1% to the purified product in S2, mix evenly to obtain a hydration heat inhibitor.

[0053] Preparation Example 4

[0054] This preparation example provides a hydration heat inhibitor, which is prepared by the following steps:

[0055] S1. Adjust corn starch into a slurry with a mass concentration of 40% with water; add medium-temperature α-amylase with a dosage of 0.06% of the starch mass, hydrolyze at 40 °C for 2 h, adjust the pH to 3 to inactivate the enzyme for 30 min, and then adjust the pH to neutral to obtain a hydrolysis product;

[0056] S2. Add ethanol to the hydrolysis product in S1. The volume ratio of the added ethanol to the water consumption in S1 is 1:4. Stir for 30 min, filter out the product, and then dry and grind it at 105 °C to obtain a purified product. The residue on a 1.18-mm sieve of the purified product is ≤0.4%;

[0057] S3. Add sodium hydroxide with a mass fraction of 1% to the purified product in S2, mix evenly to obtain a hydration heat inhibitor.

[0058] Preparation Example 5

[0059] This preparation example provides a hydration heat inhibitor, which is prepared by the following steps:

[0060] S1. Adjust corn starch with water to form a slurry with a mass concentration of 40%; add medium-temperature α-amylase with a dosage of 0.04% of the starch mass, hydrolyze at 50 °C for 2 h, adjust the pH to 3 to inactivate the enzyme for 30 min, and then adjust the pH to neutral to obtain a hydrolysis product;

[0061] S2. Add ethanol to the hydrolysis product in S1, with the volume ratio of the added ethanol to the water consumption in S1 being 1:4, stir for 30 min, filter out the product, and then dry and grind it at 105 °C to obtain a purified product, with the residue on a 1.18-mm sieve of the purified product ≤ 0.4%;

[0062] S3. Add sodium hydroxide with a mass fraction of 1% to the purified product in S2, mix evenly to obtain a hydration heat inhibitor.

[0063] Preparation Example 6

[0064] This preparation example provides a hydration heat inhibitor, which is prepared by the following steps:

[0065] S1. Adjust corn starch with water to form a slurry with a mass concentration of 40%; add medium-temperature α-amylase with a dosage of 0.02% of the starch mass, hydrolyze at 60 °C for 2 h, adjust the pH to 3 to inactivate the enzyme for 30 min, and then adjust the pH to neutral to obtain a hydrolysis product;

[0066] S2. Add ethanol to the hydrolysis product in S1, with the volume ratio of the added ethanol to the water consumption in S1 being 1:4, stir for 30 min, filter out the product, and then dry and grind it at 105 °C to obtain a purified product, with the residue on a 1.18-mm sieve of the purified product ≤ 0.4%;

[0067] S3. Add sodium hydroxide with a mass fraction of 1% to the purified product in S2, mix evenly to obtain a hydration heat inhibitor.

[0068] Preparation Example 7

[0069] This preparation example provides a hydration heat inhibitor, which is prepared by the following steps:

[0070] S1. Adjust corn starch with water to form a slurry with a mass concentration of 40%; add medium-temperature α-amylase with a dosage of 0.06% of the starch mass, hydrolyze at 40 °C for 3 h, adjust the pH to 3 to inactivate the enzyme for 30 min, and then adjust the pH to neutral to obtain a hydrolysis product;

[0071] S2. Add ethanol to the hydrolysis product in S1. The volume ratio of the added ethanol to the water consumption in S1 is 1:4. Stir for 30 min, filter out the product, and then dry and grind it at 105 °C to obtain a purified product. The residue on a 1.18-mm sieve of the purified product is ≤0.4%;

[0072] S3. Add sodium hydroxide with a mass fraction of 1% to the purified product in S2, and mix evenly to obtain a hydration heat inhibitor.

[0073] Preparation Example 8

[0074] This preparation example provides a hydration heat inhibitor, which is prepared by the following steps:

[0075] S1. Mix corn starch with water to form a slurry with a mass concentration of 40%; add medium-temperature α-amylase with a dosage of 0.06% of the starch mass, hydrolyze at 40 °C for 4 h, adjust the pH to 3 to inactivate the enzyme for 30 min, and then adjust the pH to neutral to obtain a hydrolysis product;

[0076] S2. Add ethanol to the hydrolysis product in S1. The volume ratio of the added ethanol to the water consumption in S1 is 1:4. Stir for 30 min, filter out the product, and then dry and grind it at 105 °C to obtain a purified product. The residue on a 1.18-mm sieve of the purified product is ≤0.4%;

[0077] S3. Add sodium hydroxide with a mass fraction of 1% to the purified product in S2, and mix evenly to obtain a hydration heat inhibitor.

[0078] Preparation Example 9

[0079] This preparation example provides a hydration heat inhibitor, which is prepared by the following steps:

[0080] S1. Mix corn starch with water to form a slurry with a mass concentration of 40%; add medium-temperature α-amylase with a dosage of 0.06% of the starch mass, hydrolyze at 40 °C for 3 h, adjust the pH to 3 to inactivate the enzyme for 30 min, and then adjust the pH to neutral to obtain a hydrolysis product;

[0081] S2. Add ethanol to the hydrolysis product in S1. The volume ratio of the added ethanol to the water consumption in S1 is 1:4. Stir for 30 min, filter out the product, and then dry and grind it at 105 °C to obtain a purified product. The residue on a 1.18-mm sieve of the purified product is ≤0.4%;

[0082] S3. Add sodium hydroxide with a mass fraction of 2% to the purified product in S2, and mix evenly to obtain a hydration heat inhibitor.

[0083] Preparation Example 10

[0084] This preparation example provides a hydration heat inhibitor, which is prepared by the following steps:

[0085] S1. Adjust corn starch into a slurry with a mass concentration of 40% with water; add medium-temperature α-amylase with a dosage of 0.06% of the starch mass, hydrolyze at 40 °C for 3 h, adjust the pH to 3 to inactivate the enzyme for 30 min, and then adjust the pH to neutral to obtain a hydrolysis product;

[0086] S2. Add ethanol to the hydrolysis product in S1. The volume ratio of the added ethanol to the water consumption in S1 is 1:4. Stir for 30 min, filter out the product, and then dry and grind it at 105 °C to obtain a purified product. The residue on a 1.18-mm sieve of the purified product is ≤0.4%;

[0087] S3. Add sodium hydroxide with a mass fraction of 3% to the purified product in S2, mix evenly to prepare a hydration heat inhibitor.

[0088] Preparation Example 11

[0089] This preparation example provides a hydration heat inhibitor, which is prepared by the following steps:

[0090] S1. Adjust corn starch into a slurry with a mass concentration of 40% with water; add medium-temperature α-amylase with a dosage of 0.06% of the starch mass, hydrolyze at 40 °C for 3 h, adjust the pH to 3 to inactivate the enzyme for 30 min, and then adjust the pH to neutral to obtain a hydrolysis product;

[0091] S2. Add ethanol to the hydrolysis product in S1. The volume ratio of the added ethanol to the water consumption in S1 is 1:4. Stir for 30 min, filter out the product, and then dry and grind it at 105 °C to obtain a purified product. The residue on a 1.18-mm sieve of the purified product is ≤0.4%;

[0092] S3. Add urea with a mass fraction of 2% to the purified product in S2, mix evenly to prepare a hydration heat inhibitor.

[0093] Preparation Example 12

[0094] This preparation example provides a hydration heat inhibitor, which is prepared by the following steps:

[0095] S1. Adjust corn starch into a slurry with a mass concentration of 40% with water; add medium-temperature α-amylase with a dosage of 0.06% of the starch mass, hydrolyze at 40 °C for 3 h, adjust the pH to 3 to inactivate the enzyme for 30 min, and then adjust the pH to neutral to obtain a hydrolysis product;

[0096] S2. Add ethanol to the hydrolysis product in S1. The volume ratio of the added ethanol to the water consumption in S1 is 1:4. Stir for 30 min, filter out the product, and then dry and grind it at 105 °C to obtain a purified product. The residue on a 1.18-mm sieve of the purified product is ≤0.4%;

[0097] S3. Add ammonia water with a mass fraction of 2% to the purified product in S2, mix evenly to obtain a hydration heat inhibitor.

[0098] Preparation Example 13

[0099] This preparation example provides a hydration heat inhibitor, which is prepared by the following steps:

[0100] S1. Adjust corn starch into a slurry with a mass concentration of 40% with water; add medium-temperature α-amylase with a dosage of 0.06% of the starch mass, hydrolyze at 40 °C for 3 h, adjust the pH to 3 to inactivate the enzyme for 30 min, and then adjust the pH to neutral to obtain a hydrolysis product;

[0101] S2. Add ethanol to the hydrolysis product in S1, and the volume ratio of the added ethanol to the water consumption in S1 is 1:4. Stir for 30 min, filter out the product, and then dry and grind it at 105 °C to obtain a purified product. The residue on a 1.18-mm sieve of the purified product is ≤ 0.4%;

[0102] S3. Add magnesium sulfate with a mass fraction of 3% to the purified product in S2, mix evenly to obtain a hydration heat inhibitor.

[0103] Preparation Example 14

[0104] This preparation example provides a hydration heat inhibitor, which is prepared by the following steps:

[0105] S1. Adjust corn starch into a slurry with a mass concentration of 40% with water; add medium-temperature α-amylase with a dosage of 0.06% of the starch mass, hydrolyze at 40 °C for 3 h, adjust the pH to 3 to inactivate the enzyme for 30 min, and then adjust the pH to neutral to obtain a hydrolysis product;

[0106] S2. Add ethanol to the hydrolysis product in S1, and the volume ratio of the added ethanol to the water consumption in S1 is 1:4. Stir for 30 min, filter out the product, and then dry and grind it at 105 °C to obtain a purified product. The residue on a 1.18-mm sieve of the purified product is ≤ 0.4%;

[0107] S3. Add sodium sulfate with a mass fraction of 3% to the purified product in S2, mix evenly to obtain a hydration heat inhibitor.

[0108] Preparation Example 15

[0109] This preparation example provides a hydration heat inhibitor, which is prepared by the following steps:

[0110] S1. Adjust corn starch into a slurry with a mass concentration of 40% with water; add medium-temperature α-amylase with a dosage of 0.06% of the starch mass, hydrolyze at 40 °C for 3 h, adjust the pH to 3 to inactivate the enzyme for 30 min, and then adjust the pH to neutral to obtain a hydrolysis product;

[0111] S2. Add ethanol to the hydrolysis product in S1. The volume ratio of the added ethanol to the water consumption in S1 is 1:4. Stir for 30 min, filter out the product, and then dry and grind it at 105 °C to obtain a purified product. The residue on a 1.18-mm sieve of the purified product is ≤0.4%.

[0112] S3. Add calcium nitrate with a mass fraction of 3% to the purified product in S2 and mix evenly to prepare a hydration heat inhibitor.

[0113] Table 1 Raw material table of Preparation Examples 1-15

[0114]

[0115] Example

[0116] In the examples of this application, the cement used is Yadong P.O42.5R cement; the fine aggregate is river sand, medium sand, with an apparent density of 2.62 g / cm 3 ; the coarse aggregate is 5-31.5 mm continuously graded gravel; the fly ash is Class I fly ash; the slag powder is S75 slag powder.

[0117] Example 1

[0118] This example provides a concrete, which is prepared by mixing the following raw materials: 240 kg of cement, 60 kg of fly ash, 85 kg of slag powder, 815 kg of sand, 1030 kg of gravel, 170 kg of water, and 1.32 kg of the hydration heat inhibitor prepared in Preparation Example 1.

[0119] Example 2

[0120] The difference between this example and Example 1 is that the hydration heat inhibitor used is the one prepared in Preparation Example 2.

[0121] Example 3

[0122] The hydration heat inhibitor used is the one prepared in Preparation Example 3.

[0123] Example 4

[0124] The hydration heat inhibitor used is the one prepared in Preparation Example 4.

[0125] Example 5

[0126] The hydration heat inhibitor used is the one prepared in Preparation Example 5.

[0127] Example 6

[0128] The hydration heat inhibitor used is the one prepared in Preparation Example 6.

[0129] Example 7

[0130] The heat of hydration inhibitor used was prepared in Preparation Example 7.

[0131] Example 8

[0132] The heat of hydration inhibitor used was prepared in Preparation Example 8.

[0133] Example 9

[0134] The heat of hydration inhibitor used was prepared in Preparation Example 9.

[0135] Example 10

[0136] The heat of hydration inhibitor used was prepared in Preparation Example 10.

[0137] Example 11

[0138] The heat of hydration inhibitor used was prepared in Preparation Example 11.

[0139] Example 12

[0140] The heat of hydration inhibitor used was prepared in Preparation Example 12.

[0141] Example 13

[0142] The heat of hydration inhibitor used was prepared in Preparation Example 13.

[0143] Example 14

[0144] The heat of hydration inhibitor used was prepared in Preparation Example 14.

[0145] Example 15

[0146] The heat of hydration inhibitor used was prepared in Preparation Example 15.

[0147] Comparative Example

[0148] Comparative Example 1

[0149] The difference between this comparative example and Example 1 is that the heat of hydration inhibitor used was provided by Sichuan Tongdao Technology Co., Ltd., with the model SYZ-1.

[0150] Comparative Example 2

[0151] The difference between this comparative example and Example 1 is that the heat of hydration inhibitor used was provided by Sichuan Tongdao Technology Co., Ltd., with the model SYZ-2.

[0152] Comparative Example 3

[0153] The difference between this comparative example and Example 1 is that the heat of hydration inhibitor used was provided by Sichuan Tongdao Technology Co., Ltd., with the model SYZ-3.

[0154] Comparative Example 4

[0155] The difference between this comparative example and Example 1 is that the heat of hydration inhibitor used is provided by Sichuan Tongdao Technology Co., Ltd. and the model is SYZ-4.

[0156] Another reference group is set up. The difference between the reference group and Example 1 is that no heat of hydration inhibitor is added.

[0157] Performance detection test

[0158] Refer to GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete" to detect the compressive strength of concrete; refer to GB / T 50080-2016 "Standard for Test Methods of Properties of Ordinary Concrete Mixtures" to detect the setting time of concrete.

[0159] Use an adiabatic temperature rise instrument to test the adiabatic temperature rise of concrete.

[0160] Table 2 Test results of adiabatic temperature rise, setting time and strength of the embodiments and comparative examples of the present application

[0161]

[0162]

[0163] Combined with Comparative Examples 1-4 and the reference group and Table 2, it can be seen that commercially available heat of hydration inhibiting materials can reduce the adiabatic temperature rise value of concrete at 7 days by 7-9 °C, but will significantly prolong the setting time of concrete and reduce the strength of concrete.

[0164] Combined with the examples, comparative examples and reference group and Table 2, it can be seen that compared with commercially available products, the heat of hydration inhibiting material prepared by the present application has a more significant ability to reduce the temperature rise of concrete, and has basically no negative impact on the setting time and strength development of concrete. Even some products can even promote the strength development of concrete.

[0165] This specific embodiment is only an explanation of the present application, and it is not a limitation of the present application. Those skilled in the art can make modifications without creative contributions to this embodiment after reading this specification, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A hydration heat inhibitor for concrete, characterized in that, it is prepared from starch hydrolyzate and an additive, and the weight ratio of the starch hydrolyzate to the additive is 100:(1-3). The starch hydrolyzate is prepared from the following raw materials: starch, water, a hydrolase, and a purifying agent. The weight ratio of the starch, water, and hydrolase is 100:(250-500):(0.02-0.08), and the volume ratio of the water to the purifying agent is 4:1; the starch is corn starch; the additive is selected from one of sodium hydroxide, urea, and ammonia, which are alkaline substances, or is selected from one of magnesium sulfate, sodium sulfate, and calcium nitrate, which are salt substances; The preparation of the inhibitor includes the following steps: S1. Mix the starch with water to form a slurry with a mass concentration of 20%-40%; add a hydrolase with a dosage of 0.02%-0.08% of the starch mass, and hydrolyze at 30-60°C for 2-4 hours. Adjust the pH to 3 to inactivate the enzyme for 30 minutes, and then adjust the pH to neutral to obtain a hydrolysis product; S2. Add a purifying agent to the hydrolysis product in S1. The addition amount of the purifying agent and the water consumption in S1 have a volume ratio of 1:

4. Stir for 30 minutes, filter out the product, and then dry and grind it at 105°C to obtain a purified product. The residue on a 1.18 mm sieve of the purified product is ≤0.4%; S3. Add an additive with a mass fraction of 1%-3% to the purified product in S2, and mix evenly to prepare a hydration heat inhibitor.

2. The hydration heat inhibitor for concrete according to claim 1, characterized in that, the hydrolase is one of medium-temperature α-amylase or low-temperature α-amylase.

3. The hydration heat inhibitor for concrete according to claim 1, characterized in that, the purifying agent is ethanol.

4. The hydration heat inhibitor for concrete according to claim 1, characterized in that, the substance used to adjust the pH to 3 in S1 is one of hydrochloric acid or sulfuric acid.

5. The hydration heat inhibitor for concrete according to claim 1, characterized in that, the substance used to adjust the pH to neutral in S1 is a saturated sodium hydroxide solution.

6. The usage method of the hydration heat inhibitor for concrete according to any one of claims 1-5, characterized in that, mix the hydration heat inhibitor and the cementitious material evenly and then add them to the concrete. The dosage is 0.55% of the cementitious material.

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