阅读说明：本技术 一种公路用混凝土外加剂及其制备方法 (Concrete additive for highway and preparation method thereof ) 是由 王伟 覃文 吴可永 于 2021-09-18 设计创作，主要内容包括：本发明公开了一种公路用混凝土外加剂及其制备方法,涉及混凝土技术领域,本发明包括按重量份数包括以下物质：60～90份工业萘、40～60份共沸剂、54～81份浓硫酸、39～59份甲醛、三乙醇胺5～15份、乙二醇8～16份、抗磨剂15～25份、硝酸钠3～19份,其制备方法包括磺化反应、添加共沸剂、水解反应、缩合反应以及中和反应,最终得到产品。本发明为一种公路用混凝土外加剂及其制备方法,通过使用1,2-二氯乙烷作为共沸剂生产萘系高效减水剂可减少硫酸的用量,且无论在净浆流动度或是混凝土试验当中,相同条件下,其性能都优于石灰法生产的高浓减水剂,同时共沸法除去了过滤工序,减少了后续人力和资源的投入。(The invention discloses a concrete admixture for roads and a preparation method thereof, relating to the technical field of concrete, and the concrete admixture comprises the following substances in parts by weight: 60-90 parts of industrial naphthalene, 40-60 parts of entrainer, 54-81 parts of concentrated sulfuric acid, 39-59 parts of formaldehyde, 5-15 parts of triethanolamine, 8-16 parts of ethylene glycol, 15-25 parts of antiwear agent and 3-19 parts of sodium nitrate. The invention relates to a concrete admixture for roads and a preparation method thereof, which can reduce the dosage of sulfuric acid by using 1, 2-dichloroethane as an entrainer to produce a naphthalene-based high-efficiency water reducing agent, and the performance of the naphthalene-based high-efficiency water reducing agent is superior to that of a high-concentration water reducing agent produced by a lime method under the same conditions no matter in the net paste fluidity or concrete tests, and meanwhile, the azeotropic method removes a filtering process, thereby reducing the subsequent investment of manpower and resources.)

1. A concrete admixture for roads is characterized in that: the composition comprises the following substances in parts by weight: 60-90 parts of industrial naphthalene, 40-60 parts of an entrainer, 54-81 parts of concentrated sulfuric acid, 39-59 parts of formaldehyde, 5-15 parts of triethanolamine, 8-16 parts of ethylene glycol, 15-25 parts of an antiwear agent and 3-19 parts of sodium nitrate.

2. The concrete admixture for roads of claim 1, wherein the concrete admixture comprises: the entrainer is 1, 2-dichloroethane.

3. A road concrete admixture according to claim 1, wherein: the weight ratio of the concentrated sulfuric acid to the industrial naphthalene is 0.9-1.1, wherein the optimal ratio is 0.9: 1.

4. A road concrete admixture according to claim 1, wherein: the optimal weight ratio of the formaldehyde to the industrial naphthalene is 0.65: 1.

5. A road concrete admixture according to claim 1, wherein: the weight optimal ratio of the industrial naphthalene to the 1, 2-dichloroethane is 1.5: 1.

6. The method for preparing a concrete admixture for roads according to claim 1, wherein: comprises a neutralization reagent, wherein the neutralization reagent is sodium hydroxide or lime.

7. The method for producing a concrete admixture for roads as recited in any one of claims 1 to 6, wherein: the method comprises the following steps:

s1, sulfonation reaction: weighing a plurality of industrial naphthalene, placing the industrial naphthalene in a four-neck flask, heating the industrial naphthalene to melt the industrial naphthalene, heating the industrial naphthalene to 120 ℃ after the industrial naphthalene is completely melted, then weighing concentrated sulfuric acid according to a certain proportion, slowly dropwise adding the concentrated sulfuric acid into the four-neck flask through a liquid-sharing funnel, heating the four-neck flask to 150-160 ℃, and preserving the heat for 3-6 hours;

s2, adding an entrainer: adding a proper amount of 1, 2-dichloroethane as an entrainer into a sulfonation reaction device, and evaporating the 1, 2-dichloroethane along with the sulfonation;

s3, hydrolysis reaction: after the sulfonation reaction is finished, cooling to about 120 ℃, adding a proper amount of water, and controlling the temperature to about 120 ℃ to hydrolyze the solution in the container;

s4, condensation reaction: after the hydrolysis reaction is finished, cooling, weighing a plurality of formaldehyde solutions by weight in the cooling process, placing the formaldehyde solutions into a solution funnel for later use, starting to dropwise add formaldehyde when the temperature is reduced to 95 ℃, slowly dropwise adding, controlling the dropwise adding time to be about 2 hours, and after the formaldehyde is dropwise added, heating to 115 ℃, preserving heat and condensing for about 3 hours;

s5, neutralization reaction: and after the condensation reaction is finished, stirring and cooling to below 80 ℃, adding weighed sodium hydroxide, and neutralizing the pH value of the solution to 7-9 to obtain the product.

8. The method for preparing a concrete admixture for roads according to claim 7, wherein: the optimal sulfonation time of the steps S1-S2 is 5h, and the sulfonation temperature is kept between 150 ℃ and 160 ℃.

9. The method for preparing a concrete admixture for roads according to claim 8, wherein: the azeotrope in the step S2 is evaporated out of the container, can be collected and condensed, then is subjected to oil-water separation, and then the solvent can be added into the reaction again for recycling, and the separated water can be used as the production water of other water reducing agents after being neutralized.

10. The method for preparing a concrete admixture for roads according to claim 9, wherein: the content of the industrial naphthalene is 80%, the content of the concentrated sulfuric acid is 98%, the content of the formaldehyde is 37% -40%, and the content of the sodium hydroxide is 96%.

Technical Field

The invention relates to the technical field of concrete, in particular to a concrete admixture for roads and a preparation method thereof.

Background

The concrete admixture is called additive for short, and is a substance which is added before or in the process of mixing the mixed concrete and is used for improving the performance of the concrete. The external additive is reasonably selected and used in the highway cement concrete engineering, so that the quality and durability of the highway cement concrete can be improved, and the performance of the cement concrete can be improved. In particular, the naphthalene-based high-efficiency water reducing agent has the characteristics of high water reducing rate, small influence on the setting time, no air entraining, good adaptability with cement, relatively low price, capability of being used in combination with other various additives and the like. Has a higher share in the water reducing agent market.

The polycarboxylic acid high-efficiency water reducing agent in the current market has become a water reducing agent with optimal comprehensive performance and best application prospect in the world due to the advantages of low mixing amount, low slump loss, high water reducing rate, no influence of mixing time and the like. In the production of a naphthalene based water reducing agent, concentrated sulfuric acid is usually added in an appropriate amount in order to complete the sulfonation reaction.

But with an excess of H₂SO₄As a sulfonating agent, the content of sodium sulfate in the product is too high, and the existence of excessive sodium sulfate can reduce some properties of the water reducing agent, such as weakening the dispersion property of the water reducing agent; so that the slump loss of the concrete mixture is increased and the like.

Disclosure of Invention

The invention mainly aims to provide a concrete admixture for roads and a preparation method thereof, which can effectively solve the problem of excessive H adopted in the background technology₂SO₄The sulfonating agent has the problems that the dispersing performance of the water reducing agent is weakened, and the slump loss of the concrete mixture is increased.

In order to achieve the purpose, the invention adopts the technical scheme that: the concrete admixture for the highway comprises the following substances in parts by weight: 60-90 parts of industrial naphthalene, 40-60 parts of an entrainer, 54-81 parts of concentrated sulfuric acid, 39-59 parts of formaldehyde, 5-15 parts of triethanolamine, 8-16 parts of ethylene glycol, 15-25 parts of an antiwear agent and 3-19 parts of sodium nitrate.

Preferably, the entrainer is 1, 2-dichloroethane.

Preferably, the weight ratio of the concentrated sulfuric acid to the industrial naphthalene is 0.9-1.1, wherein the optimal ratio is 0.9: 1.

Preferably, the optimal weight ratio of the formaldehyde to the industrial naphthalene is 0.65: 1.

Preferably, the weight optimal ratio of the industrial naphthalene to 1, 2-dichloroethane is 1.5: 1.

Preferably, a neutralizing agent is included, and sodium hydroxide or lime is selected as the neutralizing agent.

Preferably, the preparation method of the concrete admixture for the road is characterized by comprising the following steps: the method comprises the following steps:

s1, sulfonation reaction: weighing a plurality of industrial naphthalene, placing the industrial naphthalene in a four-neck flask, heating the industrial naphthalene to melt the industrial naphthalene, heating the industrial naphthalene to 120 ℃ after the industrial naphthalene is completely melted, then weighing concentrated sulfuric acid according to a certain proportion, slowly dripping the concentrated sulfuric acid into the four-neck flask through a liquid sharing funnel, heating the four-neck flask to 150-160 ℃, and preserving the heat for 3-6 hours;

s2, adding an entrainer: adding a proper amount of 1, 2-dichloroethane as an entrainer into a sulfonation reaction device, and evaporating the 1, 2-dichloroethane along with the sulfonation;

s3, hydrolysis reaction: after the sulfonation reaction is finished, cooling to about 120 ℃, adding a proper amount of water, and controlling the temperature to about 120 ℃ to hydrolyze the solution in the container;

s4, condensation reaction: after the hydrolysis reaction is finished, cooling, weighing a plurality of formaldehyde solutions by weight in the cooling process, placing the formaldehyde solutions into a solution funnel for later use, starting dropwise adding formaldehyde when the temperature is reduced to 95 ℃, slowly dropwise adding the formaldehyde, controlling the dropwise adding time to be about 2 hours, and after the formaldehyde is dropwise added, heating to 115 ℃, preserving heat and condensing for about 3 hours;

and S5, after the condensation reaction is finished, stirring and cooling to below 80 ℃, adding weighed sodium hydroxide, and neutralizing the pH value of the solution to 7-9 to obtain the product.

Preferably, the optimal sulfonation time of the steps S1-S2 is 5h, and the sulfonation temperature is kept between 150 ℃ and 160 ℃.

Preferably, the azeotrope in step S2 is evaporated out of the container, can be collected and condensed, and then subjected to oil-water separation, and then the solvent can be added to the reaction again for recycling, and the separated water can be used as the process water for other water reducing agents after neutralization.

Preferably, the content of the industrial naphthalene is 80%, the content of the concentrated sulfuric acid is 98%, the content of the formaldehyde is 37% -40%, and the content of the sodium hydroxide is 96%.

Compared with the prior art, the invention has the following beneficial effects:

in the invention, 1, 2-dichloroethane is used as an entrainer, the high-concentration naphthalene water reducing agent is produced by adopting an azeotropic principle, the amount of used acid is reduced due to the improvement of the sulfonation conversion rate, and the high-concentration naphthalene water reducing agent can be obtained by directly adopting alkali liquor for neutralization in the neutralization stage. Compared with the prior art, under the doping amount of 0.6 percent, the cement paste fluidity of the high-concentration water reducing agent produced by adopting 1, 2-dichloroethane as the entrainer is increased, the water reducing rate, the concrete strength and other performance indexes are also improved, and the flexural strength and the compressive strength of the concrete can be ensured to be basically unchanged by adding triethanolamine, ethylene glycol, an antiwear agent and sodium nitrate.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.

In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear", "both ends", "one end", "the other end", and the like indicate orientations or positional relationships only for the convenience of description and simplification of the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," "connected," and the like are to be construed broadly, such as "connected," which may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Example 1

The composition comprises the following substances in parts by weight: 60 parts of industrial naphthalene, 40 parts of entrainer, 54 parts of concentrated sulfuric acid, 39 parts of formaldehyde, 5 parts of triethanolamine, 8 parts of ethylene glycol, 15 parts of antiwear agent and 3 parts of sodium nitrate.

The entrainer is 1, 2-dichloroethane.

The weight ratio of the concentrated sulfuric acid to the industrial naphthalene is 0.9-1.1, wherein the optimal ratio is 0.9: 1.

The optimal weight ratio of the formaldehyde to the industrial naphthalene is 0.65: 1.

The weight optimal ratio of the industrial naphthalene to the 1, 2-dichloroethane is 1.5: 1.

Comprises a neutralization reagent, wherein the neutralization reagent is sodium hydroxide or lime.

A preparation method of a concrete admixture for roads comprises the following steps:

weighing 60 parts of industrial naphthalene, 5 parts of triethanolamine, 8 parts of ethylene glycol, 15 parts of an antiwear agent and 3 parts of sodium nitrate, placing the materials in a four-neck flask, heating the materials to be molten, heating the materials to 120 ℃ after the materials are completely molten, then weighing 54 parts of concentrated sulfuric acid, slowly dropwise adding the concentrated sulfuric acid into the four-neck flask through a liquid funnel, heating the four-neck flask to 150-160 ℃, and preserving heat for 5 hours; adding 40 parts of 1, 2-dichloroethane as an entrainer into a sulfonation reaction device, evaporating the 1, 2-dichloroethane as the entrainer along with the sulfonation, collecting and condensing the evaporated entrainer, separating oil from water, adding the solvent into the reaction again for recycling, and neutralizing the separated water to be used as the production water of other water reducers; after the sulfonation reaction is finished, cooling to about 120 ℃, adding a proper amount of water, and controlling the temperature to about 120 ℃ to hydrolyze the solution in the container; after the hydrolysis reaction is finished, cooling and cooling are started, 39 parts of formaldehyde solution is weighed in a solution funnel for later use in the cooling process, formaldehyde is dripped when the temperature is reduced to 95 ℃, the dripping is slowly carried out, the dripping time is controlled to be 2 hours, and after the dripping of the formaldehyde is finished, the formaldehyde is heated to 115 ℃ and is subjected to heat preservation and condensation for 3 hours; after the condensation reaction is finished, stirring and cooling to below 80 ℃, adding weighed sodium hydroxide, and neutralizing the pH value of the solution to 8 to obtain the product.

Setting the mass ratio of seven groups of acid naphthalene to be 1.1, 1.05, 1.0, 0.95, 0.9, 0.85 and 0.8 in sequence according to the steps, wherein the sulfonation temperature is 150-160 ℃, the sulfonation time is 3h, the condensation temperature is 115 ℃, the condensation time is 3h, and the experimental results are shown in the following table 1:

TABLE 1 influence of acid naphthalene ratio on cement paste fluidity

From table 1 above, it can be seen that: when the mass ratio of the acid naphthalene to the acid naphthalene is 0.9-1.1, the fluidity of the cement paste is not greatly different. When the acid naphthalene ratio is lower than 0.9, qualified naphthalene water reducer products cannot be produced even by adopting an azeotropic method, namely, the acid naphthalene ratio cannot be lower than 0.9 when the high-concentration naphthalene water reducer is synthesized by adopting the azeotropic method. When the naphthalene acid ratio is larger than a certain value, the fluidity of the cement paste tends to be slightly reduced, because the unreacted sulfuric acid is increased along with the increase of the acid amount, so that the content of sodium sulfate in a final product is high, the effective components in the water reducer product are reduced, and the fluidity of the cement paste tends to be reduced. Considering the production cost problem and the content of sodium sulfate in the product, the optimal naphthalene acid ratio of the invention is 0.9.

Six groups of sulfonation temperatures are set according to the steps, and the temperatures are 150 ℃, 155 ℃, 160 ℃, 165 ℃ and 170 ℃ for experiments, the sulfonation time is 3 hours, the mass ratio of formaldehyde to naphthalene is 0.65, and the mass ratio of acid naphthalene is 0.9. The condensation temperature was set at 115 ℃ and the condensation time was 3 h. The results of the experiment are shown in table 2 below:

TABLE 2 Effect of sulfonation temperature on neat paste fluidity

From table 2 above, it can be seen that: when the temperature is 155-160 ℃, the fluidity of the cement paste is higher, and when the temperature is higher than 160 ℃, the fluidity of the cement paste begins to decrease, so the optimal sulfonation temperature for producing the high-concentration naphthalene high-efficiency water reducing agent by adopting the azeotropic method is 155-160 ℃.

Setting four groups of sulfonation time to be 3h, 4h, 5h and 6h in sequence according to the steps, keeping the sulfonation temperature between 150 ℃ and 160 ℃, setting the mass ratio of formaldehyde to naphthalene to be 0.65 and setting the mass ratio of acid naphthalene to be 0.9. The condensation temperature was set at 115 ℃ and the condensation time was 3 h. The results of the experiment are shown in table 3 below:

TABLE 3 Effect of sulfonation time on neat paste fluidity

From table 3 above, it can be seen that: the net cement slurry fluidity gradually increases with the reaction time. However, after more than 5 hours, the fluidity of the cement paste tends to decrease. Therefore, the optimal sulfonation time for producing the high-concentration naphthalene high-efficiency water reducing agent by using the azeotropic method is 5 h.

Example 2

The difference between the embodiment 2 and the embodiment 1 is that the parts by weight of the components are different, wherein, the parts by weight of the industrial naphthalene is 90, the parts by weight of the entrainer is 60, the parts by weight of the concentrated sulfuric acid is 81, the parts by weight of the formaldehyde is 59, the parts by weight of the triethanolamine is 15, the parts by weight of the ethylene glycol is 16, the parts by weight of the antiwear agent is 25, and the parts by weight of the sodium nitrate is 19.

Example 3

The difference between the embodiment 3 and the embodiment 1 is that the parts by weight of the components are different, wherein, 70 parts of industrial naphthalene, 50 parts of entrainer, 70 parts of concentrated sulfuric acid, 46 parts of formaldehyde, 10 parts of triethanolamine, 12 parts of ethylene glycol, 20 parts of antiwear agent and 10 parts of sodium nitrate.

Comparative example 1

Comparative example 1 is different from example 1 in that comparative example 1 does not add an azeotropic agent.

Comparative example 2

Comparative example 2 is different from example 1 in that comparative example 2 does not add an entrainer and step S5 is neutralized with lime and further filtration is required to obtain the product.

According to the optimal proportion optimized by experiments, the high-concentration naphthalene water reducer is synthesized by an azeotropic method, and the mixing amount is selected from 0.2%, 0.6%, 1.0% and 1.4%. The water cement ratio is 0.29, the cement is geocement, and the experimental results are shown in the following table 4:

TABLE 4 Effect of the amount of the admixture on the fluidity of the cement paste

From table 4 above, it can be seen that: the high-concentration naphthalene water reducing agents produced in the example 1 and the comparative example 2 have basically the same cement paste fluidity and are higher than those produced by the common process under the same mixing amount, which shows that the method for producing the high-concentration naphthalene water reducing agent by using 1,2 dichloroethane as the entrainer is feasible and can replace the process for producing the high-concentration naphthalene water reducing agent by the lime method.

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are given by way of illustration of the principles of the present invention, and that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.