CN110183138B - Inorganic permeable concrete modifying agent and preparation method and application thereof - Google Patents

Abstract

The invention discloses an inorganic pervious concrete modifier and a preparation method and application thereof. The concrete modifier comprises, by weight, 220 parts of calcium chloride 165-containing materials, 6-12 parts of aqueous solution ferrous salt, 0.4-2.8 parts of water-soluble iron (III) salt, 4-8 parts of anhydrous sodium sulfate, 4.4-7.2 parts of water-soluble magnesium salt, 4.4-7.2 parts of water-soluble potassium salt, 0.8-3.6 parts of ammonium chloride, 0.2-1.6 parts of molasses retarder, 0.23-2.2 parts of calcium oxide and 280 parts of water 180-containing materials. By adopting the concrete modifier, the strength, the retardation, the water permeability and the water retention performance of a concrete material can be obviously improved at lower cost, and the technical problems to be solved in the current ecological environment-friendly city construction are solved.

Description

Inorganic permeable concrete modifying agent and preparation method and application thereof

Technical Field

The invention relates to a concrete modifier, in particular to an inorganic permeable water-retaining cement concrete road material which is prepared by refining various analytical grade inorganic salts through a special process.

Background

In modern large-scale engineering construction, the requirements on the performance of concrete materials are increasingly raised. On the one hand, from the viewpoint of modern concrete construction, it is required that the mixed concrete can maintain good workability after being transported over a long distance and be hardened as soon as possible after casting. Meanwhile, in order to prevent excessive concentration of the hydration heat of cement, it is also desirable that the heat generation is slow and the setting time of concrete is relatively prolonged when cement is hydrated. On the other hand, from the view point of ecological and environment-friendly city construction, the permeable pavement is more and more emphasized by people, the water permeability of the urban concrete pavement is improved, energy and water conservation can be effectively realized, and the impact of the city construction on the ecological environment is reduced.

All these concrete technical performance improvements and enhancements have to date been achieved by means of additives. The prior art has various additives. The water reducing agent mainly comprises lignosulfonate, naphthalene sulfonate, melamine sulfonate and the like. The early strength water reducing agent compounded by lignosulfonate, naphthalenesulfonate and melamine sulfonate has good early strength effect and high later strength of concrete, but is difficult to adapt to long-distance transportation of concrete for road construction and summer construction of large-volume concrete engineering due to no delayed coagulation, and has high cost and high price. In addition, in order to improve the water permeability and water retention of concrete pavements, organic concrete cementitious materials, polymeric water permeable materials and sintered water permeable materials are widely used in the prior art. However, (1) the organic concrete cementing material contains more communicated pores, and has poor strength, abrasion resistance and freezing resistance and short service life; (2) the high polymer water permeable concrete has higher strength but higher cost, and the performance of the concrete is greatly influenced by temperature, and particularly when the temperature is increased, the concrete is easy to soften and flow, so that the water permeability is influenced; (3) the sintered water-permeable product has high strength, good wear resistance and excellent durability, but consumes a large amount of energy in the high-temperature sintering process, has higher cost and is not suitable for paving large-scale concrete pavements.

In order to solve the above problems, molasses is widely used in concrete additives. Molasses contains a large number of hydroxyl and carboxyl groups in the molecule, and reacts with free Ca in the alkaline medium of cement hydration products²⁺Formation of unstable complex to suppress Ca in liquid phase at the initial stage of hydration²⁺The concentration of (3) produces a retarding effect. Along with the progress of the hydration process, the complex is automatically decomposed, and the hydration is continued, so that the later hydration of the cement is not influenced. However, in practical use, the molasses molecular structure is too large, so that the functional groups are too concentrated, and the hydration assisting effect cannot be fully exerted.

Molasses spent liquor typically contains relatively small amounts of by-products compared to the original molasses. This by-product is obtained from the fermentation process of sugars, which are mainly present in the form of different organic acids. These acids increase the surface activity of the molasses spent liquor to some extent. However, the major disadvantage of molasses fermentation by-products (molasses spent liquor) is still insufficient surface activity compared to conventional water reducing agents such as lignosulphonates. In addition, "molasses fermentation by-products" contain a plethora of variants. These by-products are therefore rarely used in concrete additive applications.

In addition, in the prior art, there is a proposal that molasses is used as a binder, and is mixed with particles such as talc or zeolite, and the cement particles are coated with the talc or zeolite particles to prevent aggregation of the cement particles, thereby realizing a retardation effect. However, the molasses in the method can not fully exert the function of the surface active substance, has poor retardation effect and is not widely applied.

Therefore, there is an urgent need for a low-cost concrete improver which can simultaneously improve the strength, retardation, water permeability and water retention of a concrete material.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides an inorganic pervious concrete modifier which comprises the following raw materials in parts by weight:

the inorganic porous concrete improver according to the present invention, wherein the inorganic salt components are all analytically pure.

As the calcium chloride component, it is used in an amount of typically 40 wt% to 45 wt%, more preferably 41 wt% to 43.5 wt%, based on the total weight of the concrete improver.

As the water-soluble ferrous salt, any known divalent water-soluble ferrous salt suitable for cement additives can be used. Typically, the water-soluble ferrous salt is selected from one or a combination of ferrous chloride and ferrous sulfate; more preferably, the water-soluble ferrous salt is ferrous sulfate. The water soluble ferrous salt is typically used in a ratio of 1.6 wt% to 2.3 wt%, preferably 1.9 wt% to 2.2 wt%, based on the total weight of the concrete improver.

As the water-soluble iron (III) salt, typically iron chloride or iron sulfate may be used. The amount ratio of the water-soluble iron (III) salt is typically 0.3 wt% to 0.7 wt%, more preferably 0.35 wt% to 0.55 wt%, based on the total weight of the concrete improver.

As the anhydrous sodium sulfate, the amount ratio thereof is typically not more than 2.1 wt%, more preferably 1.25 wt% to 1.5 wt%, based on the total weight of the concrete improver.

As the water-soluble magnesium salt and the water-soluble potassium salt, any water-soluble magnesium salt and potassium salt known in the field of concrete additives can be used. Typically, it may use its chloride, sulfate, nitrate or a combination thereof. Preferably, magnesium chloride and potassium chloride are used separately. Typically in an amount of 1.2 wt% to 1.8 wt%, more preferably 1.25 wt% to 1.31 wt%, respectively, based on the total weight of the concrete improver.

The molasses retarder used in the invention is prepared by using molasses waste liquid as a raw material and sequentially carrying out oxidation, acidification, alkalization and neutralization reactions.

Specifically, it can be prepared by the following method:

(A) adjusting the pH value of the molasses waste liquid to be neutral or alkalescent by using an alkaline substance, and filtering to obtain filtrate A;

(B) sufficiently mixing the molasses filtrate A with an oxidant, putting the mixture into a high-pressure reaction kettle, and reacting for 2-5 hours at the temperature of 70-85 ℃ under the condition of 15-18KPa to obtain molasses solution B;

(C) acidifying the molasses solution B to the pH value of 0.5-1 to obtain molasses solution C;

(D) adding alkali into the molasses solution C at the temperature of 70-150 ℃, and carrying out an alkalization reaction to obtain a molasses solution D;

(E) and adding a weak acid solution into the obtained molasses solution D, and adjusting the pH value to be neutral to obtain the molasses retarder solution.

Among them, as the basic substance used in the step (a), a weak base or a strong base and a weak acid salt can be used. Typically, the alkaline substance is selected from ammonia, sodium carbonate or sodium bicarbonate, and the like.

As the oxidizing agent used in step (B), any substance having strong oxidizing property known in the art can be used. By way of example, hydrogen peroxide or potassium permanganate; the amount used is typically 5 to 20 parts by weight, preferably 7 to 17 parts by weight, particularly preferably 7.5 to 11 parts by weight, relative to 100 parts by weight of the molasses solution B. If the amount of the oxidizing agent is insufficient, the molasses molecules cannot be sufficiently oxidized, the molecular structure of the molasses is reduced, and it is difficult to impart sufficient surface activity thereto. If the amount of the oxidizing agent is too large, it may result in excessive oxidation of molasses molecules, thereby making it difficult to achieve a satisfactory retarding effect.

As the reaction pressure and temperature in the step (B), it is further preferable to use 16 to 17.5KPa and 75 to 80 ℃. When the pressure and temperature are too low, sufficient oxidation cannot be achieved; when the pressure and temperature are too high, the oxidation reaction becomes difficult to control, resulting in deterioration of the oxidation product properties.

The acidification method as the step (C) specifically includes: adding weak acid into the molasses solution B at normal pressure and 70-150 ℃, and adjusting the pH value of the molasses solution B to 2-3; hydrochloric acid is added thereto to a pH of 0.5 to 1, and an acidification reaction is carried out. Wherein the weak acid comprises organic or inorganic weak acid, such as phosphoric acid or acetic acid.

As the base used in the step (D), any strong base known in the art may be used. Typically, the base is selected from hydroxides of alkali metals. Preferably, potassium hydroxide or sodium hydroxide may be used. The alkalization reaction is preferably carried out at a pH of from 13 to 14.

As the weak acid used in step (E), any organic weak acid, inorganic weak acid or acidic salt known in the art may be used. Typically, the weak acid may be selected from citric acid, acetic acid or phosphoric acid and the like.

The molasses set retarder is preferably used in an amount ratio of 0.05 wt% to 0.3 wt%, more preferably 0.08wt% to 0.15wt%, based on the total weight of the concrete improver. When the consumption of the molasses retarder is too low, the effective retarding effect cannot be realized, and the water permeation and water retention effects of the product can be adversely affected; when the amount of the molasses retarder is too large, the cement hardening time may be prolonged and the strength may be deteriorated.

As the calcium oxide used in the present invention, high-purity calcium oxide is preferably used, and calcium oxide having a purity of 97% or more is particularly preferably used. The mass ratio thereof to the molasses set retarder (calcium oxide: molasses set retarder) is typically 1:0.9-0.75, more preferably 1: 0.86-0.8. If the dosage of the calcium oxide is too low, an effective water reducing effect cannot be obtained; if the amount of calcium oxide is too high, the setting retarding effect is deteriorated.

Further, the present invention also provides a method for preparing the inorganic type pervious concrete improving agent, which comprises the following steps:

(1) weighing the raw materials according to the proportion;

(2) respectively putting the water-soluble iron (III) salt, the water-soluble magnesium salt, the water-soluble potassium salt and the ammonium chloride which are weighed into 4 dissolving barrels to prepare aqueous solution for later use;

(3) adding the weighed anhydrous sodium sulfate into another dissolving bucket, and dissolving with warm water at 70 ℃ to prepare a solution for later use;

(4) preparing a modifier in a mixing barrel: i) injecting 120-160 parts by weight of water into the main barrel in advance, starting a stirrer to slowly pour the water-soluble ferrous salt, and adding the dissolved water-soluble iron (III) salt solution for continuous stirring after the water-soluble ferrous salt is completely dissolved; ii) slowly adding 80-110 parts by weight of calcium chloride particles in batches, stopping feeding when the temperature rises to 70 ℃, cooling, and continuously and slowly adding calcium chloride until the calcium chloride particles are completely added; iii) after the calcium chloride particles are completely dissolved, slowly adding a sodium sulfate solution, and standing for 25-35 min. iv) adding water-soluble magnesium salt solution, and standing for 15-30 min; v) adding a water-soluble potassium salt solution, and standing for 15-30 min; vi) adding an ammonium chloride solution, and standing for 20-45 min; vii) adding the remaining calcium chloride particles in portions in the same manner as in step ii) above until the calcium chloride particles are completely added.

(5) Slowly adding a molasses retarder;

(6) adding calcium oxide into water, dissolving, stirring, and pouring into a mixing barrel until the color of the mixed solution turns into red brown; and continuously stirring until the temperature is reduced to the room temperature, and filling to obtain the inorganic cement concrete modifier.

Wherein, the cooling and temperature reduction of ii) in the step (4) can be implemented by standing and temperature reduction or injecting cooling water.

Further, the present invention also provides the use of the inorganic type concrete improver in the construction of an ecological city.

Typically, the ecological city construction includes the paving of freeze resistant, permeable roads.

By using the inorganic porous concrete modifier of the present invention, the following excellent technical effects can be achieved.

1. The inorganic permeable water-retaining concrete road has high compression strength and high breaking strength, and is suitable for paving permeable roads with light and heavy loads.

2. The environment-friendly type environment-.

3. The water permeability is good, and the water permeability can reach more than 0.95mm/s through tests.

4. The freeze-thaw resistance is good, and after 25 times of freeze-thaw resistance cycles, the compressive strength and the quality loss both accord with CJJ/T135 standard.

5. The heat dissipation and cooling effects are good, and the urban heat island effect is relieved.

6. Has the functions of sound absorption and noise reduction, ecological environmental protection and water drainage and skid resistance.

7. Mineral materials such as zeolite, talc and the like are not needed, so that resources are saved, and the cost is reduced.

Examples

The invention is further explained below by means of exemplary embodiments, but the invention is not limited to the specific embodiments described below.

Preparation example 1: preparation of molasses retarder a

100g of molasses spent liquor was weighed, placed in a container, to which was added sodium bicarbonate, the pH was adjusted to 8.0, and filtered. The obtained filtrate is added into a high-pressure reaction kettle, 10g of potassium permanganate is added into the reaction kettle, and oxidation reaction is carried out for 4 hours at 17KPa and 80 ℃ to obtain an oxidation product. Heating the obtained oxidation product to 125 ℃ under normal pressure, adding acetic acid into the oxidation product until the pH value is 2.0, then slowly adding hydrochloric acid, adjusting the pH value to 0.5, and stirring for 2 hours to obtain an acidification product. Further adding sodium hydroxide to the obtained acidified product under stirring, adjusting pH to 14.0, keeping at 125 deg.C for 1.5h, and cooling to room temperature to obtain alkalified product. And further adding a small amount of acetic acid into the obtained alkalized product at room temperature, and adjusting the pH value to be neutral to obtain the molasses retarder a.

Preparation example 2: preparation of molasses retarder b1 (reference example)

100g of molasses spent liquor was weighed, placed in a container, to which was added sodium bicarbonate, the pH was adjusted to 8.0, and filtered. The obtained filtrate was added to a high-pressure reaction vessel, 3.5g of potassium permanganate was added thereto, and oxidation reaction was carried out at 25KPa and 90 ℃ for 4 hours to obtain an oxidation product. Heating the obtained oxidation product to 125 ℃ under normal pressure, adding acetic acid into the oxidation product until the pH value is 2.0, then slowly adding hydrochloric acid, adjusting the pH value to 0.5, and stirring for 1.5h to obtain an acidified product. Further adding sodium hydroxide to the obtained acidified product under stirring, adjusting pH to 14.0, maintaining at 125 deg.C for 1.5h, and cooling to room temperature to obtain alkalified product. A small amount of acetic acid was further added to the obtained alkalized product at room temperature to adjust the pH to neutral, to obtain molasses set retarder b 1.

Preparation example 3: preparation of molasses retarder b2 (reference example)

Molasses retarder b2 was prepared in the same manner as in preparation example 1, except that the molasses filtrate was subjected to acidification treatment after filtration, and then to oxidation, alkalization and neutralization reactions to prepare molasses retarder b 2.

Example 1: preparation of concrete modifier 1

Slowly adding 10g of ferrous sulfate into a barrel filled with 140g of distilled water, stirring until the ferrous sulfate is fully dissolved, continuously adding 20g of 10% ferric sulfate aqueous solution into the barrel, and stirring for 30 min. To the resulting solution was added slowly 84g of calcium chloride particles under stirring, the addition was suspended when the temperature of the solution rose to 70 ℃, and about 20g of cold water was added to the solution to cool the solution and the addition was continued until 84g of calcium chloride was added in its entirety. Weighing 6g of anhydrous sodium sulfate, adding into water at 70 ℃, and stirring for dissolving; and slowly adding the sodium sulfate solution into the prepared solution, and standing for 40 min. Then, 6g of magnesium chloride and potassium chloride were added to the obtained mixed solution, and after standing for 15min, 2g of ammonium sulfate was added and the mixture was left standing for 30 min. To the resulting mixture was further added the remaining 96g of calcium chloride, and the temperature was controlled not to exceed 70 ℃. To the resulting mixed solution, 0.4g of the above molasses retarder a was slowly added, and 11.8g of a 4% calcium oxide aqueous solution was added under stirring, and stirring was continued for 24 hours to obtain a reddish-brown inorganic concrete improver 1.

Example 2: preparation of concrete improver 2

Concrete improver 2 was prepared in the same manner as in example 1 except that the amount of molasses retarder a was adjusted to 0.35g, and 10.2g of a 4% aqueous solution of calcium oxide was added to obtain inorganic type concrete improver 2.

Example 3: preparation of concrete improver 3

Concrete modifier 3 was prepared in the same manner as in example 1, except that the amount of molasses retarder a was adjusted to 0.7g, to obtain inorganic type concrete modifier 3.

Example 4: preparation of concrete improver 4

A concrete improver 4 was prepared in the same manner as in example 1, except that ferrous chloride and ferric chloride were used instead of ferrous sulfate and ferric sulfate, respectively, to obtain an inorganic type concrete improver 4.

Example 5: preparation of concrete improver 5

Concrete improver 5 was prepared in the same manner as in example 1, except that 5.1g of anhydrous sodium sulfate was used, to obtain inorganic type concrete improver 5.

Comparative example 1: preparation of concrete improver 6

Concrete modifier 6 was prepared in the same manner as in example 1, except that molasses retarder b1 was used in place of molasses retarder a, to give inorganic type concrete modifier 6.

Comparative example 2: preparation of concrete improver 7

Concrete improver 7 was prepared in the same manner as in example 1, except that molasses retarder b2 was used in place of molasses retarder a, to give inorganic type concrete improver 7.

Comparative example 3: preparation of concrete improver 8

Concrete improver 8 was prepared in the same manner as in example 1, except that 2.6g of molasses retarder a was used, to obtain inorganic type concrete improver 8.

Performance detection：

1. Preparing a cement sample:

the concrete improvers 1 to 8 prepared as described above were added to cement raw materials in a proportion of 0.07 wt% based on the total weight, respectively, to prepare cement samples 1 to 8, and the following tests were carried out, and the test results are shown in table 1 below.

Wherein the cement raw material comprises the following components: 55.0 percent of cement clinker, 23.0 percent of limestone, 2.0 percent of slag, 5.0 percent of gypsum, 5.0 percent of high silica sandstone and 10.0 percent of furnace bottom slag.

2. The detection method comprises the following steps:

(1) cubic compression strength and bending tensile strength: according to JTG E30-2005 test Specification for road engineering Cement and Cement concrete, detection is carried out at 20-22 ℃ and 44% -52% (R.H) relative humidity.

(2) Water permeability: and (4) detecting according to the standard of CJJ/T135-2009 technical Specification for pervious concrete pavements.

(3) Wear resistance: detection was performed according to the T0567-2005 standard.

Table 1: cement sample performance test result

As can be seen from the data in Table 1, the concrete modifier prepared by mixing the molasses retarder prepared by the method of the invention and other inorganic concrete additive components in a specific proportion can obviously improve the compressive strength and the bending tensile strength of a cement product while obtaining good water permeability and wear resistance after being mixed with a cement raw material.

The foregoing is merely an example of the present invention and common general knowledge of known specific structures and features of the embodiments is not described herein in any greater detail. It should be noted that, for those skilled in the art, without departing from the structure of the present invention, several changes and modifications can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicability of the patent. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.

Claims (7)

1. An inorganic permeable concrete modifying agent is prepared from the following raw materials in parts by weight:

165 portions of calcium chloride

6-12 parts of aqueous solution ferrous salt

0.4-2.8 parts of water-soluble iron (III) salt

4-8 parts of anhydrous sodium sulfate

4.4 to 7.2 portions of water-soluble magnesium salt

4.4 to 7.2 portions of water-soluble potassium salt

0.8-3.6 parts of ammonium chloride

0.2 to 1.6 portions of molasses retarder

0.23 to 2.2 portions of calcium oxide

180 portions of water and 280 portions of water;

the molasses retarder is prepared by the following method:

(A) adjusting the pH value of the molasses waste liquid to be neutral or alkalescent by using an alkaline substance, and filtering to obtain molasses filtrate A;

(B) sufficiently mixing the molasses filtrate A with an oxidant, putting the mixture into a high-pressure reaction kettle, and reacting for 2-5 hours at the temperature of 70-85 ℃ under the condition of 15-18KPa to obtain molasses solution B;

(C) acidifying the molasses solution B to the pH value of 0.5-1 to obtain molasses solution C;

(D) adding alkali into the molasses solution C at the temperature of 70-150 ℃, and carrying out an alkalization reaction to obtain a molasses solution D;

(E) adding a weak acid solution into the obtained molasses solution D, and adjusting the pH value to be neutral to obtain the molasses retarder;

wherein the oxidant used in the step (B) is selected from potassium permanganate or hydrogen peroxide, and the dosage of the oxidant is 7.5-11 parts by weight relative to 100 parts by weight of the molasses solution B.

2. The inorganic type pervious concrete improving agent according to claim 1, characterized in that the weight ratio of calcium oxide to molasses retarder is 1: 0.9-0.75.

3. The inorganic pervious concrete modifier of claim 1, characterized in that said molasses retarder is used in an amount of 0.08-0.15 wt% with respect to the total weight of said concrete modifier.

4. A method for preparing the inorganic type pervious concrete improving agent as claimed in any one of claims 1 to 3, comprising the steps of:

(1) weighing the raw materials according to the proportion;

(2) respectively putting the weighed water-soluble iron (III) salt, water-soluble magnesium salt, water-soluble potassium salt and ammonium chloride into independent dissolving barrels to prepare aqueous solutions;

(3) dissolving the weighed anhydrous sodium sulfate with warm water at 70 ℃ to prepare a sodium sulfate solution;

(4) respectively mixing the inorganic salt water solution, calcium chloride and water in a mixing barrel to prepare modifier mixed solution;

(5) slowly adding a molasses retarder into the obtained modifier mixed liquor;

(6) adding calcium oxide into water, dissolving, stirring, and pouring into a mixing barrel until the color of the mixed solution turns into red brown.

5. The production method according to claim 4, characterized in that the step (4) comprises:

i) injecting 120-160 parts by weight of water into the main barrel in advance, starting the stirrer, pouring the water-soluble ferrous salt, adding the dissolved water-soluble iron (III) salt solution after the water-soluble ferrous salt is completely dissolved, and continuing stirring;

ii) adding 80-110 parts by weight of calcium chloride particles in batches, stopping feeding when the temperature is raised to 70 ℃, cooling, and then continuously and slowly adding the calcium chloride until the calcium chloride particles are completely added;

iii) after the calcium chloride particles are completely dissolved, adding a sodium sulfate solution, and standing for 25-35 min;

iv) adding water-soluble magnesium salt solution, and standing for 15-30 min;

v) adding a water-soluble potassium salt solution, and standing for 15-30 min;

vi) adding an ammonium chloride solution, and standing for 20-45 min;

vii) adding the remaining calcium chloride particles in portions in the same manner as in step ii) above until the calcium chloride particles are completely added.

6. Use of the inorganic type pervious concrete improving agent as claimed in any one of claims 1 to 3 in the construction of ecological cities.

7. Use of the inorganic porous concrete modifier according to claim 6, wherein the ecological city construction comprises the pavement of frost-resistant porous roads.