CN113372047B - Cementing material of dolomite composite emulsified asphalt and preparation method thereof - Google Patents

Abstract

The invention belongs to the technical field of building materials, and particularly relates to a cementing material of dolomite composite emulsified asphalt and a preparation method thereof. The cementing material comprises, by weight, 100-120 parts of dolomite mineral powder, 1-3 parts of emulsified asphalt and 8-15 parts of alkali activator, wherein the emulsified asphalt comprises, by weight, 1-6 parts of emulsifier, 90-130 parts of water and 90-130 parts of asphalt. According to the invention, the dolomite is mixed with the emulsified asphalt by utilizing the capabilities of promoting hydration and generating gel of the dolomite to form an interpenetrating network structure of organic polymer and inorganic gel, so that the defects of insufficient toughness and large brittleness of geopolymer materials can be improved, and the problem of insufficient early compressive strength of common emulsified asphalt composite materials can be effectively solved by virtue of the characteristics of high strength and early strength of geopolymer.

Description

A kind of cementing material of dolomite composite emulsified asphalt and its preparation method

technical field

The invention belongs to the technical field of building materials, and in particular relates to a cementing material of dolomite composite emulsified asphalt and a preparation method thereof.

Background technique

Dolomite (CaMg(CO ₃ ) ₂ ) is a kind of abundant and cheap carbonate rock material. A large amount of discarded dolomite dust produced in the mining process of the quarry is very easy to generate dust and endanger human health, and it is an industrial waste that needs to be resolved urgently. As a main concrete-bonding material, asphalt has become the first choice material for modern highways because of improving the driving comfort, safety and service life of highway pavement. However, general emulsified asphalt composites have the technical problem of insufficient early strength. Combining emulsified asphalt with geopolymers can not only improve the shortcomings of geopolymers, such as insufficient toughness and high brittleness, but also can effectively solve the early compressive strength of general emulsified asphalt composites by virtue of the characteristics of high strength and early strength of geopolymers. Insufficient problem. Dolomite has been found in previous studies to promote the hydration of cement, and can form a gel with consolidation properties in an alkaline environment. Therefore, dolomite and asphalt can be combined to form an interpenetrating network structure of organic polymers and inorganic gels, turning waste into treasure, and obtaining composite materials that enhance the toughness of geopolymers and the high-strength and early-strength properties of emulsified asphalt.

CN103232182A discloses a geopolymer/emulsified asphalt composite material and its preparation method, specifically disclosing that it is mainly composed of the following components in parts by weight: 75-95 parts of geopolymer slurry and 5-25 parts of emulsified asphalt; The geopolymer slurry is mainly composed of the following components in parts by weight: 50-60 parts of alkali-activated active materials and 50-60 parts of modified water glass. The alkali-activated active material is one or a mixture of two or more selected from metakaolin, slag and fly ash. Although this technical solution uses oligomers and emulsified asphalt to obtain a high-strength and high-toughness cementitious material, it does not disclose the synergistic effect of dolomite and asphalt.

CN102531471A discloses emulsified asphalt, a mixture containing it, and a road surface formed from the mixture, and specifically discloses an emulsified asphalt cold recycled mixture, which contains milling material, fresh aggregate, optional mineral powder, emulsified asphalt , Optional cement and water, according to the weight of the emulsified asphalt cold recycled mixture, it contains: milling material 60-95%, cement 0-2%, mineral powder 0-5%, emulsified asphalt 3.0-5.0%, 1-4% of water and an appropriate amount of new aggregate are added, and the new aggregate is selected from one or more of limestone, dolomite, basalt, sandstone, and granite. Although this technical solution discloses the combination of emulsified asphalt and limestone, it does not disclose the combination of dolomite and asphalt to form an interpenetrating network structure of organic polymers and inorganic gels.

Therefore, the prior art still lacks high-strength and early-strength performance composite materials that fully exert the effects of dolomite and emulsified asphalt.

Contents of the invention

In view of the above defects or improvement needs of the prior art, the present invention provides a dolomite composite emulsified asphalt cementing material, the purpose of which is to use dolomite to promote hydration and gel formation by adjusting the composition and activity of the emulsified asphalt, Dolomite is mixed with emulsified asphalt to form an interpenetrating network structure of organic polymers and inorganic gels, so that the synergistic effect of dolomite and asphalt can not only improve the shortcomings of insufficient toughness and high brittleness of geopolymer materials, but also can use The high-strength and early-strength characteristics of geopolymers can effectively solve the problem of insufficient early compressive strength of general emulsified asphalt composite materials.

In order to achieve the above object, according to one aspect of the present invention, a kind of cementitious material of dolomite composite emulsified asphalt is provided, comprising 100-120 parts of dolomite mineral powder, 1-3 parts of emulsified asphalt and 8-15 parts of alkali activator, The emulsified asphalt comprises 1-6 parts of emulsifier, 90-130 parts of water and 90-130 parts of asphalt in parts by weight.

Preferably, the mass ratio of dolomite mineral powder to emulsified asphalt is 100:(1.5-2).

Preferably, the emulsifier is JY-C2 cationic medium-cracked asphalt emulsifier, SQBIO M1 cationic medium-cracked asphalt emulsifier or SQBIO M3 cationic medium-cracked asphalt emulsifier.

Preferably, the asphalt is 70# petroleum asphalt or 90# petroleum asphalt.

Preferably, the alkali activator is formed by mixing sodium silicate water glass and sodium hydroxide.

As preferably, the ratio of the amount of substance of sodium silicate water glass and sodium hydroxide is 1:(1.5-8).

Preferably, the particle size of the dolomite mineral powder does not exceed 0.075mm.

According to another aspect of the present invention, a kind of preparation method of the cementitious material of dolomite composite emulsified asphalt is provided, comprising the following steps:

(1) Heat and melt the asphalt first, then continuously add molten asphalt into the mixing system of emulsifier and water to obtain emulsified asphalt;

(2) Add dolomite mineral powder to alkali activator and mix uniformly to obtain wet powder, then add emulsified asphalt, and mix uniformly to form wet powder containing emulsified asphalt;

(3) The wet powder containing the emulsified asphalt is pressed into a mould, and the aforementioned cementitious material can be obtained after demoulding.

Preferably, the pressure of the compression molding is 50-80 MPa, and the time is 1-5 minutes.

The beneficial effects of the present invention have:

(1) The present invention adjusts the composition and activity of the emulsified asphalt, so that the synergistic effect of dolomite and asphalt, utilizes the ability of dolomite to promote hydration and generate gel, and mixes dolomite with emulsified asphalt to form organic polymer and inorganic gel The interpenetrating network structure can not only improve the shortcomings of insufficient toughness and high brittleness of geopolymer materials, but also can effectively solve the problem of insufficient early compressive strength of general emulsified asphalt composite materials by virtue of the high-strength and early-strength characteristics of geopolymers.

(2) Dolomite undergoes dedolomitization reaction and ion cross-linking reaction in alkaline environment to form hydrated calcium magnesium silicate gel, and the inorganic gel binds undissolved particles to form a skeleton. Due to the polar surface of the particle skeleton, the emulsified asphalt will demulsify on its surface, so that the asphalt can be tightly coated on the surface of the inorganic particle skeleton, forming a tough interpenetrating bond inside the skeleton.

(3) The preparation method of the present invention is completed under normal temperature conditions, without the need for externally applied energy, and has the advantage of energy saving in technology; the added alkaline activation dose is less and is in a wet powder state, which is conducive to cost control and environmental protection. Protection, using waste dolomite powder as solid raw material, energy saving and environmental protection, low cost, and broaden the application range of waste dolomite dust.

(4) The production cycle of the present invention is short, and the prepared samples have high-strength and early-strength properties, and have better toughness than pure geopolymer samples.

Detailed ways

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

Example

Preparation Example

Preparation of alkali activator: weigh 15g of sodium silicate water glass with a modulus of 3.1 (i.e. in Na ₂ O nSiO ₂ , n=3.1), add 1.5g of NaOH solid therein, stir and dissolve as alkali activator ,spare.

Preparation of dolomite mineral powder: Grind dolomite into powder in a disc mill, with a particle size of no more than 0.075 mm.

Example 1

A cementing material of dolomite composite emulsified asphalt prepared by the following method:

(1) Use a metal container to weigh 450g of heated asphalt and keep it warm in an oven at 165°C for later use. Use a metal container to weigh 20g of emulsifier and add 450g of water to heat and stir, pour it into the colloid mill and start the instrument for 10-15 seconds Finally, slowly add asphalt and keep stirring, after 40 seconds, take a sample and seal it up to obtain emulsified asphalt;

(2) Add 30g of dolomite mineral powder to 3.3g of alkali activator and mix uniformly to obtain a wet powder, then add 1.2g of emulsified asphalt, and mix evenly to form a wet powder containing emulsified asphalt;

Add 2.7-3.3 g of alkali activator (2) dropwise to the solid component (1) while grinding, make it mix evenly, and form a state of wet powder. Then add 0.3g-1.2g emulsified asphalt (3) therein, and mix uniformly to form a wet powder containing emulsified asphalt.

(3) Put the wet powder containing emulsified asphalt into a cylindrical mold with a diameter of 10mm, hold the load under a pressure of 50MPa for 1 minute, and then demould to obtain the cementitious material.

Example 2-Example 7, the preparation method is the same as Comparative Example 1-4, the main difference is that the quality and ratio of dolomite, emulsified asphalt and alkali activator are different, as shown in Table 1.

Test Example

Compressive strength test, the test method is: use a universal press MTS (Meters Industrial Systems (China) Co., Ltd.) to test the compressive strength (uniaxial compression method) of the sample. The loading method is displacement loading, and the loading rate is 2 mm/min. The test results are shown in Table 1.

The flexural strength test, the test method is: the flexural strength (three-point bending method) of the sample is tested by a universal press MTS (Meters Industrial Systems (China) Co., Ltd.). The loading method is displacement loading, and the loading rate is 2 mm/min. The test results are shown in Table 1.

The formula of the embodiment of table 1 and test result table

Analysis of the data in Table 1 shows that the dolomite composite emulsified asphalt cementitious material has excellent compressive strength and flexural strength. When the amount of emulsified asphalt added is small, the compressive strength of the sample is higher. Regarding the flexural strength of the sample, when the amount of emulsified asphalt added is between 0.8% and 3% by mass of dolomite, the flexural strength of the sample is significantly higher than that of the sample without emulsified asphalt. When the amount of emulsified asphalt added is between 1.5% and 2% by mass of dolomite, the overall performance is more excellent. The results show that the appropriate amount of emulsified asphalt can further improve the flexural strength of the sample on the premise of ensuring that the sample has excellent compressive strength.

In summary, the present invention utilizes the ability of dolomite to generate gel in an alkaline environment, and mixes it with emulsified asphalt to form an interpenetrating network structure of organic polymer and inorganic gel, so that the sample has both geopolymer and asphalt The combination of rigidity and softness can be used as a new type of cement-based pavement repair material.

It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.

Claims (8)

1. The cementing material of the dolomite composite emulsified asphalt is characterized by comprising 100 parts by weight of dolomite mineral powder, 1.5-2 parts by weight of emulsified asphalt and 8-15 parts by weight of alkali activator, wherein the emulsified asphalt comprises 1-6 parts by weight of emulsifier, 90-130 parts by weight of water and 90-130 parts by weight of asphalt; carrying out dolomization reaction and ionic crosslinking reaction on the dolomite mineral powder in an alkaline environment of an alkali activator to form hydrated magnesium calcium silicate gel, wherein undissolved particles are bonded by the hydrated magnesium calcium silicate gel to form a framework; the emulsified asphalt is demulsified on the surface of the framework, so that the asphalt can be tightly coated on the surface of the inorganic particle framework to form tough interpenetrating adhesion in the framework.

2. A cementitious material as claimed in claim 1 wherein the emulsifier is JY-C2 cation split asphalt emulsifier, SQBIO M1 cation split asphalt emulsifier or SQBIO M3 cation split asphalt emulsifier.

3. The cementitious material of claim 2, wherein the asphalt is 70# petroleum asphalt or 90# petroleum asphalt.

4. The cementitious material of claim 1, wherein the alkali activator is a mixture of sodium silicate waterglass and sodium hydroxide.

5. A cementitious material according to claim 4 characterised in that the ratio of the amounts of the sodium silicate waterglass and the sodium hydroxide species is 1 (1.5-8).

6. The cementitious material of claim 1, wherein the dolomite mineral fines have a particle size of no more than 0.075mm.

7. A method for preparing a cementitious material of dolomitic composite emulsified asphalt according to any one of claims 1 to 6, comprising the steps of:

(1) Heating and melting asphalt, and continuously adding molten asphalt into a mixed system of an emulsifier and water to obtain emulsified asphalt;

(2) Adding the dolomite mineral powder into an alkali activator, uniformly mixing to obtain wet powder, then adding emulsified asphalt, and uniformly mixing to form wet powder containing the emulsified asphalt;

(3) Pressing and molding the wet powder containing the emulsified asphalt in a mold, and demolding to obtain the cementing material of any one of claims 1 to 6.

8. The method for preparing a cementitious material according to claim 7, wherein the pressure of the press forming is 50 to 80MPa and the time is 1 to 5 minutes.