CN115010387B - High-performance cement and preparation method thereof - Google Patents

Abstract

The invention discloses high-performance cement and a preparation method thereof, belonging to the technical field of cement, wherein the cement comprises a component A and a component B; the component A comprises the following raw materials in parts by weight: 50-60 parts of silicate cement clinker, 16-20 parts of dihydrate gypsum, 25-30 parts of modified gangue powder and nano ZrO (high-performance organic silicon) ₂ 0.8-1 part; the component B is an auxiliary agent, and the addition amount of the auxiliary agent is 10-12% of the mass of the component A. The cement comprises a component A and a component B, wherein the component B is matched with the component A for use when the cement is pulped; the component B is a self-made auxiliary agent, is a high molecular polymer, and contains benzene ring, carboxyl directly connected with the benzene ring and alcohol amine group on a molecular side chain; wherein, carboxyl and alcohol amine groups play a role in mutual synergism and play a role in grinding aid; in addition, the auxiliary agent molecules are adsorbed on the surface layer of the cement particles through electrostatic action to form a polymer film, so that mesoporous pores are filled in a blocking manner, and the effects of toughening the finished cement and improving the mechanical properties are achieved.

Description

High-performance cement and preparation method thereof

Technical Field

The invention belongs to the technical field of cement, and particularly relates to high-performance cement and a preparation method thereof.

Background

The cement is a powdery hydraulic inorganic cementing material, and can become plastic slurry after adding a proper amount of water, so that the cement can be hardened in air and water, and sand, stone and other materials can be firmly cemented together. It has long been an important gelling material, the method is widely applied to civil construction, water conservancy, national defense and other projects. The existing finished cement has the problems of low strength after solidification and easiness in cracking and increasing maintenance cost, so that the improvement of the strength of the cement has important significance.

The common cement-based composite material (common concrete or cement mortar) is heterogeneous and heterogeneous inorganic brittle material, and the porous material can accelerate the damage and greatly shorten the service life under the erosion action of external aggressive media such as carbon dioxide, water, chloride ions, sulfate and the like. With the development of industry, attempts have been made to add high molecular weight polymers having toughness and elastohydrodynamic properties to cement concrete and mortar. After the polymer material is added, many properties of the cement-based material such as strength, deformability, adhesive property, waterproof property, durability and the like are improved.

In the prior art, high molecular polymers are easy to flocculate and flash or increase viscosity after being added into cement paste, so that dispersibility is reduced, and various performances of cement are affected. In addition, the cement production process requires a large amount of energy consumption, and the grinding aid is the best means for saving energy, reducing consumption and saving cost in cement factories. At present, the cement grinding aid mainly uses alcohol amine substances such as triethanolamine, triisopropanolamine and the like as main raw materials, has good use effect, can reduce energy consumption by more than 20% under reasonable mixing amount, and has a certain early strength effect on produced cement. However, the alcohol amine grinding aid has poor performance stability, is very sensitive to parameter variation, and has high price, thus restricting further application.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides high-performance cement and a preparation method thereof.

The cement comprises a component A and a component B, wherein the component B is matched with the component A for use when the cement is pulped; the component B is a self-made auxiliary agent, is a high molecular polymer, and contains benzene ring, -COOH directly connected with the benzene ring and alcohol amine groups on molecular side chains; wherein-COOH and alcohol amine groups play a role in mutual synergism, and play a role in grinding aid; in addition, the-COOH in the auxiliary agent molecule and Ca in the cement paste ²⁺ The composite material has complexation effect, positive and negative charges are mutually attracted and adsorbed on the surface layer of cement particles through electrostatic effect to form a polymer film, so that mesoporous pores are blocked and filled, and the effects of toughening finished cement and improving mechanical properties are achieved.

The aim of the invention can be achieved by the following technical scheme:

a high-performance cement comprises a component A and a component B;

the component A comprises the following raw materials in parts by weight: 50-60 parts of silicate cement clinker, 16-20 parts of dihydrate gypsum, 25-30 parts of modified gangue powder and nano ZrO (high-performance organic silicon) ₂ 0.8-1 part;

the component B is an auxiliary agent, and the addition amount of the auxiliary agent is 10-12% of the mass of the component A.

Further, the modified gangue powder is prepared by the following steps:

crushing coal gangue, drying in a drying oven to constant weight, grinding into powder with particle size smaller than 10 μm, calcining in a high-temperature electric furnace at 1000-1200deg.C for 100-150min, cooling to room temperature, standing in-30deg.C and 30deg.C for 3 hr, and circulating for 8-10 times to obtain modified coal gangue powder.

The gangue is an ore, and has certain excitation after calcination and cold-hot alternate treatment, so that other components and cement powder particles can be promoted to form a stacked structure in the cement, the void ratio in the cement is reduced, the compressive strength of the cement mortar is improved, and the mechanical property and durability of the cement are improved.

Further, the auxiliary agent is prepared by the following steps:

s1, adding 4-carboxyl cinnamic acid and acetone into a flask with a mechanical stirrer and a thermometer, stirring and dissolving, heating to 50 ℃, slowly dropwise adding triethanolamine, continuously carrying out heat preservation reaction for 3 hours after the dropwise adding is finished, cooling to room temperature, and distilling under reduced pressure to remove the acetone to obtain a functional monomer; the dosage ratio of the 4-carboxyl cinnamic acid, the acetone and the triethanolamine is 0.1mol:80-100mL:0.11mol;

the functional monomer is prepared by adopting the esterification reaction of carboxyl on 4-carboxyl cinnamic acid and-OH on triethanolamine; although the 4-carboxyl cinnamic acid molecule contains two-COOH, the steric hindrance effect exists on the carboxyl directly connected with the benzene ring, so that the other-COOH has higher reaction activity, and the triethanolamine is controlled to be slightly excessive and the reaction conditions are controlled, so that the-COOH connected with the benzene ring does not participate in the reaction, and the specific reaction process is as follows:

s2, respectively dissolving an initiator APS and an emulsifier SDS in deionized water to form an initiator solution with the mass fraction of 1% and an emulsifier solution with the mass fraction of 1.5% for later use;

s3, dissolving half of the functional monomer into half of the emulsifier solution, adding the solution into a four-neck flask, adding half of the styrene monomer and 1/3 of the initiator solution, and reacting at the constant temperature of 70 ℃ for 1h to obtain seed emulsion;

s4, mixing the rest half of styrene with polybutadiene (low molecular weight), adding the rest half of emulsifier solution, stirring at a high speed of 1000r/min to uniformly disperse the mixture to obtain stable monomer micro-emulsion, uniformly mixing the monomer micro-emulsion with the rest of functional monomers, simultaneously dripping the mixture and the rest 2/3 of initiator solution into a four-neck flask containing seed emulsion, keeping a constant temperature condition of 70 ℃ in the dripping process, and continuously carrying out a constant temperature reaction for 3 hours after the dripping is completed to obtain an auxiliary agent;

the mass ratio of the low molecular weight polybutadiene to the styrene to the functional monomer is 60:50:13, and the amount of the initiator APS and the emulsifier SDS is 1% and 2% of the total mass of the monomers (the total mass of the low molecular weight polybutadiene, the styrene and the functional monomer) respectively;

using low molecular weight polybutadiene, styrene and functional monomer as polymerization monomers, and performing emulsion polymerization under the action of an initiator and an emulsifier to obtain a latex-type auxiliary agent; the molecular structural formula of the auxiliary agent is shown as follows:

introducing benzene ring, -COOH directly connected with the benzene ring and alcohol amine groups into a molecular side chain through the participation of functional monomers in polymerization reaction; the COOH groups are electronegative polar groups, and can be adsorbed on cement particles with positive charges in the cement grinding process, so that the surface electric field of the cement particles is eliminated, and the re-healing of the cement particles is avoided; the alcohol amine group has better softening effect on cement particles, the-COOH and the alcohol amine group have synergistic effect, so that the active dispersion effect can be achieved, the powder can be sufficiently ground, the coarse powder is avoided, and the auxiliary agent has grinding assisting effect;

the auxiliary agent is a high molecular polymer and forms a layer of film on the surface of cement particles through adsorption, so that the hydration process of cement can be delayed, aggregation is prevented, and the sedimentation stability of cement paste is improved; furthermore, the benzene ring is directly connected with the carboxyl, and the benzene ring is a rigid group and has a larger steric hindrance effect, so that particles are more dispersed among cement particles after being attached to the cement surface layer, and therefore, the dispersion performance of cement paste is better;

the auxiliary agent molecules are adsorbed on the surface layer of silicate mineral phase with positive charges through electrostatic action, and the-COOH in the molecules and Ca in cement paste ²⁺ The complex effect is also provided, and a polymer film is formed on the surface layer of the cement particles, so that the effect of filling pores is achieved, the filling effect can reduce the number of macropores of the finished cement and reduce the pore diameter of micropores, and the phenomenon that the stress of a local area is larger than the average stress is avoided, so that the toughness of the finished cement is improved; the auxiliary agent is adsorbed and filled between cement molecules in the hydration process, and when external impact force is applied, the auxiliary agent can absorb a part of acting force, so that the external impact force is reduced, the brittleness of the finished cement is reduced, and the toughness of the finished cement is improved.

A preparation method of high-performance cement comprises the following steps:

firstly, mixing silicate cement clinker and dihydrate gypsum, grinding by using a ball mill, and sieving by a 300-mesh sieve to obtain a cement matrix;

step two, placing the cement matrix in a high-temperature electric furnace, calcining at 1300-1350 ℃ for 40-50min, cooling to 160-180 ℃, and then mixing with nano ZrO ₂ Uniformly mixing the modified gangue powder and the modified gangue powder, and cooling to room temperature to obtain a component A;

and thirdly, when the composition is used, the component B and the component A are matched according to the proportion.

Further, the specific operation of the matched use is as follows: firstly grinding the component A and the component B of 1/4, then adding external water to prepare cement mortar, then adding the rest component B of 3/4 into the cement mortar, uniformly mixing, and finally forming and curing.

The invention has the beneficial effects that:

the cement comprises a component A and a component B, wherein the component B is matched with the component A for use when the cement is pulped; the component B is a self-made auxiliary agent, is a high molecular polymer, and contains benzene ring, -COOH directly connected with the benzene ring and alcohol amine groups on molecular side chains; wherein-COOH and alcohol amine groupsThe clusters have mutual synergistic effect and have the effect of the grinding aid; in addition, the-COOH in the auxiliary agent molecule and Ca in the cement paste ²⁺ The composite material has complexation effect, positive and negative charges are mutually attracted and adsorbed on the surface layer of cement particles through electrostatic effect to form a polymer film, so that mesoporous pores are blocked and filled, and the effects of toughening finished cement and improving mechanical properties are achieved.

The modified gangue powder is added into the component A, and the gangue is an ore, has certain excitation after calcination and cold-hot alternate treatment, can promote other components to form a stacked structure with cement powder particles in cement, reduces the void ratio in the cement, improves the compressive strength of cement mortar, and improves the mechanical property and durability of the cement.

Detailed Description

The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Example 1

Preparing modified gangue powder:

crushing coal gangue, drying in a drying oven to constant weight, grinding into powder with particle size smaller than 10 μm, placing the powder in a high-temperature electric furnace at 1000 ℃ for calcining for 100min, taking out, cooling to room temperature, placing in an environment of-30 ℃ and an environment of 30 ℃ for 3h respectively, and circulating for 8 times to obtain modified coal gangue powder.

Example 2

Preparing modified gangue powder:

crushing coal gangue, drying in a drying oven to constant weight, grinding into powder with particle size smaller than 10 μm, calcining in a 1200 deg.C high temperature electric furnace for 150min, cooling to room temperature, and standing in-30deg.C environment and 30deg.C environment for 3 hr for 10 times to obtain modified coal gangue powder.

Example 3

Preparing an auxiliary agent:

s1, adding 19.2g of 4-carboxyl cinnamic acid and 80mL of acetone into a flask with a mechanical stirrer and a thermometer, stirring and dissolving, heating to 50 ℃, slowly dropwise adding 16.39g of triethanolamine, continuously preserving heat for reaction for 3 hours after the dropwise adding is finished, cooling to room temperature, and distilling under reduced pressure to remove the acetone to obtain a functional monomer;

s2, respectively dissolving an initiator APS and an emulsifier SDS in deionized water to form an initiator solution with the mass fraction of 1% and an emulsifier solution with the mass fraction of 1.5% for later use;

s3, dissolving 6.5g of functional monomer in 82mL of emulsifier solution, adding the solution into a four-neck flask, adding 25g of styrene monomer and 41mL of initiator solution, and reacting for 1h at a constant temperature of 70 ℃ to obtain seed emulsion;

s4, mixing 25g of styrene and 60g of polybutadiene, adding 82mL of emulsifier solution, stirring at a high speed of 1000r/min to uniformly disperse the mixture to obtain stable monomer micro-emulsion, uniformly mixing the monomer micro-emulsion and 6.5g of functional monomer, and then simultaneously dripping the monomer micro-emulsion and 82mL of initiator solution into a four-neck flask containing seed emulsion, keeping a constant temperature condition of 70 ℃ in the dripping process, and continuing to perform constant temperature reaction for 3 hours after the dripping is completed to obtain the auxiliary agent.

Example 4

Preparing an auxiliary agent:

s1, adding 19.2g of 4-carboxyl cinnamic acid and 100mL of acetone into a flask with a mechanical stirrer and a thermometer, stirring and dissolving, heating to 50 ℃, slowly dropwise adding 16.39g of triethanolamine, continuously preserving heat for reaction for 3 hours after the dropwise adding is finished, cooling to room temperature, and distilling under reduced pressure to remove the acetone to obtain a functional monomer;

s2, respectively dissolving an initiator APS and an emulsifier SDS in deionized water to form an initiator solution with the mass fraction of 1% and an emulsifier solution with the mass fraction of 1.5% for later use;

s3, dissolving 6.5g of functional monomer in 82mL of emulsifier solution, adding the solution into a four-neck flask, adding 25g of styrene monomer and 41mL of initiator solution, and reacting for 1h at a constant temperature of 70 ℃ to obtain seed emulsion;

s4, mixing 25g of styrene and 60g of polybutadiene, adding 82mL of emulsifier solution, stirring at a high speed of 1000r/min to uniformly disperse the mixture to obtain stable monomer micro-emulsion, uniformly mixing the monomer micro-emulsion and 6.5g of functional monomer, and then simultaneously dripping the monomer micro-emulsion and 82mL of initiator solution into a four-neck flask containing seed emulsion, keeping a constant temperature condition of 70 ℃ in the dripping process, and continuing to perform constant temperature reaction for 3 hours after the dripping is completed to obtain the auxiliary agent.

Example 5

Preparing high-performance cement:

firstly, mixing 50g of silicate cement clinker and 16g of gypsum dihydrate, grinding by using a ball mill, and sieving by a 300-mesh sieve to obtain a cement matrix;

second, placing the cement matrix in a high-temperature electric furnace, calcining at 1300 ℃ for 40min, cooling to 160 ℃, and then mixing with 0.8g of nano ZrO ₂ And 25g of the modified gangue powder prepared in the example 1 are uniformly mixed, and cooled to room temperature to obtain a component A;

and thirdly, when the adhesive is used, the component B (the auxiliary agent prepared in the example 3) and the component A are matched according to the mass ratio of 10:100.

Example 6

Preparing high-performance cement:

firstly, mixing 55g of silicate cement clinker and 18g of gypsum dihydrate, grinding by using a ball mill, and sieving by a 300-mesh sieve to obtain a cement matrix;

second, placing the cement matrix in a high-temperature electric furnace, calcining at 1330 ℃ for 45min, cooling to 170 ℃, and then mixing with 0.9g of nano ZrO ₂ And 28g of the modified gangue powder prepared in the example 2 are uniformly mixed and cooled to room temperature to obtain a component A;

and thirdly, when the composition is used, the component B (the auxiliary agent prepared in the example 4) and the component A are matched according to the mass ratio of 11:100.

Example 7

Preparing high-performance cement:

firstly, mixing 60g of silicate cement clinker and 20g of gypsum dihydrate, grinding by using a ball mill, and sieving by a 300-mesh sieve to obtain a cement matrix;

second step, water is addedPlacing the mud matrix in a high-temperature electric furnace, calcining at 1350 ℃ for 50min, cooling to 180 ℃, and mixing with 1g of nano ZrO ₂ And 30g of the modified gangue powder prepared in the example 1 are uniformly mixed, and cooled to room temperature to obtain a component A;

and thirdly, when the composition is used, the component B (the auxiliary agent prepared in the example 3) and the component A are matched according to the mass ratio of 12:100.

Comparative example 1

The A component in example 5 was used as cement without adding any auxiliary agent.

Comparative example 2

The modified gangue powder in example 5 is changed into common gangue powder, and the rest raw materials and the preparation process are unchanged.

The cements obtained in examples 5-7 and comparative examples 1-2 were subjected to the following performance tests:

grinding the component A and the component B (auxiliary agent) 1/4 by using a grinding machine with the diameter of SM phi of 500mm multiplied by 500mm according to the specification of GB/T26748-2011, and keeping the grinding time at 30min and the grinding time at 5min in the grinding process to obtain a cement main body;

preparing cement mortar by a cement main body according to GBT 1346-2011 'inspection of water consumption, setting time and stability of cement standard consistency', adding the rest component B (auxiliary agent), uniformly mixing, and testing the sedimentation stability of cement paste;

according to the standard requirements of the test method of the mechanical properties of common concrete (GB 50081), firstly respectively preparing cement mortar into test blocks with the size of 70.7mm multiplied by 70.7mm, placing the test blocks into a standard curing box for curing 28d for compressive strength test, then respectively preparing the cement mortar into test blocks with the size of 40mm multiplied by 160mm, placing the test blocks into the standard curing box for curing 28d, and performing flexural strength test on the test samples;

the results are shown in the following table:

as is clear from the above data, in examples 5 to 7, the difference in density between the upper and lower layers of the cement mortar was 0.04 g.cm ^-3 The method has the advantages that the sedimentation stability of the cement mortar can be improved by adding the auxiliary agent into the cement mortar, so that the cement mortar has uniform up-down density after solidification, and various properties of a finished product are improved; the compressive strength of the finished products after curing of the cement prepared in the examples 5-7 is more than 52.5MPa, and the flexural strength is more than 8.0MPa, which shows that the finished products of the cement prepared in the invention have higher mechanical properties; the data of the comparative example 1 are combined, so that the addition of the auxiliary agent can effectively improve the sedimentation performance of the cement mortar and the mechanical strength of the finished product after the cement is cured; the data of comparative example 2 shows that the modified gangue powder can promote the improvement of the mechanical properties of cement to a certain extent.

In the description of the present specification, the descriptions of the terms "one embodiment," "example," "specific example," and the like, mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing is merely illustrative and explanatory of the invention, as various modifications and additions may be made to the particular embodiments described, or in a similar manner, by those skilled in the art, without departing from the scope of the invention or exceeding the scope of the invention as defined in the claims.

Claims (3)

1. The high-performance cement is characterized by comprising a component A and a component B;

the component A comprises the following raw materials in parts by weight: 50-60 parts of silicate cement clinker, 16-20 parts of dihydrate gypsum, 25-30 parts of modified gangue powder and nano ZrO (high-performance organic silicon) ₂ 0.8-1 part;

the component B is an auxiliary agent, and the addition amount of the auxiliary agent is 10-12% of the mass of the component A;

the modified gangue powder is prepared by the following steps:

crushing coal gangue, drying in a drying oven to constant weight, grinding into powder with particle size smaller than 10 μm, placing the powder in a high-temperature electric furnace with temperature of 1000-1200 ℃ for calcining for 100-150min, taking out, cooling to room temperature, placing in an environment with temperature of-30 ℃ and an environment with temperature of 30 ℃ for 3h respectively, and circulating for 8-10 times to obtain modified coal gangue powder;

the auxiliary agent is prepared by the following steps:

s1, adding 4-carboxyl cinnamic acid and acetone into a flask with a mechanical stirrer and a thermometer, stirring and dissolving, heating to 50 ℃, slowly dropwise adding triethanolamine, continuously carrying out heat preservation reaction for 3 hours after the dropwise adding is finished, cooling to room temperature, and distilling under reduced pressure to remove the acetone to obtain a functional monomer;

wherein the dosage ratio of the 4-carboxyl cinnamic acid, the acetone and the triethanolamine is 0.1mol:80-100mL:0.11mol;

s2, respectively dissolving an initiator APS and an emulsifier SDS in deionized water to form an initiator solution with the mass fraction of 1% and an emulsifier solution with the mass fraction of 1.5% for later use;

s3, dissolving half of the functional monomer into half of the emulsifier solution, adding the solution into a four-neck flask, adding half of the styrene monomer and 1/3 of the initiator solution, and reacting at the constant temperature of 70 ℃ for 1h to obtain seed emulsion;

s4, mixing the rest half of styrene with low molecular weight polybutadiene, adding the rest half of emulsifier solution, stirring at a high speed of 1000r/min to uniformly disperse the mixture to obtain stable monomer micro-emulsion, uniformly mixing the monomer micro-emulsion with the rest of functional monomers, simultaneously dripping the mixture and the rest 2/3 of initiator solution into a four-neck flask containing seed emulsion, keeping a constant temperature condition of 70 ℃ in the dripping process, and continuously carrying out a constant temperature reaction for 3 hours after the dripping is completed to obtain the auxiliary agent.

2. The high-performance cement according to claim 1, wherein the amount of the low-molecular weight polybutadiene, the amount of the styrene and the amount of the functional monomer are respectively 1% and 2% by mass of the total mass of the low-molecular weight polybutadiene, the amount of the styrene and the amount of the emulsifier SDS are respectively 60:50:13 by mass.

3. The method for preparing high-performance cement according to claim 1, comprising the steps of:

firstly, mixing silicate cement clinker and dihydrate gypsum, grinding by using a ball mill, and sieving by a 300-mesh sieve to obtain a cement matrix;

step two, placing the cement matrix in a high-temperature electric furnace, calcining at 1300-1350 ℃ for 40-50min, cooling to 160-180 ℃, and then mixing with nano ZrO ₂ Uniformly mixing the modified gangue powder and the modified gangue powder, and cooling to room temperature to obtain a component A;

and thirdly, when the composition is used, the component B and the component A are matched according to the proportion.