阅读说明：本技术 一种双网络增强复合快干凝胶水泥材料及其制备方法 (Double-network reinforced composite quick-drying gel cement material and preparation method thereof ) 是由 陈克坚 于 2019-11-01 设计创作，主要内容包括：本发明提供一种双网络增强复合快干凝胶水泥材料及其制备方法,按重量组分计包括以下成分：聚甲基丙烯酸羟乙基酯30份～40份；碳纤维-有机-无机双网络聚合物35份～48份；植物纤维15份～20份；膨润土纳米颗粒10份～20份；表面活性剂10份～20份；石墨烯10份～20份；六方氮化硼10份～20份；硼酸2份～5份；磷酸三钙10份～15份；氧化还原体系引发剂5份～10份；交联剂4份～8份；聚羧酸系高效减水剂3份～5份。采用利用工业生产废弃物生产的碳纤维-有机-无机双网络聚合物接枝植物纤维与聚甲基丙烯酸羟基酯达到良好的接枝共聚效果,增强了合成的水泥材料的抗弯曲强度和延展性；添加石墨烯可以使水泥系统形成监测混凝土各个参数的自监测系统。(The invention provides a double-network reinforced composite quick-drying gel cement material and a preparation method thereof, wherein the double-network reinforced composite quick-drying gel cement material comprises the following components in parts by weight: 30-40 parts of polyhydroxyethyl methacrylate; 35-48 parts of carbon fiber-organic-inorganic double-network polymer; 15-20 parts of plant fiber; 10-20 parts of bentonite nanoparticles; 10-20 parts of a surfactant; 10-20 parts of graphene; 10-20 parts of hexagonal boron nitride; 2-5 parts of boric acid; 10-15 parts of tricalcium phosphate; 5-10 parts of redox system initiator; 4-8 parts of a crosslinking agent; 3-5 parts of polycarboxylic high-efficiency water reducing agent. The carbon fiber-organic-inorganic double-network polymer produced by industrial production waste is adopted to graft the plant fiber and the polyhydroxy methacrylate to achieve good graft copolymerization effect, so that the bending strength and the ductility of the synthesized cement material are enhanced; the addition of the graphene enables a cement system to form a self-monitoring system for monitoring each parameter of the concrete.)

1. The double-network reinforced composite quick-drying gel cement material is characterized by comprising the following components in parts by weight:

30-40 parts of polyhydroxyethyl methacrylate;

35-48 parts of carbon fiber-organic-inorganic double-network polymer;

15-20 parts of plant fiber;

10-20 parts of bentonite nanoparticles;

10-20 parts of a surfactant;

10-20 parts of graphene;

10-20 parts of hexagonal boron nitride;

2-5 parts of boric acid;

10-15 parts of tricalcium phosphate;

5-10 parts of redox system initiator;

4-8 parts of a crosslinking agent;

3-5 parts of polycarboxylic high-efficiency water reducing agent.

2. The dual network reinforced composite quick-drying gel cement material as claimed in claim 1, wherein the carbon fiber-organic-inorganic dual network polymer is prepared by a method comprising the steps of:

s1: drying the industrial waste rich in mineral components in an oven at 100-110 ℃ to constant weight, grinding and sieving by a 200-mesh sieve to obtain the industrial waste grinding material; calcining 30-40 parts of the industrial waste abrasive in a furnace, gradually raising the temperature in the furnace to 1150-1300 ℃ at the speed of 30 ℃/min, calcining at the final temperature for 6-6.5 h to form an inorganic salt precursor, then reducing the temperature of the inorganic salt precursor at 25-27 ℃/min for 30min, adding distilled water and 5-8 parts of carbon fiber, stirring, and hydrating inorganic salt to form micro-particles, so as to gradually form grid-shaped carbon fiber-polyelectrolyte matrix colloid;

s2: dissolving NaOH in distilled water to form a NaOH solution with the concentration of 1-1.5M, slowly adding an organic polymer raw material into the NaOH solution, adding the grid-shaped carbon fiber polyelectrolyte matrix colloid formed in the step S1 to form an organic matter filled grid-shaped carbon fiber-polyelectrolyte double-network colloid with the organic polymer mass fraction of 30-35%, and adding 5-10 ml of tetramethylethylenediamine for crosslinking to form the carbon fiber-organic-inorganic double-network polymer.

3. The dual-network reinforced composite quick-drying gel cement material as claimed in claim 2, wherein the industrial waste is one or more of fly ash, blast furnace slag, bottom ash or steel slag.

4. The dual-network reinforced composite quick-drying gel cement material as claimed in claim 1, wherein the carbon fiber-organic-inorganic dual-network polymer is composed of a first network structure synthesized by hydration of inorganic substances and a first network structure synthesized by the polymerization of organic substances and a second network structure synthesized by the growth of inorganic salts along carbon fibers.

5. The dual network reinforced composite quick-drying gel cement material as claimed in claim 4, wherein the hydrated inorganic salt is one or more of hydrated calcium silicate salt, hydrated sulfate salt, hydrated sulphoaluminate salt or hydrated aluminosilicate; the organic matter is one or more of polyacrylamide, polyacrylic acid, polyethylene glycol or polylactic acid.

6. The dual-network reinforced composite quick-drying gel cement material as claimed in any one of claims 1 to 5, wherein the oxidant in the initiator is one or more of sodium sulfite, sodium bisulfite or sodium hydrosulfite, and the reductant in the initiator is one or more of potassium persulfate or ammonium persulfate.

7. The dual-network reinforced composite quick-drying gel cement material as claimed in claim 6, wherein the molar ratio of the oxidant to the reductant in the initiator is 1: 5-3: 5.

8. The dual network reinforced composite quick-drying gel cement material as claimed in any one of claims 1 to 5, wherein the cross-linking agent is one or more of sorbitol, D-mannitol or galactitol.

9. The dual network reinforced composite quick-drying gel cement material as claimed in any one of claims 1 to 5, wherein the plant fiber is one or more of straw, wheat straw, corn straw, palm fiber, sisal fiber or sugar cane fiber.

10. The preparation method of the double-network reinforced composite quick-drying gel cement material according to claim 1, characterized by comprising the following steps:

s1: dissolving the carbon fiber-organic-inorganic double-network polymer in the weight portion in ethanol, adding the initiator and the plant fiber in the weight portion into the double-network polymer ethanol solution, and stirring for 3-5 min at the temperature of 18-20 ℃;

s2: adding the graphene and the hexagonal boron nitride in parts by weight to the mixed solution of the step S1, and dropwise adding the surfactant in parts by weight while uniformly stirring at a rotation speed of 150-200 rpm;

s3: dissolving the calcium triphosphate in parts by weight in a Na2HPO4 solution with the mass fraction of 3.0%, uniformly stirring, adding the polyhydroxyethyl methacrylate, the bentonite nanoparticles, the carbon fibers, the boric acid, the cross-linking agent and the polycarboxylic acid-based high-efficiency water reducing agent in parts by weight, uniformly stirring with the mixture obtained in the step S2 at the rotating speed of 200-300 rpm for 15-20 min, and obtaining the double-network reinforced composite quick-drying gel cement material.

Technical Field

The invention relates to cement, belongs to the technical field of building materials, and particularly relates to a double-network reinforced composite quick-drying gel cement material and a preparation method thereof.

Background

Cement concrete is one of the building materials widely used in the world nowadays, however, cement concrete structures often suffer some non-mechanical damage when the designed service life is not reached. Sulfate attack failure is one of the common non-mechanical failure forms of concrete. China has a wide ocean area and a long coastline, the concentration of sulfate ions in seawater is about 2.54-3.06 g/L, and the salt content in coastal saline soil is generally higher than 5%, so that a cement concrete structure in the ocean environment cannot be corroded by sulfate in seawater in the service process. For example, sulfate erosion damage of different degrees exists in ocean engineering, cross-sea bridges, offshore oil production platforms, harbors and submarine tunnels in China.

A large number of saline-alkali zones are possessed in regions such as Xinjiang, Tibet, Qinghai, Gansu, Ningxia and inner Mongolia in the western China, and a large number of sulfate ions exist in saline soil. The concrete structure buildings such as roads, bridge tunnels, ground and underground buildings, underground pipelines, electric wire towers and the like in western regions are seriously damaged due to sulfate corrosion only after being used for a few years, large-scale repair work has to be carried out, and huge maintenance cost is consumed, so that huge economic loss is generated. It can be seen that the problem of concrete sulfate erosion is a very prominent problem in China, not only is the high maintenance cost required for the damaged concrete structure, but also the lack of cement materials which are resistant to corrosion, highly resistant to bending and not easy to crack from the source.

Chinese patent 201710897493.7 discloses an environment-friendly decorative cement, which adopts the technical scheme that: the cement is prepared from silicate cement, an expanding agent, metakaolin, silicon powder, whiskers, redispersible latex powder, a water reducing agent, a defoaming agent, cellulose ether, heavy calcium, an environment-friendly material and the like, although the environment-friendly material is adopted and has workability and corrosion resistance, a large amount of auxiliary additives such as the water reducing agent, the defoaming agent, the cellulose ether and the like are used in the adopted material, so that the porosity of the decorative cement is high, the corrosion resistance effect is not particularly good, the used environment-friendly material and silicate cement clinker cannot be well fused, the compressive strength and the ductility of a cement material finished product are reduced, and the decorative cement is easy to break.

Disclosure of Invention

Aiming at the defects, the invention provides the double-network reinforced composite quick-drying gel cement material which has high bending strength, good ductility, difficult fracture and corrosion, recycles industrial and agricultural production wastes and can form a self-monitoring system.

The invention provides the following technical scheme:

a double-network reinforced composite quick-drying gel cement material comprises the following components in parts by weight:

30-40 parts of polyhydroxyethyl methacrylate;

35-48 parts of carbon fiber-organic-inorganic double-network polymer;

15-20 parts of plant fiber;

10-20 parts of bentonite nanoparticles;

10-20 parts of a surfactant;

10-20 parts of graphene;

10-20 parts of hexagonal boron nitride;

2-5 parts of boric acid;

10-15 parts of tricalcium phosphate;

5-10 parts of redox system initiator;

4-8 parts of a crosslinking agent;

3-5 parts of polycarboxylic high-efficiency water reducing agent.

Further, the preparation method of the organic-inorganic double-network polymer comprises the following steps:

s1: drying the industrial waste rich in mineral components in an oven at 100-110 ℃ to constant weight, grinding and sieving by a 200-mesh sieve to obtain the industrial waste grinding material; calcining 30-40 parts of the industrial waste abrasive in a furnace, gradually raising the temperature in the furnace to 1150-1300 ℃ at the speed of 30 ℃/min, calcining at the final temperature for 6-6.5 h to form an inorganic salt precursor, then reducing the temperature of the inorganic salt precursor at 25-27 ℃/min for 30min, adding distilled water and 5-8 parts of carbon fiber, stirring, and hydrating inorganic salt to form micro-particles, so as to gradually form grid-shaped carbon fiber-polyelectrolyte matrix colloid;

s2: dissolving NaOH in distilled water to form a NaOH solution with the concentration of 1-1.5M, slowly adding an organic polymer raw material into the NaOH solution, adding the grid-shaped carbon fiber polyelectrolyte matrix colloid formed in the step S1 to form an organic matter filled grid-shaped carbon fiber-polyelectrolyte double-network colloid with the organic polymer mass fraction of 30-35%, and adding 5-10 ml of tetramethylethylenediamine for crosslinking to form the carbon fiber-organic-inorganic double-network polymer.

Further, the industrial waste is one or more of fly ash, blast furnace slag, bottom ash or steel slag.

Further, the carbon fiber-organic-inorganic double-network polymer is composed of a first network structure synthesized by the hydration of inorganic matters and the growth of the polyhydrated inorganic salt along the carbon fiber and an organic second network structure synthesized by the polymerization of organic matters.

Further, the hydrated inorganic salt is one or more of hydrated calcium silicate salt, hydrated sulfate, hydrated sulphoaluminate or hydrated aluminosilicate; the organic matter is one or more of polyacrylamide, polyacrylic acid, polyethylene glycol or polylactic acid.

Further, the oxidant in the initiator is one or more of sodium sulfite, sodium bisulfite or sodium hydrosulfite, and the reducing agent in the initiator is one or more of potassium persulfate or ammonium persulfate.

Further, the molar ratio of the oxidizing agent to the reducing agent in the initiator is 1: 5-3: 5.

further, the cross-linking agent is one or more of sorbitol, D-mannitol or galactitol.

Further, the plant fiber is one or more of straw, wheat straw, corn straw, palm fiber, sisal fiber or sugarcane fiber.

The invention also provides a preparation method of the double-network reinforced composite quick-drying gel cement material, which comprises the following steps:

s1: dissolving the carbon fiber-organic-inorganic double-network polymer in the weight portion in ethanol, adding the initiator and the plant fiber in the weight portion into the double-network polymer ethanol solution, and stirring for 3-5 min at the temperature of 18-20 ℃;

s2: adding the graphene and the hexagonal boron nitride in parts by weight to the mixed solution of the step S1, and dropwise adding the surfactant in parts by weight while uniformly stirring at a rotation speed of 150-200 rpm;

s3: dissolving the calcium triphosphate in parts by weight in a Na2HPO4 solution with the mass fraction of 3.0%, uniformly stirring, adding the polyhydroxyethyl methacrylate, the bentonite nanoparticles, the carbon fibers, the boric acid, the cross-linking agent and the polycarboxylic acid-based high-efficiency water reducing agent in parts by weight, uniformly stirring with the mixture obtained in the step S2 at the rotating speed of 200-300 rpm for 15-20 min, and obtaining the double-network reinforced composite quick-drying gel cement material.

The invention has the beneficial effects that:

1) the addition of the polyhydroxyethyl methacrylate can cooperate with a carbon fiber-organic-inorganic double-network polymer to contain bentonite nanoparticles and plant fibers, and can improve the mechanical property and the bending strength and the ductility of the cement system on the premise of not influencing the workability and the processability of the cement system.

2) The carbon fiber-organic-inorganic double-network polymer is adopted to prepare the cement material, in the process of preparing the double-network polymer, firstly, inorganic matter is subjected to hydration reaction to form an inorganic gel component, the inorganic gel component is used as a first relatively hard skeleton structure network, then, organic monomers are copolymerized to form a second relatively soft polymer network with good toughness and is attached to the first skeleton structure network, the inorganic first network structure provides a rigid support for the composite gel cement material, and the soft organic second network structure is attached to and filled in the inorganic first network structure, so that the gel state of the cement material can be ensured, external stress is absorbed, the first network structure is effectively prevented from being broken in a large area range, and the condition that the composite gel cement material is easily broken is further prevented.

3) The graphene is added in the manufacturing components, so that the mechanical energy of the manufactured cement material can be increased, the cement material can be used as a sensor base material, the self-monitoring of a concrete structure manufactured by using the cement can be realized, a sensor network capable of measuring parameters such as displacement, strain and temperature is formed, real-time data of a structural state can be provided for the damage of the concrete, an early warning signal is triggered in time, and the damage position is roughly judged. By adding the surfactant, the graphene can be uniformly dispersed in the cement material, and a self-monitoring system with stable mechanical properties and pressure-sensitive electrical properties is formed.

4) The hexagonal boron nitride is added into the manufacturing components, has similar characteristics with the graphene, further enhances the mechanical energy of the cement material, and has good electrical insulation, thermal conductivity and chemical corrosion resistance; the heat stability and the wear resistance are strong, the corrosion by inorganic acid and water is avoided, and the adaptability to salt and alkali is strong; chemically inert to almost all molten metals. In the practical use process of the invention, when the cement is solidified, the hexagonal boron nitride and tricalcium phosphate are adsorbed and gathered in network pores, and as the hexagonal boron nitride is in a hexagonal crystal form and has compactness, the hexagonal boron nitride and graphite fill the residual pores with generated apatite-Ca 5(PO4)3OH and calcium phosphate-CaHPO 4.2H2O, so that a more compact structure is formed, the penetration of salt and alkali is reduced, the compressive strength is increased, the expansion rate is reduced, and the service life of the cement is prolonged.

5) The carbon fiber has high axial strength and modulus, low density, no creep, high temperature resistance in non-oxidizing environment, high fatigue resistance, specific heat and conductivity between that of nonmetal and metal, small thermal expansion coefficient, anisotropy, no swelling in organic solvent, acid and alkali and outstanding corrosion resistance. The organic network and the inorganic network in the carbon fiber-organic-inorganic double-network polymer grow along the carbon fiber to compound the carbon fiber, thereby improving the strength of the carbon fiber-organic-inorganic double-network polymer and forming a three-dimensional structure. The hexagonal boron nitride and the graphite grow in a three-dimensional and multi-directional manner with the generated apatite-Ca 5(PO4)3OH and phosphorus calcium-CaHPO 4.2H2O to form an internal structure network of the gel cement, and the structural strength, the compressive strength and the tensile strength of the gel cement are obviously improved. The carbon fiber further reinforces the plant fiber, the plant fiber connects and grafts the carbon fiber, and the strong adhesive force of the pores on the surface of the carbon fiber provides an adhesion basis of the carbon fiber-organic-inorganic double-network polymer for the cement material.

6) The boric acid is added to inhibit the reversible reaction of the hexagonal boron nitride under the action of tricalcium phosphate, so that the stability of the hexagonal boron nitride is improved. And meanwhile, the boric acid plays a role of an early water reducing agent of the cement material, so that cement particles are dispersed, the workability is improved, and the water consumption is reduced, thereby improving the compactness and hardness of the cement-based material and increasing the fluidity of the cement-based material.

7) The method adopts a redox system initiator, an oxidant in the initiator and a reducing agent generate redox reaction, and generated free radicals SO4 & lt- & gt and SO3 & lt- & gt can initiate added plant fiber surface active groups to generate primary free radicals to initiate free radicals of grafting reaction on the surface of fabric fibers.

8) The industrial waste is adopted to synthesize the inorganic salt precursor in the carbon fiber-organic-inorganic double-network polymer, and the industrial waste contains rich calcium-rich compounds, amorphous glass, silicate, limestone and bauxite, so that the industrial waste is a good synthetic raw material of the inorganic substance precursor of the cement clinker, and the inorganic salt precursor is synthesized by utilizing the industrial waste to recycle the waste in industrial production, so that the production cost is reduced.

9) Tricalcium phosphate is added into the polymer body of the polyhydroxyethyl methacrylate, and the polyhydroxyethyl methacrylate and the tricalcium phosphate are adsorbed and gathered in network pores to react through a double-network structure formed by an organic-inorganic double-network polymer to generate hydroxyapatite-Ca 5(PO4)3OH and phosphorus calcium-CaHPO 4.2H2O, wherein the two components can effectively improve the hardness of the cement composite material, and the cement material is prevented from being easily corroded by corrosive acid gas, water vapor or rainwater in the air.

10) The polycarboxylic acid high-efficiency water reducing agent is beneficial to preventing the exposed unhydrated surface of the cross-linking agent from diffusing and hydrating prematurely in an early stage, so that the early mechanical strength of the cement material is increased, and the boric acid also plays a role of the water reducing agent in the early stage, so that the mechanical property of the cement material is improved.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.