CN113233850B - Modified concrete and preparation method thereof - Google Patents

Modified concrete and preparation method thereof Download PDF

Info

Publication number
CN113233850B
CN113233850B CN202110524083.4A CN202110524083A CN113233850B CN 113233850 B CN113233850 B CN 113233850B CN 202110524083 A CN202110524083 A CN 202110524083A CN 113233850 B CN113233850 B CN 113233850B
Authority
CN
China
Prior art keywords
concrete
parts
modified
agent
expanding agent
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202110524083.4A
Other languages
Chinese (zh)
Other versions
CN113233850A (en
Inventor
李可
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Linyi Lancheng Zaoyuan Building Materials Supply Co ltd
Original Assignee
Linyi Lancheng Zaoyuan Building Materials Supply Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Linyi Lancheng Zaoyuan Building Materials Supply Co ltd filed Critical Linyi Lancheng Zaoyuan Building Materials Supply Co ltd
Priority to CN202110524083.4A priority Critical patent/CN113233850B/en
Publication of CN113233850A publication Critical patent/CN113233850A/en
Application granted granted Critical
Publication of CN113233850B publication Critical patent/CN113233850B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
    • C04B28/06—Aluminous cements
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00017—Aspects relating to the protection of the environment
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/34—Non-shrinking or non-cracking materials
    • C04B2111/343—Crack resistant materials
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
    • C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/91—Use of waste materials as fillers for mortars or concrete

Abstract

The invention provides modified concrete, which comprises a concrete base material, a concrete expanding agent, a silane coupling agent graft modified polystyrene emulsion, an early strength agent, a water reducing agent, weakly acidic water and weakly alkaline water, wherein the concrete expanding agent is a mixture of a silane coupling agent graft modified polystyrene emulsion and a silane coupling agent; the concrete base material comprises the following preparation raw materials: aluminate cement, fly ash, building waste, lignin fiber and glass fiber; the concrete expanding agent is a microcapsule type and consists of a core material and a shell material, wherein the core material comprises metal oxide, sodium lignosulfonate and sodium tripolyphosphate, and the shell material comprises calcium alginate; when in construction, after the concrete expanding agent is added, the weakly acidic aqueous solution is added firstly and stirred, and then the weakly alkaline aqueous solution is added and stirred. The concrete prepared by the invention has good anti-cracking and anti-cracking performance and good strength, improves the compactness and the bonding performance of the concrete, and is more energy-saving and environment-friendly as the raw materials adopt building wastes.

Description

Modified concrete and preparation method thereof
Technical Field
The invention relates to the technical field of concrete, in particular to modified concrete and a preparation method thereof.
Background
Concrete is one of the most important civil engineering materials of the present generation. The artificial stone is prepared by a cementing material, granular aggregate, water, an additive and an admixture which are added if necessary according to a certain proportion, and is formed by uniformly stirring, compacting, forming, curing and hardening. In the process of preparing the cement concrete, a large amount of natural sand and gravel are required to be used, but the resources belong to nonrenewable resources, and the long-term exploitation and use of the natural sand and gravel can cause gradual reduction of the nonrenewable resources, even influence the ecological environment and cause irreversible damage to the ecology.
In addition, in the process of pouring and hardening concrete, the volume of the concrete is shrunk due to chemical shrinkage reduction, cold shrinkage, dry shrinkage and the like, the shrinkage value of the concrete is about 0.04-0.06 percent of the self volume, and the phenomena of cracking damage of the concrete, leakage damage caused by poor impermeability of the concrete, corrosion of reinforcing steel bars caused by cracking, unstable volume and the like exist. These shrinkage cracking failures compromise the volumetric stability of the concrete and thereby affect its structural function, reducing the durability of the concrete and thereby shortening its service life.
Therefore, the concrete needs to be modified by adding a series of additional modifiers, so that the environment-friendly high-performance concrete is obtained.
Disclosure of Invention
The invention aims to provide modified concrete and a preparation method thereof, the prepared concrete has good anti-cracking and anti-cracking performance and good strength by adding the modified polymer emulsion and the microcapsule type expanding agent, the total porosity is reduced, the improvement effect on pore grading is obvious, the compactness and the associativity of the concrete are improved, the concrete with high performance is prepared, and meanwhile, the raw materials adopt building wastes, so that the energy is saved and the environment is protected.
The technical scheme of the invention is realized as follows:
the invention provides modified concrete, which comprises a concrete base material, a concrete expanding agent, a silane coupling agent graft modified polystyrene emulsion, an early strength agent, a water reducing agent, weakly acidic water and weakly alkaline water; the concrete base material comprises the following preparation raw materials: aluminate cement, fly ash, building waste, lignin fiber and glass fiber; the concrete expanding agent is a microcapsule type and consists of a core material and a shell material, wherein the core material comprises metal oxide, sodium lignosulfonate and sodium tripolyphosphate, and the shell material comprises calcium alginate; when in construction, after the concrete expanding agent is added, the weakly acidic aqueous solution is added firstly and stirred, and then the weakly alkaline aqueous solution is added and stirred.
The weakly acidic aqueous solution is 1-3wt% acetic acid solution, the weakly alkaline solution is 1-3wt% sodium carbonate solution, the mixing amount of the concrete expanding agent is 2-3%, and the dosage of the concrete expanding agent, the weakly acidic aqueous solution and the weakly alkaline solution is 1-3: 30-60: 30-60, preferably 2:35-45: 35-45.
The concrete base material comprises the following preparation raw materials in parts by weight: 40-60 parts of aluminate cement, 10-15 parts of fly ash, 10-20 parts of building waste, 0.5-2 parts of lignin fiber and 3-7 parts of glass fiber; the concrete expanding agent is 1-3 parts by mass, the weakly acidic water is 30-60 parts by mass, the weakly alkaline water is 30-60 parts by mass, the water reducing agent is 1-3 parts by mass, the modified polystyrene emulsion is 5-10 parts by mass, and the early strength agent is 0.5-2 parts by mass.
Further, the concrete expanding agent is prepared from the following raw materials in parts by weight: 12-20 parts of metal oxide, 1-3 parts of sodium lignosulfonate, 10-20 parts of sodium alginate, 5-10 parts of calcium chloride and 1-2 parts of sodium tripolyphosphate.
As a further improvement of the invention, the metal oxide is modified, and the modified metal oxide is prepared from the following raw materials in parts by weight: 30-50 parts of metal oxide, 2-4 parts of citric acid, 5-10 parts of bentonite and 30-50 parts of ethanol;
further, the modification method of the metal oxide comprises the following steps:
s1, drying metal oxide at 80-100 ℃, then adding citric acid, bentonite and ethanol according to a proportion, and carrying out ball milling and mixing for 2-4 h;
s2, filtering and washing the mixed material in the step S1, and drying at 80-100 ℃ for 10-20 min;
s3, calcining the dried substance obtained in the step S2 at the temperature of 400-500 ℃ for 0.5-1h, and crushing to 100-200 meshes to obtain the modified metal oxide.
Further, the metal oxide is selected from at least one of calcium oxide, magnesium oxide and barium oxide; preferably calcium oxide and magnesium oxide, more preferably calcium oxide and magnesium oxide in a mass ratio of 5-10: 7-12.
As a further improvement of the invention, the preparation method of the concrete expanding agent comprises the following steps:
t1, grinding the sodium tripolyphosphate to 100-200 meshes, adding a metal oxide, ball-milling for 1-2h, and uniformly mixing;
and T2, adding the mixed material obtained in the step T1 into water, uniformly dispersing by ultrasonic, adding sodium lignosulfonate and sodium alginate, stirring and dissolving, increasing the stirring speed, stirring for 0.5-1h, dropwise adding a calcium chloride solution, keeping the stirring speed unchanged, reacting for 0.5-1h, stopping stirring, and filtering to obtain the concrete expanding agent.
The stirring speed is 200-500r/min, and the stirring speed is increased to 1000-2000 r/min.
Preferably, the metal oxide is a modified metal oxide. The modification method is as described above.
As a further improvement of the present invention, the water reducing agent is at least one selected from the group consisting of lignosulfonate, naphthalene sulfonate water reducing agent, melamine water reducing agent, and polycarboxylic acid water reducing agent; the early strength agent is at least one of triethanolamine, calcium formate, urea, nitrite and chromate.
The building waste material is at least one of waste concrete blocks, waste bricks and waste tiles.
As a further improvement of the invention, the silane coupling agent graft modified polystyrene emulsion is prepared by the following method:
s1, irradiation: carrying out irradiation treatment on the polystyrene emulsion;
s2, free radical polymerization: adding a silane coupling agent with double bonds into the pre-irradiated polystyrene emulsion, and adding an initiator to carry out heating polymerization reaction under the condition of nitrogen to obtain the modified polystyrene emulsion.
As a further improvement of the invention, the irradiation treatment is carried out for 3 to 7 seconds under a Co-60 lamp, and the absorbed dose is 40 to 60 kGy; the molecular weight of the polystyrene is 5000-10000, and the solid content of the emulsion is 40-60%.
As a further improvement of the present invention, the silane coupling agent having a double bond is selected from KH 570; the initiator consists of a thermal decomposition initiator and a reducing agent, and the mass ratio of the initiator to the reducing agent is (4-7): 1; the thermal decomposition initiator is selected from one or a mixture of more of ammonium persulfate, potassium persulfate and sodium persulfate; the reducing agent is selected from one or a mixture of more of sodium bisulfite, potassium bisulfite, sodium metabisulfite, naphthenate, hypophosphorous acid, sodium hypophosphite, potassium hypophosphite and ferrous salt.
As a further improvement of the invention, the mass ratio of the polystyrene emulsion to the silane coupling agent with double bonds to the initiator is 100: (5-10): (0.5-2).
The invention further provides a preparation method of the modified concrete, which comprises the following steps:
s1, treating construction waste: cutting waste concrete blocks into blocks by a cutting machine, crushing the blocks into particles of 80-100 meshes by a stone crusher, adding fly ash, and uniformly mixing to obtain powder;
s2, mixing the lignin fiber and the glass fiber, heating to the temperature of 100-120 ℃, continuously stirring, mixing and reacting for 10-20min, and cooling to the normal temperature to obtain a fiber material;
s3, adding aluminate cement into a reactor, adding the powder prepared in the step S1 and the fiber prepared in the step S2, adding a silane coupling agent graft modified polystyrene emulsion, heating to 40-50 ℃, adding a concrete expanding agent and weakly acidic water, stirring and mixing for 10-30min, adding a weakly alkaline solution, continuously stirring for 10-30min, adding an early strength agent and a water reducing agent, uniformly mixing to obtain the product, pouring the mixture into a mold when in use, naturally cooling for more than 24h in a cool and ventilated place, and taking the mold down to obtain a finished product.
The invention has the following beneficial effects: the modified polystyrene polymer emulsion is polymerized with the silane coupling agent with double bonds, so that a large number of silicon-oxygen bonds are connected on a polystyrene molecular chain, coupling with particles such as cement, fly ash and the like is facilitated, the pore structure of concrete can be improved by doping the modified polymer emulsion, the total porosity is reduced, and the improvement effect on pore gradation is obvious. The polymer and the cement product are interwoven into a net structure, so that the structure of a transition area, the structure of pores and the like are improved; the chemical action mainly comprises the reaction of the polymer and cement hydration products or metal ions in the concrete to generate a bridge bond effect, and the compactness and the bonding property of the concrete are improved.
The calcium oxide and the magnesium oxide in the concrete expanding agent of the invention are hydrated to generate Ca (OH)2Or Mg (OH)2The solid phase volume increases, causing the slurry to expand in volume. By modifying calcium oxide or magnesium oxide, a coating layer is formed on the surface of the particles, so that the hydration speed is effectively controlled, the expansion speed is slowed down, most of the expansion is carried out in the plastic stage after the concrete generates strength, and the expansion effect is improved. The modified calcium oxide and the modified magnesium oxide are compounded, so that the expansion effect is enhanced, and meanwhile, the calcium oxide and the magnesium oxide are combined to generate a synergistic effect, so that the compensation capacity is improved.
After the microcapsule type concrete expanding agent is added into concrete, shell material calcium alginate is acidified by a weak acid solution to become alginic acid, and then the alginic acid is neutralized by a weak alkaline solution to become sodium alginate dissolved in water, so that the shell material is dissolved, the inner core material is dissolved out, and a good effect of expanding when meeting water is achieved in cement;
the microcapsule type concrete expanding agent is added into concrete, and cannot be immediately hydrated and expanded, so that the phenomenon that the common expanding agent plays a role when concrete slurry is in fluid, most of generated expansion is absorbed by the slurry, the slurry expansion cannot be caused, expansion materials are greatly consumed, and the expansion cannot be generated after cement slurry is hardened is avoided; the hydration speed of the expanding agent is synchronous with the formation speed of a cement paste structure under the same maintenance condition, the expanding agent begins to hydrate when the cement paste structure is formed, when the cement paste has lower gel strength, the reaction rate of the expanding material reaches the maximum, and after the cement paste is hardened, the reaction rate of the expanding material is gradually slowed down, so that sufficient plastic expansion and certain later expansion can be generated, and the effect of double expansion is achieved. In addition, the sodium tripolyphosphate plays a role in retarding coagulation, can slow down the expansion of calcium oxide in the sulfur-fixing waste residues and the red mud, and enables the expansion effect of the expanding agent to be better. The sodium lignosulfonate has the function of a surfactant, promotes the mixing of the modified calcium oxide and the modified magnesium oxide, is beneficial to preparing microcapsules, and also has a certain water reducing function.
According to the invention, by adding the modified polymer emulsion and the microcapsule type expanding agent, the prepared concrete has good anti-cracking and anti-cracking performance and good strength, the total porosity is reduced, the improvement effect on pore grading is obvious, the compactness and the associativity of the concrete are improved, the concrete with high performance is prepared, and meanwhile, the raw materials adopt building wastes, so that the concrete is more energy-saving and environment-friendly.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a TEM image of a microcapsule-type concrete expansive agent prepared in preparation example 4 of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all 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.
In the polystyrene emulsion, the polystyrene has a number average molecular weight of about 6000 and the emulsion has a solids content of 43%.
Preparation example 1 preparation of modified polystyrene emulsion
The preparation method comprises the following steps:
s1, pre-irradiation: carrying out irradiation treatment on 100g of polystyrene emulsion; the irradiation treatment is carried out for 3s under a Co-60 lamp, and the absorbed dose is 40 kGy;
s2, free radical polymerization: and (3) adding 5g of silane coupling agent KH570 into 100g of the pre-irradiated polystyrene emulsion, and adding 0.5g of initiator under the condition of nitrogen to perform heating polymerization reaction to obtain the silane coupling agent graft modified polystyrene emulsion.
The initiator consists of ammonium persulfate and potassium bisulfite, and the mass ratio is 4: 1.
preparation example 2 preparation of modified polystyrene emulsion
The preparation method comprises the following steps:
s1, pre-irradiation: carrying out irradiation treatment on 100g of polystyrene emulsion; the irradiation treatment is carried out for 7s under a Co-60 lamp, and the absorbed dose is 60 kGy;
s2, free radical polymerization: and adding 10g of silane coupling agent KH570 into 100g of the pre-irradiated polystyrene emulsion, and adding 0.5g of initiator under the condition of nitrogen to carry out heating polymerization reaction to obtain the silane coupling agent graft modified polystyrene emulsion.
The initiator consists of potassium persulfate and sodium hypophosphite in a mass ratio of 7: 1.
preparation example 3 preparation of concrete expansive agent
The concrete expanding agent comprises the following raw materials: 7 parts of calcium oxide, 10 parts of magnesium oxide, 2 parts of sodium lignosulfonate, 15 parts of sodium alginate, 7 parts of calcium chloride and 1.5 parts of sodium tripolyphosphate.
The preparation method of the concrete expanding agent comprises the following steps:
s1, grinding sodium tripolyphosphate to 150 meshes, adding calcium oxide and magnesium oxide, carrying out ball milling for 2h, and uniformly mixing;
s2, adding the mixed material obtained in the step S1 into water, uniformly dispersing by ultrasonic, adding sodium lignosulfonate and sodium alginate, stirring and dissolving, increasing the stirring speed, stirring for 0.5h, dropwise adding a calcium chloride solution, keeping the stirring speed unchanged, reacting for 0.5h, stopping stirring, and filtering to obtain the concrete expanding agent.
Preparation example 4 preparation of concrete expansive agent
Compared with preparation example 3, calcium oxide and magnesium oxide are modified, and other conditions are not changed.
The modified metal oxide is prepared from the following raw materials in parts by weight: 16.5 parts of calcium oxide, 23.5 parts of magnesium oxide, 3 parts of citric acid, 8 parts of bentonite and 40 parts of ethanol;
the preparation method of the modified metal oxide comprises the following steps:
s1, drying calcium oxide and magnesium oxide at 90 ℃, then adding citric acid, bentonite and ethanol in proportion, and carrying out ball milling and mixing for 3 hours;
s2, filtering and washing the mixed material in the step S1, and drying for 15min at 90 ℃;
s3, calcining the dried substance obtained in the step S2 at 450 ℃ for 0.5h, and carrying out ball milling to obtain the modified metal oxide.
The concrete expanding agent comprises the following raw materials: 17 parts of modified metal oxide, 2 parts of sodium lignosulphonate, 15 parts of sodium alginate, 7 parts of calcium chloride and 1.5 parts of sodium tripolyphosphate.
The preparation method of the concrete expanding agent comprises the following steps:
s1, grinding sodium tripolyphosphate to 150 meshes, adding a modified metal oxide, carrying out ball milling for 2h, and uniformly mixing;
s2, adding the mixed material obtained in the step S1 into water, uniformly dispersing by ultrasonic, adding sodium lignosulfonate and sodium alginate, stirring and dissolving, increasing the stirring speed, stirring for 0.5h, dropwise adding a calcium chloride solution, keeping the stirring speed unchanged, reacting for 0.5h, stopping stirring, and filtering to obtain the concrete expanding agent. The TEM image of the prepared concrete expanding agent is shown in FIG. 1, and a remarkable core-shell structure is formed in the image.
Preparation example 5
Compared with preparation example 4, modified calcium oxide was not added, and other conditions were not changed.
The modified magnesium oxide is prepared from the following raw materials in parts by weight: 30 parts of magnesium oxide, 2.5 parts of triethanolamine, 4 parts of kieselguhr and 40 parts of ethanol;
the preparation method of the modified magnesium oxide comprises the following steps:
s1, drying magnesium oxide at 90 ℃, then adding triethanolamine, diatomite and ethanol in proportion, and carrying out ball milling and mixing for 3 hours;
s2, filtering and washing the mixed material in the step S1, and drying for 15min at 90 ℃;
s3, calcining the dried substance obtained in the step S2 at 450 ℃ for 0.5h, and carrying out ball milling to obtain the modified magnesium oxide.
The concrete expanding agent comprises the following raw materials: 17 parts of modified magnesium oxide, 2 parts of sodium lignosulphonate, 15 parts of sodium alginate, 7 parts of calcium chloride and 1.5 parts of sodium tripolyphosphate.
The preparation method of the concrete expanding agent comprises the following steps:
s1, grinding sodium tripolyphosphate to 150 meshes, adding modified magnesium oxide, carrying out ball milling for 2h, and uniformly mixing;
s2, adding the mixed material obtained in the step S1 into water, uniformly dispersing by ultrasonic, adding sodium lignosulfonate and sodium alginate, stirring and dissolving, increasing the stirring speed, stirring for 0.5h, dropwise adding a calcium chloride solution, keeping the stirring speed unchanged, reacting for 0.5h, stopping stirring, and filtering to obtain the concrete expanding agent.
Preparation example 6
Compared with preparation example 4, no modified magnesium oxide was added, and other conditions were not changed.
The modified calcium oxide is prepared from the following raw materials in parts by weight: 40 parts of calcium oxide, 3 parts of citric acid, 8 parts of bentonite and 40 parts of ethanol;
the preparation method of the modified calcium oxide comprises the following steps:
s1, drying calcium oxide at 90 ℃, then adding citric acid, bentonite and ethanol in proportion, and carrying out ball milling and mixing for 3 hours;
s2, filtering and washing the mixed material in the step S1, and drying for 15min at 90 ℃;
s3, calcining the dried substance obtained in the step S2 at 450 ℃ for 0.5h, and carrying out ball milling to obtain the modified calcium oxide.
The concrete expanding agent comprises the following raw materials: 17 parts of modified calcium oxide, 2 parts of sodium lignosulphonate, 15 parts of sodium alginate, 7 parts of calcium chloride and 1.5 parts of sodium tripolyphosphate.
The preparation method of the concrete expanding agent comprises the following steps:
s1, grinding sodium tripolyphosphate to 150 meshes, adding modified calcium oxide, carrying out ball milling for 2h, and uniformly mixing;
s2, adding the mixed material obtained in the step S1 into water, uniformly dispersing by ultrasonic, adding sodium lignosulfonate and sodium alginate, stirring and dissolving, increasing the stirring speed, stirring for 0.5h, dropwise adding a calcium chloride solution, keeping the stirring speed unchanged, reacting for 0.5h, stopping stirring, and filtering to obtain the concrete expanding agent.
Example 1
The raw materials comprise the following components in parts by weight: 50 parts of aluminate cement, 12 parts of fly ash, 15 parts of waste concrete, 1.2 parts of lignin fiber, 5 parts of glass fiber, 2 parts of concrete expanding agent prepared in preparation example 3, 45 parts of weak acidic water, 45 parts of weak alkaline water, 2 parts of water reducing agent, 7 parts of modified polystyrene emulsion prepared in preparation example 1 and 1.2 parts of early strength agent. The weakly acidic water is 2 wt% acetic acid solution. The weakly alkaline water was a 1.5 wt% sodium carbonate solution.
The preparation method comprises the following steps:
s1, treating construction waste: cutting waste concrete blocks into blocks by a cutting machine, crushing the blocks into 80-mesh particles by a stone crusher, adding fly ash and uniformly mixing to obtain powder;
s2, mixing the lignin fiber and the glass fiber, heating to 110 ℃, continuously stirring, mixing and reacting for 15min, and cooling to normal temperature to obtain a fiber material;
s3, adding aluminate cement into a reactor, adding the powder prepared in the step S1 and the fiber material prepared in the step S2, adding the modified polystyrene emulsion, heating to 45 ℃, adding the concrete expanding agent and 2 wt% of acetic acid solution, stirring and mixing for 20min, adding 1.5 wt% of sodium carbonate solution, continuing stirring for 20min, then adding the early strength agent and the naphthalenesulfonate water reducer, mixing uniformly, pouring the mixture into a mold, naturally cooling for 24h in a cool and ventilated place, and taking down the mold to obtain a finished product.
Formulations of examples 2 to 5 and comparative examples 1 to 3 concrete was prepared under the same conditions and procedures as in example 1, as shown in table 1 below.
TABLE 1
Figure BDA0003065152910000111
Figure BDA0003065152910000121
TABLE 1
Figure BDA0003065152910000122
Figure BDA0003065152910000131
Test example 1 crack resistance test
The concrete prepared in examples 1 to 5 and comparative examples 1 to 3 was used as a test sample, and after curing for 28 days, the compressive strength, the splitting tensile strength, whether cracks were generated on the surface of each group of samples or not was measured, and the length of the cracks was recorded. The test specimens are cube standard specimens of 150mm by 150 mm. The compressive strength and the splitting compressive strength are tested according to GB/T50081-2002 'test method for mechanical properties of common concrete'. Specific results are shown in table 3.
TABLE 3
Figure BDA0003065152910000132
It can be seen that the concrete prepared in the examples has better mechanical properties and better crack resistance. Compared with the prior art, the modified polystyrene polymer emulsion disclosed by the invention is polymerized with a silane coupling agent with double bonds, so that a large number of silicon-oxygen bonds are connected on a polystyrene molecular chain, the coupling with cement, fly ash and other particles is facilitated, the pore structure of concrete can be improved by doping the modified polymer emulsion, the total porosity is reduced, and the improvement effect on pore grading is obvious. The polymer and the cement product are interwoven into a net structure, so that the structure of a transition area, the structure of pores and the like are improved; the chemical action mainly comprises the reaction of the polymer and cement hydration products or metal ions in the concrete to generate a bridge bond effect, and the compactness and the bonding property of the concrete are improved.
The calcium oxide and the magnesium oxide in the concrete expanding agent of the invention are hydrated to generate Ca (OH)2Or Mg (OH)2The solid phase volume increases, causing the slurry to expand in volume. By modifying calcium oxide or magnesium oxide, a coating layer is formed on the surface of the particles, so that the hydration speed is effectively controlled, the expansion speed is slowed down, most of the expansion is carried out in the plastic stage after the concrete generates strength, and the expansion effect is improved. The modified calcium oxide and the modified magnesium oxide are compounded, so that the expansion effect is enhanced, and meanwhile, the calcium oxide and the magnesium oxide are combined to generate a synergistic effect, so that the compensation capacity is improved.
After the microcapsule type concrete expanding agent is added into concrete, shell material calcium alginate is acidified by a weak acid solution to become alginic acid, and then the alginic acid is neutralized by a weak alkaline solution to become sodium alginate dissolved in water, so that the shell material is dissolved, the inner core material is dissolved out, and a good effect of expanding when meeting water is achieved in cement;
the microcapsule type concrete expanding agent is added into concrete, and cannot be immediately hydrated and expanded, so that the phenomenon that the common expanding agent plays a role when concrete slurry is in fluid, most of generated expansion is absorbed by the slurry, the slurry expansion cannot be caused, expansion materials are greatly consumed, and the expansion cannot be generated after cement slurry is hardened is avoided; the hydration speed of the expanding agent is synchronous with the formation speed of a cement paste structure under the same maintenance condition, the expanding agent begins to hydrate when the cement paste structure is formed, when the cement paste has lower gel strength, the reaction rate of the expanding material reaches the maximum, and after the cement paste is hardened, the reaction rate of the expanding material is gradually slowed down, so that sufficient plastic expansion and certain later expansion can be generated, and the effect of double expansion is achieved. In addition, the sodium tripolyphosphate plays a role in retarding coagulation, can slow down the expansion of calcium oxide in the sulfur-fixing waste residues and the red mud, and enables the expansion effect of the expanding agent to be better. The sodium lignosulfonate added has the function of a surfactant, promotes the mixing of the modified calcium oxide and the modified magnesium oxide, is beneficial to preparing a nucleation-shell structure, and also has a certain water reducing function.
According to the invention, by adding the modified polymer emulsion and the microcapsule type expanding agent, the prepared concrete has good anti-cracking and anti-cracking performance and good strength, the total porosity is reduced, the improvement effect on pore grading is obvious, the compactness and the associativity of the concrete are improved, the concrete with high performance is prepared, and meanwhile, the raw materials adopt building wastes, so that the concrete is more energy-saving and environment-friendly.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and should not be taken as limiting the scope of the present invention, which is intended to cover any modifications, equivalents, improvements, etc. within the spirit and scope of the present invention.

Claims (10)

1. A modified concrete comprises a concrete base material, a concrete expanding agent, a silane coupling agent graft modified polystyrene emulsion, an early strength agent, a water reducing agent, weakly acidic water and weakly alkaline water; the concrete base material comprises the following preparation raw materials: aluminate cement, fly ash, building waste, lignin fiber and glass fiber; the concrete expanding agent is a microcapsule type and consists of a core material and a shell material, wherein the core material comprises metal oxide, sodium lignosulfonate and sodium tripolyphosphate, and the shell material comprises calcium alginate; during construction, after adding the concrete expanding agent, firstly adding a weak acidic aqueous solution and stirring, and then adding a weak alkaline aqueous solution and stirring;
the weakly acidic aqueous solution is 1-3wt% acetic acid solution, the weakly alkaline aqueous solution is 1-3wt% sodium carbonate solution, the mixing amount of the concrete expanding agent is 2-3%, and the dosage of the concrete expanding agent, the weakly acidic aqueous solution and the weakly alkaline solution is 1-3: 30-60: 30-60 parts of;
the metal oxide is modified, and the modified metal oxide is prepared from the following raw materials in parts by weight: 30-50 parts of metal oxide, 2-4 parts of citric acid, 5-10 parts of bentonite and 30-50 parts of ethanol.
2. The modified concrete of claim 1, wherein the amount of the concrete expansive agent, the weakly acidic aqueous solution and the weakly alkaline solution is 2:35-45: 35-45.
3. The modified concrete of claim 1, wherein the concrete base material comprises the following preparation raw materials in parts by weight: 40-60 parts of aluminate cement, 10-15 parts of fly ash, 10-20 parts of building waste, 0.5-2 parts of lignin fiber and 3-7 parts of glass fiber; the concrete expanding agent is 1-3 parts by mass, the weakly acidic water is 30-60 parts by mass, the weakly alkaline water is 30-60 parts by mass, the water reducing agent is 1-3 parts by mass, the modified polystyrene emulsion is 5-10 parts by mass, and the early strength agent is 0.5-2 parts by mass.
4. The modified concrete of claim 3, wherein the concrete expanding agent is prepared from the following raw materials in parts by weight: 12-20 parts of metal oxide, 1-3 parts of sodium lignosulfonate, 10-20 parts of sodium alginate, 5-10 parts of calcium chloride and 1-2 parts of sodium tripolyphosphate.
5. The modified concrete according to claim 1, wherein the method for modifying a metal oxide comprises the steps of:
s1, drying metal oxide at 80-100 ℃, then adding citric acid, bentonite and ethanol according to a proportion, and carrying out ball milling and mixing for 2-4 h;
s2, filtering and washing the mixed material in the step S1, and drying at 80-100 ℃ for 10-20 min;
s3, calcining the dried substance obtained in the step S2 at the temperature of 400-500 ℃ for 0.5-1h, and crushing to 100-200 meshes to obtain the modified metal oxide.
6. The modified concrete according to claim 1, wherein the metal oxide is at least one selected from the group consisting of calcium oxide, magnesium oxide, and barium oxide.
7. The modified concrete according to claim 1, wherein the metal oxide is calcium oxide and magnesium oxide in a mass ratio of 5-10: 7-12.
8. The modified concrete according to claim 1, wherein the preparation method of the concrete expanding agent comprises the following steps:
t1, grinding the sodium tripolyphosphate to 100-200 meshes, adding a metal oxide, ball-milling for 1-2h, and uniformly mixing;
and T2, adding the mixed material obtained in the step T1 into water, uniformly dispersing by ultrasonic, adding sodium lignosulfonate and sodium alginate, stirring for dissolving, increasing the stirring speed, stirring for 0.5-1h, dropwise adding a calcium chloride solution, keeping the stirring speed unchanged, reacting for 0.5-1h, stopping stirring, and filtering to obtain the concrete expanding agent.
9. The modified concrete of claim 1, wherein the silane coupling agent graft-modified polystyrene emulsion is prepared by the following method:
s1, irradiation: carrying out irradiation treatment on the polystyrene emulsion;
s2. free radical polymerization: adding a silane coupling agent with double bonds into the pre-irradiated polystyrene emulsion, and adding an initiator to carry out heating polymerization reaction under the condition of nitrogen to obtain the modified polystyrene emulsion.
10. A process for the preparation of a modified concrete according to any one of claims 1 to 9, comprising the steps of:
s1, treatment of construction waste: cutting waste concrete blocks into blocks by a cutting machine, crushing the blocks into particles of 80-100 meshes by a stone crusher, adding fly ash, and uniformly mixing to obtain powder;
s2, mixing the lignin fiber and the glass fiber, heating to 100-120 ℃, continuously stirring, mixing and reacting for 10-20min, and cooling to normal temperature to obtain a fiber material;
s3, adding aluminate cement into a reactor, adding the powder prepared in the step S1 and the fiber prepared in the step S2, adding a silane coupling agent graft modified polystyrene emulsion, heating to 40-50 ℃, adding a concrete expanding agent and weakly acidic water, stirring and mixing for 10-30min, adding a weakly alkaline solution, continuing stirring for 10-30min, adding an early strength agent and a water reducing agent, and uniformly mixing to obtain the material.
CN202110524083.4A 2021-05-13 2021-05-13 Modified concrete and preparation method thereof Active CN113233850B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110524083.4A CN113233850B (en) 2021-05-13 2021-05-13 Modified concrete and preparation method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110524083.4A CN113233850B (en) 2021-05-13 2021-05-13 Modified concrete and preparation method thereof

Publications (2)

Publication Number Publication Date
CN113233850A CN113233850A (en) 2021-08-10
CN113233850B true CN113233850B (en) 2022-07-05

Family

ID=77134186

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110524083.4A Active CN113233850B (en) 2021-05-13 2021-05-13 Modified concrete and preparation method thereof

Country Status (1)

Country Link
CN (1) CN113233850B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114083669A (en) * 2021-11-24 2022-02-25 山东港基建设集团有限公司 Steel wire mesh rack insulation board and preparation method thereof

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104671697B (en) * 2015-02-05 2017-10-10 江苏苏博特新材料股份有限公司 A kind of modified oxidized calcium class cement concrete swelling agent and preparation method thereof
CN108409178A (en) * 2018-03-12 2018-08-17 北京工业大学 A kind of swelling type microcapsules/cement base self-healing system
KR102098039B1 (en) * 2019-07-15 2020-04-09 주식회사 아이앤엘 Eco-friendly Mortar composition for repairing and reinforcing underwater concrete structures, and method of repairing and reinforcing using the same
CN112608122B (en) * 2020-12-08 2022-08-19 广东省水利电力勘测设计研究院有限公司 Micro-expansive epoxy emulsion modified self-compacting concrete for composite lining structure

Also Published As

Publication number Publication date
CN113233850A (en) 2021-08-10

Similar Documents

Publication Publication Date Title
CN107512924B (en) Wooden light building concrete and preparation method thereof
CN112250355A (en) Alkali-activated fly ash/slag recycled concrete and preparation method thereof
CN110627423A (en) High-heat-resistance self-insulation building block for energy-saving building and preparation process thereof
CN111606637A (en) Excellent-performance sleeve grouting material for steel bar connection
CN110550921A (en) anti-cracking autoclaved aerated concrete block and production method thereof
CN111960775A (en) Aerated concrete dry-mixed plastering mortar and preparation method thereof
CN113233850B (en) Modified concrete and preparation method thereof
CN111925165A (en) Building waste concrete block and preparation method thereof
CN111196704A (en) Concrete for prefabricated part and preparation method thereof
CN111253130A (en) High-strength heat-resistant self-repairing concrete and preparation method thereof
CN115745447B (en) Concrete prepared by regenerating waste concrete and preparation method thereof
CN111517729A (en) Sleeve grouting material for connecting steel bars of fabricated building
CN103992082A (en) Heatproof sound insulation aerated brick and making method thereof
CN110845188A (en) Sand-free macroporous concrete and preparation method thereof
CN114477873B (en) Recycled aggregate self-compacting concrete and preparation method thereof
CN114085055B (en) Secondary lining concrete suitable for high-ground-temperature tunnel in high-temperature and low-humidity environment and preparation method thereof
CN116120014A (en) Dam danger-removing reinforcing material and reinforcing method
CN112094367B (en) Bleeding-preventing polymer, low-retraction filling solid waste material, preparation method and application
CN106747639A (en) A kind of foamed concrete thermal-insulating material
CN111908852A (en) Concrete for prefabricated part and preparation method thereof
CN110653936A (en) Novel light wall material with good compression resistance and manufacturing method thereof
CN113121152B (en) Concrete expanding agent and preparation and use methods thereof
US11970425B2 (en) Liquid regulator for ultra-dispersed, high-mud-resistance, high-foam-stability, low-shrinkage and enhanced autoclaved aerated concrete, and preparation method and application thereof
CN114560667B (en) Light energy-saving foam concrete and preparation method thereof
CN114988837B (en) Light heat-insulating material and preparation method and application thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
TA01 Transfer of patent application right
TA01 Transfer of patent application right

Effective date of registration: 20220608

Address after: 276000 Zaoyuan Zhen Yan Jia Tun Cun, Lanshan District, Linyi City, Shandong Province

Applicant after: Linyi Lancheng (Zaoyuan) building materials supply Co.,Ltd.

Address before: 620-18, 6 / F, Zhiyuan building, 58 Tianyuan East Road, gaoxinyuan, Jiangning District, Nanjing City, Jiangsu Province

Applicant before: Nanjing maohuiying Technology Co.,Ltd.

GR01 Patent grant
GR01 Patent grant