CN114751702A - Self-repairing concrete based on renewable porous material and preparation method thereof - Google Patents
Self-repairing concrete based on renewable porous material and preparation method thereof Download PDFInfo
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- CN114751702A CN114751702A CN202210532436.XA CN202210532436A CN114751702A CN 114751702 A CN114751702 A CN 114751702A CN 202210532436 A CN202210532436 A CN 202210532436A CN 114751702 A CN114751702 A CN 114751702A
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- 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
- C04B28/04—Portland cements
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- 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
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- 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 discloses self-repairing concrete based on a renewable porous material and a preparation method thereof; according to the invention, carbonic anhydrase bacteria are coated in microcapsules and loaded in a porous material, and then a compact silicon dioxide layer is generated on the surface of the microcapsules by using tetraethoxysilane for protection, so that bacterial inactivation caused by contact with a high-pH environment in concrete is avoided, and bacterial inactivation caused by overhigh temperature and heat accumulation caused by a large amount of hydration heat generated in the cement hydration process is avoided. The self-repairing concrete prepared by the invention has excellent self-repairing performance, utilizes building wastes as raw materials, is energy-saving and environment-friendly, and has wide application space.
Description
Technical Field
The invention relates to the technical field of concrete, in particular to self-repairing concrete based on a renewable porous material and a preparation method thereof.
Background
Concrete is widely applied to the field of buildings as a high-quality material which has good mechanical property, low price and easy preparation, but concrete as a brittle material can generate defects such as microcracks and the like under the action of external force, so that the mechanical property and the durability of the concrete are reduced, and the application range and the service life of the concrete are greatly influenced. At present, most concrete defects are repaired afterwards, the cost is high, meanwhile, the problems of incomplete repair, secondary cracking and the like also occur, and therefore, a self-diagnosis and self-repair concrete material needs to be developed to meet the special requirements of the current form on concrete.
Disclosure of Invention
The invention aims to provide self-repairing concrete based on a renewable porous material and a preparation method thereof, so as to solve the problems in the background technology.
In order to solve the technical problems, the invention provides the following technical scheme: self-repairing concrete based on renewable porous materials has the following characteristics: the self-repairing concrete comprises the following components in parts by weight: 550 parts of cement, 1200 parts of coarse aggregate, 1300 parts of fine aggregate, 400 parts of mixing water, 300 parts of mixing water, 5-8 parts of water reducing agent, 6-10 parts of retarder, 50-150 parts of regenerated porous material and 2-6 parts of calcium nitrate;
the regenerated porous material is prepared by crushing, screening and cleaning construction waste and then loading carbonic anhydrase bacteria.
Further, the cement is low-heat portland cement.
Further, the coarse aggregate is natural macadam, and the particle size is 5-20 mm; the fine aggregate is medium sand with the grain diameter of 0.5-0.8 mm.
Further, the water reducing agent is a polycarboxylic acid high-efficiency water reducing agent; the retarder is one or a mixture of more of calcium lignosulphonate, hydroxymethyl cellulose and hydroxyethyl cellulose.
Further: the regenerated porous material is prepared by crushing, screening and cleaning construction waste and then loading carbonic anhydrase bacteria.
A preparation method of self-repairing concrete based on renewable porous materials comprises the following steps:
s1, crushing, cleaning, grinding and granulating construction waste to prepare a porous material;
s2, breeding carbonic anhydrase bacteria with high pH value resistance:
inoculating carbonic anhydrase bacteria into a culture dish, and gradually screening the carbonic anhydrase bacteria by using the culture dish with a high pH value until the carbonic anhydrase bacteria which can tolerate the pH value of 10 are obtained;
s3, preparing carbonic anhydrase bacteria microcapsules:
centrifuging to obtain carbonic anhydrase bacterium mud, adding sodium alginate saturated solution, stirring and mixing, adding calcium chloride solution, fully stirring, and centrifuging to obtain carbonic anhydrase bacterium microcapsules;
s4, soaking the porous material in carbonic anhydrase microcapsule and bacterial liquid for 15-20min under vacuum negative pressure, and coating a silicon dioxide layer on the surface of the carbonic anhydrase immobilized porous material to form a wrapping shell to obtain a regenerated porous material;
s5, weighing cement, coarse aggregate, fine aggregate and the regenerated porous material, uniformly mixing, adding mixing water, a retarder, calcium nitrate and a water reducing agent, and uniformly stirring to obtain the self-repairing concrete.
Further, the preparation method of the self-repairing concrete based on the renewable porous material comprises the following steps:
s1, crushing the construction waste, removing waste plastics, waste wood and iron materials in the construction waste through flotation and magnetic attraction, cleaning the construction waste with clean water, transferring the construction waste into a ball mill for grinding, and granulating the construction waste into a porous material with the particle size of 0.5-0.8mm after grinding;
s2, breeding carbonic anhydrase bacteria with high pH value resistance;
s21, inoculating the carbonic anhydrase bacteria screened from the mine into a beef extract peptone liquid culture medium, adding 3-5g/L of calcium nitrate into the liquid culture medium, performing shake-flask culture at 28-35 ℃ for 48h, dropwise adding a sodium hydroxide solution, adjusting the pH to 8.0-8.5, continuing to cultivate for 24h, and screening the residual viable carbonic anhydrase bacteria;
s22, inoculating the screened carbonic anhydrase bacteria into a new beef extract peptone liquid culture medium, additionally adding 5-8g/L of calcium nitrate, dropwise adding a sodium hydroxide solution, adjusting the pH value to the pH value used in the previous screening, performing shake-flask culture for 48 hours, dropwise adding a sodium hydroxide solution, adjusting the pH value to be increased by 0.5, continuing to cultivate for 24 hours, and screening the residual viable carbonic anhydrase bacteria;
s23, repeating the step S22 until carbonic anhydrase bacteria capable of tolerating the pH value of 10 are obtained, transferring the carbonic anhydrase bacteria into a culture barrel, and performing amplification culture;
s3, preparing carbonic anhydrase bacteria microcapsules:
taking the culture solution at the lower layer of the culture barrel, centrifuging to obtain carbonic anhydrase bacterium mud, adding a sodium alginate saturated solution, stirring at the speed of 300-450rpm, adding the mixture into a calcium chloride solution with the concentration of 30-45 wt%, fully stirring, and centrifuging to obtain the carbonic anhydrase bacterium microcapsules;
s4, preparing a regenerated porous material:
s41, adding the porous material and the carbonic anhydrase bacteria microcapsules into the rest culture solution, soaking for 15-20min under vacuum negative pressure, and performing centrifugal separation to obtain the porous material loaded with the microcapsules;
s42, mixing the porous material loaded with the microcapsules with hexadecyl trimethyl ammonium bromide, adding pure water, stirring at the speed of 300rpm of 150-;
s43, after the reaction is finished, performing centrifugal separation, washing the separated solid product for 2-3 times by using pure water, and performing freeze drying at-50 ℃ for 10-15h to obtain a regenerated porous material;
s5, premixing cement, fine aggregate and the regenerated porous material for 3-5min, adding mixing water in which a water reducing agent, calcium nitrate and a retarder are dissolved, stirring for 2-3min, adding coarse aggregate, and continuously stirring for 5-8min to obtain the self-repairing concrete based on the regenerated porous material.
Carbonic anhydrase bacteria are a classGeneral term for bacteria capable of secreting carbonic anhydrase capable of capturing CO in the environment2And with the formation of CO3 2-While continuously chelating Ca in the environment2+Thereby producing CaCO3When the microbial agent is applied to concrete, as the concrete can be stressed to generate various tiny gaps in the using process to influence the using strength of the concrete, the carbonic anhydrase bacteria can secrete the carbonic anhydrase to induce CaCO3Thereby achieving the purpose of repairing the concrete defects.
But the concrete can release a large amount of hydration heat in the preparation process, so that the internal temperature of the concrete at the initial stage of hydration can even reach more than 70 ℃, most of protein and bacteria can be inactivated at the temperature, and the distribution of carbonic anhydrase bacteria in a concrete system is seriously influenced; meanwhile, calcium nitrate is introduced into a concrete system to serve as a calcium source of carbonic anhydrase bacteria, and in the hydration process of concrete, the calcium nitrate serving as soluble salt can greatly improve the content of calcium ions in a hydration liquid, so that the hydration action of cement is accelerated, the hydration process of the cement is accelerated, and the hydration heat release speed is increased.
The pH value of the most environment-friendly carbonic anhydrase bacteria is 7.5-8.5, and the carbonic anhydrase bacteria are slightly alkaline, but can firstly react with water molecules to generate a large amount of Ca (OH) in the cement hydration process2The pH value of the whole concrete can rise to 11-12, and the carbonic anhydrase bacteria can be rapidly inactivated at the pH value, and the self-repairing effect of the carbonic anhydrase bacteria is lost. In order to enhance the self-repairing function of concrete and improve the survival rate of carbonic anhydrase bacteria, firstly, the high pH value resistant growth is carried out on the strains of the carbonic anhydrase bacteria, the strains which are resistant to the high pH environment are bred by utilizing a mode of screening for multiple times, then, the strains are coated with microcapsules, the strains are mixed with a sodium alginate solution, the sodium alginate and calcium nitrate react to generate a water-insoluble calcium alginate coating, the strains are protected in the calcium alginate coating, and then, the calcium alginate coating is carried outThe microcapsule is loaded on a porous material, and a silicon dioxide shell layer is prepared again and coated on the surface of the porous material, so that the binding force between the microcapsule and the porous material is enhanced, and simultaneously, the microcapsule is also used as a protective layer to coat carbonic anhydrase bacteria again to form a plurality of spaced protective layers, thereby preventing the transmission of external high temperature and obstructing the corrosion of external high pH.
When concrete is broken under stress change, cracks appear, and are influenced by Van der Waals force, the silica shell of the regenerated porous material at the cracks is damaged by external force, so that the carbonic anhydrase microcapsules loaded inside are released, and the carbonic anhydrase microcapsules can react with carbon dioxide under the action of external carbon dioxide by using calcium elements in calcium diatomate as a calcium source to generate calcium carbonate deposition through induction, so that the cracks are repaired.
Further, in step S3, the weight ratio of the carbonic anhydrase bacteria, the sodium alginate saturated solution, and the calcium nitrate solution is (0.5-1): (200-250): (80-120).
Further, in step S4, the mass ratio of the porous material, the carbonic anhydrase bacterium microcapsule, the cetyl trimethyl ammonium bromide, the pure water, the concentrated ammonia water and the mixed solution is (5-8): (0.5-1): (0.1-0.3): (150-200): (50-60): (100- > 150); the mixed solution is 2 of absolute ethyl alcohol and ethyl orthosilicate: 1 mixing the solution.
Compared with the prior art, the invention has the following beneficial effects: according to the invention, carbonic anhydrase bacteria are coated in microcapsules and loaded in a porous material, and then a compact silicon dioxide layer is generated on the surface of the microcapsules by using tetraethoxysilane for protection, so that bacterial inactivation caused by contact with a high-pH environment in concrete is avoided, and bacterial inactivation caused by overhigh temperature and heat accumulation caused by a large amount of hydration heat generated in the cement hydration process is avoided. The self-repairing concrete prepared by the invention has excellent self-repairing performance, and the construction waste is used as the raw material, so that the energy is saved, the environment is protected, and the application space is wide.
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.
Example 1.
A preparation method of self-repairing concrete based on renewable porous materials comprises the following steps:
s1, collecting construction waste, primarily crushing the construction waste by using a crusher, removing organic matters and iron impurities in the construction waste by utilizing flotation and magnetic attraction, transferring the rest construction waste into a ball mill, continuously grinding and granulating to prepare a porous material with the particle size of 0.5-0.8 mm;
s2, breeding carbonic anhydrase bacteria with high pH value resistance;
s21, inoculating the carbonic anhydrase bacteria screened from the mine into a beef extract peptone liquid culture medium, adding 5g/L of calcium nitrate into the liquid culture medium, performing shake-flask culture at 35 ℃ for 48h, then dropwise adding a sodium hydroxide solution, adjusting the pH to 8.5, continuing to cultivate for 24h, and screening the residual alive carbonic anhydrase bacteria;
s22, inoculating the screened carbonic anhydrase bacteria into a new beef extract peptone liquid culture medium, additionally adding 8g/L of calcium nitrate, dropwise adding a sodium hydroxide solution, adjusting the pH value to the pH value used in the previous screening, performing shake-flask culture for 48 hours, dropwise adding a sodium hydroxide solution, adjusting the pH value to be increased by 0.5, continuing to cultivate for 24 hours, and screening the residual viable carbonic anhydrase bacteria;
s23, repeating the step S22 until carbonic anhydrase bacteria capable of tolerating the pH value of 10 are obtained, transferring the carbonic anhydrase bacteria into a culture barrel, and performing amplification culture;
s3, preparing carbonic anhydrase bacteria microcapsules:
taking a culture solution on the lower layer of a culture barrel, centrifuging to obtain carbonic anhydrase bacteria mud, weighing 1 part of carbonic anhydrase bacteria, adding the carbonic anhydrase bacteria mud into 200 parts of sodium alginate saturated solution, stirring at the speed of 450rpm, adding the mixture into 80 parts of calcium chloride solution with the concentration of 45 wt%, fully stirring, and centrifuging to obtain calcium alginate-coated microcapsules;
s4, preparing a regenerated porous material:
s41, mixing 5 parts of porous material, carbonic anhydrase bacteria microcapsules and upper-layer culture solution, soaking for 20min under vacuum negative pressure, and performing centrifugal separation to obtain a microcapsule-loaded porous material;
s42, mixing the porous material loaded with the microcapsules with 0.3 part of hexadecyl trimethyl ammonium bromide, adding 150 parts of pure water, stirring at 300rpm for 10min, adding 50 parts of strong ammonia water, dropwise adding 100 parts of a mixed solution of absolute ethyl alcohol and tetraethoxysilane, and continuously stirring to react for 5h after dropwise adding is finished;
s43, after the reaction is finished, performing centrifugal separation, washing the separated solid product for 3 times by using pure water, and performing freeze drying at-50 ℃ for 15 hours to obtain a regenerated porous material;
s5, weighing the raw material components in parts by weight, premixing 520 parts of low-heat portland cement, 440 parts of fine aggregate and 60 parts of regenerated porous material for 3-5min, adding mixing water in which 5.2 parts of water reducing agent, 3 parts of calcium nitrate and 6 parts of retarder are dissolved, stirring for 3min, adding 1211 parts of coarse aggregate, and continuously stirring for 5min to obtain the self-repairing concrete based on the regenerated porous material.
Example 2.
Compared with the embodiment 1, the embodiment increases the addition amount of the regenerated porous material;
a preparation method of self-repairing concrete based on renewable porous materials comprises the following steps:
s1, collecting construction waste, primarily crushing the construction waste by using a crusher, removing organic matters and iron impurities in the construction waste by using flotation and magnetic attraction, moving the rest construction waste into a ball mill, continuously grinding and granulating to prepare a porous material with the particle size of 0.5-0.8 mm;
s2, breeding carbonic anhydrase bacteria with high pH value resistance;
s21, inoculating the carbonic anhydrase bacteria screened from the mine into a beef extract peptone liquid culture medium, adding 5g/L of calcium nitrate into the liquid culture medium, performing shake-flask culture at 35 ℃ for 48 hours, then dropwise adding a sodium hydroxide solution, adjusting the pH to 8.5, continuing to cultivate for 24 hours, and screening the residual viable carbonic anhydrase bacteria;
s22, inoculating the screened carbonic anhydrase bacteria into a new beef extract peptone liquid culture medium, additionally adding 8g/L of calcium nitrate, dropwise adding a sodium hydroxide solution, adjusting the pH value to the pH value used in the previous screening, performing shake-flask culture for 48 hours, dropwise adding a sodium hydroxide solution, adjusting the pH value to be increased by 0.5, continuing to cultivate for 24 hours, and screening the residual viable carbonic anhydrase bacteria;
s23, repeating the step S22 until carbonic anhydrase bacteria capable of tolerating the pH value of 10 are obtained, transferring the carbonic anhydrase bacteria into a culture barrel, and performing amplification culture;
s3, preparing carbonic anhydrase bacteria microcapsules:
taking a culture solution on the lower layer of the culture barrel, centrifuging to obtain carbonic anhydrase bacteria mud, weighing 1 part of carbonic anhydrase bacteria, adding the carbonic anhydrase bacteria mud into 200 parts of sodium alginate saturated solution, stirring at the speed of 450rpm, adding the carbonic anhydrase bacteria mud into 80 parts of 45 wt% calcium chloride solution, fully stirring, and centrifuging to obtain calcium alginate-coated microcapsules;
s4, preparing a regenerated porous material:
s41, mixing 5 parts of porous material, carbonic anhydrase bacteria microcapsule and upper-layer culture solution, soaking for 20min under vacuum negative pressure, and performing centrifugal separation to obtain a microcapsule-loaded porous material;
s42, mixing the porous material loaded with the microcapsules with 0.3 part of hexadecyl trimethyl ammonium bromide, adding 150 parts of pure water, stirring at 300rpm for 10min, adding 50 parts of strong ammonia water, dropwise adding 100 parts of a mixed solution of absolute ethyl alcohol and tetraethoxysilane, and continuously stirring to react for 5h after dropwise adding is finished;
s43, after the reaction is finished, performing centrifugal separation, washing the separated solid product for 3 times by using pure water, and performing freeze drying at the temperature of 50 ℃ below zero for 15 hours to obtain a regenerated porous material;
s5, weighing the raw material components in parts by weight, premixing 520 parts of low-heat portland cement, 400 parts of fine aggregate and 100 parts of regenerated porous material for 3-5min, adding mixing water in which 5.2 parts of water reducing agent and 6 parts of retarder are dissolved, stirring for 3min, adding 1211 parts of coarse aggregate, and continuing stirring for 5min to obtain the self-repairing concrete based on the regenerated porous material.
Example 3.
Compared with the embodiment 1, the embodiment further increases the addition amount of the regenerated porous material;
a preparation method of self-repairing concrete based on renewable porous materials comprises the following steps:
s1, collecting construction waste, primarily crushing the construction waste by using a crusher, removing organic matters and iron impurities in the construction waste by utilizing flotation and magnetic attraction, transferring the rest construction waste into a ball mill, continuously grinding and granulating to prepare a porous material with the particle size of 0.5-0.8 mm;
s2, breeding carbonic anhydrase bacteria with high pH value resistance;
s21, inoculating the carbonic anhydrase bacteria screened from the mine into a beef extract peptone liquid culture medium, adding 5g/L of calcium nitrate into the liquid culture medium, performing shake-flask culture at 35 ℃ for 48 hours, then dropwise adding a sodium hydroxide solution, adjusting the pH to 8.5, continuing to cultivate for 24 hours, and screening the residual viable carbonic anhydrase bacteria;
s22, inoculating the screened carbonic anhydrase bacteria into a new beef extract peptone liquid culture medium, additionally adding 8g/L of calcium nitrate, dropwise adding a sodium hydroxide solution, adjusting the pH value to the pH value used in the previous screening, performing shake-flask culture for 48 hours, dropwise adding a sodium hydroxide solution, adjusting the pH value to be increased by 0.5, continuing to cultivate for 24 hours, and screening the residual viable carbonic anhydrase bacteria;
s23, repeating the step S22 until carbonic anhydrase bacteria capable of tolerating the pH value of 10 are obtained, transferring the carbonic anhydrase bacteria into a culture barrel, and performing amplification culture;
s3, preparing carbonic anhydrase bacterium microcapsules:
taking a culture solution on the lower layer of a culture barrel, centrifuging to obtain carbonic anhydrase bacteria mud, weighing 1 part of carbonic anhydrase bacteria, adding the carbonic anhydrase bacteria mud into 200 parts of sodium alginate saturated solution, stirring at the speed of 450rpm, adding the mixture into 80 parts of calcium chloride solution with the concentration of 45 wt%, fully stirring, and centrifuging to obtain calcium alginate-coated microcapsules;
s4, preparing a regenerated porous material:
s41, mixing 5 parts of porous material, carbonic anhydrase bacteria microcapsules and upper-layer culture solution, soaking for 20min under vacuum negative pressure, and performing centrifugal separation to obtain a microcapsule-loaded porous material;
s42, mixing the porous material loaded with the microcapsules with 0.3 part of hexadecyl trimethyl ammonium bromide, adding 150 parts of pure water, stirring at 300rpm for 10min, adding 50 parts of strong ammonia water, dropwise adding 100 parts of a mixed solution of absolute ethyl alcohol and tetraethoxysilane, and continuously stirring to react for 5h after dropwise adding is finished;
s43, after the reaction is finished, performing centrifugal separation, washing the separated solid product for 3 times by using pure water, and performing freeze drying at-50 ℃ for 15 hours to obtain a regenerated porous material;
s5, weighing the raw material components in parts by weight, premixing 520 parts of low-heat portland cement, 360 parts of fine aggregate and 140 parts of regenerated porous material for 3-5min, adding mixing water in which 5.2 parts of water reducing agent and 6 parts of retarder are dissolved, stirring for 3min, adding 1211 parts of coarse aggregate, and continuing stirring for 5min to obtain the self-repairing concrete based on the regenerated porous material.
Comparative example 1.
In contrast to example 1, no regenerated porous material was prepared for this comparative example.
A preparation method of concrete comprises the following steps:
s1, weighing raw material components in parts by weight, premixing 500 parts of fine aggregate of 520 parts of low-heat portland cement for 3-5min, adding mixing water in which 5.2 parts of water reducing agent and 6 parts of retarder are dissolved, stirring for 3min, adding 1211 parts of coarse aggregate, and continuing stirring for 5min to obtain the self-repairing concrete based on the regenerated porous material.
Comparative example 2.
In contrast to example 1, this comparative example did not prepare calcium diatomate coated microcapsules;
a preparation method of self-repairing concrete based on renewable porous materials comprises the following steps:
s1, collecting construction waste, primarily crushing the construction waste by using a crusher, removing organic matters and iron impurities in the construction waste by using flotation and magnetic attraction, moving the rest construction waste into a ball mill, continuously grinding and granulating to prepare a porous material with the particle size of 0.5-0.8 mm;
s2, breeding carbonic anhydrase bacteria with high pH value resistance;
s21, inoculating the carbonic anhydrase bacteria screened from the mine into a beef extract peptone liquid culture medium, adding 5g/L of calcium nitrate into the liquid culture medium, performing shake-flask culture at 35 ℃ for 48 hours, then dropwise adding a sodium hydroxide solution, adjusting the pH to 8.5, continuing to cultivate for 24 hours, and screening the residual viable carbonic anhydrase bacteria;
s22, inoculating the screened carbonic anhydrase bacteria into a new beef extract peptone liquid culture medium, additionally adding 8g/L of calcium nitrate, dropwise adding a sodium hydroxide solution, adjusting the pH value to the pH value used in the previous screening, performing shake-flask culture for 48 hours, dropwise adding a sodium hydroxide solution, adjusting the pH value to be increased by 0.5, continuing to cultivate for 24 hours, and screening the residual viable carbonic anhydrase bacteria;
s23, repeating the step S22 until carbonic anhydrase bacteria capable of tolerating the pH value of 10 are obtained, transferring the carbonic anhydrase bacteria into a culture barrel, and performing amplification culture;
s4, preparing a regenerated porous material:
s41, mixing 5 parts of porous material with the upper layer culture solution, soaking for 20min under vacuum negative pressure, and performing centrifugal separation to obtain the porous material loaded with carbonic anhydrase bacteria;
s42, mixing the porous material loaded with the carbonic anhydrase bacteria with 0.3 part of hexadecyl trimethyl ammonium bromide, adding 150 parts of pure water, stirring at 300rpm for 10min, adding 50 parts of concentrated ammonia water, dropwise adding 100 parts of a mixed solution of anhydrous ethanol and ethyl orthosilicate, and continuously stirring for reacting for 5h after dropwise adding is finished;
s43, after the reaction is finished, performing centrifugal separation, washing the separated solid product for 3 times by using pure water, and performing freeze drying at-50 ℃ for 15 hours to obtain a regenerated porous material;
s5, weighing the raw material components in parts by weight, premixing 520 parts of low-heat portland cement, 440 parts of fine aggregate and 60 parts of regenerated porous material for 3-5min, adding mixing water in which 5.2 parts of water reducing agent and 6 parts of retarder are dissolved, stirring for 3min, adding 1211 parts of coarse aggregate, and continuously stirring for 5min to obtain the self-repairing concrete based on the regenerated porous material.
Detection, namely forming the concrete prepared in the examples 1-3 and the concrete prepared in the comparative examples 1-2, respectively detecting the compressive strength and the flexural strength, and the monitoring results are shown in the table 1; standing in a curing room for 24h, demolding, curing for 7d according to a standard method, and presetting cracks; loading a test piece by an electro-hydraulic servo pressure testing machine by adopting a three-point method to preset a crack, and stopping loading when a crack of 0.2-0.4mm appears at the lower end of the tensioned side face of the test piece; the loaded test piece is watered and maintained, the crack repairing performance is measured through a crack observation instrument, and the detection result is shown in table 2:
TABLE 1 flexural and compressive strengths
TABLE 2 fracture repair
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (9)
1. A self-repairing concrete based on renewable porous materials is characterized in that: the self-repairing concrete comprises the following components in parts by weight: 550 parts of cement, 1200 parts of coarse aggregate, 1300 parts of fine aggregate, 400 parts of fine aggregate, 300 parts of mixing water, 5-8 parts of a water reducing agent, 6-10 parts of a retarder, 50-150 parts of a regenerated porous material and 2-6 parts of calcium nitrate;
the regenerated porous material is prepared by crushing, screening and cleaning construction waste and then loading carbonic anhydrase bacteria.
2. The self-repairing concrete based on renewable porous materials as claimed in claim 1, characterized in that: the cement is low-heat portland cement.
3. The self-repairing concrete based on renewable porous materials as claimed in claim 1, characterized in that: the coarse aggregate is natural macadam with the particle size of 5-20 mm; the fine aggregate is medium sand with the grain diameter of 0.5-0.8 mm.
4. The self-repairing concrete based on renewable porous materials as claimed in claim 1, characterized in that: the water reducing agent is a polycarboxylic acid high-efficiency water reducing agent.
5. The self-repairing concrete based on renewable porous materials as claimed in claim 1, characterized in that: the retarder is one or a mixture of more of calcium lignosulphonate, hydroxymethyl cellulose and hydroxyethyl cellulose.
6. A preparation method of self-repairing concrete based on renewable porous materials is characterized by comprising the following steps:
s1, crushing, cleaning, grinding and granulating construction waste to prepare a porous material;
s2, breeding carbonic anhydrase bacteria with high pH value resistance:
inoculating carbonic anhydrase bacteria into a culture dish, and gradually screening the carbonic anhydrase bacteria by using the culture dish with a high pH value until the carbonic anhydrase bacteria which can tolerate the pH value of 10 are obtained;
s3, preparing carbonic anhydrase bacteria microcapsules:
centrifuging to obtain carbonic anhydrase bacterium mud, adding sodium alginate saturated solution, stirring and mixing, adding calcium chloride solution, fully stirring, and centrifuging to obtain carbonic anhydrase bacterium microcapsules;
s4, soaking the carbonic anhydrase bacterium microcapsules in the porous material for 15-20min under vacuum negative pressure, and coating a silicon dioxide layer on the surface of the carbonic anhydrase bacterium immobilized porous material to form a wrapping shell to obtain a regenerated porous material;
s5, weighing cement, coarse aggregate, fine aggregate and the regenerated porous material, uniformly mixing, adding mixing water, a retarder, calcium nitrate and a water reducing agent, and uniformly stirring to obtain the self-repairing concrete.
7. The preparation method of the self-repairing concrete based on the renewable porous material as claimed in claim 6, characterized by comprising the following steps:
s1, crushing the construction waste, removing waste plastics, waste wood and iron materials in the construction waste through flotation and magnetic attraction, cleaning the construction waste with clean water, transferring the construction waste into a ball mill for grinding, and granulating the construction waste into a porous material with the particle size of 0.5-0.8mm after grinding;
s2, breeding carbonic anhydrase bacteria with high pH value resistance;
s21, inoculating the carbonic anhydrase bacteria screened from the mine into a beef extract peptone liquid culture medium, adding 3-5g/L of calcium nitrate into the liquid culture medium, performing shake-flask culture at 28-35 ℃ for 48h, dropwise adding a sodium hydroxide solution, adjusting the pH to 8.0-8.5, continuing to cultivate for 24h, and screening the residual viable carbonic anhydrase bacteria;
s22, inoculating the screened carbonic anhydrase bacteria into a new beef extract peptone liquid culture medium, additionally adding 5-8g/L of calcium nitrate, dropwise adding a sodium hydroxide solution, adjusting the pH value to the pH value used in the previous screening, performing shake-flask culture for 48 hours, dropwise adding a sodium hydroxide solution, adjusting the pH value to be increased by 0.5, continuing to cultivate for 24 hours, and screening the residual viable carbonic anhydrase bacteria;
s23, repeating the step S22 until carbonic anhydrase bacteria capable of tolerating the pH value of 10 are obtained, transferring the carbonic anhydrase bacteria into a culture barrel, and performing amplification culture;
s3, preparing carbonic anhydrase bacteria microcapsules:
taking the culture solution at the lower layer of the culture barrel, centrifuging to obtain carbonic anhydrase bacterium mud, adding a sodium alginate saturated solution, stirring at the speed of 300-450rpm, adding the mixture into a calcium chloride solution with the concentration of 30-45 wt%, fully stirring, and centrifuging to obtain the carbonic anhydrase bacterium microcapsules;
s4, preparing a regenerated porous material:
s41, adding the porous material and the carbonic anhydrase bacteria microcapsules into the rest culture solution, soaking for 15-20min under vacuum negative pressure, and performing centrifugal separation to obtain the porous material loaded with the microcapsules;
s42, mixing the porous material loaded with the microcapsules with hexadecyl trimethyl ammonium bromide, adding pure water, stirring at the speed of 300rpm of 150-;
s43, after the reaction is finished, performing centrifugal separation, washing the separated solid product for 2-3 times by using pure water, and performing freeze drying at-50 ℃ for 10-15h to obtain a regenerated porous material;
s5, premixing cement, fine aggregate and the regenerated porous material for 3-5min, adding mixing water in which a water reducing agent, calcium nitrate and a retarder are dissolved, stirring for 2-3min, adding coarse aggregate, and continuously stirring for 5-8min to obtain the self-repairing concrete based on the regenerated porous material.
8. The preparation method of the self-repairing concrete based on the renewable porous material as claimed in claim 7, wherein the preparation method comprises the following steps: in step S3, the weight ratio of the carbonic anhydrase bacterial mud, the sodium alginate saturated solution and the calcium chloride solution is (0.5-1): (200-250): (80-120).
9. The preparation method of the self-repairing concrete based on the renewable porous material as claimed in claim 7, wherein the preparation method comprises the following steps: in step S4, the mass ratio of the porous material, the carbonic anhydrase bacterium microcapsule, the cetyl trimethyl ammonium bromide, the pure water, the concentrated ammonia water and the mixed solution is (5-8): (0.5-1): (0.1-0.3): (150-200): (50-60): (100- > 150); the mixed solution is 2 of absolute ethyl alcohol and ethyl orthosilicate: 1 mixing the solution.
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