CN116730685A - Crack self-repairing cement-based material and preparation method thereof - Google Patents
Crack self-repairing cement-based material and preparation method thereof Download PDFInfo
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- CN116730685A CN116730685A CN202310732405.3A CN202310732405A CN116730685A CN 116730685 A CN116730685 A CN 116730685A CN 202310732405 A CN202310732405 A CN 202310732405A CN 116730685 A CN116730685 A CN 116730685A
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- 239000004568 cement Substances 0.000 title claims abstract description 87
- 239000000463 material Substances 0.000 title claims abstract description 87
- 238000002360 preparation method Methods 0.000 title claims abstract description 14
- 241000193830 Bacillus <bacterium> Species 0.000 claims abstract description 97
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 claims abstract description 65
- 229910001424 calcium ion Inorganic materials 0.000 claims abstract description 65
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 25
- 238000000034 method Methods 0.000 claims abstract description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 50
- 230000001580 bacterial effect Effects 0.000 claims description 44
- 239000000725 suspension Substances 0.000 claims description 38
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 28
- 239000001963 growth medium Substances 0.000 claims description 22
- 108010046334 Urease Proteins 0.000 claims description 17
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 15
- 239000004202 carbamide Substances 0.000 claims description 15
- 239000007788 liquid Substances 0.000 claims description 15
- 238000001179 sorption measurement Methods 0.000 claims description 15
- 239000002244 precipitate Substances 0.000 claims description 14
- 239000011780 sodium chloride Substances 0.000 claims description 14
- 239000000843 powder Substances 0.000 claims description 13
- 239000000243 solution Substances 0.000 claims description 12
- CBOCVOKPQGJKKJ-UHFFFAOYSA-L Calcium formate Chemical compound [Ca+2].[O-]C=O.[O-]C=O CBOCVOKPQGJKKJ-UHFFFAOYSA-L 0.000 claims description 10
- 239000001888 Peptone Substances 0.000 claims description 10
- 108010080698 Peptones Proteins 0.000 claims description 10
- 239000004281 calcium formate Substances 0.000 claims description 10
- 229940044172 calcium formate Drugs 0.000 claims description 10
- 235000019255 calcium formate Nutrition 0.000 claims description 10
- 238000002156 mixing Methods 0.000 claims description 10
- 235000019319 peptone Nutrition 0.000 claims description 10
- 238000009630 liquid culture Methods 0.000 claims description 9
- 239000005909 Kieselgur Substances 0.000 claims description 8
- 239000012153 distilled water Substances 0.000 claims description 8
- 239000004576 sand Substances 0.000 claims description 8
- 230000003213 activating effect Effects 0.000 claims description 7
- 159000000007 calcium salts Chemical class 0.000 claims description 7
- 238000012258 culturing Methods 0.000 claims description 7
- 235000015097 nutrients Nutrition 0.000 claims description 7
- 239000000126 substance Substances 0.000 claims description 7
- 241000894006 Bacteria Species 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 239000000758 substrate Substances 0.000 claims description 6
- 240000004808 Saccharomyces cerevisiae Species 0.000 claims description 5
- -1 organic acid calcium salt Chemical class 0.000 claims description 4
- 239000002504 physiological saline solution Substances 0.000 claims description 4
- 241000193395 Sporosarcina pasteurii Species 0.000 claims description 3
- 229910021536 Zeolite Inorganic materials 0.000 claims description 3
- 229960000892 attapulgite Drugs 0.000 claims description 3
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 claims description 3
- 230000004060 metabolic process Effects 0.000 claims description 3
- 229910052625 palygorskite Inorganic materials 0.000 claims description 3
- 239000010451 perlite Substances 0.000 claims description 3
- 235000019362 perlite Nutrition 0.000 claims description 3
- 239000010455 vermiculite Substances 0.000 claims description 3
- 235000019354 vermiculite Nutrition 0.000 claims description 3
- 229910052902 vermiculite Inorganic materials 0.000 claims description 3
- 239000010457 zeolite Substances 0.000 claims description 3
- 239000003575 carbonaceous material Substances 0.000 claims description 2
- 239000002994 raw material Substances 0.000 claims description 2
- 239000006228 supernatant Substances 0.000 claims description 2
- 230000033558 biomineral tissue development Effects 0.000 abstract description 18
- 244000005700 microbiome Species 0.000 abstract description 9
- 230000008021 deposition Effects 0.000 abstract description 6
- 238000005336 cracking Methods 0.000 abstract description 5
- 239000004566 building material Substances 0.000 abstract description 3
- 238000004092 self-diagnosis Methods 0.000 abstract description 2
- 230000008439 repair process Effects 0.000 description 38
- 239000004567 concrete Substances 0.000 description 15
- 239000002609 medium Substances 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 11
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 10
- 239000002585 base Substances 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 238000009928 pasteurization Methods 0.000 description 7
- 230000008569 process Effects 0.000 description 6
- 239000000047 product Substances 0.000 description 6
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 5
- 239000007983 Tris buffer Substances 0.000 description 5
- 239000011575 calcium Substances 0.000 description 5
- 229910052791 calcium Inorganic materials 0.000 description 5
- 229910000019 calcium carbonate Inorganic materials 0.000 description 5
- 229940041514 candida albicans extract Drugs 0.000 description 5
- 230000035515 penetration Effects 0.000 description 5
- LENZDBCJOHFCAS-UHFFFAOYSA-N tris Chemical compound OCC(N)(CO)CO LENZDBCJOHFCAS-UHFFFAOYSA-N 0.000 description 5
- 239000012138 yeast extract Substances 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- VSGNNIFQASZAOI-UHFFFAOYSA-L calcium acetate Chemical compound [Ca+2].CC([O-])=O.CC([O-])=O VSGNNIFQASZAOI-UHFFFAOYSA-L 0.000 description 4
- 239000001639 calcium acetate Substances 0.000 description 4
- 235000011092 calcium acetate Nutrition 0.000 description 4
- 229960005147 calcium acetate Drugs 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 108090000790 Enzymes Proteins 0.000 description 3
- 102000004190 Enzymes Human genes 0.000 description 3
- 210000004027 cell Anatomy 0.000 description 3
- 230000006911 nucleation Effects 0.000 description 3
- 238000010899 nucleation Methods 0.000 description 3
- 239000010802 sludge Substances 0.000 description 3
- BCZXFFBUYPCTSJ-UHFFFAOYSA-L Calcium propionate Chemical compound [Ca+2].CCC([O-])=O.CCC([O-])=O BCZXFFBUYPCTSJ-UHFFFAOYSA-L 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- ZCCIPPOKBCJFDN-UHFFFAOYSA-N calcium nitrate Chemical compound [Ca+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ZCCIPPOKBCJFDN-UHFFFAOYSA-N 0.000 description 2
- 239000004330 calcium propionate Substances 0.000 description 2
- 235000010331 calcium propionate Nutrition 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 239000000969 carrier Substances 0.000 description 2
- 210000002421 cell wall Anatomy 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- 230000002503 metabolic effect Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 239000013049 sediment Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 230000001954 sterilising effect Effects 0.000 description 2
- 229940099259 vaseline Drugs 0.000 description 2
- 238000011041 water permeability test Methods 0.000 description 2
- 229910021532 Calcite Inorganic materials 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 241001052560 Thallis Species 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 235000010633 broth Nutrition 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000035784 germination Effects 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 230000003100 immobilizing effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
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- 230000006698 induction Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000000813 microbial effect Effects 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 230000003204 osmotic effect Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
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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
- C04B28/04—Portland cements
Abstract
The invention discloses a crack self-repairing cement-based material based on bacillus pasteurizus mineralization deposition and a preparation method thereof. The invention divides the diatomite loaded with the microorganism into two parts, wherein one part is the diatomite loaded with the microorganism which does not adsorb the calcium ions in advance, and the other part is the diatomite loaded with the microorganism which adsorbs the calcium ions in advance. Therefore, the method can ensure that the cracks of the cement-based material are repaired in time after cracking, and can improve the durability of the repaired cement-based material. The prepared regenerated cement-based material for self-repairing the cracks based on the mineralized deposition of the bacillus barbiturae is a regenerated cement-based material which has the functions of self-diagnosis and self-repairing of the cracks, is green and environment-friendly, and meets the requirements of the current economic society on the environment-friendliness, the environment-friendliness and the intelligence of building materials.
Description
Technical Field
The invention relates to a self-repairing cement-based material, in particular to a crack self-repairing cement-based material based on bacillus pasteurizus mineralized deposition and a preparation method thereof.
Background
Concrete is the building material with the largest use amount and the largest application range at present. However, because the tensile strength is low, cracks are easily generated to reduce the strength of the concrete, and harmful chemical substances (such as chloride ions) easily enter the concrete through the cracks, so that the concrete is degraded and the steel bars are corroded, and the service time is reduced.
Although the traditional crack repairing method can fill the crack to a certain extent, the defects of complex operation, high labor cost, damage to the concrete structure, incapability of repairing in time and the like are exposed in the implementation process. The microbial self-repairing cement-based material can meet the requirement of crack repairing, does not need manual detection and repairing, and is low in energy consumption and environment-friendly.
Bacillus pasteurisus is a type of enzyme capable of producing urease by its own metabolism, breaking down urea intoAndis a microorganism of the genus (A). The bacillus barbituralis has strong mineralization capability, certain alkali resistance and high urease yield, and is a high-quality microorganism suitable for self-repairing mortar. The induction mineralization process of the bacillus pasteurizer comprises the following steps: when the concrete microcrack is formed, the environment where the spore is located changes, oxygen and water enter the crack, the spore germinates into vegetative cells, normal metabolic activity is carried out to generate urease, and urea hydrolysis is promoted to +.>And->Under alkaline conditions, < "> a->And calcium ions react to form calcium carbonate to fill the crack area, so that the crack is self-repaired, and the concrete and the internal steel bars are protected, as shown in fig. 5. However, the extremely high urease production rate of Bacillus pasteurisation accelerates the deposition of mineralized products, but the resulting oreThe products of the chemical conversion are mostly large diameter, loose calcium carbonate precipitates, which are disadvantageous for the improvement of the durability of cement-based materials.
Literature (Qian C, wang J, wang R, et al Corrosion protection of cement-based building materials by surface deposition of CaCO) 3 by Bacillus pasteurii[J]Materials Science and Engineering C,2009,29 (4): 1273-1280.) shows that when calcium ions are added into a mineralization system, the bacillus pasteurizer adsorbs the calcium ions in advance to inhibit the rate of urease formation to a certain extent, so as to obtain calcite with smaller, denser and more stable precipitate particles (as shown in figures 1 and 2, the first group in figure 2 is urea added simultaneously with a calcium source; the second group is urea added 24 hours after the calcium source is added; the third group is urea added after the calcium source is added for 48 hours), so that the possibility that the bacillus pasteurizer capable of absorbing calcium ions in advance becomes a nucleation site is greatly improved, the utilization efficiency of the bacillus pasteurizer and the possibility that mineralized products are generated at all positions of the cement-based material are further improved, and the possibility of repairing after cracking of all positions of the cement-based material is further improved. However, the early adsorption of calcium ions can lead to the slow down of the urease production rate of the bacillus pasteurizer, the slow down of the sediment production rate and the slow down of the repair rate, and the problem that the early stage of cracking of the cement-based material can not be repaired in time can be caused.
Disclosure of Invention
The invention aims to: the invention aims to provide a crack self-repairing cement-based material based on bacillus pasteurizus mineralization deposition, which solves the problem that the repairing speed and the durability cannot be considered when the existing self-repairing material utilizes bacillus pasteurizus mineralization to repair cracks. The invention further aims to provide a preparation method of the crack self-repairing cement-based material, which solves the problem of how to apply bacillus pasteurizer to prepare the crack self-repairing cement-based material.
The technical scheme is as follows: the self-repairing cement-based material for the cracks comprises a cement base material, a first premix and a second premix, wherein the first premix comprises urease-producing bacteria and carriers which are adsorbed with calcium ions, the second premix comprises urease-producing bacteria and carriers which are not adsorbed with calcium ions, and the total weight of the first premix and the second premix is 1-25% of the weight of the cement base material.
The invention innovatively provides two types of premixes added into cement-based materials, wherein one type is a porous adsorption carrier for loading bacillus pasteurizer which does not adsorb calcium ions in advance, and the other type is a porous adsorption carrier for loading bacillus pasteurizer which adsorbs calcium ions in advance. After the cement-based material is cracked, the mineralization process can be divided into two steps, and urease is generated for bacillus pasteurizer which does not adsorb calcium ions in advance to decompose urea, so that loose precipitate is rapidly generated to primarily repair the crack. Whereas the relatively slow rate of production of the urease from the bacillus pastoris that has previously adsorbed calcium ions can be seen as the second step in the mineralization process, the denser precipitate produced at this time can improve the durability of the cement-based material after repair.
Preferably, the urease-producing bacteria is bacillus pasteurizer and the carrier is a porous adsorption substrate, the cement substrate comprising cement, sand, water and nutrients for metabolism and growth of bacillus pasteurizer. Bacillus pasteurium as a urease producing microorganism is capable of producing urease to hydrolyze urea to ammonia and carbon dioxide, wherein ammonia increases the pH of the surrounding environment, and facilitates the conversion of carbon dioxide to carbonate ions and thus CaCO 3 The precipitation, the cell wall of which is negatively charged, is an ideal nucleation site for calcium carbonate crystals, and the probability that the bacillus pasteurizer which adsorbs calcium ions in advance becomes the nucleation site is higher, so that the probability of repairing cracks of the cement-based material after cracking is improved; the bacillus pasteurizer used in the invention has strong adaptability to high alkaline environment, can better survive in the alkaline environment in the cement-based material, and can better improve the service time of the cement-based material when the cement-based material is in a dormant state when not cracked; the nutrient is mainly used for germination and metabolic activity of the bacillus pasteurizer.
Preferably, the porous adsorption substrate comprises one or more of diatomaceous earth, porous carbon material, attapulgite, zeolite, vermiculite, perlite. The porous adsorption base material such as diatomite has the advantages of porosity, light weight, chemical stability, biological inertia and the like, and can be used as a carrier for immobilizing the bacillus pasteurizer. The nano pore structure of the bacillus pasteurization agent is easy to adsorb bacillus pasteurization agent, so that the bacillus pasteurization agent is free from the influence of alkaline environment in the cement-based material, and is favorable for uniformly dispersing the bacillus pasteurization agent in the cement-based material, thereby greatly improving the self-repairing performance of the cement-based material.
Preferably, the mixture ratio of the crack self-repairing cement-based material comprises the following raw materials in parts by weight: 3500-4500 parts of cement base material, 135-215 parts of premix one and 135-215 parts of premix two.
Preferably, the weight ratio of the premix one to the premix two is 1: (1-1.5). The two premixes are reasonably proportioned, so that the interference of the first-step quick repair effect on the second-step compact repair effect can be effectively avoided, and the contradiction that the quick repair and the durable repair cannot be achieved is solved.
The preparation method of the crack self-repairing cement-based material comprises the following steps:
(1) Preparation of premix one: adding the carrier into the bacillus pasteurizus suspension for absorbing calcium ions in advance, and fully mixing;
(2) Preparation of premix two: adding the carrier into the bacillus pasteurizer suspension without calcium ions, and fully mixing;
(3) And fully mixing the cement base material with the first premix and the second premix according to the proportion to obtain the self-repairing cement base material.
In some embodiments, the preparation method of the bacillus pasteurizer suspension with calcium ions adsorbed in advance in the step (1) comprises the following steps:
adding calcium salt into liquid culture medium or bacterial body heavy suspension, activating and culturing Bacillus pasteurii with the liquid culture medium to obtain bacterial body culture solution, centrifuging the bacterial body culture solution, discarding supernatant to obtain bacterial body precipitate, and re-suspending the bacterial body precipitate with the bacterial body heavy suspension to obtain bacterial body concentration of 10 6 ～10 9 individual/mL of the bacillus pasteurizer suspension with early adsorption of calcium ions. And adding extra concentration of calcium ions in the culturing process or the re-suspending process of the bacillus pasteurizer to enable the bacillus pasteurizer to adsorb the calcium ions in advance, thereby improving the durability of the cement-based material after repair. Advance addition ofCalcium ions are added, so that on one hand, the cell can keep osmotic balance and the growth of the bacillus pasteurizer is promoted; on the other hand, calcium ions are adsorbed around the cell wall in advance, so that the rate of producing urease by the bacillus pasteurizer can be reduced, thereby obtaining denser calcium carbonate sediment, improving the utilization efficiency of the bacillus pasteurizer, and improving the repairing possibility and the durability of the cement-based material after repairing.
Preferably, the carrier addition in the step (1) is 20-70 wt% of the bacillus pasteurizer suspension for absorbing calcium ions in advance; the carrier addition amount in the step (2) is 20-70 wt% of the bacillus pasteurizer suspension without calcium ions adsorbed; adding calcium salt according to the proportion of 7.8-10.4 g/L.
Preferably, the calcium salt is organic acid calcium salt, and the liquid of the re-suspension thalli is distilled water or physiological saline; the method for activating and culturing the bacillus pasteurizer comprises the following steps: inoculating the bacillus pasteurizer freeze-dried powder into an alkaline liquid bacterial culture medium with the pH of 9.0 under the aseptic condition, culturing by shaking, taking bacterial liquid in a platform stage for subculture, and repeating the subculture for at least two times to obtain a bacterial culture solution. The organic acid calcium salt may be selected from calcium formate, calcium acetate, calcium propionate, calcium acetate, etc.
Preferably, the preparation method of the cement base material comprises the following steps:
(1) Fully mixing 40-50 parts by weight of urea, 8-11 parts by weight of calcium formate, 15-25 parts by weight of peptone, 15-25 parts by weight of yeast powder and 4-6 parts by weight of sodium chloride to prepare a nutrient substance;
(2) The cement base material is prepared by mixing 900-1100 parts by weight of cement, 2700-3000 parts by weight of sand, 225-325 parts by weight of water and 25-40 parts by weight of nutrient substances.
The beneficial effects are that: compared with the prior art, the invention has the following remarkable advantages: the crack self-repairing cement-based material prepared by the method can not only quickly fill and repair cracks in the early stage of crack generation and meet the requirement of early-stage water penetration resistance repair, but also continuously and compactly repair the cracks, finally achieve higher water penetration resistance repair rate and effectively improve the durability of the self-repairing cement-based material. The invention successfully utilizes the porous adsorption carrier and the bacillus barbituralis to prepare the green environment-friendly water mud-based material with crack self-diagnosis and self-repair and with repair speed and durability, and the preparation method is simple and reliable and has better application prospect.
Drawings
FIG. 1 is an SEM image of the precipitate produced by Bacillus pasteurisus;
wherein, (a) is a precipitate generated by adding urea and a calcium source simultaneously; (b) graph shows the precipitate formed by urea added after the calcium source;
FIG. 2 is an XRD pattern of the precipitate obtained with different modes of addition of urea;
FIG. 3 is a schematic diagram of the self-repairing principle of concrete cracks;
FIG. 4 is a graph showing the comparison of calcium carbonate production from different Bacillus pasteurisation broths at the same time of mineralization in vitro;
FIG. 5 is a graph showing the water penetration resistance repair rate of the samples after 8 days and 28 days of concrete self-repair;
FIG. 6 is a schematic diagram of a test apparatus for determining the water permeation resistant repair rate of a test piece.
Detailed Description
The technical scheme of the invention is further described below with reference to the accompanying drawings.
Example 1: the self-repairing cement-based material comprises the following components in percentage by weight:
(1) 5g of yeast extract, 5g of peptone and 1.25g of sodium chloride were dissolved in 225mL of distilled water, the pH of the above medium was adjusted to 9.0 with Tris, and the medium was sterilized at 120℃for 30 minutes to prepare a first type of liquid medium;
(2) A second type of liquid medium was prepared by dissolving 5g of yeast extract, 5g of peptone, 1.25g of sodium chloride, 2.03g of calcium formate in 225mL of distilled water, adjusting the pH of the above medium to 9.0 with Tris, and sterilizing at 120℃for 30 minutes; the calcium formate in this embodiment may be replaced by other organic acid calcium salts such as calcium acetate, calcium propionate, and calcium acetate, or inorganic calcium salts such as calcium nitrate.
(3) Activating the bacillus pasteurizer freeze-dried powder under the aseptic condition, respectively inoculating the bacillus pasteurizer freeze-dried powder into a first liquid culture medium and a second liquid culture medium, and carrying out shake culture;
(4) The wavelength of an enzyme-labeled instrument is selected to be 600nm, the concentration of microorganisms in a culture medium is roughly measured at intervals of 2-4 hours, and when the OD value in the culture medium reaches the maximum, namely, the plateau phase of a thallus growth curve, 1% of culture solution containing bacillus barbituralis is inoculated into a new culture medium for subculture;
(5) Repeating the step (3) twice to obtain the third generation of bacillus pasteurizers with and without the advanced adsorption of calcium ions;
(6) Respectively centrifuging Bacillus pasteurism bacterial liquid with and without calcium ions of the third generation at 4000r/min for 20min to collect bacterial mud, and re-suspending the bacterial mud with physiological saline with sodium chloride concentration of 8.5g/L to prepare bacterial mud with concentration of 1×10 respectively 9 Bacterial suspension in individual/mL;
(7) 45g of diatomaceous earth was added to 160g of a bacterial suspension previously adsorbed with calcium ions and mixed for 1 hour at 30℃on a shaker at 100rpm to prepare a premix I;
(8) 45g of diatomaceous earth was added to 159.5g of a bacterial suspension not previously adsorbed with calcium ions, and mixed for 1 hour at 30℃on a shaker at 100rpm to prepare a second premix;
(9) 900g of cement, 2400g of sand and 225g of water are poured into a stirrer to be uniformly stirred, and the self-repairing regenerated cement-based material is obtained by pouring 8.95g of urea, 3.65g of calcium formate, 9.04g of peptone, 9.04g of yeast powder and 2.25g of sodium chloride into the stirrer to be uniformly stirred.
Example 2: the self-repairing cement-based material comprises the following components in percentage by weight:
(1) 5g of yeast extract, 5g of peptone, 1.25g of sodium chloride were dissolved in 250mL of distilled water, the pH of the above medium was adjusted to 9.0 with Tris, and sterilized at 120℃for 30 minutes to prepare a liquid medium;
(2) Activating the bacillus pasteurizer freeze-dried powder under the aseptic condition, inoculating the bacillus pasteurizer freeze-dried powder into a liquid culture medium, and carrying out shake culture;
(3) The wavelength of an enzyme-labeled instrument is selected to be 600nm, the concentration of microorganisms in a culture medium is roughly measured at intervals of 2-4 hours, when the OD value in the culture medium reaches the maximum, 1% of culture solution containing the bacillus pasteurizer is inoculated into a new culture medium, and subculture is carried out;
(4) Repeating the step (3) for two times to obtain the third generation of the bacillus pasteurizer;
(5) Centrifuging the third generation Bacillus pasteurizer bacterial liquid at 4000r/min for 20min to collect bacterial sludge, and re-suspending half of bacterial sludge with aqueous solution with sodium chloride concentration of 8.5g/L and calcium formate concentration of 62.5mM to obtain Bacillus pasteurizer with early calcium ion adsorption concentration of 1×10 9 Resuspension of the remaining bacterial sludge with 8.5g/L aqueous sodium chloride solution to prepare Bacillus pasteurizer with concentration of 1×10 without calcium ion adsorption 9 Bacterial suspension in individual/mL;
(6) 45g of diatomaceous earth was added to 160g of a bacterial suspension not previously adsorbed with calcium ions and mixed for 1 hour at 30℃on a shaker at 100rpm to prepare a premix I;
(7) 45g of diatomaceous earth was added to 159.5g of a bacterial suspension previously adsorbed with calcium ions and mixed for 1 hour at 30℃on a shaker at 100rpm to prepare a premix II;
(8) 900g of cement, 2700g of sand and 225g of water are poured into a stirrer to be uniformly stirred, and the self-repairing regenerated cement-based material is obtained by pouring the two types of premixes (135 g of premix I and 135g of premix II), 8.95g of urea, 3.65g of calcium formate, 9.04g of peptone and 9.04g of yeast powder and 2.25g of sodium chloride into the stirrer.
Example 3: the self-repairing cement-based material comprises the following components in percentage by weight:
(1) 5g of yeast extract, 5g of peptone and 1.25g of sodium chloride were dissolved in 225mL of distilled water, the pH of the above medium was adjusted to 9.0 with Tris, and the medium was sterilized at 120℃for 30 minutes to prepare a first type of liquid medium;
(2) A second type of liquid medium was prepared by dissolving 5g of yeast extract, 5g of peptone, 1.25g of sodium chloride, 2.03g of calcium formate in 225mL of distilled water, adjusting the pH of the above medium to 9.0 with Tris, and sterilizing at 120℃for 30 minutes;
(3) Activating the bacillus pasteurizer freeze-dried powder under the aseptic condition, respectively inoculating the bacillus pasteurizer freeze-dried powder into a first liquid culture medium and a second liquid culture medium, and carrying out shake culture;
(4) The concentration of microorganisms in a culture medium is roughly measured at 600nm intervals for 2-4 hours, when the OD value in the culture medium reaches the maximum, 1% of culture solution containing the bacillus pasteurizer is inoculated into a new culture medium, and subculture is carried out;
(5) Repeatedly carrying out subculture twice to obtain the bacillus pasteurizer with the third generation of calcium ions adsorbed in advance and the bacillus pasteurizer without the calcium ions adsorbed in advance;
(6) Respectively centrifuging Bacillus pasteurism bacterial liquid with and without calcium ions of the third generation at 4000r/min for 20min to collect bacterial mud, and re-suspending the bacterial mud with physiological saline with sodium chloride concentration of 8.5g/L to prepare bacterial mud with concentration of 1×10 respectively 9 Bacterial suspension in individual/mL;
(7) 67.5g of diatomaceous earth was added to 112.5g of a bacterial suspension having calcium ions previously adsorbed thereto and mixed for 1 hour at 30℃on a shaker at 100rpm to prepare a premix I;
(8) 67.5g of diatomaceous earth was added to 112.5g of a bacterial suspension not previously adsorbed with calcium ions and mixed for 1 hour at 30℃on a shaker at 100rpm to prepare a premix II;
(9) 900g of cement, 2700g of sand and 225g of water, wherein the two types of premixes (182.5 g of premix I and 182g of premix II), 8.95g of urea, 3.08g of calcium formate, 9.04g of peptone, 9.04g of yeast powder and 2.25g of sodium chloride are poured into a stirrer to be uniformly stirred, and the self-repairing cement-based material is obtained.
Example 4 the remainder was the same as in example 1 except that the bacterial suspension after resuspension had a bacterial cell concentration of 1X 10 6 And each mL. The cement base was 1100g cement, 3000g sand, 325g water, and the premix was added in 215g premix one and 215g premix two.
Example 5 the remainder were the same as in example 1 except that:
the diatomite in the premix I is added in an amount of 70 weight percent of the bacillus pasteurizer suspension for absorbing calcium ions in advance; the diatomite addition amount in the premix II is 70wt% of the bacillus pasteurizer suspension without calcium ions adsorbed;
the diatomite can be replaced by one or more of active carbon, porous graphite, attapulgite, zeolite, vermiculite and perlite according to actual needs.
Comparative example 1 the remainder was the same as in example 1 except that: only premix two was added and premix one was replaced with an equal amount of premix two.
Comparative example 2 the remainder was the same as comparative example 1 except that: an equal amount of the bacillus pasteurizer suspension, which did not adsorb calcium ions in advance, was used instead of premix one.
Comparative example 3 the remainder was the same as comparative example 1 except that: the bacterial suspension was replaced with an equal amount of distilled water.
Example 6 self-repairing cement-based material samples were prepared by the method of example 2 with the weight ratio of premix one loaded with bacillus pasteurizer that had previously adsorbed calcium ions to premix two loaded with bacillus pasteurizer that had not adsorbed calcium ions as a variable, and with the weight ratios of premix one to premix two set to 4:1, 2:1, 1:1, 1:2, 1:3, 1:4, and the crack water penetration resistance repair rates were measured for 8 days and 28 days. The water permeability test detects the water permeability repairing rate, (1) a concrete test piece with the repairing time t is arranged in a container shown in fig. 6, and Vaseline is coated on the side surface and the bottom of the test piece, so that the side surface and the bottom of the concrete test piece are tightly attached to the container; (2) Continuously injecting water from the upper part of the container to the inside of the container to keep the water level constant, and ensuring that the water pressure of the test piece is kept stable; (3) And when the water at the bottom of the test piece oozes out, starting timing, recording the volume of water permeated by the test piece within 1min, and recording the water outlet quality M.
Using the formula:
wherein: epsilon-water permeation resistance repair rate (%)
M 0 Test piece initial water seepage flow (g/s)
M t Water seepage flow (g/s) of test piece at t days of repair age
The results were as follows:
TABLE 1 influence of different ratios of premix one and premix two on crack Water penetration resistance repair Rate
| Group of | 8 days water permeation resistant repair rate (%) | 28 days water permeation resistant repair rate (%) |
| 4:1 | 34.3 | 89.2 |
| 2:1 | 43.2 | 87.6 |
| 1:1 | 49.4 | 86.8 |
| 1:2 | 52.7 | 84.3 |
| 1:3 | 53.2 | 74.2 |
| 1:4 | 54.6 | 66.7 |
The results in table 1 show that when the premix is added relatively more, the 8-day water permeation resistant repair rate of the crack is lower, but the 28-day water permeation resistant repair rate is higher, which indicates that the quick repair capability of the self-repair material is lower, the effective repair can not be provided at the early stage of crack generation, slow and compact repair is required for a longer time, and finally, the better water permeation resistant repair rate is achieved at 28 days, so that the durability of the repair material is improved. When the adding proportion of the premix II is gradually increased, particularly when the proportion exceeds 1:3, although the early repair capability of the self-repair material is enhanced, the subsequent compact repair effect is greatly weakened, and the water permeation resistance repair rate is obviously lower than that of other proportions in 28 days, which is probably because the premix II which plays the role of early repair rapidly generates a large amount of loose mineralization products to fill the cracks, water and oxygen cannot enter the cracks although the cracks can be rapidly plugged, and the compact mineralization of the bacillus pasteurizer which adsorbs calcium ions in advance is blocked, so that the subsequent slow compact repair stage is stopped, and the durable repair of the self-repair material is finally influenced.
Example 7 two types of culture solutions as described in example 1 were prepared separately, and after autoclaving, 5 test groups were prepared, each group having the composition of the two types of culture solutions as shown in the following table. Shaking culture is carried out for three days at 30 ℃, precipitates of each group of tests are collected by filtration, and after drying, the weights of each group of precipitates are obtained by weighing.
| Group of | First-class culture medium (mL) | Second type of culture medium (mL) |
| A | 100 | 0 |
| B | 75 | 25 |
| C | 50 | 50 |
| D | 25 | 75 |
| E | 0 | 100 |
Wherein, the group A is a Bacillus pasteurizer suspension with 100mL of calcium ions absorbed in advance; group B is prepared by adding 75mL of Bacillus pasteurizer suspension with calcium ions adsorbed in advance and 25mL of untreated Bacillus pasteurizer suspension; group C is to add 50mL of the bacillus pasteurizer suspension with calcium ions adsorbed in advance and 50mL of the bacillus pasteurizer culture solution without calcium ions adsorbed; group D is to add 25mL of Bacillus pasteurizer suspension with calcium ions adsorbed in advance and 75mL of Bacillus pasteurizer suspension without calcium ions adsorbed; group E was added 100mL of a suspension of Bacillus pasteurisation without calcium ion adsorption.
As can be seen from the results of FIG. 4, the mineralization rate of the Bacillus pasteurizer which adsorbs calcium ions in advance is slower and the mineralization products are less, while the higher the proportion of the Bacillus pasteurizer which does not adsorb calcium ions in advance, the more rapid the mineralization, and the mineralization products are significantly higher than the proportion of the Bacillus pasteurizer which does not adsorb calcium ions in advance. Analysis shows that when the proportion of the bacillus pasteurizer which does not adsorb the calcium ions in advance in the group is less than 50%, the factor of whether to adsorb the calcium ions in advance has a remarkable effect on the mineralization rate of the bacillus pasteurizer, but the effect degree is reduced when the proportion exceeds 50%. Comprehensively considering whether the bacillus barbituralis adsorbs calcium ions in advance or not to influence the crack repairing effect of concrete after cracking, the proportion of the bacillus barbituralis which does not adsorb the calcium ions in advance has an optimal value.
Example 8: preparing 5 groups of concrete, wherein group A is the cement-based material prepared in example 1; group B is the cement-based material prepared in example 2; group C is the cement-based material prepared in comparative example 1; group D is the cement-based material prepared in comparative example 2; group E is the cement-based material prepared in comparative example 3. Cracks were made and cured under standard conditions and water permeability tests were performed at 8 days and 28 days. The method comprises the steps of (1) mounting a concrete test piece with repair time t in a container shown in fig. 6, and coating Vaseline on the side surface and the bottom of the test piece to enable the side surface and the bottom of the concrete test piece to be tightly attached to the container; (2) Continuously injecting water from the upper part of the container to the inside of the container to keep the water level constant, and ensuring that the water pressure of the test piece is kept stable; (3) When the moisture at the bottom of the test piece oozes out, the timing is started,
the volume of water that the test piece permeated within 1min was recorded and the water mass M was recorded.
Using the formula:
wherein: epsilon-water permeation resistance repair rate (%)
M 0 Test piece initial water seepage flow (g/s)
M t Water seepage flow (g/s) of test piece at t days of repair age
The experimental results are shown in fig. 5, wherein group a is the cement-based material prepared in example 1; group B is the cement-based material prepared in example 2; group C is the cement-based material prepared in comparative example 1; group D is the cement-based material prepared in comparative example 2; group E is the cement-based material prepared in comparative example 3;
as can be seen from the results of fig. 5, the group E material without the addition of the bacillus pasteurizer does not have mineralization restoration capability, and the comparison of the group D and the group E shows that the diatomite can effectively promote the mineralization restoration effect of the bacillus pasteurizer by taking the diatomite as a carrier, but the promotion effect is limited; compared with the group C, the group A and the group B have the advantages that although the bacillus barbituralis which does not adsorb calcium ions in advance has better quick repairing capability, the durability of the material is improved poorly in the later period (the 28-day water-resistant permeability repairing rate of the group C is obviously lower than that of the group A and the group B), and the self-repairing material prepared in the embodiment 1 and the embodiment 2 has better early quick repairing capability and slow compact repairing capability, so that the slow compact repairing can be continuously carried out after the crack is filled quickly, and the durability of the material is effectively improved.
Claims (10)
1. A crack self-repairing cement-based material, comprising a cement base material, a first premix comprising urease-producing bacteria having adsorbed calcium ions and a carrier, and a second premix comprising urease-producing bacteria having no adsorbed calcium ions and a carrier, wherein the total weight of the first and second premixes is 1-25% of the weight of the cement base material.
2. The crack self-repairing cement-based material of claim 1, wherein the urease producing bacteria is bacillus pasteurizus and the carrier is a porous adsorption substrate, the cement substrate comprising cement, sand, water and nutrients for metabolism and growth of bacillus pasteurizus.
3. The crack self-healing cement-based material of claim 2, wherein the porous adsorption substrate comprises one or more of diatomaceous earth, porous carbon material, attapulgite, zeolite, vermiculite, perlite.
4. The crack self-repairing cement-based material according to claim 1, comprising the following raw materials in parts by weight: 3500-4500 parts of cement base material, 135-215 parts of premix one and 135-215 parts of premix two.
5. The crack self-healing cement-based material of claim 4, wherein the weight ratio of premix one to premix two is 1:1-1.5.
6. A method of preparing a crack self-healing cement-based material according to any one of claims 1 to 5, comprising the steps of:
(1) Preparation of premix one: adding the carrier into the bacillus pasteurizus suspension for absorbing calcium ions in advance, and fully mixing;
(2) Preparation of premix two: adding the carrier into the bacillus pasteurizer suspension without calcium ions, and fully mixing;
(3) And fully mixing the cement base material with the first premix and the second premix according to the proportion to obtain the self-repairing cement base material.
7. The method for preparing a crack self-repairing cement-based material according to claim 6, wherein the preparation method of the bacillus pasteurizer suspension for absorbing calcium ions in advance in the step (1) comprises the following steps: adding calcium salt into liquid culture medium or bacterial body heavy suspension, activating and culturing Bacillus pasteurii with the liquid culture medium to obtain bacterial body culture solution, centrifuging the bacterial body culture solution, discarding supernatant to obtain bacterial body precipitate, and re-suspending the bacterial body precipitate with the bacterial body heavy suspension to obtain bacterial body concentration of 10 6 ～10 9 individual/mL of the bacillus pasteurizer suspension with early adsorption of calcium ions.
8. The method for preparing a crack self-repairing cement-based material according to claim 6, wherein the carrier addition amount in the step (1) is 20-70 wt% of the bacillus pasteurizer suspension for absorbing calcium ions in advance; the carrier addition amount in the step (2) is 20-70 wt% of the bacillus pasteurizer suspension without calcium ions adsorbed; adding calcium salt according to the proportion of 7.8-10.4 g/L.
9. The method for producing a crack self-repairing cement-based material according to claim 8, wherein the calcium salt is an organic acid calcium salt, and the liquid of the resuspension cells is distilled water or physiological saline; the method for activating and culturing the bacillus pasteurizer comprises the following steps: inoculating the bacillus pasteurizer freeze-dried powder into an alkaline liquid bacterial culture medium under the aseptic condition, culturing by shaking, taking bacterial liquid in a platform stage for subculture, and repeating the subculture at least twice to obtain a bacterial culture liquid.
10. The method for preparing a crack self-repairing cement-based material according to claim 9, wherein the method for preparing the cement-based material is as follows:
(1) Fully mixing 40-50 parts by weight of urea, 8-11 parts by weight of calcium formate, 15-25 parts by weight of peptone, 15-25 parts by weight of yeast powder and 4-6 parts by weight of sodium chloride to prepare a nutrient substance;
(2) The cement base material is prepared by mixing 900-1100 parts by weight of cement, 2700-3000 parts by weight of sand, 225-325 parts by weight of water and 25-40 parts by weight of nutrient substances.
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