Preparation method and application of cement-based material retarder

Abstract

The invention discloses a preparation method and application of a cement-based material retarder. The method comprises the following steps: cleaning and crushing tilapia skin; soaking the crushed tilapia skin in a GS modification liquid for modification, filtering and cleaning; adding a compound protease suspension into the modified tilapia skin for enzymolysis, and then heating to inactivate enzyme, so as to obtain a collagen stock solution; then adding an adsorption material into the collagen stock solution, stirring and filtering to obtain a collagen secondary clear solution; and finally, centrifuging the collagen secondary clear liquid, and taking the supernate, namely the retarder. According to the invention, a modified collagen extracting solution is used as a cement-based material retarder, colloid released and formed in a dissolving process is adsorbed on the surface of a hydration product, peptide bonds and carboxyl groups in a protein structure form chemical adsorption on the surface of the cement hydration product and are adsorbed on crystal nucleuses of the hydration product, so that continuous growth of crystals is hindered, and the cement-based material retarder is formed. The crystallization conversion process of C3S hydrate is delayed, so that the retarding effect of the cement-based material is realized.

Description

Technical Field

[0001] The invention relates to a preparation method and application of a cement-based material admixture, and in particular to a preparation method and application of a cement-based material retarder. Background Art

[0002] With the rapid development of civil engineering infrastructure construction, the demand for large buildings (high-rise buildings, ports, dams, large bridges) is increasing, and the application of mass concrete in civil engineering construction is becoming more and more common. In order to keep the plasticity of concrete for a long time, it is convenient for pouring and molding, or to slow down the hydration heat release rate, and reduce the cracks in the concrete structure caused by the temperature stress generated by concentrated heat release.

[0003] Based on the above reasons, in order to address the problem of temperature cracks in large-volume concrete caused by shortened concrete setting time and cracks due to high temperature, or the inevitable delay between mixing and pouring that has an adverse effect on concrete construction performance, there is an urgent need for low-cost, widely available coagulants that can enhance the retarding effect of cement-based materials to reduce cracks caused by temperature stress, delay the hydration heat release rate and improve the setting time. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a method for preparing a cement-based material retarder with a wide source, low cost and improved retarding effect;

[0005] The second object of the present invention is to provide the application of the cement-based material retarder obtained by the above method.

[0006] Technical solution: The preparation method of the cement-based material retarder of the present invention comprises the following steps:

[0007] (1) cleaning and crushing tilapia skin;

[0008] (2) immersing the crushed tilapia skin in GS modification liquid for modification, filtering, and washing;

[0009] (3) adding a composite protease suspension to the modified tilapia skin for enzymolysis, and then heating to inactivate the enzyme to obtain a collagen stock solution;

[0010] (4) adding an adsorption material to the collagen stock solution, stirring, and filtering to obtain a collagen secondary clear solution;

[0011] (5) Centrifuge the collagen secondary supernatant and take the supernatant to obtain a cement-based material retarder.

[0012] Wherein, in step (2), the GS modified liquid comprises, by mass, 20 to 40 parts of calcium hydroxide, 5 to 10 parts of stearic acid, 5 to 10 parts of sodium hydroxide, and 100 parts of deionized water.

[0013] Wherein, in step (3), the composite protease suspension comprises, by mass, 20 to 40 parts of neutral protease derived from Bacillus subtilis; 60 to 80 parts of bromelain derived from pineapple, and 100 parts of deionized water.

[0014] The activity of the neutral protease of Bacillus subtilis is 300-600u / g; the activity of bromelain is 4500-5500u / g.

[0015] Wherein, in step (3), the temperature for enzymatic hydrolysis of the composite protease suspension is 20 to 40° C. and the time is 4 to 6 hours.

[0016] Wherein, in step (3), the temperature is then raised to 70-80°C to inactivate the enzyme for 2-4 hours.

[0017] Wherein, in step (4), the amount of the adsorbent material added is 1 to 10% of the net fish skin weight; the adsorbent material is at least one of activated carbon and adsorbent resin.

[0018] Wherein, in step (2), the crushed tilapia skin is immersed in a GS modification liquid at 20-40° C. for modification for 8-12 hours.

[0019] Wherein, in step (5), the centrifuge speed is set to 5000-7000 r / min, and the centrifugation time is 10-15 min.

[0020] The cement-based material retarder obtained by the above method is used in the preparation of cement-based materials, and the dosage of the retarder is 0.1% to 0.5% of the cementitious material.

[0021] Principle of the invention: A cement-based material retarder of the present invention mainly comprises a modified collagen extract, which forms a colloid during the dissolution process and is adsorbed on the surface of cement hydration products. The peptide bonds and carboxyl groups in the protein structure form chemical adsorption on the surface of cement hydration products and adsorb on the crystal nuclei of the hydrate, thereby hindering the continued growth of crystals and delaying the crystallization transformation process of C3S hydrates, thereby achieving the retarding effect of cement-based materials.

[0022] Beneficial effects: Compared with the prior art, the present invention achieves the following significant effects: (1) The present invention uses modified collagen extract as a cement-based material retarder. The colloid released during the dissolution process is adsorbed on the surface of the hydration product. The peptide bonds and carboxyl groups in the protein structure form chemical adsorption on the surface of the cement hydration product and adsorb on the crystal nuclei of the hydrate, hindering the continued growth of crystals and delaying the crystallization transformation process of C3S hydrates, thereby achieving the retarding effect of cement-based materials. (2) The present invention uses modified collagen extract as a cement-based material coagulant, and the 28d strength is significantly improved compared to that of the unadulterated material. DETAILED DESCRIPTION

[0023] The present invention is described in further detail below.

[0024] Example 1

[0025] A method for preparing a cement-based material retarder comprises the following steps:

[0026] The tilapia skin was cleaned and chopped, and the cleaned tilapia skin was soaked in GS modification liquid at 25°C for modification, the modification time was 12h, and the cleaning modification liquid was filtered; the modified tilapia skin was placed in a magnetic stirrer at 30°C, and a composite protease suspension was added for enzymolysis, the enzymolysis time was 6h, and the enzymolysis process was continuously stirred, the speed was set to 400r / min, and then the temperature was raised to 80°C to inactivate the enzyme for 3h; activated carbon powder with a weight of 5% of the net fish skin was added for stirring, the speed was set to 400r / min, impurities were filtered, and the mixture was placed in a centrifuge for centrifugation, the speed was set to 7000r / min, the centrifugation time was 10min, and the supernatant was taken to obtain a light yellow viscous liquid coagulant, the main component of which was a modified collagen extract. The coagulant was mixed with mixing water at a cement slurry mass ratio of 0.1% and stirred for 5min, and the mixed solution was added to cement and stirred to make a test piece. The water-cement ratio of the cement slurry in each embodiment of the present invention is 0.3.

[0027] Among them, the GS modified liquid includes, by mass, 30 parts of calcium hydroxide, 10 parts of stearic acid, 10 parts of sodium hydroxide, and 100 parts of deionized water; the composite protease suspension includes, by mass, 40 parts of neutral protease derived from Bacillus subtilis, with an enzyme activity of 500u / g; 60 parts of bromelain derived from pineapple, with an enzyme activity of 5000u / g, and 100 parts of deionized water.

[0028] Example 2

[0029] A method for preparing a cement-based material retarder comprises the following steps:

[0030] The tilapia skin was cleaned and chopped, and the cleaned tilapia skin was soaked in GS modification liquid at 25°C for modification, the modification time was 12h, and the cleaning modification liquid was filtered; the modified tilapia skin was placed in a magnetic stirrer at 30°C, and a composite protease suspension was added for enzymolysis, the enzymolysis time was 6h, and the enzymolysis process was continuously stirred, the speed was set to 400r / min, and then the temperature was raised to 80°C to inactivate the enzyme for 3h; activated carbon powder with a mass ratio of 5% of the net fish skin was added for stirring, the speed was set to 400r / min, impurities were filtered, and the skin was placed in a centrifuge for centrifugation, the speed was set to 7000r / min, the centrifugation time was 10min, and the supernatant was taken to obtain a light yellow viscous liquid coagulant, the main component of which was a modified collagen extract. The coagulant was mixed and stirred with mixing water at a cement slurry mass ratio of 0.3% for 5min, and the mixed solution was added to cement for stirring to prepare a test piece.

[0031] Among them, the GS modified liquid includes, by mass, 30 parts of calcium hydroxide, 10 parts of stearic acid, 10 parts of sodium hydroxide, and 100 parts of deionized water; the composite protease suspension includes, by mass, 40 parts of neutral protease derived from Bacillus subtilis, with an enzyme activity of 500u / g; 60 parts of bromelain derived from pineapple, with an enzyme activity of 5000u / g, and 100 parts of deionized water.

[0032] Example 3

[0033] A method for preparing a cement-based material retarder comprises the following steps:

[0034] The tilapia skin was cleaned and chopped, and the cleaned tilapia skin was soaked in GS modification liquid at 25°C for modification, the modification time was 12h, and the cleaning modification liquid was filtered; the modified tilapia skin was placed in a magnetic stirrer at 30°C, and a composite protease suspension was added for enzymolysis, the enzymolysis time was 6h, and the enzymolysis process was continuously stirred, the speed was set to 400r / min, and then the temperature was raised to 80°C to inactivate the enzyme for 3h; activated carbon powder with a mass ratio of 5% of the net fish skin was added for stirring, the speed was set to 400r / min, impurities were filtered, and the skin was placed in a centrifuge for centrifugation, the speed was set to 7000r / min, the centrifugation time was 10min, and the supernatant was taken to obtain a light yellow viscous liquid coagulant, the main component of which was a modified collagen extract. The coagulant was mixed with mixing water at a cement slurry mass ratio of 0.5% and stirred for 5min, and the mixed solution was added to cement and stirred to prepare a test piece.

[0035] Among them, the GS modified liquid includes, by mass, 30 parts of calcium hydroxide, 10 parts of stearic acid, 10 parts of sodium hydroxide, and 100 parts of deionized water; the composite protease suspension includes, by mass, 40 parts of neutral protease derived from Bacillus subtilis, with an enzyme activity of 500u / g; 60 parts of bromelain derived from pineapple, with an enzyme activity of 5000u / g, and 100 parts of deionized water.

[0036] Example 4

[0037] A method for preparing a cement-based material retarder comprises the following steps:

[0038] The tilapia skin was cleaned and chopped, and the cleaned tilapia skin was soaked in GS modification liquid at 25°C for modification, the modification time was 12h, and the cleaning modification liquid was filtered; the modified tilapia skin was placed in a magnetic stirrer at 30°C, and a composite protease suspension was added for enzymolysis, the enzymolysis time was 6h, and the enzymolysis process was continuously stirred, the speed was set to 400r / min, and then the temperature was raised to 80°C to inactivate the enzyme for 3h; activated carbon powder with a mass ratio of 5% of the net fish skin was added for stirring, the speed was set to 400r / min, impurities were filtered, and the skin was placed in a centrifuge for centrifugation, the speed was set to 7000r / min, the centrifugation time was 10min, and the supernatant was taken to obtain a light yellow viscous liquid coagulant, the main component of which was a modified collagen extract. The coagulant was mixed and stirred with mixing water at a cement slurry mass ratio of 1.0% for 5min, and the mixed solution was added to cement for stirring to prepare a test piece.

[0039] Among them, the GS modified liquid includes, by mass, 30 parts of calcium hydroxide, 10 parts of stearic acid, 10 parts of sodium hydroxide, and 100 parts of deionized water; the composite protease suspension includes, by mass, 40 parts of neutral protease derived from Bacillus subtilis, with an enzyme activity of 500u / g; 60 parts of bromelain derived from pineapple, with an enzyme activity of 5000u / g, and 100 parts of deionized water.

[0040] Example 5

[0041] A method for preparing a cement-based material retarder comprises the following steps:

[0042] The tilapia skin was cleaned and chopped, and the cleaned tilapia skin was soaked in GS modification liquid at 25°C for modification, the modification time was 12h, and the cleaning modification liquid was filtered; the modified tilapia skin was placed in a magnetic stirrer at 30°C, and a composite protease suspension was added for enzymolysis, the enzymolysis time was 6h, and the enzymolysis process was continuously stirred, the speed was set to 400r / min, and then the temperature was raised to 80°C to inactivate the enzyme for 3h; activated carbon powder with a mass ratio of 5% of the net fish skin was added for stirring, the speed was set to 400r / min, impurities were filtered, and the skin was placed in a centrifuge for centrifugation, the speed was set to 7000r / min, the centrifugation time was 10min, and the supernatant was taken to obtain a light yellow viscous liquid coagulant, the main component of which was a modified collagen extract. The coagulant was mixed and stirred with mixing water at a cement slurry mass ratio of 2.0% for 5min, and the mixed solution was added to cement for stirring to prepare a test piece.

[0043] Among them, the GS modified liquid includes, by mass, 30 parts of calcium hydroxide, 10 parts of stearic acid, 10 parts of sodium hydroxide, and 100 parts of deionized water; the composite protease suspension includes, by mass, 40 parts of neutral protease derived from Bacillus subtilis, with an enzyme activity of 500u / g; 60 parts of bromelain derived from pineapple, with an enzyme activity of 5000u / g, and 100 parts of deionized water.

[0044] Example 6

[0045] A method for preparing a cement-based material retarder comprises the following steps:

[0046] The tilapia skin was cleaned and chopped, and the cleaned tilapia skin was soaked in GS modification liquid at 25°C for modification, the modification time was 12h, and the cleaning modification liquid was filtered; the modified tilapia skin was placed in a magnetic stirrer at 30°C, and a neutral protease suspension was added for enzymolysis, the enzymolysis time was 6h, and the enzymolysis process was continuously stirred, the speed was set to 400r / min, and then the temperature was raised to 80°C to inactivate the enzyme for 3h; activated carbon powder with a mass ratio of 5% of the net fish skin was added for stirring, the speed was set to 400r / min, impurities were filtered, and the skin was placed in a centrifuge for centrifugation, the speed was set to 7000r / min, the centrifugation time was 10min, and the supernatant was taken to obtain a light yellow viscous liquid coagulant, the main component of which was a modified collagen extract. The coagulant was mixed and stirred with mixing water at a cement slurry mass ratio of 0.3% for 5min, and the mixed solution was added to cement for stirring to prepare a test piece.

[0047] The GS modified liquid includes, by weight: 30 parts of calcium hydroxide, 10 parts of stearic acid, 10 parts of sodium hydroxide, and 100 parts of deionized water; the neutral protease suspension includes, by weight: 100 parts of neutral protease derived from Bacillus subtilis, with an enzyme activity of 500u / g, and 100 parts of deionized water.

[0048] Example 7

[0049] A method for preparing a cement-based material retarder comprises the following steps:

[0050] The tilapia skin was cleaned and chopped, and the cleaned tilapia skin was soaked in GS modification liquid at 25°C for modification, the modification time was 12h, and the cleaning modification liquid was filtered; the modified tilapia skin was placed in a magnetic stirrer at 30°C, and a composite protease suspension was added for enzymolysis, the enzymolysis time was 6h, and the enzymolysis process was continuously stirred, the speed was set to 400r / min, and then the temperature was raised to 80°C to inactivate the enzyme for 3h; activated carbon powder with a mass ratio of 5% of the net fish skin was added for stirring, the speed was set to 400r / min, impurities were filtered, and the skin was placed in a centrifuge for centrifugation, the speed was set to 7000r / min, the centrifugation time was 10min, and the supernatant was taken to obtain a light yellow viscous liquid coagulant, the main component of which was a modified collagen extract. The coagulant was mixed and stirred with mixing water at a cement slurry mass ratio of 0.3% for 5min, and the mixed solution was added to cement for stirring to prepare a test piece.

[0051] Among them, the GS modified liquid includes, by mass, 30 parts of calcium hydroxide, 10 parts of stearic acid, 10 parts of sodium hydroxide, and 100 parts of deionized water; the composite protease suspension includes, by mass, 80 parts of neutral protease derived from Bacillus subtilis, with an enzyme activity of 500u / g; 20 parts of bromelain derived from pineapple, with an enzyme activity of 5000u / g, and 100 parts of deionized water.

[0052] Example 8

[0053] A method for preparing a cement-based material retarder comprises the following steps:

[0054] The tilapia skin was cleaned and chopped, and the cleaned tilapia skin was soaked in GS modification liquid at 25°C for modification, the modification time was 12h, and the cleaning modification liquid was filtered; the modified tilapia skin was placed in a magnetic stirrer at 30°C, and a composite protease suspension was added for enzymolysis, the enzymolysis time was 6h, and the enzymolysis process was continuously stirred, the speed was set to 400r / min, and then the temperature was raised to 80°C to inactivate the enzyme for 3h; activated carbon powder with a mass ratio of 5% of the net fish skin was added for stirring, the speed was set to 400r / min, impurities were filtered, and the skin was placed in a centrifuge for centrifugation, the speed was set to 7000r / min, the centrifugation time was 10min, and the supernatant was taken to obtain a light yellow viscous liquid coagulant, the main component of which was a modified collagen extract. The coagulant was mixed and stirred with mixing water at a cement slurry mass ratio of 0.3% for 5min, and the mixed solution was added to cement for stirring to prepare a test piece.

[0055] Among them, the GS modified liquid includes, by mass, 30 parts of calcium hydroxide, 10 parts of stearic acid, 10 parts of sodium hydroxide, and 100 parts of deionized water; the composite protease suspension includes, by mass, 60 parts of neutral protease derived from Bacillus subtilis, with an enzyme activity of 500u / g; 40 parts of bromelain derived from pineapple, with an enzyme activity of 5000u / g, and 100 parts of deionized water.

[0056] Example 9

[0057] A method for preparing a cement-based material retarder comprises the following steps:

[0058] The tilapia skin was cleaned and chopped, and the cleaned tilapia skin was soaked in GS modification liquid at 25°C for modification, the modification time was 12h, and the cleaning modification liquid was filtered; the modified tilapia skin was placed in a magnetic stirrer at 30°C, and a composite protease suspension was added for enzymolysis, the enzymolysis time was 6h, and the enzymolysis process was continuously stirred, the speed was set to 400r / min, and then the temperature was raised to 80°C to inactivate the enzyme for 3h; activated carbon powder with a mass ratio of 5% of the net fish skin was added for stirring, the speed was set to 400r / min, impurities were filtered, and the skin was placed in a centrifuge for centrifugation, the speed was set to 7000r / min, the centrifugation time was 10min, and the supernatant was taken to obtain a light yellow viscous liquid coagulant, the main component of which was a modified collagen extract. The coagulant was mixed and stirred with mixing water at a cement slurry mass ratio of 0.3% for 5min, and the mixed solution was added to cement for stirring to prepare a test piece.

[0059] Among them, the GS modified liquid includes, by mass, 30 parts of calcium hydroxide, 10 parts of stearic acid, 10 parts of sodium hydroxide, and 100 parts of deionized water; the composite protease suspension includes, by mass, 50 parts of neutral protease derived from Bacillus subtilis, with an enzyme activity of 500u / g; 50 parts of bromelain derived from pineapple, with an enzyme activity of 5000u / g, and 100 parts of deionized water.

[0060] Example 10

[0061] A method for preparing a cement-based material retarder comprises the following steps:

[0062] The tilapia skin was cleaned and chopped, and the cleaned tilapia skin was soaked in GS modification liquid at 25°C for modification, the modification time was 12h, and the cleaning modification liquid was filtered; the modified tilapia skin was placed in a magnetic stirrer at 30°C, and bromelain suspension was added for enzymolysis, the enzymolysis time was 6h, and the enzymolysis process was continuously stirred, the speed was set to 400r / min, and then the temperature was raised to 80°C to inactivate the enzyme for 3h; activated carbon powder with a weight of 5% of the net fish skin was added for stirring, the speed was set to 400r / min, impurities were filtered, and the skin was placed in a centrifuge for centrifugation, the speed was set to 7000r / min, the centrifugation time was 10min, and the supernatant was taken to obtain a light yellow viscous liquid coagulant, the main component of which was a modified collagen extract. The coagulant was mixed and stirred with mixing water at a cement slurry weight ratio of 0.3% for 5min, and the mixed solution was added to cement for stirring to prepare a test piece.

[0063] The GS modified liquid includes, by mass, 30 parts of calcium hydroxide, 10 parts of stearic acid, 10 parts of sodium hydroxide, and 100 parts of deionized water; the bromelain suspension includes, by mass, 100 parts of bromelain from pineapple, with an enzyme activity of 5000u / g, and 100 parts of deionized water.

[0064] Embodiment 11

[0065] A method for preparing a cement-based material retarder comprises the following steps:

[0066] The tilapia skin was cleaned and chopped, and the cleaned tilapia skin was soaked in GS modification liquid at 25°C for modification, the modification time was 12h, and the cleaning modification liquid was filtered; the modified tilapia skin was placed in a magnetic stirrer at 30°C, and alkaline protease suspension was added for enzymolysis, the enzymolysis time was 6h, and the enzymolysis process was continuously stirred, the speed was set to 400r / min, and then the temperature was raised to 80°C to inactivate the enzyme for 3h; activated carbon powder with a mass ratio of 5% of the net fish skin was added for stirring, the speed was set to 400r / min, impurities were filtered, and the skin was placed in a centrifuge for centrifugation, the speed was set to 7000r / min, the centrifugation time was 10min, and the supernatant was taken to obtain a light yellow viscous liquid coagulant, the main component of which was a modified collagen extract. The coagulant was mixed and stirred with mixing water at a cement slurry mass ratio of 0.3% for 5min, and the mixed solution was added to cement for stirring to prepare a test piece.

[0067] The GS modified liquid includes, by mass, 30 parts of calcium hydroxide, 10 parts of stearic acid, 10 parts of sodium hydroxide, and 100 parts of deionized water; the alkaline protease suspension includes, by mass, 100 parts of alkaline protease derived from Bacillus subtilis, with an enzyme activity of 200,000 u / g, and 100 parts of deionized water.

[0068] Example 12

[0069] A method for preparing a cement-based material retarder comprises the following steps:

[0070] The tilapia skin was cleaned and chopped, and the cleaned tilapia skin was soaked in GS modification liquid at 25°C for modification, the modification time was 12h, and the cleaning modification liquid was filtered; the modified tilapia skin was placed in a magnetic stirrer at 30°C, and a composite protease suspension was added for enzymolysis, the enzymolysis time was 6h, and the enzymolysis process was continuously stirred, the speed was set to 400r / min, and then the temperature was raised to 80°C to inactivate the enzyme for 3h; activated carbon powder with a mass ratio of 5% of the net fish skin was added for stirring, the speed was set to 400r / min, impurities were filtered, and the skin was placed in a centrifuge for centrifugation, the speed was set to 7000r / min, the centrifugation time was 10min, and the supernatant was taken to obtain a light yellow viscous liquid coagulant, the main component of which was a modified collagen extract. The coagulant was mixed and stirred with mixing water at a cement slurry mass ratio of 0.3% for 5min, and the mixed solution was added to cement for stirring to prepare a test piece.

[0071] Among them, the GS modified liquid includes, by mass, 10 parts of calcium hydroxide, 30 parts of stearic acid, 10 parts of sodium hydroxide, and 100 parts of deionized water; the composite protease suspension includes, by mass, 40 parts of neutral protease derived from Bacillus subtilis, with an enzyme activity of 500u / g; 60 parts of bromelain derived from pineapple, with an enzyme activity of 5000u / g, and 100 parts of deionized water.

[0072] Example 13

[0073] A method for preparing a cement-based material retarder comprises the following steps:

[0074] The tilapia skin was cleaned and chopped, and the cleaned tilapia skin was soaked in GS modification liquid at 25°C for modification, the modification time was 12h, and the cleaning modification liquid was filtered; the modified tilapia skin was placed in a magnetic stirrer at 30°C, and a composite protease suspension was added for enzymolysis, the enzymolysis time was 6h, and the enzymolysis process was continuously stirred, the speed was set to 400r / min, and then the temperature was raised to 80°C to inactivate the enzyme for 3h; activated carbon powder with a mass ratio of 5% of the net fish skin was added for stirring, the speed was set to 400r / min, impurities were filtered, and the skin was placed in a centrifuge for centrifugation, the speed was set to 7000r / min, the centrifugation time was 10min, and the supernatant was taken to obtain a light yellow viscous liquid coagulant, the main component of which was a modified collagen extract. The coagulant was mixed and stirred with mixing water at a cement slurry mass ratio of 0.3% for 5min, and the mixed solution was added to cement for stirring to prepare a test piece.

[0075] Among them, the GS modified liquid includes, by mass, 10 parts of calcium hydroxide, 10 parts of stearic acid, 30 parts of sodium hydroxide, and 100 parts of deionized water; the composite protease suspension includes, by mass, 40 parts of neutral protease derived from Bacillus subtilis, with an enzyme activity of 500u / g; 60 parts of bromelain derived from pineapple, with an enzyme activity of 5000u / g, and 100 parts of deionized water.

[0076] Embodiment 14

[0077] A method for preparing a cement-based material retarder comprises the following steps:

[0078] The tilapia skin was cleaned and chopped, and the cleaned tilapia skin was soaked in GS modification liquid at 25°C for modification, the modification time was 12h, and the cleaning modification liquid was filtered; the modified tilapia skin was placed in a magnetic stirrer at 30°C, and a composite protease suspension was added for enzymolysis, the enzymolysis time was 6h, and the enzymolysis process was continuously stirred, the speed was set to 400r / min, and then the temperature was raised to 80°C to inactivate the enzyme for 3h; activated carbon powder with a mass ratio of 5% of the net fish skin was added for stirring, the speed was set to 400r / min, impurities were filtered, and the skin was placed in a centrifuge for centrifugation, the speed was set to 7000r / min, the centrifugation time was 10min, and the supernatant was taken to obtain a light yellow viscous liquid coagulant, the main component of which was a modified collagen extract. The coagulant was mixed and stirred with mixing water at a cement slurry mass ratio of 0.3% for 5min, and the mixed solution was added to cement for stirring to prepare a test piece.

[0079] Among them, the GS modified liquid includes, by mass, 10 parts of calcium hydroxide, 0 parts of stearic acid, 0 parts of sodium hydroxide, and 100 parts of deionized water; the composite protease suspension includes, by mass, 40 parts of neutral protease derived from Bacillus subtilis, with an enzyme activity of 500u / g; 60 parts of bromelain derived from pineapple, with an enzyme activity of 5000u / g, and 100 parts of deionized water.

[0080] Embodiment 15

[0081] A method for preparing a cement-based material retarder comprises the following steps:

[0082] The tilapia skin was cleaned and chopped, and the cleaned tilapia skin was soaked in GS modification liquid at 25°C for modification, the modification time was 12h, and the cleaning modification liquid was filtered; the modified tilapia skin was placed in a magnetic stirrer at 30°C, and a composite protease suspension was added for enzymolysis, the enzymolysis time was 6h, and the enzymolysis process was continuously stirred, the speed was set to 400r / min, and then the temperature was raised to 80°C to inactivate the enzyme for 3h; activated carbon powder with a mass ratio of 5% of the net fish skin was added for stirring, the speed was set to 400r / min, impurities were filtered, and the skin was placed in a centrifuge for centrifugation, the speed was set to 7000r / min, the centrifugation time was 10min, and the supernatant was taken to obtain a light yellow viscous liquid coagulant, the main component of which was a modified collagen extract. The coagulant was mixed and stirred with mixing water at a cement slurry mass ratio of 0.3% for 5min, and the mixed solution was added to cement for stirring to prepare a test piece.

[0083] Among them, the GS modified liquid includes, by mass: 0 parts of calcium hydroxide, 10 parts of stearic acid, 0 parts of sodium hydroxide, and 100 parts of deionized water; the composite protease suspension includes, by mass: 40 parts of neutral protease derived from Bacillus subtilis, with an enzyme activity of 500u / g; 60 parts of bromelain derived from pineapple, with an enzyme activity of 5000u / g, and 100 parts of deionized water.

[0084] Example 16

[0085] A method for preparing a cement-based material retarder comprises the following steps:

[0086] The tilapia skin was cleaned and chopped, and the cleaned tilapia skin was soaked in GS modification liquid at 25°C for modification, the modification time was 12h, and the cleaning modification liquid was filtered; the modified tilapia skin was placed in a magnetic stirrer at 30°C, and a composite protease suspension was added for enzymolysis, the enzymolysis time was 6h, and the enzymolysis process was continuously stirred, the speed was set to 400r / min, and then the temperature was raised to 80°C to inactivate the enzyme for 3h; activated carbon powder with a mass ratio of 5% of the net fish skin was added for stirring, the speed was set to 400r / min, impurities were filtered, and the skin was placed in a centrifuge for centrifugation, the speed was set to 7000r / min, the centrifugation time was 10min, and the supernatant was taken to obtain a light yellow viscous liquid coagulant, the main component of which was a modified collagen extract. The coagulant was mixed and stirred with mixing water at a cement slurry mass ratio of 0.3% for 5min, and the mixed solution was added to cement for stirring to prepare a test piece.

[0087] Among them, the GS modified liquid includes, by mass: 0 parts of calcium hydroxide, 0 parts of stearic acid, 10 parts of sodium hydroxide, and 100 parts of deionized water; the composite protease suspension includes, by mass: 40 parts of neutral protease derived from Bacillus subtilis, with an enzyme activity of 500u / g; 60 parts of bromelain derived from pineapple, with an enzyme activity of 5000u / g, and 100 parts of deionized water.

[0088] Comparative Example 1

[0089] Compared with Example 1, the difference is that the present ratio does not add tilapia skin extract as a coagulant. A cement paste specimen with a water-cement ratio of 0.3 is prepared.

[0090] In each embodiment and comparative example of the present invention, a PP mold is used to form a test block.

[0091] Specimen compressive strength and setting time test:

[0092] Specimen curing conditions: temperature: 20°C, humidity: 90%.

[0093] Specimen curing age: 3d, 7d, 28d.

[0094] The compressive strength test was carried out using an electronic universal testing machine (DNS100) with a loading rate of 0.5 kN / s.

[0095] The setting time test uses a Vicat apparatus, with a test needle for initial setting and a test needle for final setting.

[0096] The first setting time is measured 30 minutes after adding water. When it is close to the initial setting, measure it every 5 minutes. When the test needle sinks to 4mm±1mm from the bottom plate, it is the initial setting state of cement. After the initial setting test is completed, the test mold and the slurry are immediately removed from the glass plate in a horizontal manner, turned 180°, placed on the glass plate with the large end facing up and the small end facing down, and continue to cure. When it is close to the final setting, measure it every 15 minutes.

[0097] The compressive strength and setting time of Examples 1-16 and Comparative Example 1 were tested, and the results are shown in Table 1.

[0098] Table 1 Compressive strength and setting time of Examples 1-16 and Comparative Example 1

[0099]

[0100]

[0101] It can be seen from Table 1 that compared with the initial setting time and final setting time of Control Example 1, the setting time of the cement slurry specimens to which the modified collagen extract coagulant was added was significantly prolonged. Compared with the setting time of Control Example 1, the initial setting time of Examples 1-5 was increased by 160.0%, 233.3%, 286.7%, 340.0% and 386.7%, respectively; the final setting time of Examples 1-5 was extended by 46.2%, 61.5%, 83.1%, 101.5% and 111.8%, respectively. Compared with the compressive strength of control example 1, the early compressive strength of the cement paste specimens added with the modified collagen extract coagulant is reduced to a certain extent, and gradually decreases with the increase of the modified collagen extract dosage. The 3d compressive strength of Examples 1-5 changed by -3.5%, -12.4%, -21.7%, -27.2% and -35.3% respectively; the 7d compressive strength of Examples 1-5 changed by -4.0%, +0.5%, -0.4%, -14.9% and -24.1% respectively; the 28d compressive strength of Examples 1-5 changed by +0.7%, +6.8%, +4.35%, -0.82% and -19.7% respectively. This shows that the coagulant of the present invention improves the retarding effect of cement-based materials to a certain extent, among which Example 2 is the best ratio and 0.3% is the best dosage.

[0102] It can be seen from Table 1 that, compared with the initial coagulation time and final coagulation time of Example 2, the initial coagulation time and final coagulation time of the modified collagen extract coagulant change with the change of the protease ratio in the composite protease suspension. Compared with the coagulation time of Example 2, the initial coagulation time of Examples 6-11 changed by +15.2%, +10.0%, +6.4%, -6.0%, -49.6%, and -42.0%, respectively; the final coagulation time of Examples 6-11 changed by +8.2%, +5.3%, +3.0%, +1.0%, -37.7%, and -18.9%, respectively. Compared with the compressive strength of Example 2, the 3d compressive strength of Examples 6-11 changed by +4.9%, +3.8%, +3.4%, +2.7%, -6.7%, +6.7% respectively; the 7d compressive strength changed by -5.9%, -3.9%, -4.5%, -2.8%, -7.8%, -8.9% respectively; the 28d compressive strength changed by -7.9%, -6.5%, -4.9%, -2.2%, -12.1%, -8.4% respectively. It can be seen that different protease ratios and protease types also affect the coagulation time and compressive strength of the coagulant. The comprehensive coagulation time and compressive strength can prove that neutral protease: bromelain in the composite protease suspension = 4:6 is the best ratio of the composite protease suspension.

[0103] It can be seen from Table 1 that, compared with the initial coagulation time and final coagulation time of Example 2, the initial coagulation time and final coagulation time of the modified collagen extract coagulant change with the change of the ratio in the GS modified liquid. Compared with the coagulation time of the control group 2, the initial coagulation time of Examples 12-16 changed by -60.8%, -14.4%, -16.0%, -64.8%, and -17.6%, respectively; the final coagulation time of Examples 12-16 changed by -30.5%, -10.7%, -12.8%, -34.3%, and -14.9%, respectively. Compared with the compressive strength of Example 2, the 3d compressive strength of Examples 6-11 changed by -6.4%, -3.6%, -1.4%, -19.4%, -6.7% respectively; the 7d compressive strength changed by -5.2%, -1.2%, -1.8%, -9.1%, -2.9% respectively; the 28d compressive strength changed by -15.8%, -1.3%, -5.8%, -13.2%, -5.0% respectively. It can be seen that the ratio of the components in the GS modified liquid will also affect the coagulation time and compressive strength of the coagulant. The comprehensive coagulation time and compressive strength can prove that, by mass, 30 parts of calcium hydroxide, 10 parts of stearic acid, 10 parts of sodium hydroxide, and 100 parts of deionized water are the best ratios of the GS modified liquid.

Claims

1. A method for preparing a cement-based material retarder, characterized in that: The following steps are involved: (1) cleaning and crushing tilapia skin; (2) immersing the crushed tilapia skin in GS modification liquid for modification, filtering, and washing; (3) adding a composite protease suspension to the modified tilapia skin for enzymolysis, and then heating to inactivate the enzyme to obtain a collagen stock solution; (4) adding an adsorption material to the collagen stock solution, stirring, and filtering to obtain a collagen secondary clear solution; (5) Centrifuge the collagen secondary supernatant and take the supernatant to obtain a cement-based material retarder.

2. The method for preparing a cement-based material retarder according to claim 1, characterized in that: In step (2), the GS modified liquid comprises, by mass, 20 to 40 parts of calcium hydroxide, 5 to 10 parts of stearic acid, 5 to 10 parts of sodium hydroxide, and 100 parts of deionized water.

3. The method for preparing a cement-based material retarder according to claim 1, characterized in that: In step (3), the composite protease suspension comprises, by weight: 20 to 40 parts of neutral protease derived from Bacillus subtilis; 60 to 80 parts of bromelain derived from pineapple, and 100 parts of deionized water.

4. The method for preparing a cement-based material retarder according to claim 3, characterized in that: The activity of the neutral protease of Bacillus subtilis is 300-600u / g; the activity of bromelain is 4500-5500u / g.

5. The method for preparing a cement-based material retarder according to claim 1, characterized in that: In step (3), the temperature of adding the composite protease suspension for enzymatic hydrolysis is 20 to 40° C. and the time is 4 to 6 hours.

6. The method for preparing a cement-based material retarder according to claim 1, characterized in that: In step (3), the temperature is then raised to 70-80°C to inactivate the enzyme for 2-4 hours.

7. The method for preparing a cement-based material retarder according to claim 1, characterized in that: In step (4), the adsorbent material is added in an amount of 1 to 10% of the net fish skin weight.

8. The method for preparing a cement-based material retarder according to claim 1, characterized in that: In step (2), the crushed tilapia skin is immersed in a GS modification liquid at 20-40° C. for modification for 8-12 hours.

9. The method for preparing a cement-based material retarder according to claim 1, characterized in that: In step (5), the centrifuge speed is set to 5000-7000 r / min, and the centrifugation time is 10-15 min.

10. Use of a cement-based material retarder obtained by the method according to claim 1 in preparing cement-based materials, characterized in that: The dosage of the coagulant is 0.1% to 0.5% of the gelling material.

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