CN118063155A

CN118063155A - Method for manufacturing concrete partition wall brick by using biochar

Info

Publication number: CN118063155A
Application number: CN202211482525.4A
Authority: CN
Inventors: 曾超华; 陈良; 王磊; 张钰莹
Original assignee: Hong Kong Polytechnic University HKPU
Current assignee: Hong Kong Polytechnic University HKPU
Priority date: 2022-11-24
Filing date: 2022-11-24
Publication date: 2024-05-24

Abstract

The application provides a method for manufacturing a concrete partition brick by using biochar. The concrete drier comprises the following components, by weight, 2-35 parts of biochar, 10-40 parts of environment-friendly aggregate and 20-30 parts of cement. The concrete slurry includes water and a concrete drier dispersed in the water. The prefabricated member is prepared by curing concrete slurry. The dry concrete material, slurry and prefabricated member have high content of biochar, the compressive strength of the prepared prefabricated member can reach C7.5, part of the compressive strength can reach C15 grade, the mechanical property of the prefabricated member meets the application requirements of part of building material fields, the weight of the building material is lighter, the carbon emission of the whole building material is reduced, even the carbon emission is reduced, and the carbon can be fixed for a long time.

Description

Method for manufacturing concrete partition wall brick by using biochar

Technical Field

The application belongs to the field of green building materials, and particularly relates to a concrete dry material, a concrete slurry, a preparation method and a prefabricated member.

Background

In order to reduce carbon emission, china proposes a peak reaching carbon before 2030 and achieves the aim of carbon neutralization before 2060. Cement is an essential material for building industry, and is indispensable in building materials. However, a large amount of carbon dioxide gas is discharged during the cement production process, and the carbon dioxide discharged during the cement production at the present time accounts for about 7% of the global carbon emissions. Therefore, the reduction of carbon emission of cement building materials and the development of low-carbon or carbon-negative building materials are important tasks for inorganic nonmetallic material researchers.

Biochar is a carbon negative emission material. The biomass waste is subjected to respiration, soil microbial decomposition and the like, organic carbon finally returns to the atmosphere, and the biomass waste is pyrolyzed under the anaerobic condition, so that unstable organic carbon in biomass can be converted into stable biochar, and the stable biochar can be not decomposed for hundreds or even thousands of years, and finally carbon sequestration is realized, namely carbon sequestration. The whole production-utilization process of biochar has typical carbon emission characteristics and is considered to be one of the most effective materials for realizing carbon neutralization by high-efficiency carbon fixation. However, at present, biochar is mainly used in the agricultural field, enters the deep soil layer mainly through the form of an organic fertilizer or a soil conditioner, and is used for fixing carbon for a long time or even permanently, so that the huge carbon fixing potential of the biochar is difficult to be exerted.

Although it has been found in recent researches that the mechanical properties of cement-based materials can be improved by adding 2% of biochar to cement, the amount of biochar added in the current products related to the biochar building materials is low (generally lower than 5%), mainly because the mechanical properties of cement-based materials are reduced when the content of biochar is further increased, so that the application requirements of the building material field are difficult to meet.

Disclosure of Invention

The application aims to overcome the defects of the prior art, and provides a concrete dry material, a concrete slurry, a preparation method and a precast member, so as to solve the problems that the mechanical property of the material is reduced and the application requirement in the field of building materials is difficult to meet when a large amount of biochar is doped in the concrete material.

In order to achieve the above purpose, the present application provides the following technical solutions:

In a first aspect of the application, a concrete drier is provided. The concrete drier comprises the following components in parts by weight of 2-35 parts of biochar, 10-40 parts of environment-friendly aggregate and 20-30 parts of cement.

In this way, the concrete dry material of the application is doped with a large proportion of biochar, and the compressive strength of the prepared prefabricated member can reach C7.5, and part of the prefabricated member can reach C15 grade, thereby meeting the application requirements of part of building material fields, and being applicable to wall tiles, cushion layers, enlarged foundations, terraces and the like according to performances.

In some embodiments, the biochar is produced from waste biomass by anaerobic pyrolysis.

In some embodiments, the waste biomass comprises at least one of waste wood, straw, waste fruit shells.

In some embodiments, the biochar is prepared from waste wood including drying at 40-80 ℃ and further performing anaerobic pyrolysis at 350-850 ℃ for 0.5-10 hours.

In some embodiments, the biochar has a particle size of 0.25mm to 5mm.

In some embodiments, the environmentally friendly aggregate comprises at least one of recycled aggregate, steel slag, glass slag.

In some embodiments, the particle size of the environmentally friendly aggregate is less than or equal to 2.5mm.

In some embodiments, the cement comprises at least one of Portland cement, pozzolanic Portland cement, aluminate cement.

In some embodiments, the Portland cement comprises 52.5 grade Portland cement.

In some embodiments, the concrete drier also comprises at least one of the following components in parts by weight, 5-10 parts of auxiliary cementing material and 0.01-0.03 part of anti-cracking fiber.

In some embodiments, the auxiliary cementitious material comprises at least one of granulated blast furnace slag, fly ash, metakaolin, silica fume, shell dust, household waste incineration bottom ash, sewage sludge incineration ash, rice hull ash, limestone powder.

In some embodiments, the anti-crack fibers comprise at least one of chopped polypropylene fibers, polyvinyl alcohol fibers.

In a second aspect of the present application, a concrete slurry is provided. The concrete slurry of the application comprises water and the above text application concrete dry material dispersed in the water.

In this way, in the concrete slurry, cement in the concrete dry material can be subjected to hydration reaction with water, and a large proportion of biochar can also absorb water, so that the continuous internal curing effect is achieved.

In some embodiments, the weight ratio of water to biochar is 9:140 to 5:2.

In some embodiments, the concrete slurry further comprises a water reducer, wherein the weight ratio of the water reducer to the biochar is 1:2000-1:25; specifically, the water reducer comprises ether polycarboxylate or naphthalene sulfonate.

In a third aspect of the application, a method for preparing concrete slurry is provided. The preparation method of the concrete slurry comprises the step of mixing the concrete dry material of the application with water.

Thus, the concrete dry material of the application can be prepared into the concrete slurry of the application, cement can be subjected to hydration reaction with water, and a large proportion of biochar can absorb water, so that the effect of continuous internal curing is achieved.

In some embodiments, the mixing process includes the steps of:

pre-wetting the biochar with part of water to obtain pre-wetted biochar;

Carrying out first mixing treatment on the prewetted biochar, the environment-friendly aggregate and the cement to obtain a mixture;

And carrying out second mixing treatment on the mixture and the residual water to obtain the concrete slurry.

In some embodiments, the auxiliary cementitious material contained in the dry concrete mix of the present application is also added during the first mixing process.

In some embodiments, the anti-crack fibers contained in the concrete dry mix of the present application are also added in batches during the second mixing process.

In some embodiments, during the second mixing process, the water reducer contained in the concrete slurry of the present application is also added.

In a fourth aspect of the application, a concrete preform is provided. The concrete prefabricated part is prepared by curing the concrete slurry according to the application.

Therefore, the concrete slurry disclosed by the application can be prepared into prefabricated parts, and the biochar has the porous water-absorbing, water-storing and water-releasing properties, so that the biochar fully absorbs water and stores water when preparing the slurry, and can continuously release water in curing treatment, so that the concrete has a continuous internal curing effect. The compressive strength of the composite material can reach C7.5, part of the composite material can reach C15 grade, the application requirements of part of building material fields are met, and the composite material can be used for partition bricks, cushion layers, expanded foundations, terraces and the like according to performances.

In some embodiments, the curing process is layering the concrete slurry into molds, each of which is then post-mold release and curing.

In some embodiments, the surface of the concrete preform is also provided with a fire-resistant coating.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments or the description of the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a flow chart of a method of preparing a concrete slurry of the present application;

FIG. 2 is a graph showing the compressive strength test of the prefabricated parts of examples C1 to C3 and comparative example C according to the present application, wherein the transverse line is the compressive strength standard 7MPa of the wall brick;

FIG. 3 is a comparative graph of compressive strength testing of preforms of example C3 and examples C4-C7 of the present application, wherein the transverse line is the compressive strength standard 7MPa for the wall blocks.

Detailed Description

The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.

In the present application, the term "and/or" describes an association relationship of an association object, which means that three relationships may exist, for example, a and/or B may mean that a exists alone, a and B exist together, and B exists alone. Wherein A, B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship.

In a first aspect, embodiments of the present application provide a concrete drier. The concrete drier comprises, by weight, 2-35 parts of biochar, 10-40 parts of environment-friendly aggregate and 20-30 parts of cement.

According to the embodiment of the application, the concrete dry material is doped with a large proportion of biochar, and aggregate and cement are matched, so that the compressive strength of the prepared prefabricated member can reach C7.5, part of the compressive strength can reach C15 grade, the application requirements of part of building material fields are met, and the prefabricated member can be used for partition bricks, cushion layers, expanded foundations, terraces and the like according to performances.

In addition, the concrete dry material is doped with a large proportion of biochar, so that the weight of the building material is lighter; the effects of carbon reduction emission, carbon negative emission and long-term carbon fixation can be realized, and the economic benefit and the environmental benefit are good.

In an example, the weight part of biochar in the concrete drier can be 8-15 parts, and the 28-day compressive strength of the prepared prefabricated part can reach the C15 grade.

In an exemplary embodiment, the weight portion of biochar in the concrete drier can be 18-25 portions, and the 28-day compressive strength of the prepared prefabricated part is slightly lower than the C15 grade.

In an exemplary embodiment, the weight portion of the biochar in the concrete drier can be 28-35 portions, and the 28-day compressive strength of the prepared prefabricated member is between the grade C7.5 and the grade C15.

In an exemplary embodiment, the biochar may be 6 parts, 8 parts, 10 parts, 12 parts, 15 parts, 17 parts, 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 33 parts, 35 parts, etc. by weight, typically but not limited to.

Therefore, the proportion of biochar in the concrete drier can be designed, and balance and selection can be made between the compressive strength required by the prefabricated part finished product and the environmental benefit.

In some embodiments, the biochar is produced from waste biomass by anaerobic pyrolysis. In an exemplary embodiment, the waste biomass may be at least one of waste wood, straw, and waste fruit shells. In an exemplary embodiment, the biochar is prepared by drying waste wood at 40-80 ℃ and performing anaerobic pyrolysis at 350-850 ℃ for 0.5-10 hours.

In the embodiment of the application, the raw materials for preparing the biochar have wide selection range, such as various waste biomasses including waste wood, straw, waste fruit shells and the like. The waste biomass is pyrolyzed into biochar, and the biochar is applied to building materials in large scale, so that economic benefit and environmental benefit are considered. Wherein, the waste wood is used as raw material, the source is wide, the cost is low; the biochar prepared from waste wood has stable and orderly micro-pore structure and a large number of micro-pores. The pyrolysis temperature and time are scientific and reasonable, if the temperature is too high for too long, the energy consumption is wasted, and the pore structure is damaged to a certain extent due to the too long carbonization time. The inventors have tested that the temperature and time of the examples of the present application are preferred.

In some embodiments, the biochar has a particle size of 0.25mm to 5mm. In an exemplary embodiment, the particle size of the biochar may be, but is not limited to, a typical particle size of 0.25mm, 0.5mm, 1mm, 2mm, 3mm, 4mm, 5mm, etc.

In the embodiment of the application, the particle size of the biochar is not too small, otherwise, the biochar can not replace aggregate; too large is not preferred, otherwise the porous structure would lead to difficult filling and reduced compressive strength of the finished preform. The inventors have tested that the particle size of the examples of the present application is preferred.

In the embodiment of the application, the aggregate of the concrete drier is mainly environment-friendly aggregate, plays a role of a skeleton and a role of filling in the material, and can comprise various industrial wastes, thereby changing waste into valuable.

In the embodiment of the application, the grain size of the aggregate can be not more than 2.5mm, and the aggregate mainly serves as fine aggregate to be filled in the material and also serves as a framework. In an exemplary embodiment, the particle size of the environmentally friendly aggregate may be a typical, but non-limiting, particle size of 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, etc.

In some embodiments, the cement comprises at least one of Portland cement, pozzolanic Portland cement, aluminate cement. In an exemplary embodiment, the Portland cement may include 52.5 grade Portland cement.

In the embodiment of the application, the cement can be selected in various ways, and the cement mainly plays roles of lubrication, filling and gelation in the concrete according to the purpose design type and the use amount of the final product.

In some embodiments, the concrete drier further includes 5-10 parts by weight of auxiliary cementing material, which may be, for example, exemplary but not limiting, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.

The auxiliary cementing material is mainly used for partially replacing cement and has the auxiliary cementing effect. Meanwhile, the pores of the material can be filled by the finer particle size, so that the compressive strength of the material is improved. In addition, the corresponding components are properly mixed according to the application, and the effects of adjusting early and later strength, improving mechanical properties, enhancing corrosion resistance and the like are also achieved. In addition, the auxiliary cementing materials are mainly industrial wastes, and the auxiliary cementing materials are reasonably applied, so that economic and environmental benefits can be achieved.

In some embodiments, the concrete drier further includes 0.01-0.03 parts by weight of anti-cracking fiber, and in an exemplary embodiment, the anti-cracking fiber may be 0.01 parts by weight, 0.02 parts by weight, 0.03 parts by weight, etc. typical but not limiting parts.

The anti-cracking fiber with the content and the type is added to reduce the formation and the growth of cracks in the material forming process.

In a second aspect, embodiments of the present application provide a concrete slurry. The concrete slurry of the embodiment of the application comprises water and the concrete drier of the embodiment of the application dispersed in the water.

In the embodiment of the application, the concrete slurry comprises concrete dry materials and water, wherein the biochar can absorb and store water, and cement and water gradually start hydration reaction.

In some embodiments, the weight ratio of water to biochar is 9:140-5:2, in examples, the weight ratio of water to biochar may be typical but non-limiting ratios of 9:140, 1:12, 1:8, 1:5, 1:3, 1:2, 3:4, 1:1, 4:3, 3:2, 2:1, 5:2, etc.

In the embodiment of the application, the water content is not too low, so that the slurry has poor fluidity and is difficult to form; too high a water content is not preferred, which leads to bleeding. The inventor has tested that the water consumption of the embodiment of the application is suitable.

In some embodiments, the concrete slurry of the present application further includes a water reducer, where the weight ratio of the water reducer to the biochar is 1:2000-1:25, and in an exemplary embodiment, the weight ratio of the water reducer to the biochar may be a typical but non-limiting ratio of 1:2000, 1:1000, 1:500, 1:200, 1:100, 1:50, 1:25, etc.

In some embodiments, the water reducing agent may include an ether polycarboxylate or naphthalene sulfonate.

The water reducer with the content and the type is mainly added to improve the fluidity of the slurry; here, these two types of water reducers are not miscible, and after being compounded, they can generate chemical reaction, and the performance of the finished product is affected.

In a third aspect, an embodiment of the present application provides a method for preparing concrete slurry. The preparation method of the concrete slurry comprises the step of mixing the concrete dry material of the embodiment of the application with water.

In the embodiment of the application, the slurry can be obtained by mixing the concrete dry material with water, and the treatment method is numerous, for example, the raw materials can be sequentially added into a stirrer for fully and uniformly mixing.

In some embodiments, the mixing process includes the steps of:

s01: pre-wetting the biochar with part of water to obtain pre-wetted biochar;

S02: carrying out first mixing treatment on the prewetted biochar, the environment-friendly aggregate and the cement to obtain a mixture;

S03: and carrying out second mixing treatment on the mixture and the residual water to obtain the concrete slurry.

The biochar in the step S01 has water absorption property due to a large number of micro-pores, and the biochar is mixed in the concrete in a large proportion, so that the fluidity of concrete slurry is greatly affected, and even the concrete slurry is difficult to form. The preparation method of the embodiment of the application fully absorbs water by pre-wetting the biochar, avoids continuous water absorption of the biochar in the mixing treatment of the prepared slurry, improves the fluidity of the slurry and facilitates subsequent molding, wherein the solid content of the pre-wetted biochar is actually measured at 40% -70%, and the weight of the pre-wetted biochar in the concrete slurry is about 5% -50%.

In addition, the biochar is pre-wetted and fully absorbs water, and in the subsequent concrete curing, the pre-wetted biochar gradually releases water, and the absorbed water is slowly released in the concrete to react with cement, so that the hydration degree of the cement is improved, the effect of curing the concrete internally is achieved, and the shrinkage deformation and cracking risk of the concrete material can be reduced.

In some embodiments, the auxiliary cementing material contained in the concrete drier of the embodiment of the application is also added in the first mixing treatment process in S02.

In the embodiment of the application, the biochar is in a porous structure, so that the hardened concrete has increased pore weakness, and the compressive strength of the biochar is reduced due to the fact that the biochar is doped in a large proportion in the concrete. The auxiliary cementing material is added, so that the cement can be subjected to more sufficient hydration reaction in the curing period, and more hydrated calcium silicate gel is generated; meanwhile, the pore space of the material can be filled by the finer particle size of the auxiliary cementing material, so that the compressive strength of the material is improved.

In some embodiments, the anti-cracking fiber contained in the concrete drier of the embodiment of the application is also added in batches during the second mixing treatment in S03.

According to the embodiment of the application, the anti-cracking fiber is added, and the biochar is matched for continuous water release to maintain the concrete, so that the shrinkage deformation and cracking risk of the concrete material can be further reduced.

In some embodiments, the water reducer contained in the concrete slurry of the embodiment of the application is also added during the second mixing process.

According to the embodiment of the application, the water reducer is added, and the biochar according to the embodiment of the application is matched with the biochar to pre-wet and absorb water and then mix, so that the fluidity of concrete slurry can be further improved.

In a fourth aspect, embodiments of the present application provide a concrete preform. The concrete prefabricated part provided by the embodiment of the application is prepared by curing the concrete slurry comprising the concrete slurry provided by the embodiment of the application.

In the embodiment of the application, the precast concrete prepared by curing the concrete slurry of the embodiment of the application has the compressive strength higher than the C7.5 grade for 28 days, and part of the concrete precast concrete has the strength reaching the C15 grade, and can be used for wall tiles, cushion layers, enlarged foundations, terraces and the like according to the performance. For example, the compressive strength requirement (BS EN 771-3:2011) of the partition brick is 7MPa, and in the embodiment C3, when 30 parts by weight of solid biochar are mixed, the compressive strength of the prefabricated part is tested to be 9.6MPa for 3 days and 10.4MPa for 28 days, so that the prefabricated part meets the requirement. In the example C7, the prefabricated member prepared by adding metakaolin into the slurry is tested to have the compressive strength of 11.3MPa for 3 days and 13.1MPa for 28 days, and the compressive strength is further improved. Therefore, the embodiment of the application is a novel method for preparing green building materials and prefabricated parts by utilizing biochar in a resource-based and large-scale manner, and has good economic benefit and environmental benefit.

In some embodiments, the curing process is layering the concrete slurry into molds, filling each time with a layer, compacting, demolding, and curing for 3 days and 28 days. Wherein the compaction process may be, but is not limited to, a full compaction process using a universal tester.

In the embodiment of the application, in order to prevent the molding difficulty caused by the existence of pores in the biochar, the slurry can be quickly compacted after being put into a mold, for example, the slurry can be layered into the mold, and each layer is compacted, so that the porosity of the material is reduced, and the molding effect is further improved.

In embodiments of the application, when the preform is for use as a wall tile, a fire-resistant coating, such as white cement-based inorganic material, may be provided on the surface.

The concrete dry material, the slurry, the preparation method, the partition brick, the performance and the like are exemplified by a plurality of examples.

1. Concrete drier examples

Example A1

The embodiment provides a concrete drier which comprises 10 parts by weight of biochar, 40 parts by weight of environment-friendly aggregate, 30 parts by weight of cement and 0.02 part by weight of anti-cracking fiber.

The concrete dry material is prepared by fully mixing 10 parts by weight of biochar, 40 parts by weight of environment-friendly aggregate, 30 parts by weight of cement and 0.02 part by weight of anti-cracking fiber.

Wherein the biochar is prepared by drying waste wood at 60 ℃ and performing anaerobic pyrolysis at 500 ℃ for 10 hours, and the grain diameter is 0.5-2.5 mm; the environment-friendly aggregate is recycled aggregate with the grain diameter of 0.5 mm-2.5 mm; the cement is ordinary Portland cement of 52.5 grade; the anti-crack fiber is a chopped polypropylene fiber.

Example A2

This example differs from example A1 in that the weight parts of biochar are 20 parts.

Example A3

This example differs from example A1 in that the weight parts of biochar are 30 parts.

Example A4

This example is different from example A3 in that 10 parts by weight of granulated blast furnace slag is further included in the concrete drier.

Example A5

This example differs from example A3 in that the concrete drier also includes 10 parts by weight of silica fume.

Example A6

The difference between this example and example A3 is that the concrete drier also includes 10 parts by weight of fly ash.

Example A7

This example differs from example A3 in that 10 parts by weight of metakaolin was also included in the concrete dry mix.

Example A8

The difference between this example and example A3 is that the weight of the environment-friendly aggregate is 20 parts.

Example A9

The difference between this example and example A3 is that the weight of the environment-friendly aggregate is 10 parts.

Example A10

This example differs from example A3 in that the cement is 20 parts by weight.

Comparative example A

Comparative example a differs from example A1 in that the dry concrete material does not contain biochar.

2. Concrete slurry and preparation method thereof

Example B1

Referring to fig. 1, the present embodiment provides a concrete slurry and a preparation method thereof.

The concrete slurry of this example was prepared by thoroughly mixing the concrete dry material of example A1, 12 parts by weight of water and 0.1 part by weight of an ether polycarboxylate water reducer.

The preparation method of the concrete slurry in the embodiment comprises the following steps:

S01, soaking 10 parts by weight of the biochar contained in the embodiment A1 in water for pre-wetting for 24 hours, and then draining surface water to obtain 20 parts by weight of pre-wetted biochar with 50% of solid content;

S02, taking the following components in parts by weight, namely adding the prewetted biochar obtained in the step S1, the recycled aggregate contained in the embodiment A1 and the ordinary Portland cement contained in the embodiment A1 into a stirrer in sequence, and fully mixing for 4 minutes;

s03, rapidly adding 2 parts by weight of water, 0.1 part by weight of an ether polycarboxylate water reducer, and stirring for 4 minutes; the polyvinyl alcohol fibers were added in portions at 30 seconds intervals, with a total of 0.02 parts by weight.

Example B2

This example differs from example B1 in that the dry concrete mix of example A2 containing 20 parts by weight of biochar was used.

Example B3

This example differs from example B1 in that the dry concrete mix of example A2 containing 30 parts by weight of biochar was used.

Example B4

This example differs from example B3 in that a concrete drier containing 10 parts by weight of granulated blast furnace slag in example A4 is used; in step S2, after adding ordinary portland cement, 10 parts by weight of granulated blast furnace slag is added.

Example B5

This example differs from example B3 in that a dry concrete mix containing 10 parts by weight of silica fume in example A5 was used; in the step S2, after the ordinary Portland cement is added, 10 parts by weight of silica fume is added.

Example B6

This example differs from example B3 in that a concrete drier containing 10 parts by weight of fly ash from example A6 was used; in the step S2, after the common silicate cement is added, 10 parts by weight of fly ash is added.

Example B7

This example differs from example B3 in that a dry concrete mix of example A7 containing 10 parts by weight of metakaolin was used; in the step S2, after the ordinary Portland cement is added, 10 parts by weight of metakaolin is added.

Example B8

This example differs from example B3 in that the dry concrete of example A8 was used.

Example B9

This example differs from example B3 in that the dry concrete of example A9 was used.

Example B10

This example differs from example B3 in that the dry concrete of example A10 was used.

Comparative example B

The comparative example differs from example B1 in that the dry concrete of comparative example A was used.

3. Preform embodiment

Example C1

Referring to FIG. 2, the present embodiment provides a concrete preform, which is prepared by uniformly pouring the concrete slurry of the embodiment B1 into a steel mold (240 mm. Times.115 mm. Times.53 mm), pressing for 0.5 to 1 minute by applying a pressure of 70kN to 100kN using a universal tester, and fully compacting;

immediately demolding after compacting, placing the demolded sample in an environment with the temperature of 20+/-1 ℃ and the humidity of 60+/-5% for 3 days and 28 days to obtain a prefabricated member, and testing the compressive strength of the prefabricated member. The 3-day compressive strength of the preform was measured to be 12.8MPa and the 28-day compressive strength of the preform was measured to be 15.2MPa.

After 28 days of hardening, the surface of the prefabricated part is coated with white cement fireproof paint to prepare the partition brick.

Example C2

Referring to fig. 2, the difference between this embodiment and embodiment C1 is that the concrete paste is the concrete paste of embodiment B2.

The 3-day compressive strength of the preform was measured to 12MPa and the 28-day compressive strength was measured to 14.2MPa.

Example C3

Referring to fig. 2, the difference between this embodiment and embodiment C1 is that the concrete paste is the concrete paste of embodiment B3.

The 3-day compressive strength of the preform was measured to be 9.6MPa and the 28-day compressive strength was measured to be 10.4MPa.

Example C4

Referring to fig. 3, the difference between this embodiment and embodiment C1 is that the concrete paste is the concrete paste of embodiment B4.

The 3-day compressive strength of the preform was measured to be 7.3MPa and the 28-day compressive strength was measured to be 11MPa.

Example C5

Referring to fig. 3, the difference between this embodiment and embodiment C1 is that the concrete paste is the concrete paste of embodiment B5.

The 3-day compressive strength of the preform was measured to 10MPa and the 28-day compressive strength was measured to 12.1MPa.

Example C6

Referring to fig. 3, the difference between this embodiment and embodiment C1 is that the concrete paste is the concrete paste of embodiment B6.

The 3-day compressive strength of the preform was measured to be 7.4MPa and the 28-day compressive strength was measured to be 10.3MPa.

Example C7

Referring to fig. 3, the difference between this embodiment and embodiment C1 is that the concrete paste is the concrete paste of embodiment B7.

The 3-day compressive strength of the preform was measured to be 11.3MPa and the 28-day compressive strength was measured to be 13.1MPa.

Example C8

This example differs from example C1 in that the concrete grout is the concrete grout of example B8.

The 3 day/28 day compressive strength of the preform was measured to approximate the results of example C3.

Example C9

This example differs from example C1 in that the concrete grout is the concrete grout of example B9.

Example C10

This example differs from example C1 in that the concrete grout is the concrete grout of example B10.

Comparative example C

Referring to fig. 2, the present comparative example is different from example C1 in that the concrete paste is the concrete paste of comparative example B.

The 3-day compressive strength of the preform was measured to be 13.9MPa and the 28-day compressive strength was measured to be 15.8MPa.

Preform performance analysis

In fig. 2, as can be seen from the results of examples C1 to C3, in combination with comparative example C, as the weight portion of biochar increases, the 3-day strength and the 28-day compressive strength of the concrete preform of the embodiment of the present application gradually decrease, but are both greater than 7MPa, which can satisfy the requirements of a part of materials in the construction field.

In FIG. 3, it can be seen from the results of examples C4 to C7, in combination with example C3, that the concrete preform of the present application can be improved in compressive strength by adding an auxiliary binder when biochar is incorporated in a large proportion, wherein the 3-day strength and the 28-day compressive strength of the preform obtained by adding metakaolin are high.

Although embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the application, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The concrete drier comprises the following components in parts by weight:

2-35 parts of biochar

10-40 Parts of environment-friendly aggregate

20-30 Parts of cement.

2. The dry concrete material of claim 1, wherein the biochar is prepared from waste biomass by anaerobic pyrolysis; and/or

The particle size of the biochar is 0.25 mm-5 mm; and/or

The environment-friendly aggregate comprises at least one of recycled aggregate, steel slag and glass slag; and/or

The particle size of the environment-friendly aggregate is less than or equal to 2.5mm; and/or

The cement comprises at least one of ordinary silicate cement, pozzolanic silicate cement and aluminate cement.

3. The concrete drier of claim 2, wherein the waste biomass comprises at least one of waste wood, straw, and waste fruit shells; and/or

The biochar is prepared by drying waste wood at 40-80 ℃ and performing anaerobic pyrolysis at 350-850 ℃ for 0.5-10 hours; and/or

The Portland cement includes 52.5 grade Portland cement.

4. The concrete drier as claimed in any one of claims 1 to 3, further comprising at least one of the following components in parts by weight:

5-10 parts of auxiliary cementing material;

0.01 to 0.03 portion of anticracking fiber.

5. The concrete drier of claim 4, wherein the auxiliary cementing material comprises at least one of granulated blast furnace slag, fly ash, metakaolin, silica fume, shell powder, household garbage incineration bottom ash, sewage sludge incineration ash, rice hull ash and limestone powder; and/or

The anti-cracking fiber comprises at least one of chopped polypropylene fiber and polyvinyl alcohol fiber.

6. The concrete slurry is characterized by comprising water and concrete dry materials dispersed in the water, wherein the concrete dry materials are the concrete dry materials according to any one of claims 1 to 5.

7. The concrete slurry of claim 6, wherein the weight ratio of water to biochar is 9:140-5:2; and/or

The concrete slurry also comprises a water reducer, wherein the weight ratio of the water reducer to the biochar is 1:2000-1:25.

8. The concrete slurry of claim 7, wherein the water reducing agent comprises an ether polycarboxylate or naphthalene sulfonate.

9. A method for preparing concrete slurry, comprising the step of mixing the concrete dry material according to any one of claims 1 to 3 with water.

10. The method of claim 9, wherein the mixing process comprises the steps of:

Pre-wetting the biochar and part of the water to obtain pre-wetted biochar;

And carrying out second mixing treatment on the mixture and the rest of water to obtain concrete slurry.

11. The method according to claim 10, wherein the auxiliary gelling material contained in the dry concrete according to any one of claims 4 to 5 is further added during the first mixing process; and/or

In the second mixing treatment process, the anti-cracking fibers contained in the concrete dry material according to any one of claims 4 to 5 are added in batches; and/or

The water reducing agent contained in the concrete slurry according to any one of claims 7 to 8 is further added during the second mixing treatment.

12. A concrete preform characterized by comprising the concrete slurry according to any one of claims 6 to 8.

13. The concrete preform of claim 12, wherein said curing process is layering said concrete slurry into molds, each of which is compression molded, followed by a mold release process and a curing process; and/or

And a fireproof coating is further arranged on the surface of the concrete prefabricated member.