CN113135710A

CN113135710A - Special concrete product and preparation method thereof

Info

Publication number: CN113135710A
Application number: CN202110431683.6A
Authority: CN
Inventors: 向嵘; 唐金涛; 陈超
Original assignee: Sichuan Hengding Building Materials Co ltd
Current assignee: Sichuan Hengding Building Materials Co ltd
Priority date: 2021-04-21
Filing date: 2021-04-21
Publication date: 2021-07-20
Anticipated expiration: 2041-04-21
Also published as: CN113135710B

Abstract

The application relates to the field of concrete, and particularly discloses a special concrete product and a preparation method thereof, wherein the special concrete product comprises the following components in parts by weight: 850 parts of coarse aggregate, 500 parts of fine aggregate, 180 parts of cement, 160 parts of water, 45-60 parts of ground phosphate rock slag, 60-80 parts of N-methylpyrrolidone and 30-40 parts of alkali metal salt; the preparation method comprises the following steps: uniformly mixing alkali metal salt, N-methyl pyrrolidone, coarse aggregate, fine aggregate, cement, water and an admixture to obtain special concrete; and then preparing the special concrete into a product, curing, soaking the prepared product into the decomplexation solution, taking out and drying until no water drops, and thus obtaining the special concrete product. The special concrete product has the advantage of higher water permeability, and the preparation method can improve the water permeability of the concrete.

Description

Special concrete product and preparation method thereof

Technical Field

The application relates to the field of concrete, in particular to a special concrete product and a preparation method thereof.

Background

The special concrete is concrete with special purpose made of new material and industrial waste or new technology. Such as: the water permeable concrete is commonly used for processing permeable concrete products such as permeable bricks and the like. After rain, the asphalt concrete or cement concrete pavement often has a water accumulation phenomenon, and the permeable brick made of the permeable concrete is used for paving, so that water can quickly permeate into the underground, the water accumulation phenomenon on the pavement is relieved, and the possibility of wetting the shoes of pedestrians is reduced.

The existing pervious concrete product is mainly made of concrete body added with aggregates with tiny through holes such as ceramsite, waste ceramic tile or kaolin particles, and water can permeate the aggregates because the aggregates are introduced into the through holes in the concrete product system.

To the above-mentioned correlation technique, when making concrete product, because the concrete mixes the in-process, the viscidity thick liquids that cement etc. formed can wrap up on the aggregate surface that has little through-hole, causes the through-hole of aggregate to be shutoff to influence concrete product's water permeability, make correlation technique's concrete product water permeability still relatively lower.

Disclosure of Invention

In order to improve the water permeability of the pervious concrete product, the application provides a special concrete product and a preparation method thereof.

The application provides a special concrete product adopts following technical scheme:

in a first aspect, the present application provides a special concrete product, which adopts the following technical scheme:

a special concrete product is composed of the following components in parts by weight: 850 parts of coarse aggregate, 500 parts of fine aggregate, 180 parts of cement, 160 parts of water, 45-60 parts of ground phosphate rock, 60-80 parts of N-methylpyrrolidone and 30-40 parts of alkali metal salt.

By adopting the technical scheme, the coarse aggregate and the fine aggregate are mutually embedded to be used as the basic framework of the concrete matrix and used for maintaining the strength of the concrete matrix. The cement, the water and the phosphorite slag powder are bonded into a sizing material, so that the coarse aggregate and the fine aggregate are tightly bonded together, gaps formed between the coarse aggregate and the fine aggregate are filled, and the integral strength of the concrete is ensured.

The N-methyl pyrrolidone and the alkali metal salt react in a concrete system to generate a complex, the complex generated by the N-methyl pyrrolidone and the alkali metal salt can be rapidly decomposed in a decomplexation solution, and then the N-methyl pyrrolidone and the alkali metal ions are released to escape from a concrete matrix, so that a large number of micro through holes are formed in the concrete matrix, and the micro through holes are formed after the concrete product is solidified and molded, so that the micro through holes cannot be blocked by slurry during mixing, and the water permeability of the concrete product can be improved. In addition, the pore diameter of the formed micropores is small, so that the influence on the strength of the concrete product can be reduced.

Preferably, the N-methyl pyrrolidone accounts for 70-80 parts by weight, and the alkali metal salt accounts for 35-40 parts by weight.

By adopting the technical scheme, when 70-80 parts of N-methyl pyrrolidone and 35-40 parts of alkali metal salt are used, the number of the micro through holes generated in a concrete system is moderate, so that the water permeability of the concrete can be improved, and the influence on the strength of the concrete caused by excessive through holes can be reduced.

Preferably, the alkali metal salt is a lithium salt.

By adopting the technical scheme, the complex crystal formed by the lithium ions and the N-methyl pyrrolidone is moderate in size, so that the aperture of the through hole formed in the concrete at the later stage is moderate, the water permeability of the concrete can be improved, and the possibility of influencing the strength of the concrete can be further reduced.

Preferably, the alkali metal salt is an alkali metal carbonate.

By adopting the technical scheme, the alkali metal ions and the N-methyl pyrrolidone form a complex, so that the carbonate ions are dissociated, the dissociated carbonate ions and the dissociated calcium ions in the concrete are combined into calcium carbonate, the generated calcium carbonate fills large holes formed by introducing air bubbles in the concrete during stirring or gaps among aggregates, the large holes in the concrete are reduced, and the strength of the concrete is improved. Meanwhile, the possibility of forming alkaline calcium hydroxide in a concrete system can be reduced due to the consumption of free calcium ions, and the calcium hydroxide is in a needle sheet shape and is easy to concentrate on the surface of the aggregate, so that the possibility of forming larger gaps among concrete aggregates can be reduced, and the strength of the concrete is improved.

Preferably, the admixture is ground phosphate rock.

By adopting the technical scheme, the ground phosphate rock plays a certain role in reducing water for concrete mixture, and can obviously improve the macroporous structure formed during concrete mixing, thereby being beneficial to further improving the strength of concrete.

In a second aspect, the application provides a preparation method of a special concrete product, which adopts the following technical scheme: a preparation method of a special concrete product comprises the following steps:

uniformly mixing 850 parts by weight of 600-plus-850 parts of coarse aggregate, 500 parts by weight of 400-plus-500 parts of fine aggregate, 300 parts by weight of 180-plus-300 parts of cement, 160 parts by weight of 150-plus-160 parts of water, 45-60 parts of admixture, 60-80 parts of N-methylpyrrolidone and 30-40 parts of alkali metal salt to obtain the special concrete;

and (3) preparing the special concrete into a product, maintaining for 7-10 days, soaking the prepared product into the decomplexation solution for 12-24h, taking out the product, and drying until no water drops, thus obtaining the special concrete product.

By adopting the technical scheme, the alkali metal salt, the N-methyl pyrrolidone, the coarse aggregate, the fine aggregate, the cement, the water and the admixture are uniformly mixed, so that the alkali metal ions and the N-methyl pyrrolidone are fully contacted in a concrete system to generate a large amount of dispersed complex compounds. Then the special concrete is made into a product, and the product is maintained, wherein the maintenance is to ensure that the strength and other properties of the concrete reach a certain grade, and then the product is soaked in the decomplexation solution, so that the possibility of influencing the strength of the concrete is reduced. Therefore, the curing time may be set to 7 days, 8 days, 9 days, 10 days, or the like as needed.

And after the curing is finished, soaking the product into the decomplexation solution, so that the complex in the product is dissolved into the decomplexation solution, and a large number of densely distributed micro through holes are formed in the product so as to be penetrated by water. In order to completely decomplex the complex in the concrete, the soaking time can be different time periods such as 12h, 15h, 18h, 20h or 24 h.

Preferably, the decomplexation solution is methanol.

By adopting the technical scheme, the complex formed by the alkali metal ions and the N-methyl pyrrolidone is dissolved in the methanol at the highest speed, so that after the concrete product is soaked for the same time, the number of the micro through holes in the concrete product is more, and the water permeability is improved more. In addition, the methanol has little influence on other components of the concrete, and the possibility of influencing other properties of the concrete is reduced.

Preferably, the product is dried and then soaked in the water repellent for 0.5 to 1 hour, and then the product is taken out and dried until no liquid drips, so as to obtain the special concrete product.

By adopting the technical scheme, the product is soaked in the hydrophobic agent and then taken out for drying, so that a layer of hydrophobic film is formed on the surface of the product and the hole wall of the micro through hole, water flow can more quickly pass through the through hole in application, and the water permeation efficiency is improved. In order to ensure that the hole walls of the through holes can be fully contacted with the water repellent agent, the time for soaking the water repellent agent can be different time lengths such as 0.5 hour, 0.7 hour or 1 hour.

In summary, the present application has the following beneficial effects:

1. according to the method, N-methyl pyrrolidone and alkali metal salt are adopted to react in a concrete system to generate a complex, the complex generated by the N-methyl pyrrolidone and the alkali metal salt can be rapidly decomposed in a decomplexer, and then the N-methyl pyrrolidone is released to escape from a concrete matrix, so that a large number of micropores with the size of 0.5-1.5nm are formed in the concrete matrix, and the micropores are formed after the concrete product is solidified and molded and cannot be blocked by slurry during concrete mixing, therefore, the effect of improving the water permeability of the concrete product is obtained, the water permeability of the prepared concrete product reaches 70.3% -70.5%, and the 7-day strength of the concrete product is maintained between 43.1-43.7 MPa.

2. In this application, preferably adopt the lithium salt as the reactant, because the complex volume that lithium ion and N-methyl pyrrolidone formed is moderate for the aperture of the through-hole that the later stage formed in the concrete is moderate, has obtained the water permeability that can improve the concrete, can further reduce the possibility effect that influences the concrete intensity again, makes the concrete product water permeability that makes reach 62.4%, and the 7 days intensity of concrete product improves to 49.5 MPa.

3. According to the method, alkali metal salt, N-methyl pyrrolidone, coarse aggregate, fine aggregate, cement, water and an admixture are mixed uniformly, so that alkali metal ions and the N-methyl pyrrolidone are in full contact in a concrete system to generate a large amount of dispersed complex, then a product prepared from the concrete is soaked in a decomplexation solution, and the complex in the product is dissolved in the decomplexation solution, so that a large amount of densely distributed micro through holes are formed in the product, and the effect of improving the water permeability of the concrete is achieved. Then, the product is soaked in the hydrophobic agent, so that a layer of hydrophobic film is formed on the surface of the product and the hole wall of the micro through hole, the water permeability efficiency is further improved, the water permeability of the prepared concrete product reaches 71.8%, and meanwhile, the 7-day strength of the prepared concrete product can also reach 52.4 MPa.

Detailed Description

At present, the pervious concrete is mainly characterized in that aggregates with tiny through holes, such as ceramsite, waste ceramic tile or aged soil particles, are added into a concrete system, and the through holes are introduced into the concrete system, so that the water permeability of the concrete is improved. However, when concrete products are actually prepared, the water permeability of the prepared products is still found to be limited, and the actual requirements are difficult to meet.

Repeated research and analysis show that in the mixing process of concrete, the sticky slurry formed by cement and the like can wrap the surface of the aggregate with the tiny through holes of the ceramsite lamp, so that the through holes of the aggregate are blocked, and the water permeability of the product is influenced.

In order to solve the problem, the inventor considers how to avoid the blockage of micropores in the concrete, and how to form through holes in the concrete after mixing, and researches and finds that the N-methyl pyrrolidone can be complexed with lithium ions to form a stable complex, and the complex can be decomplexed in methanol to release the N-methyl pyrrolidone and the lithium ions.

After the N-methyl pyrrolidone and the lithium salt are added into a concrete system and mixed, the N-methyl pyrrolidone and the lithium salt can also generate the complex in the concrete system, and after the concrete containing the complex is processed into a product, the product is soaked in methanol, a large number of tiny through holes are formed in the concrete, so that the water permeability of the product is improved.

On this basis, the inventors of the present application tried to convert different alkali metal salts: tests carried out by replacing lithium salt with potassium salt and sodium salt can generate a large amount of micro through holes in a concrete system, and the water permeability of the concrete is improved. And further finds that the complex can be decomposed when the product is soaked in a sodium carbonate or potassium carbonate solution, micro through holes are generated in concrete, and the water permeability of the product is improved.

Further, when the invention cleans the product after decomplexation, it is discovered accidentally that in the process of washing the product, a part of liquid oil is mixed into the cleaning water accidentally, so that the water permeability of the product is better than that of the product cleaned by clean water.

The inventor adopts 5-25 continuously assembled crushed stone as coarse aggregate, river sand as fine aggregate P.O42.5R cement, phosphate rock powder as admixture and water to prepare the concrete matrix, and further tests and verifies the findings, and the water permeability of the prepared concrete is greatly improved, and the strength is kept at a higher value. In the experimental process, pebbles as coarse aggregate, machine-made sand as fine aggregate and fly ash as admixture can obtain similar water permeability, so in other embodiments, pebbles can also be used as coarse aggregate, machine-made sand can also be used as fine aggregate and fly ash can also be used as admixture.

The present application will be described in further detail with reference to examples.

The raw materials of the present application are all available by self-made or commercial sources.

Examples

The components and the amounts added in the respective examples are shown in Table 1.

TABLE 1

The preparation method of the above example is as follows:

examples 1 to 3

A preparation method of a special concrete product comprises the following steps:

s1, adding the broken stone, the river sand, the cement, the water, the slag powder, the N-methyl pyrrolidone and the potassium nitrate into a stirrer according to the mixture ratio in the table 1, stirring for 30min, and uniformly mixing to obtain the special concrete;

s2, adding the special concrete into a mould to prepare a cube product with the side length of 20cm, curing for 7 days at normal temperature and normal pressure, soaking the product into a 2% sodium carbonate solution for 12 hours, taking out, and naturally drying until no water drops to obtain the special concrete product.

Example 4

A method for preparing a special concrete product, which is different from the method in the embodiment 2 in that: in the s1 step, potassium nitrate was replaced by an equal amount of sodium nitrate.

Example 5

A method for preparing a special concrete product, which is different from the method in the embodiment 2 in that: in step s1, the potassium nitrate was replaced by an equal amount of lithium nitrate.

Example 6

A method for preparing a special concrete product, which is different from the method in example 5 in that: in the s1 step, potassium nitrate was replaced by lithium carbonate in equal amount.

Example 7

A method for preparing a special concrete product, which is different from the method in example 6 in that: in the step s1, equal amount of ground phosphate rock is used to replace the ground slag.

Example 8

A method for preparing a special concrete product, which is different from the method in the embodiment 7 in that: in the s2 step, the 2% sodium carbonate solution was replaced with an equal amount of methanol.

Example 9

A method for preparing a special concrete product, which is different from the method in the embodiment 8 in that: and in the step s2, the product is decomplexed, taken out and naturally dried until no water drops are formed, and then the product is soaked in oleic acid for 0.5h, taken out and naturally dried until no water drops are formed, so that the special concrete product is obtained.

Comparative example

The components and the amounts added in the respective examples are shown in Table 2.

TABLE 2

Comparative example 1

A method for preparing a special concrete product, which is different from the method in the embodiment 2 in that: in the step s1, ceramsite with equal mass is adopted to replace N-methyl pyrrolidone and potassium nitrate.

Comparative example 2

A method for preparing a special concrete product, which is different from the method in the embodiment 2 in that: in step s1, N-methylpyrrolidone was added in an amount of 0.

Comparative example 3

A method for preparing a special concrete product, which is different from the method in the embodiment 2 in that: in the step s1, potassium nitrate was added in an amount of 0.

Comparative example 4

A method for preparing a special concrete product, which is different from the method in the embodiment 2 in that: and in the step s2, the product is soaked for 12 hours by using the same amount of clear water instead of 2% sodium carbonate solution, and then the product is taken out and naturally dried until no water drops, so that the special concrete product is obtained.

Performance detection method

1. Strength for 7 days: in each example and comparative example, a standard test block was prepared according to GB/T50081-2002 Standard for testing mechanical Properties of ordinary concrete, and the compressive strength of the standard test block was measured after curing for 7 days.

2. Water permeability: a cubic water tank with the side length of 10cm is arranged on the center of the special concrete product obtained in each example and each comparative example, then natural water is filled in the water tank, the height h from the residual water surface to the water tank opening is measured after 1h, and the water permeability of 1h is obtained through (10-h)/10 x 100%.

3. Number of micropores and pore diameter of micropores: the special concrete product obtained in each example and comparative example was cut into two symmetrical rectangular blocks from the middle, and the number of micropores in the section was observed and the pore diameter of the micropores was measured after the magnification of the electron microscope was 80 times.

4. Apparent number of cracks and macropores: the special concrete product obtained in each example and comparative example was cut from the middle into two symmetrical rectangular blocks, and the number of cracks and the number of large holes in the cross section were visually observed.

Test results the performance test results of the above examples are shown in table 3:

TABLE 3

The results of the above comparative performance tests are shown in table 4:

TABLE 4

Analysis of results

When example 2 and comparative example 1 are combined with tables 3 to 4, it can be seen that when comparative example 1 adopts the related art to improve the water permeability of a concrete product by adding water-permeable ceramsite, and example 2 improves the water permeability of the concrete by replacing ceramsite with N-methylpyrrolidone and potassium nitrate, the water permeability rate for 1h of comparative example 1 is much smaller than that of example 2. It can be seen that N-methyl pyrrolidone and potassium nitrate can react to form a complex in a concrete system, and the complex formed by N-methyl pyrrolidone and potassium nitrate can be rapidly decomposed in a 2% sodium carbonate solution, and then N-methyl pyrrolidone and alkali metal ions are released to escape from a concrete matrix, so that a large number of micropores of 0.5-1.5nm are formed in the concrete matrix, and the micropores are formed after a concrete product is set and molded and cannot be blocked by slurry during concrete mixing, and therefore, the water permeability of the concrete product can be improved. Further, it can be seen that the 7-day compressive strength of example 2 can be maintained close to that of comparative example 1, and it can be seen that the influence on the strength of the concrete product can be reduced due to the small pore diameter of the formed micro-pores.

It can be seen from the combination of example 2 and comparative example 2 and tables 3 to 4 that, when comparative example 2 was compared to example 2 without adding N-methylpyrrolidone, the water permeability for 1h of comparative example 2 was also much smaller than example 2, even smaller than comparative example 1, while no fine through-holes were observed in the section of the sample under the electron microscope. The reason is that the concrete system of the comparative example 2 is lack of N-methyl pyrrolidone, no complex of N-methyl pyrrolidone and potassium ions is generated in the concrete system, so that tiny through holes are difficult to generate in the concrete system after the concrete system is soaked in a 2% sodium carbonate solution, and the water permeability of the comparative example 2 for 1h is far lower than that of the example 2. In addition, since no aggregate such as ceramsite with through-holes was added, the water permeability for 1 hour of comparative example 2 was also smaller than that of comparative example 1.

It can be seen from the combination of example 2 and comparative example 3 and tables 3 to 4 that, when potassium nitrate was absent in comparative example 3 relative to example 2, the 1h water permeability of comparative example 3 was also much smaller than example 2 and even smaller than comparative example 2, while no fine through-holes were observed in the cross-section of the sample under the electron microscope. Also, since potassium nitrate is absent, the concrete system of comparative example 2 does not have the complex formation of N-methylpyrrolidone and potassium ions, and thus it is difficult to generate minute through-holes in the concrete system after soaking in a 2% sodium carbonate solution, and thus the water permeability for 1 hour of comparative example 3 is also much smaller than that of example 2. And because the potassium nitrate is introduced into the comparative example 2, potassium ions are combined with hydroxide radicals in a concrete system, the alkalinity in the concrete is improved, and the concrete is easier to crack, so that the number of the apparent cracks of the concrete of the comparative example 2 is more than that of the concrete of the example 2, the cracks are beneficial to increasing the 1h water permeability of the comparative example 2, and the phenomena of smaller strength in 7 days and larger 1h water permeability of the comparative example 2 are presented.

Combining example 2 and comparative example 4 and combining tables 3-4, it can be seen that when comparative example 4 soaks the product with clear water instead of a 2% sodium carbonate solution, the 7-day compressive strength of comparative example 4 is slightly greater than example 2, but the 1h water permeability is much less than example 2, even less than comparative example 2, and no tiny through holes are observed in the sample section under an electron microscope. It can be seen that even though the complex is generated in the concrete system, it is difficult to generate a large number of micro-pores inside the concrete without being soaked in a 2% sodium carbonate solution of a decomplexation solution, so that the 1h water permeability of comparative example 4 is much smaller than that of example 2, even smaller than that of comparative example 2. But comparative example 4 has a strength slightly higher than that of example 2 because it is advantageous to increase the strength of concrete without generating too many micro-pores.

As can be seen by combining example 2 with examples 1 and 3 and by combining tables 3 to 4, when the ratio of N-methylpyrrolidone to potassium nitrate was adjusted in example 2 relative to examples 1 and 3, the number of micropores was more in example 2, the water permeability was better at 1 hour, and the strength was maintained for 7 days. The reason is that the N-methyl pyrrolidone and the alkali metal salt are compounded according to the proportion of the embodiment 2, the number of the generated micro through holes in a concrete system is moderate, the water permeability of the concrete can be improved, and the influence of excessive through holes on the strength of the concrete can be reduced.

Combining example 2 and example 4 and combining tables 3-4, it can be seen that when example 4 uses an equal amount of sodium nitrate instead of potassium nitrate as the alkali metal salt, the pore size of the micropores of the article prepared in example 4 is smaller than that of example 2, so that the 1h water permeability of example 4 is smaller than that of example 2, but the strength of the concrete is increased due to the decrease in the pore size of the micropores. Combining example 2 and example 5 with tables 3 to 4, it can be seen that when the same amount of lithium nitrate as example 5 was used as the alkali metal salt instead of potassium nitrate, the pore size of the micropores was larger than that of example 2, so that the water permeability was greatly increased for 1h and the strength was reduced to a small extent in example 5. Due to the fact that the diameter of the complex formed by the lithium ions and the N-methyl pyrrolidone is proper, the aperture of the through hole formed in the concrete in the later period is proper, the water permeability of the concrete can be improved, and the possibility of influencing the strength of the concrete can be further reduced.

Combining example 5 and example 6 with tables 3 to 4, it can be seen that in example 6, when lithium carbonate was used in place of potassium nitrate as the alkali metal salt in an amount equivalent to that in example 5, the number of micropores, apparent macropores and cracks in example 6 decreased, resulting in an increase in the 7-day strength of example 6 and a decrease in the 1-hour water permeability. The reason is that the alkali metal ions and the N-methyl pyrrolidone form a complex compound, so that carbonate ions are dissociated, the dissociated carbonate ions and the dissociated calcium ions in the concrete are combined into calcium carbonate, the generated calcium carbonate fills large holes formed by introducing air bubbles into the concrete during stirring or gaps among aggregates, the large holes existing in the concrete are reduced, and the strength of the concrete is improved. Meanwhile, because free calcium ions are consumed, the possibility of forming alkaline needle-shaped calcium hydroxide in a concrete system can be reduced, and because the alkaline needle-shaped calcium hydroxide is easily enriched on the surface of the aggregate, the possibility of forming larger gaps among concrete aggregates is reduced, and the strength of the concrete is improved.

When example 7 and example 6 are combined and tables 3-4 are combined, the apparent macropore number of example 7 is reduced when equal amount of powdered rock phosphate is used as an admixture instead of the slag powder of example 6, so that the strength of example 7 is increased, the reduction range of the water permeability after 1h is small, and the macroporous structure formed during concrete mixing can be obviously improved due to the fact that the powdered rock phosphate is used as the admixture to play a certain role in reducing water for the concrete mixture, thereby being beneficial to further improving the strength of the concrete.

Combining example 8 and example 7 and combining tables 3 to 4, it can be seen that when an equal amount of methanol was used as the decomplexation solution in example 8 instead of the 2% sodium carbonate solution in example 7, the number of cross-sectional micropores of example 8 was increased such that the 7-day strength of example 8 was slightly decreased, but the 1-hour water permeability of example 8 was increased relative to example 7. The reason is that the complex formed by the alkali metal ions and the N-methyl pyrrolidone is dissolved in the methanol at the fastest speed, so that the number of the tiny through holes in the concrete product is more and the water seepage amount is more after the concrete product is soaked for the same time. In addition, the methanol has little influence on other components of the concrete, so that the strength of the concrete is little influenced.

Combining example 8 and example 9 with tables 3-4, it can be seen that when the decomplexed product of example 9 is dried and then soaked in oleic acid, a hydrophobic agent, and then the product is taken out and dried, the number of micropores, apparent cracks and macropores of example 9 relative to example 8 is substantially unchanged, and therefore the 7-day strength remains stable, but the 1h water permeability of example 9 is increased relative to example 8. The reason for the analysis is that the oleic acid forms a layer of hydrophobic film on the surface of the product and the hole wall of the tiny through hole, so that water flow can more quickly pass through the through hole, and the water permeation efficiency is improved.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.

Claims

1. The special concrete product is characterized by comprising the following components in parts by weight: 850 parts of coarse aggregate 600-containing material, 500 parts of fine aggregate 400-containing material, 300 parts of cement 180-containing material, 160 parts of water 150-containing material, 45-60 parts of admixture, 60-80 parts of N-methylpyrrolidone and 30-40 parts of alkali metal salt.

2. The specialty concrete article of claim 1, wherein said N-methyl pyrrolidone is 70-80 parts by weight and said alkali metal salt is 35-40 parts by weight.

3. A specialty concrete article according to claim 2 wherein said alkali metal salt is a lithium salt.

4. A specialty concrete article according to claim 3 wherein said alkali metal salt is an alkali metal carbonate.

5. The specialty concrete article of claim 4, wherein the admixture is ground phosphate rock.

6. A method of making a specialty concrete article as claimed in any one of claims 1 to 5 comprising the steps of:

uniformly mixing alkali metal salt, N-methyl pyrrolidone, coarse aggregate, fine aggregate, cement, water and an admixture to obtain special concrete;

and (3) preparing the special concrete into a product, maintaining for 7-10 days, then soaking the prepared product into the decomplexation solution for 12-24 hours, taking out the product, and drying until no water drops, thus obtaining the special concrete product.

7. A method of making a specialty concrete article according to claim 6 wherein said decomplexation solution is methanol.

8. A special concrete product preparation method according to claim 7, characterized in that after the product is dried, the product is soaked in the water repellent agent for 0.5-1h, and then the product is taken out and dried until no liquid drips to obtain the special concrete product.