CN111187044A

CN111187044A - Exposed concrete and construction method thereof

Info

Publication number: CN111187044A
Application number: CN202010204375.5A
Authority: CN
Inventors: 潘晓让
Original assignee: Shaanxi Longsheng Building Materials Co Ltd
Current assignee: Shaanxi Longsheng Building Materials Co Ltd
Priority date: 2020-03-21
Filing date: 2020-03-21
Publication date: 2020-05-22
Anticipated expiration: 2040-03-21
Also published as: CN111187044B

Abstract

The invention discloses exposed concrete and a construction method thereof, relating to the technical field of concrete construction; the exposed concrete is prepared from the following raw materials in parts by weight: 300 parts of cement, 1100 parts of coarse aggregate, 850 parts of fine aggregate, 80-120 parts of mineral powder, 8-12 parts of a water reducing agent and 180 parts of water; the stone exposed concrete raw material also comprises a stone exposed agent; the dewstone agent is prepared from the following dewstone agent raw materials in parts by weight: 0.04-0.08 part of glucose, 0.025-0.045 part of sodium hexametaphosphate, 0.001-0.005 part of amantadine hydrochloride and 0.35-0.45 part of dissolved water; it has the advantages of good retarding effect and good environmental protection performance; the construction method of the exposed concrete comprises the following steps: preparing a stone exposing agent, preparing concrete, pouring a pavement, maintaining the pavement and the like; the construction method of the exposed concrete has the advantage of being convenient for improving the delayed coagulation effect of the product.

Description

Exposed concrete and construction method thereof

Technical Field

The invention relates to the technical field of processing and production of concrete materials, in particular to exposed concrete and a construction method thereof.

Background

Concrete materials are widely used in the fields of road construction and the like because of their excellent properties such as strength and the like. In the construction process of the highway, the highway pavement is required to have excellent anti-skid, anti-dazzle and other functions due to the high running speed of vehicles, and the exposed concrete has excellent anti-skid, noise reduction, anti-dazzle and drainage functions and is increasingly applied to the fields of highway and tunnel pavement construction and the like.

The patent with the publication number of CN103232218B discloses a high-performance concrete dewstone agent and a preparation and application method thereof, wherein the dewstone agent comprises a component A and a component B, and the component A is prepared by mixing and stirring water, hydroxycarboxylic acid salt, organic phosphine, fluosilicate, penetrating agent, stabilizing agent, surfactant and pigment step by step; the component B consists of water, industrial water glass, sodium hydroxide and a modifier. This patent uses the dew stone agent of fluorine-containing silicate and organophosphorus, has improved the slow setting efficiency of dew stone agent, has reduced dew stone agent quantity for preparation dew stone concrete has improved the cling compound and drainage performance of dew stone concrete.

However, the addition of the fluorine-containing silicate in the patent improves the retarding efficiency of the exposed aggregate and reduces the dosage of the exposed aggregate, and the fluorine-containing silicate is not environment-friendly and brings certain harm to the construction environment of exposed aggregate concrete. Therefore, it is important to develop an environmentally friendly exposed concrete excellent in retardation efficiency.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide the exposed rock concrete with good environmental protection performance, which has the advantage of good retarding effect.

The second purpose of the invention is to provide a construction process of the exposed concrete convenient for improving the delayed coagulation effect, which has the advantage of facilitating the improvement of the delayed coagulation effect of the product.

In order to achieve the first object, the invention provides the following technical scheme: the exposed concrete is prepared from the following raw materials in parts by weight: 300 parts of cement, 1100 parts of coarse aggregate, 850 parts of fine aggregate, 80-120 parts of mineral powder, 8-12 parts of a water reducing agent and 180 parts of water; the stone exposed concrete raw material also comprises a stone exposed agent; the dewstone agent is prepared from the following dewstone agent raw materials in parts by weight: 0.04-0.08 part of glucose, 0.025-0.045 part of sodium hexametaphosphate, 0.001-0.005 part of amantadine hydrochloride and 0.35-0.45 part of dissolved water.

Through adopting above-mentioned technical scheme, glucose in the dew stone agent contains a plurality of hydroxyl functional groups, can take place chemical reaction with the cement surface, can slow down the speed that cement and water take place hydration reaction to a certain extent, play the effect of delayed coagulation, and add a certain amount of amantadine hydrochloride in the dew stone agent, amantadine hydrochloride has surfactant's function, with glucose, sodium hexametaphosphate synergism, the delayed coagulation that can effectively improve the dew stone agent, improve dew stone concrete's skid resistance, avoided the use of fluorine-containing silicate not friendly to the environment simultaneously, the feature of environmental protection of product has been improved.

Preferably, the dewing agent is prepared from the following dewing agent raw materials in parts by weight: 0.05 to 0.07 part of glucose, 0.03 to 0.04 part of sodium hexametaphosphate, 0.002 to 0.004 part of amantadine hydrochloride and 0.38 to 0.42 part of dissolved water.

By adopting the technical scheme, the better dew stone agent raw material proportion is used, the dew stone agent with more excellent retarding performance is prepared, and the anti-skid performance of the dew stone concrete is improved.

Preferably, the dew stone agent raw material also comprises 0.005-0.012 parts by weight of glycerol.

By adopting the technical scheme, a certain amount of glycerol is added into the exposed aggregate, the glycerol molecule contains three hydroxyl groups with stronger activity, and the hydroxyl groups in the glycerol molecule react with the surface of cement to delay the hydration reaction of the cement and water, so that the retarding efficiency is improved, and the anti-skid performance of the exposed aggregate concrete is improved.

Preferably, the stone distillate raw material also comprises 0.004 to 0.01 weight part of pigment substances.

By adopting the technical scheme, a certain amount of pigment substances are added into the exposed stone agent, and the exposed stone agent has obvious color after being sprayed on the road surface, so that the spraying positions and the quantity of the exposed stone agent can be accurately distinguished by constructors, and the construction efficiency of exposed stone concrete is improved.

Preferably, the water reducing agent is a polycarboxylic acid water reducing agent.

By adopting the technical scheme, the polycarboxylate water reducer is a cement dispersant, can improve the strength of the exposed concrete base layer, is beneficial to controlling the exposed stone depth of the exposed concrete, and is beneficial to improving the performances of skid resistance, anti-dazzle property and the like of the exposed concrete.

In order to achieve the second object, the invention provides the following technical scheme: a construction method of exposed concrete comprises the following steps:

(1) preparing a stone exposing agent: weighing the raw materials of the dewing agent according to a set proportion, and stirring at the temperature of 25-40 ℃ at the rotating speed of 200-300 r/min for 30-50 min to prepare the dewing agent;

(2) preparing concrete: weighing water according to a set proportion, adding coarse aggregates, fine aggregates and mineral powder under the stirring condition of the rotating speed of 400-600 revolutions per minute, continuing to stir for 40-60 min, adding a water reducing agent, and continuing to stir for 30-50 min to prepare concrete;

(3) pouring the pavement: pouring the concrete prepared in the step 2 into a concrete pavement, wherein the thickness of the concrete pavement is 23-27 cm, aging for 40-60 min after pouring is finished, spraying a stone exposing agent, covering by using a plastic film, retarding for 100-150 min, taking down the plastic film, washing the surface of the concrete pavement by using clear water, and exposing coarse aggregates on the surface of the concrete pavement to prepare a softened pavement;

(4) pavement maintenance: covering the softened pavement with a plastic film, and curing for 13-28 d to obtain the exposed concrete.

By adopting the technical scheme, the concrete is poured into the concrete pavement firstly, and then the exposed stone agent is sprayed on the surface of the concrete, so that the exposed stone agent reacts with the cement on the surface of the concrete to play a role in retarding, the depth of exposed stone is favorably controlled, the retarding effect is improved, and the dosage of the exposed stone agent is reduced.

Preferably, the particle size of the coarse aggregate is 5mm-40mm, the particle size of the fine aggregate is 0.16mm-5mm, and the particle size of the mineral powder is 0.02mm-0.6 mm.

By adopting the technical scheme, the large-particle-size coarse aggregate and the small-particle-size fine aggregate are used, the dew stone depth is controlled, the retarding effect of the dew stone agent is improved, the dosage of the dew stone agent is reduced, and the performances of skid resistance, drainage, noise reduction, anti-dazzle and the like of dew stone concrete are improved.

Preferably, the particle size of the coarse aggregate is 5mm-25mm, and the particle size of the fine aggregate is 0.5mm-2 mm.

Through adopting above-mentioned technical scheme, use the less fine aggregate of particle diameter, can be with dew stone degree of depth control in the scope that is not higher than 2mm, help the accurate control dew stone degree of depth, help improving the slow setting effect of dew stone agent, improve performances such as dew stone concrete antiskid and anti-dazzle.

In summary, the invention includes at least one of the following beneficial technical effects:

1. according to the invention, amantadine hydrochloride with a surfactant function is added into the dewstone agent, and the amantadine hydrochloride, the glucose and the sodium hexametaphosphate have a synergistic effect and react with the surface of cement, so that the hydration reaction of the cement is delayed, the retarding efficiency of the dewstone agent is improved, the dosage of the dewstone agent is reduced, the use of fluorine-containing silicate which is not friendly to the environment is avoided, and the environmental protection performance of the dewstone concrete is improved;

2. the glycerin is added into the dewstone agent, and the glycerin molecule contains hydroxyl functional groups with higher activity and generates chemical reaction with the surface of cement, so that the retarding efficiency of the dewstone agent is improved;

3. pigment substances are added into the exposed stone agent, so that construction personnel can accurately distinguish the spraying positions and the quantity of the exposed stone agent during exposed stone concrete construction, and the construction efficiency of the exposed stone concrete is improved;

4. the use of coarse aggregate with the particle size of 5mm-25mm and fine aggregate with the particle size of 0.5mm-2mm can control the dew stone depth within the range of not more than 2mm, thus being beneficial to accurately controlling the dew stone depth, improving the retarding effect of the dew stone agent, and improving the performances of skid resistance, anti-dazzle and the like of dew stone concrete.

Detailed Description

Examples

Example 1: a construction method of exposed concrete comprises the following steps:

(1) preparing a stone exposing agent: weighing 400g of dissolved water, stirring at 32 ℃ at the rotating speed of 250 revolutions per minute, adding 60g of glucose, 35g of sodium hexametaphosphate, 3g of amantadine hydrochloride, 8.5g of glycerol and 7g of pigment substance iron oxide, and stirring at the rotating speed of 250 revolutions per minute for 40min to obtain the dewstone agent;

(2) preparing concrete: weighing 160Kg of water, adding 1150Kg of coarse aggregate, 800Kg of fine aggregate, 100Kg of mineral powder and 275Kg of cement under the stirring condition of 500 revolutions per minute, wherein the particle size of the coarse aggregate is 5mm-25mm, the particle size of the fine aggregate is 0.5mm-2mm, and the particle size of the mineral powder is 0.02mm-0.6mm, continuing to stir for 50min, adding 10Kg of polycarboxylic acid water reducer, and continuing to stir for 40min to prepare concrete;

(3) pouring the pavement: pouring the concrete prepared in the step 2 into a concrete pavement, wherein the thickness of the concrete pavement is 25cm, aging for 50min after pouring is finished, spraying a stone exposing agent, wherein the spraying amount of the stone exposing agent is 100 g/square meter, covering by using a plastic film, delaying for 120min, taking down the plastic film, washing the surface of the concrete pavement by using clear water, and exposing coarse aggregates on the surface of the concrete pavement to prepare a softened pavement;

(4) pavement maintenance: covering the softened pavement with a plastic film, and maintaining for 20 days to obtain the exposed concrete;

a plurality of exposed concrete sample pieces with the length, width and height of 300mm, 300mm and 250mm are manufactured according to the same raw material proportion and process parameters of the example 1 and are used for testing the compressive strength and the anti-skid performance.

Example 2

Example 2 differs from example 1 in that example 2 replaces the polycarboxylate water reducer with a lignosulfonate water reducer, all otherwise in accordance with example 1.

Example 3

Example 3 differs from example 1 in that example 3 uses coarse aggregate of 5mm to 40mm, all otherwise in accordance with example 1.

Example 4

Example 4 differs from example 1 in that example 4 uses 0.16mm to 5mm fine aggregate, all otherwise in accordance with example 1.

Example 5

Example 5 differs from example 1 in that example 5 uses fine aggregate of 2mm to 5mm, all otherwise in accordance with example 1.

Example 6

Example 6 differs from example 1 in that the amount of the dew stone agent of example 6 used is 75 grams per square meter, all other things remaining the same as in example 1.

Example 7

Example 7 differs from example 1 in that the amount of amantadine hydrochloride in example 7 was reduced from 3g to 1g, all otherwise in accordance with example 1.

Example 8

Example 8 differs from example 1 in that the amount of amantadine hydrochloride in example 8 was reduced from 3g to 1.8g, all otherwise in accordance with example 1.

Examples 9 to 16

Examples 9-16 differ from example 1 in the amounts of starting materials added and the process parameters of examples 9-16.

The amounts of the starting materials used in examples 9 to 16 are shown in Table 1, and the process parameters for examples 9 to 16 are shown in Table 2.

TABLE 1 addition of the starting materials of examples 9 to 16

TABLE 2 parameters in the procedure of examples 9-16

Comparative example

Comparative example 1

Comparative example 1 differs from example 1 in that comparative example 1 does not have amantadine hydrochloride added, and otherwise remains the same as example 1.

Comparative example 2

Comparative example 2 differs from example 1 in that comparative example 2 does not have glycerol added and otherwise remains the same as example 1.

Comparative example 3

Comparative example 3 differs from example 1 in that comparative example 3 does not have sodium hexametaphosphate added, and otherwise remains the same as example 1.

Performance detection

The compression strength test is carried out on the exposed concrete samples prepared in the embodiments 1 to 16 and the comparative examples 1 to 3, the test method refers to the concrete pavement brick compression strength test method disclosed in appendix C of GB28635-2012, the exposed concrete samples are soaked according to the method disclosed in GB28635-2012, and then are placed on a testing machine, continuous and uniform loading is carried out on the testing machine at the loading rate of 0.5Mpa/S until the samples are damaged, the damage load is recorded, the compression strength is calculated, and the test results are shown in Table 3.

The samples of the exposed concrete prepared in the examples 1 to 16 and the comparative examples 1 to 3 were subjected to an anti-slip performance test, the test method was referred to the anti-slip performance test method disclosed in appendix G of GB28635-2012, the test was repeated five times, the single anti-slip value result was recorded, and then the average of the five test results was calculated to obtain the anti-slip value of the exposed concrete, the larger the anti-slip value was, the better the anti-slip performance of the exposed concrete was, and the test results are shown in Table 3.

TABLE 3 comparison table of the test results of compressive strength and skid resistance of different dew stone concrete products

Sample numbering	Compressive strength (MPa)	Anti-skid value (BPN)
			Example 1	44.3	68.2
Example 2	41.6	63.1
			Example 3	40.2	62.8
Example 4	43.8	63.5
			Example 5	43.5	61.7
Example 6	45.2	61.3
			Example 7	44.6	62.4
Example 8	44.5	63.6
			Example 9	43.8	65.2
Example 10	43.7	64.6
			Example 11	44.5	64.8
Example 12	44.2	65.5
			Example 13	43.9	68.3
Example 14	44.1	67.8
			Example 15	43.6	67.9
Example 16	44.4	68.1
			Comparative example 1	45.1	48.3
Comparative example 2	45.3	49.8
			Comparative example 3	44.8	48.6

Comparative example 1 under the experimental condition of not adding amantadine hydrochloride, the compressive strength of the prepared dewstone concrete sample is 45.1Mpa, the anti-skid value is 48.3BPN, the compressive strength is better, but the anti-skid value is smaller, and the anti-skid performance is not good. Comparative example 2 under the condition of not adding glycerol, the prepared dewstone concrete sample has the compressive strength of 45.3Mpa, the anti-skid value of 49.8BPN, better compressive strength, but smaller anti-skid value and poor anti-skid performance. In comparative example 3, sodium hexametaphosphate is not added, the compressive strength of the prepared exposed concrete sample is 44.8Mpa, the anti-skid value is 48.6BPN, the compressive strength is good, but the anti-skid value is small, the anti-skid performance is not good, and the market popularization of the product is not facilitated.

Comparing the experimental results of the example 1 and the comparative examples 1 to 3, it can be seen that, in the process of preparing the exposed concrete, the compression strength of the exposed concrete sample prepared in the example 1 is 44.3Mpa, the anti-skid value is 68.2BPN, the compression strength is better, the anti-skid value is large, the anti-skid performance is good, and the market competitiveness of the product is improved under the comprehensive influence of the three factors of adding amantadine hydrochloride, adding glycerol and adding sodium hexametaphosphate.

Comparing the experimental results of example 1 and example 2, example 2 uses lignosulfonate water reducing agent instead of polycarboxylate water reducing agent, and the prepared dewstone concrete sample has compressive strength of 41.6Mpa, slip resistance value of 63.1BPN, slightly reduced compressive strength, reduced slip resistance value and reduced slip resistance. However, the exposed concrete prepared in example 2 has better anti-skid properties than those of comparative examples 1 to 3. Therefore, the preferable scheme of the invention is to use the polycarboxylic acid water reducing agent.

Comparing the experimental results of example 1 and example 3, the coarse aggregate with a larger particle size distribution range is used in example 3, and the compressive strength of the prepared dewstone concrete sample is 40.2Mpa, the anti-skid value is 62.8BPN, the compressive strength is reduced, the anti-skid value is reduced, and the anti-skid performance is reduced. But the dewstone concrete samples prepared in example 3 had better skid resistance than comparative examples 1-3. Therefore, the invention preferably uses coarse aggregate with the grain diameter of 5mm-25 mm.

Comparing the experimental results of example 1 and example 4, example 4 uses fine aggregate with a particle size of 0.16mm-5mm, the particle size distribution range of the fine aggregate is wider, the compressive strength of the prepared dewstone concrete sample is 43.8Mpa, the anti-skid value is 63.5BPN, the difference of the compressive strength is not large, the anti-skid value is reduced, and the anti-skid performance is reduced. Comparing the experimental results of example 1 and example 5, example 5 uses fine aggregate with a particle size of 2mm-5mm, the particle size of the fine aggregate is larger, the compressive strength of the prepared dewstone concrete sample is 43.5Mpa, the anti-skid value is 61.7BPN, the difference of the compressive strength is not large, the anti-skid value is obviously reduced, and the anti-skid performance is obviously reduced. However, the dewstone concrete products prepared in examples 4 and 5 have better anti-skid properties than those prepared in comparative examples 1 to 3. Therefore, the preferable scheme of the invention is to use 0.5mm-2mm fine aggregate.

Comparing the experimental results of example 1 and example 6, the dosage of the dewstone agent in example 6 is reduced from 100 g/square meter to 75 g/square meter, the compressive strength of the prepared dewstone concrete sample is 45.2Mpa, the anti-skid value is 61.3BPN, the compressive strength difference is not large, the anti-skid value is obviously reduced, and the anti-skid performance is obviously reduced. But the dewstone concrete product prepared in example 6 has better anti-skid properties than those of comparative examples 1 to 3. Therefore, the invention has the preferred proposal that the dosage of the dewstone agent is not less than 80g per square meter.

Comparing the experiment results of example 1 and example 7, the amantadine hydrochloride dosage in example 7 is reduced from 3Kg to 1Kg, the compressive strength of the prepared dewstone concrete sample is 44.6MPa, the anti-skid value is 62.4BPN, the difference of the compressive strength is not large, the anti-skid value is reduced, and the anti-skid performance is reduced. Comparing the experiment results of example 1 and example 8, the amantadine hydrochloride dosage in example 8 is reduced from 3Kg to 1.8Kg, the compression strength of the prepared dewstone concrete sample is 44.5MPa, the anti-skid value is 63.6BPN, the compression strength difference is not large, the anti-skid value is slightly reduced, and the anti-skid performance is slightly reduced. However, the dewstone concrete products prepared in examples 7 to 8 were better in grip performance than those prepared in comparative examples 1 to 3. Therefore, the invention has the preferable scheme that the dosage of the amantadine hydrochloride is not less than 2 parts.

The feed amounts of the various materials of examples 9-16 were different and the process parameters were different compared to example 1. Wherein the weight ratio of the raw materials of the embodiments 13-16 is as follows: 300 parts of cement 250-containing material, 1200 parts of coarse aggregate 1100-containing material, 850 parts of fine aggregate 750-containing material, 80-120 parts of mineral powder, 8-12 parts of water reducing agent, 180 parts of water 140-containing material, 0.05-0.07 part of glucose, 0.03-0.04 part of sodium hexametaphosphate, 0.002-0.004 part of amantadine hydrochloride and 0.38-0.42 part of dissolved water; the dew stone concrete products prepared in the embodiments 13 to 16 have the advantages of stable compressive strength of about 44MPa, stable skid resistance value of about 68BPN, good compressive strength, excellent skid resistance and strong market competitiveness. The weight ratio of the raw materials of examples 9-12 is different from that of examples 13-16, and the prepared dewstone concrete product has the advantages of stable compressive strength of about 44MPa, stable skid resistance value of about 65BPN, good compressive strength and slightly reduced skid resistance. Therefore, the preferable weight ratio of the raw materials is as follows: 300 parts of cement 250-containing materials, 1200 parts of coarse aggregate 1100-containing materials, 850 parts of fine aggregate 750-containing materials, 80-120 parts of mineral powder, 8-12 parts of water reducing agent, 180 parts of water 140-containing materials, 0.05-0.07 part of glucose, 0.03-0.04 part of sodium hexametaphosphate, 0.002-0.004 part of amantadine hydrochloride and 0.38-0.42 part of dissolved water.

In conclusion, the preferable weight ratio of the raw materials of the invention is as follows: 300 parts of cement 250-containing materials, 1200 parts of coarse aggregate 1100-containing materials, 850 parts of fine aggregate 750-containing materials, 80-120 parts of mineral powder, 8-12 parts of water reducing agent, 180 parts of water 140-containing materials, 0.05-0.07 part of glucose, 0.03-0.04 part of sodium hexametaphosphate, 0.002-0.004 part of amantadine hydrochloride and 0.38-0.42 part of dissolved water. The preferred process conditions of the invention are as follows: the preparation method comprises the following steps of using a polycarboxylic acid water reducing agent, using coarse aggregates with the particle size of 5-25 mm, selecting fine aggregates with the particle size of 0.5-2 mm, using the dosage of the dew stone agent not less than 80g per square meter, and adding pigment substances into the dew stone agent.

The cement in the invention is Portland cement, and the cement types can be selected from P. 042.5 and P. 042.5R; the coarse aggregate is acid rock with polishing resistance, edges, cubes and rough surface, and the coarse aggregate with larger particles can be crushed by a crusher for use; the fine aggregate can be selected from natural sand, artificial sand (including machine-made sand) or stone chips, and the fine aggregate with larger particles can be crushed by a crusher for use; the mineral powder is obtained by crushing mined ores. The exposed stone depth of the exposed stone concrete is 1mm-2mm, and the optimal exposed stone depth is 1.5 mm.

The embodiments of the present invention are preferred embodiments of the present invention, and the scope of the present invention is not limited by these embodiments, so: all equivalent changes made according to the structure, shape and principle of the invention are covered by the protection scope of the invention.

Claims

1. The exposed concrete is characterized by being prepared from the following exposed concrete raw materials in parts by weight: 300 parts of cement, 1100 parts of coarse aggregate, 850 parts of fine aggregate, 80-120 parts of mineral powder, 8-12 parts of a water reducing agent and 180 parts of water; the stone exposed concrete raw material also comprises a stone exposed agent; the dewstone agent is prepared from the following dewstone agent raw materials in parts by weight: 0.04-0.08 part of glucose, 0.025-0.045 part of sodium hexametaphosphate, 0.001-0.005 part of amantadine hydrochloride and 0.35-0.45 part of dissolved water.

2. The exposed concrete of claim 1, wherein the exposed concrete is prepared from exposed concrete raw materials in parts by weight as follows: 0.05 to 0.07 part of glucose, 0.03 to 0.04 part of sodium hexametaphosphate, 0.002 to 0.004 part of amantadine hydrochloride and 0.38 to 0.42 part of dissolved water.

3. The exposed concrete according to claim 2, wherein: the stone distillate also comprises 0.005-0.012 parts by weight of glycerol.

4. The exposed concrete of claim 3, wherein: the stone distillate also comprises 0.004-0.01 weight part of pigment substances.

5. The exposed concrete of claim 1, wherein: the water reducing agent is a polycarboxylic acid water reducing agent.

6. A method of constructing a dewstone concrete as claimed in any one of claims 1 to 5, comprising the steps of:

7. The method of constructing an exposed concrete according to claim 6, wherein: the grain size of the coarse aggregate is 5mm-40mm, the grain size of the fine aggregate is 0.16mm-5mm, and the grain size of the mineral powder is 0.02mm-0.6 mm.

8. The method of constructing an exposed concrete according to claim 7, wherein: the grain size of the coarse aggregate is 5mm-25mm, and the grain size of the fine aggregate is 0.5mm-2 mm.