An environmentally friendly high low-temperature resistant carbonized concrete and its preparation method

Abstract

An environmentally friendly high low-temperature carbonation resistant concrete and its preparation method of the present invention relate to a new type of building material. Its purpose is to provide an environmentally friendly high low-temperature carbonation resistant concrete and its preparation method that can improve the strength and stability of concrete, and at the same time solve problems such as environmental pollution caused by industrial by-products such as steel slag and rice husk ash, slow early strength development of concrete during winter construction, and serious carbon dioxide corrosion. An environmentally friendly high low-temperature carbonation resistant concrete of the present invention, by weight, comprises 100-500 parts of ground steel slag powder, 100-400 parts of metakaolin, 10-50 parts of modified rice husk ash, 10-30 parts of sodium hydroxide, 200-250 parts of water glass, 750-900 parts of common sand, 850-1000 parts of stones, and 10-60 parts of water. During preparation, the solid components are placed in a mixer and stirred for 30 s, water is mixed into the water glass to form a mixed solution, then sodium hydroxide is added to the mixed solution and stirred until dissolved and cooled and left standing. The mixed solution after standing and cooling is inverted into the mixer, and after stirring for 2 min, the finished product can be obtained.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, and in particular to an environmentally friendly high-low temperature carbonization resistance concrete and a preparation method thereof. Background Art

[0002] With the development of human society, the CO2 content in the air is also rising sharply. At the same time, in the field of concrete building materials, during winter construction, due to the low temperature and dryness, the early strength development of concrete structural materials after pouring is slow, resulting in more serious erosion of the concrete surface by CO2 in the air. At present, the main method to solve this phenomenon is to add early strength agents, internal curing agents and external surface curing agents to concrete. However, the prices and labor costs of these additional component materials and external surface curing agents are often high, and they cannot be widely used in actual projects.

[0003] Concrete is the most widely used building material in the world, with an annual output of about 6 billion tons. This is mainly due to the relatively low manufacturing cost of cement, the wide source of raw materials, and the diversity of concrete structure molding. However, a large amount of harmful gases such as CO2 are released during the cement manufacturing process, and the limitations of cement in durability and in the preparation of high-strength and high-performance concrete have gradually attracted people's attention. Therefore, people began to explore the possibility of using mineral admixtures to improve the performance of cement and replacing cement with new cementitious materials. High-activity metakaolin has gradually become the research focus in the field of cement and concrete due to its superiority in raw material distribution and performance. Its unique mineral properties make it not only a cement admixture, but also a new type of high-quality ecological cementitious material.

[0004] my country produces a large amount of steel slag every year. After being processed by the market, steel slag can become industrial raw materials or energy, which is easier to realize resource utilization than wastewater and waste gas. Therefore, how to scientifically and environmentally treat the large-scale lithium slag that needs to be stored and landfilled is still a major problem that troubles many scholars.

[0005] At the same time, as a major rice-producing country, my country has a huge amount of rice husks. Currently, rice husks are mainly used as raw materials for power generation. Rice husk ash is a by-product of calcining rice husks as raw materials for power generation. If it is not treated, it will put tremendous pressure on the environment. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide an environmentally friendly, highly low-temperature-resistant carbonation concrete and a preparation method thereof that can improve the strength and stability of concrete, while solving the problems of environmental pollution caused by industrial by-products such as steel slag and rice husk ash, slow early strength development of concrete during winter construction, and severe carbon dioxide corrosion.

[0007] One technical solution provided by the present invention is an environmentally friendly high low-temperature carbonization resistant concrete, which, by weight parts, comprises 100 to 400 parts of ground steel slag powder, 0 to 400 parts of metakaolin, 10 to 50 parts of modified rice husk ash, 10 to 30 parts of sodium hydroxide, 200 to 250 parts of water glass, 750 to 900 parts of ordinary sand, 850 to 1000 parts of stones, and 10 to 60 parts of water.

[0008] For the environmentally friendly high low-temperature carbonization resistant concrete of the present invention, the ground steel slag is converter slag discharged during the production of steel in a steel plant, which is calcined and ground, with an average particle diameter of 20 to 50 μm. The content of CaO in the ground steel slag powder is 55 to 60%, the content of SiO2 is 10 to 15%, the content of FeO is 5% to 10%, the content of Fe2O3 is 0% to 5%, and the content of Al2O3 is 0% to 5%.

[0009] For the environmentally friendly high low-temperature carbonization resistant concrete of the present invention, the metakaolin raw material is kaolin, which is dehydrated to form anhydrous aluminum silicate at 600 to 900 °C. The content of SiO2 in the metakaolin is 40 - 45%, the content of Al2O3 is 25% - 30%, and the content of CaO is 0 - 2%.

[0010] For the environmentally friendly high low-temperature carbonization resistant concrete of the present invention, the modified rice husk ash is obtained by calcining rice husks, with an average particle size of 50 μm, loose agglomeration, and a large number of nano-scale pores, and irregular particle shapes. The content of SiO2 in the modified rice husk ash is 85 - 95%.

[0011] For the environmentally friendly high low-temperature carbonization resistant concrete of the present invention, the concentration of the water glass is 40 wt%.

[0012] For the environmentally friendly high low-temperature carbonization resistant concrete of the present invention, the sodium hydroxide is industrial-grade sodium hydroxide, and the purity of the sodium hydroxide is 99.50%.

[0013] For the environmentally friendly high low-temperature carbonization resistant concrete of the present invention, the ordinary sand is medium-coarse sand, and its fineness modulus is between 2.1 and 3.0.

[0014] For the environmentally friendly high low-temperature carbonization resistant concrete of the present invention, the stones are granite gravel with a particle size range of 5 to 31.5 mm.

[0015] Another technical solution provided by the present invention is a preparation method of an environmentally friendly high-low-temperature-resistant carbonized concrete, which comprises the following steps: by weight, weighing 850-1000 parts of stones, 750-900 parts of ordinary sand, 100-400 parts of metakaolin, and 10-50 parts of modified rice husk ash, placing them in a mixer and mixing and stirring for 30 s, mixing 10-60 parts of water into 200-250 parts of water glass to form a mixed solution, then adding 10-30 parts of sodium hydroxide weighed into the mixed solution, stirring and dissolving, cooling and standing, and finally pouring the cooled mixed solution into the mixer and stirring for 2 min to obtain a uniformly stirred environmentally friendly high-low-temperature-resistant carbonized concrete.

[0016] In the present invention, using steel slag in the field of concrete building materials for an environmentally friendly high-low-temperature-resistant carbonized concrete not only helps to protect the environment, but also has prominent advantages such as small water demand for alkali activation, low heat of hydration, good thermal stability, high crack resistance and water reduction, which will further optimize the durability performance such as crack resistance of the concrete.

[0017] The composite alkali-activated cementitious material in the present invention simultaneously uses industrial solid waste such as steel slag and agricultural waste such as rice husk ash to prepare the composite cementitious material, realizing the transformation of waste into treasure. The prepared cementitious material has high strength, adjustable setting time, simple preparation process, low cost and wide raw material sources. Compared with other existing concrete carbonation resistance technologies, the composite alkali-activated cementitious material of the present invention can obtain higher carbonation resistance performance and low-temperature resistance performance. In addition to optimizing the ratio of elements (active oxides) in the composite alkali-activated raw materials by adjusting the ratio between ground steel slag powder and metakaolin, the cementitious material of the present invention further adjusts the Si / Al size in the overall alkali-activated material by using the dosage of polyethylene glycol-modified rice husk ash and adjusts the Na / Al element ratio by using sodium hydroxide to improve the strength of the cementitious material; in addition, in the modified rice husk ash added to the alkali-activated material, there will be rice husk ash in which polyethylene glycol hydrolysis does not occur, and this part of rice husk ash will not participate in the reaction inside the cementitious material. At this time, this part of rice husk ash will play the role of an internal curing agent, further improving the early strength development ability of the concrete in winter.

[0018] The present invention organically combines and utilizes the physical and chemical properties of industrial wastes, which can not only effectively solve the problems of low strength and high carbonation existing in current concrete materials after winter construction, but also achieve the purpose of turning waste into treasure. First of all, starting from the properties of the hydration products of the alkali-activated metakaolin material, the hydration products contain zeolite colloid before the crystallization of zeolite. After the concrete hardens and crystallizes inside, zeolite is formed. Zeolite has the function of physically adsorbing carbon dioxide. Therefore, the zeolite in the alkali-activated reaction products in the surface area of the concrete can effectively adsorb the carbon dioxide that wants to invade the inside of the concrete, reducing the erosion of carbon dioxide on the deeper area.

[0019] In addition, since calcium hydroxide can promote the formation of zeolite-like products (three-dimensional network structures formed by the polymerization of silicon-oxygen tetrahedra and aluminum-oxygen tetrahedra in alkali-activated materials products) in alkali-activated metakaolin, the addition of ground steel slag powder (with a high CaO content) serves as an external calcium source, and the content of zeolite-like products in the alkali-activated cementitious material can be controlled by adjusting the dosage of the ground steel slag powder.

[0020] Modified rice husk ash is obtained by modifying and shaping rice husk ash with polyethylene glycol (utilizing the good adsorption performance of porous silica, adsorbing polyethylene glycol phase change material in the microporous structure of silica, and under the action of capillary force and surface tension, it is difficult for polyethylene glycol to penetrate out of the microporous structure of silica during solid-liquid phase change), then adding silicate, and under the action of a silicate (sodium silicate) coagulant, subjecting the mixture to rapid gelation treatment, and finally drying to form a polyethylene glycol / silica inorganic-organic composite shaped material. After modification, the rice husk ash can maintain a solid shape during the phase change process.

[0021] In summary, in the alkali-activated metakaolin concrete of the present invention, rice husk ash is added. Since the honeycomb void structure in the modified rice husk ash contains polyethylene glycol, and polyethylene glycol is difficult to react and decompose with alkaline solutions at room temperature, only a small amount of hydrolysis (producing ethylene glycol) will occur. The rice husk ash with hydrolyzed polyethylene glycol will participate in the alkali activation reaction. Therefore, the strength of the cementitious material can be improved by adjusting the dosage of the modified rice husk ash and thus adjusting the Si / Al and Na / Al ratios in the overall alkali-activated material. In addition, the rice husk ash without hydrolyzed polyethylene glycol will not participate in the reaction inside the cementitious material. At this time, this part of the rice husk ash will act as an internal curing agent (the rice husk ash containing unhydrolyzed polyethylene glycol can store and release water through a large number of nearly spherical micropores distributed inside, acting as an internal curing agent, alleviating the autogenous drying of the concrete, improving the early strength development, and enhancing the resistance of the concrete surface to the intrusion and corrosion of carbon dioxide). Finally, polyethylene glycol is also a surfactant. Therefore, driven by the dispersion effect of polyethylene glycol, the rice husk ash can be more evenly distributed in the concrete, more effectively improving the internal curing effect of the rice husk ash in the concrete, and further optimizing the early strength development and carbon dioxide corrosion resistance of the concrete.

[0022] The differences between an environmentally friendly high low-temperature carbonation-resistant concrete and its preparation method of the present invention and the prior art are as follows:

[0023] 1. The present invention organically combines and utilizes the physical and chemical properties of industrial wastes, which can not only effectively solve the problems of low strength and high carbonization existing in concrete materials after winter construction, but also achieve the purpose of turning waste into treasure. Compared with ordinary concrete, the hydration products of alkali-activated metakaolin materials contain zeolite colloids before the crystallization of zeolite. After the concrete hardens and crystallizes internally, zeolite is formed. Zeolite has the function of physically adsorbing carbon dioxide. Therefore, the zeolite in the alkali-activated reaction products in the surface area of the concrete can effectively adsorb the carbon dioxide that wants to invade the interior of the concrete, reducing the erosion of carbon dioxide on the deeper area;

[0024] 2. Research has proven that Ca(OH)2 can promote the formation of zeolite-like products (three-dimensional network structures formed by the polymerization of silicon-oxygen tetrahedrons and aluminum-oxygen tetrahedrons in the products of alkali-activated materials) in alkali-activated metakaolin; at the same time, due to the relatively high CaO content in ground steel slag powder, the dosage of ground steel slag powder can be appropriately adjusted to increase the content of Ca(OH)2 in the alkali-activated material, thereby promoting the content of zeolite-like products in the alkali-activated cementitious material and further improving the carbonation resistance of the concrete.

[0025] 3. The cementitious material of the present invention can not only optimize the ratio of elements (active oxides) in the composite alkali-activated raw materials by adjusting the ratio between ground steel slag powder and metakaolin, but also further add polyethylene glycol-modified rice husk ash. Among them, the polyethylene glycol in the particle structure of some modified rice husk ash undergoes hydrolysis. Therefore, the SiO2 in this part of the rice husk ash can participate in the alkali-activated reaction in the overall alkali-activated material. Finally, by adjusting the dosage of the added modified rice husk ash, the content of the rice husk ash in the part where polyethylene glycol hydrolysis occurs is adjusted, and then the Si / Al and Na / Al element ratios are adjusted to improve the strength of the cementitious material;

[0026] 4. In the modified rice husk ash added to the alkali-activated material in the present invention, there will also be rice husk ash that has not undergone polyethylene glycol hydrolysis. This part of the rice husk ash will not participate in the reaction inside the cementitious material. At this time, this part of the rice husk ash will play the role of an internal curing agent (the rice husk ash containing unhydrolyzed polyethylene glycol can store and release water through a large number of nearly spherical micropores distributed inside, playing the role of an internal curing agent, alleviating the autogenous drying of the concrete and improving the early strength development). In addition, since the element ratios (Si / Al, Na / Al) in the alkali-activated material also have an impact on the reaction rate of the alkali-activated reaction, adjusting the dosage of the modified rice husk ash to increase the reaction rate of the early alkali-activated reaction can further improve the strength development ability of the concrete in winter. Based on the above principles and properties, compared with the existing technology, the present invention has greatly improved the resistance of the concrete surface to the invasion and corrosion of carbon dioxide;

[0027] 5. Finally, since polyethylene glycol is a surfactant with good dispersion properties, the modified rice husk ash in the present invention can be more evenly distributed in the concrete under the drive of the dispersion effect of polyethylene glycol, which can more effectively improve the internal curing effect of the rice husk ash in the concrete and further optimize the early strength development and carbon dioxide erosion resistance of the concrete. Detailed Embodiments

[0028] The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0029] Example 1

[0030] For an environmentally friendly high low-temperature carbonation resistant concrete of the present invention, the components are in parts by weight and include 950 parts of gravel, 800 parts of ordinary sand, 400 parts of metakaolin, 30 parts of modified rice husk ash, 50 parts of water, 250 parts of sodium silicate, and 20 parts of sodium hydroxide.

[0031] The content of SiO2 in the metakaolin is 40%, and the content of Al2O3 is 25%.

[0032] The modified rice husk ash is obtained by calcining rice husks and then modified. Its average particle size is about 50 μm, with loose aggregation, a large number of nanoscale pores, irregular particle shapes, and the SiO2 content in the chemical composition reaches 85%.

[0033] The modification method of the modified rice husk ash is to modify and shape the rice husk ash with polyethylene glycol for 1 d, then add silicate, and under the action of the silicate (sodium silicate) coagulant, the mixture is rapidly gelated for 12 h, and finally dried to form a polyethylene glycol / silica inorganic-organic composite shaped material.

[0034] The concentration of sodium silicate is 40 wt%.

[0035] The sodium hydroxide is industrial-grade sodium hydroxide with a purity of 99.50%.

[0036] The ordinary sand is medium-coarse sand with a fineness modulus of 2.1.

[0037] The gravel is ordinary granite crushed stone with a particle size of 5 mm.

[0038] A preparation method for an environmentally friendly high low-temperature carbonation resistant concrete is as follows: Place the above solid components in a mixer and mix and stir for 30 s. Mix 50 parts of water into 250 parts of sodium silicate to form a mixed solution, then add 20 parts of sodium hydroxide to the mixed solution, stir and dissolve, cool and place, and finally pour the cooled mixed solution into the mixer and stir for 2 min to obtain a uniformly stirred environmentally friendly high low-temperature carbonation resistant concrete.

[0039] Example 2

[0040] An environmentally friendly high low temperature carbonization resistant concrete of the present invention, each component is counted by weight parts, including 950 parts of stones, 800 parts of ordinary sand, 400 parts of metakaolin, 100 parts of ground steel slag powder, 30 parts of modified rice husk ash, 50 parts of water, 250 parts of sodium silicate and 20 parts of sodium hydroxide.

[0041] Among the above materials, the content of CaO in the ground steel slag powder is 55%, the content of SiO2 is 10%, the content of FeO is 5%, and the average particle diameter is 20μm.

[0042] The content of SiO2 in metakaolin is 41%, the content of Al2O3 is 25%, and the content of CaO is 0.5%;

[0043] The modified rice husk ash is obtained by calcining rice husks and then modified. Its average particle size is about 50μm, loosely agglomerated, and has a large number of nano-scale pores. The particle shape is irregular, and the content of SiO2 in the chemical composition reaches 85%;

[0044] The modification method of the modified rice husk ash is to modify and shape the rice husk ash with polyethylene glycol for 1d, then add silicate, and under the action of the silicate (sodium silicate) coagulant, the mixed solution is quickly gelated for 12h, and finally dried to form a polyethylene glycol / silica inorganic-organic composite shaped material;

[0045] The concentration of sodium silicate is 40wt%;

[0046] The sodium hydroxide is industrial grade sodium hydroxide, and the purity of sodium hydroxide is 99.50%;

[0047] The ordinary sand is medium coarse sand, and its fineness modulus is 2.2.

[0048] The stones are ordinary granite crushed stones, and their particle size is 7mm.

[0049] A preparation method of an environmentally friendly high low temperature carbonization resistant concrete is as follows: place the above solid components in a mixer and mix and stir for 30s, mix 50 parts of water into 250 parts of sodium silicate to form a mixed solution, then add 20 parts of sodium hydroxide to the mixed solution and stir to dissolve and cool and place, and finally pour the placed and cooled mixed solution into the mixer and stir for 2min to obtain a uniformly stirred environmentally friendly high low temperature carbonization resistant concrete.

[0050] Example 3

[0051] An environmentally friendly high low temperature carbonization resistant concrete of the present invention, each component is counted by weight parts, including 950 parts of stones, 800 parts of ordinary sand, 300 parts of metakaolin, 200 parts of ground steel slag powder, 30 parts of modified rice husk ash, 50 parts of water, 250 parts of sodium silicate and 20 parts of sodium hydroxide.

[0052] In the above materials, the content of CaO in the ground granulated blast-furnace slag powder is 56%, the content of SiO2 is 12%, the content of FeO is 7%, and the average particle diameter is 25 μm.

[0053] The SiO2 content in metakaolin is 41%, the Al2O3 content is 26%, and the CaO content is 0.5%;

[0054] The modified rice husk ash is obtained by calcining rice husk and then modifying it. Its average particle size is about 50 μm, it is loosely agglomerated, and has a large number of nano-scale pores. The particle shape is irregular, and the SiO2 content in the chemical composition reaches 87%;

[0055] The modification method of the modified rice husk ash is to use polyethylene glycol to modify and shape the rice husk ash for 1 d, then add silicate, and under the action of a silicate (sodium silicate) coagulant, the mixed solution is quickly gelated for 12 h, and finally dried to form a polyethylene glycol / silica inorganic-organic composite shaped material;

[0056] The concentration of sodium silicate is 40 wt%;

[0057] The sodium hydroxide is industrial-grade sodium hydroxide, and the purity of sodium hydroxide is 99.50%;

[0058] The ordinary sand is medium-coarse sand, and its fineness modulus is 2.3.

[0059] The gravel is ordinary granite crushed stone, and its particle size is 10 mm.

[0060] A preparation method of an environmentally friendly high low-temperature carbonization-resistant concrete is as follows: place the above solid components in a mixer and mix and stir for 30 s, mix 50 parts of water into 250 parts of sodium silicate to form a mixed solution, then add 20 parts of sodium hydroxide to the mixed solution, stir and dissolve, cool and place, and finally pour the cooled mixed solution into the mixer and stir for 2 min to obtain a uniformly stirred environmentally friendly high low-temperature carbonization-resistant concrete.

[0061] Example 4

[0062] For an environmentally friendly high low-temperature carbonization-resistant concrete of the present invention, calculated by weight parts, each component includes 950 parts of gravel, 800 parts of ordinary sand, 200 parts of metakaolin, 300 parts of ground granulated blast-furnace slag powder, 30 parts of modified rice husk ash, 50 parts of water, 250 parts of sodium silicate, and 20 parts of sodium hydroxide.

[0063] In the above materials, the content of CaO in the ground granulated blast-furnace slag powder is 58%, the content of SiO2 is 12%, the content of FeO is 8%, and the average particle diameter is 28 μm.

[0064] The SiO2 content in metakaolin is 43%, the Al2O3 content is 26%, and the CaO content is 1%;

[0065] Modified rice husk ash is obtained by calcining rice husk and then modifying it. Its average particle size is about 50μm, it is loosely agglomerated, and has a large number of nano-scale pores. The particle shape is irregular, and the SiO2 content in the chemical composition reaches 87%;

[0066] The modified rice husk ash modification method comprises the following steps: using polyethylene glycol to modify and shape the rice husk ash for 1 day, then adding silicate, and under the action of silicate (water glass) coagulant, rapidly gelling the mixed solution for 12 hours, and finally drying to form a polyethylene glycol / silicon dioxide inorganic-organic composite shaping material;

[0067] The concentration of water glass is 40wt%;

[0068] Sodium hydroxide is industrial grade sodium hydroxide with a purity of 99.50%;

[0069] Ordinary sand is medium-coarse sand with a fineness modulus of 2.5.

[0070] The stone is ordinary granite crushed stone with a particle size of 12mm.

[0071] A preparation method of environmentally friendly high-low-temperature-resistant carbonized concrete is as follows: placing the above solid components in a mixer and mixing and stirring for 30 seconds, mixing 50 parts of water into 250 parts of water glass to form a mixed solution, then adding 20 parts of sodium hydroxide to the mixed solution and stirring to dissolve, cooling and placing, finally placing the cooled mixed solution in an inverted mixer, stirring for 2 minutes to obtain a uniformly stirred environmentally friendly high-low-temperature-resistant carbonized concrete.

[0072] Example 5

[0073] The invention discloses an environmentally friendly high-low temperature carbonization resistance concrete. The components, measured by weight, include 950 parts of gravel, 800 parts of ordinary sand, 100 parts of metakaolin, 400 parts of ground steel slag powder, 30 parts of modified rice husk ash, 50 parts of water, 250 parts of water glass and 20 parts of sodium hydroxide.

[0074] In the above materials, the ground steel slag powder has a CaO content of 59%, a SiO2 content of 12%, a FeO content of 10%, and an average particle diameter of 32 μm.

[0075] The SiO2 content in metakaolin is 43%, the Al2O3 content is 28%, and the CaO content is 1%;

[0076] Modified rice husk ash is obtained by calcining rice husk and then modifying it. Its average particle size is about 50μm, it is loosely agglomerated, and has a large number of nano-scale pores. The particle shape is irregular, and the SiO2 content in the chemical composition reaches 89%;

[0077] The modification method of modified rice husk ash is to modify and shape rice husk ash with polyethylene glycol for 1 day, then add silicate, and under the action of a silicate (sodium silicate) coagulant, subject the mixed solution to rapid gelation treatment for 12 hours, and finally dry to form a polyethylene glycol / silica inorganic-organic composite shaped material;

[0078] The concentration of sodium silicate is 40 wt%;

[0079] The sodium hydroxide is industrial-grade sodium hydroxide with a purity of 99.50%;

[0080] The common sand is medium-coarse sand with a fineness modulus of 2.8.

[0081] The gravel is ordinary granite crushed stone with a particle size of 16 mm.

[0082] A preparation method of an environmentally friendly high anti-low-temperature carbonization concrete is as follows: Place the above solid components in a mixer and mix and stir for 30 s, mix 50 parts of water into 250 parts of sodium silicate to form a mixed solution, then add 20 parts of sodium hydroxide to the mixed solution, stir and dissolve, cool and place, and finally pour the cooled mixed solution into the mixer and stir for 2 min to obtain a uniformly stirred environmentally friendly high anti-low-temperature carbonization concrete.

[0083] Example 6

[0084] For an environmentally friendly high anti-low-temperature carbonization concrete of the present invention, calculated by weight parts, each component includes 950 parts of gravel, 800 parts of common sand, 300 parts of metakaolin, 200 parts of ground granulated blast-furnace slag powder, 50 parts of modified rice husk ash, 50 parts of water, 250 parts of sodium silicate, and 20 parts of sodium hydroxide.

[0085] In the above materials, the content of CaO in the ground granulated blast-furnace slag powder is 60%, the content of SiO2 is 15%, the content of FeO is 10%, and the average particle diameter is 50 μm.

[0086] The content of SiO2 in the metakaolin is 45%, the content of Al2O3 is 30%, and the content of CaO is 2%;

[0087] The modified rice husk ash is obtained by calcining rice husk and then modifying it. Its average particle diameter is about 50 μm, it is loosely agglomerated, has a large number of nano-scale pores, the particle shape is irregular, and the content of SiO2 in the chemical composition reaches 95%;

[0088] The modification method of modified rice husk ash is to modify and shape rice husk ash with polyethylene glycol for 1 day, then add silicate, and under the action of a silicate (sodium silicate) coagulant, subject the mixed solution to rapid gelation treatment for 12 hours, and finally dry to form a polyethylene glycol / silica inorganic-organic composite shaped material;

[0089] The concentration of water glass is 40wt%;

[0090] Sodium hydroxide is industrial grade sodium hydroxide with a purity of 99.50%;

[0091] Ordinary sand is medium-coarse sand with a fineness modulus of 3.0.

[0092] The stone is ordinary granite crushed stone with a particle size of 30mm.

[0093] A preparation method of environmentally friendly high-low-temperature-resistant carbonized concrete is as follows: placing the above solid components in a mixer and mixing and stirring for 30 seconds, mixing 50 parts of water into 250 parts of water glass to form a mixed solution, then adding 20 parts of sodium hydroxide to the mixed solution and stirring to dissolve, cooling and placing, finally placing the cooled mixed solution in an inverted mixer, stirring for 2 minutes to obtain a uniformly stirred environmentally friendly high-low-temperature-resistant carbonized concrete.

[0094] Example 7

[0095] The invention discloses an environmentally friendly high-low temperature carbonization resistance concrete. The components, measured by weight, include 950 parts of gravel, 800 parts of ordinary sand, 300 parts of metakaolin, 200 parts of ground steel slag powder, 40 parts of modified rice husk ash, 50 parts of water, 250 parts of water glass and 20 parts of sodium hydroxide.

[0096] In the above materials, the ground steel slag powder has a CaO content of 60%, a SiO2 content of 13%, a FeO content of 9%, and an average particle diameter of 30 μm.

[0097] The SiO2 content in metakaolin is 43%, the Al2O3 content is 30%, and the CaO content is 1.5%;

[0098] Modified rice husk ash is obtained by calcining rice husk and then modifying it. Its average particle size is about 50μm, it is loosely agglomerated, and has a large number of nano-scale pores. The particle shape is irregular, and the SiO2 content in the chemical composition reaches 90%;

[0099] The modified rice husk ash modification method comprises the following steps: using polyethylene glycol to modify and shape the rice husk ash for 1 day, then adding silicate, and under the action of silicate (water glass) coagulant, rapidly gelling the mixed solution for 12 hours, and finally drying to form a polyethylene glycol / silicon dioxide inorganic-organic composite shaping material;

[0100] The concentration of water glass is 40wt%;

[0101] Sodium hydroxide is industrial grade sodium hydroxide with a purity of 99.50%;

[0102] Ordinary sand is medium-coarse sand with a fineness modulus of 2.7.

[0103] The gravel is ordinary granite gravel with a particle size of 31.5 mm.

[0104] A preparation method of an environmentally friendly high low-temperature carbonization-resistant concrete is as follows: Place the above solid components in a mixer and mix for 30 s. Mix 50 parts of water into 250 parts of water glass to form a mixed solution. Then add 20 parts of sodium hydroxide to the mixed solution, stir and dissolve it, cool it, and let it stand. Finally, pour the cooled mixed solution into the mixer and stir for 2 min to obtain a uniformly stirred environmentally friendly high low-temperature carbonization-resistant concrete.

[0105] Example 8

[0106] For an environmentally friendly high low-temperature carbonization-resistant concrete of the present invention, calculated by weight parts, each component includes 950 parts of gravel, 800 parts of ordinary sand, 300 parts of metakaolin, 200 parts of ground steel slag powder, 20 parts of modified rice husk ash, 50 parts of water, 250 parts of water glass, and 20 parts of sodium hydroxide.

[0107] In the above materials, the content of CaO in the ground steel slag powder is 58%, the content of SiO2 is 13%, the content of FeO is 9%, and the average particle diameter is 35 μm.

[0108] The content of SiO2 in the metakaolin is 43%, the content of Al2O3 is 28%, and the content of CaO is 1.5%;

[0109] The modified rice husk ash is obtained by calcining rice husk and then modifying it. Its average particle diameter is about 50 μm, it is loosely agglomerated, and has a large number of nanoscale pores. The particle shape is irregular, and the content of SiO2 in the chemical composition reaches 92%;

[0110] The modification method of the modified rice husk ash is to use polyethylene glycol to modify and shape the rice husk ash for 1 d, then add silicate, and under the action of a silicate (water glass) coagulant, quickly gel the mixed solution for 12 h, and finally dry it to form a polyethylene glycol / silica inorganic-organic composite shaped material;

[0111] The concentration of water glass is 40 wt%;

[0112] The sodium hydroxide is industrial-grade sodium hydroxide with a purity of 99.50%;

[0113] The ordinary sand is medium-coarse sand with a fineness modulus of 2.7.

[0114] The gravel is ordinary granite gravel with a particle size of 30.5 mm.

[0115] A preparation method of environmentally friendly high-low-temperature-resistant carbonized concrete is as follows: placing the above solid components in a mixer and mixing and stirring for 30 seconds, mixing 50 parts of water into 250 parts of water glass to form a mixed solution, then adding 20 parts of sodium hydroxide to the mixed solution and stirring to dissolve, cooling and placing, finally placing the cooled mixed solution in an inverted mixer, stirring for 2 minutes to obtain a uniformly stirred environmentally friendly high-low-temperature-resistant carbonized concrete.

[0116] Example 9

[0117] The invention discloses an environmentally friendly high-low temperature carbonization resistance concrete. The components, measured by weight, include 950 parts of gravel, 800 parts of ordinary sand, 300 parts of metakaolin, 200 parts of ground steel slag powder, 10 parts of modified rice husk ash, 50 parts of water, 250 parts of water glass and 20 parts of sodium hydroxide.

[0118] In the above materials, the ground steel slag powder has a CaO content of 58%, a SiO2 content of 13%, a FeO content of 9%, and an average particle diameter of 28 μm.

[0119] The SiO2 content in metakaolin is 43%, the Al2O3 content is 28%, and the CaO content is 1.8%;

[0120] Modified rice husk ash is obtained by calcining rice husk and then modifying it. Its average particle size is about 50μm, it is loosely agglomerated, and has a large number of nano-scale pores. The particle shape is irregular, and the SiO2 content in the chemical composition reaches 90%;

[0121] The modified rice husk ash modification method comprises the following steps: using polyethylene glycol to modify and shape the rice husk ash for 1 day, then adding silicate, and under the action of silicate (water glass) coagulant, rapidly gelling the mixed solution for 12 hours, and finally drying to form a polyethylene glycol / silicon dioxide inorganic-organic composite shaping material;

[0122] The concentration of water glass is 40wt%;

[0123] Sodium hydroxide is industrial grade sodium hydroxide with a purity of 99.50%;

[0124] Ordinary sand is medium-coarse sand with a fineness modulus of 2.7.

[0125] The stone is ordinary granite crushed stone with a particle size of 28.5mm.

[0126] A preparation method of environmentally friendly high-low-temperature-resistant carbonized concrete is as follows: placing the above solid components in a mixer and mixing and stirring for 30 seconds, mixing 50 parts of water into 250 parts of water glass to form a mixed solution, then adding 20 parts of sodium hydroxide to the mixed solution and stirring to dissolve, cooling and placing, finally placing the cooled mixed solution in an inverted mixer, stirring for 2 minutes to obtain a uniformly stirred environmentally friendly high-low-temperature-resistant carbonized concrete.

[0127] Example 10

[0128] The invention discloses an environmentally friendly high-low temperature carbonization resistance concrete. The components, measured by weight, include 950 parts of gravel, 800 parts of ordinary sand, 300 parts of metakaolin, 200 parts of ground steel slag powder, 30 parts of modified rice husk ash, 50 parts of water, 250 parts of water glass and 30 parts of sodium hydroxide.

[0129] In the above materials, the ground steel slag powder has a CaO content of 58%, a SiO2 content of 13%, a FeO content of 9%, and an average particle diameter of 28 μm.

[0130] The SiO2 content in metakaolin is 43%, the Al2O3 content is 28%, and the CaO content is 1.8%;

[0131] Modified rice husk ash is obtained by calcining rice husk and then modifying it. Its average particle size is about 50μm, it is loosely agglomerated, and has a large number of nano-scale pores. The particle shape is irregular, and the SiO2 content in the chemical composition reaches 90%;

[0132] The modified rice husk ash modification method comprises the following steps: using polyethylene glycol to modify and shape the rice husk ash for 1 day, then adding silicate, and under the action of silicate (water glass) coagulant, rapidly gelling the mixed solution for 12 hours, and finally drying to form a polyethylene glycol / silicon dioxide inorganic-organic composite shaping material;

[0133] The concentration of water glass is 40wt%;

[0134] Sodium hydroxide is industrial grade sodium hydroxide with a purity of 99.50%;

[0135] Ordinary sand is medium-coarse sand with a fineness modulus of 2.7.

[0136] The stone is ordinary granite crushed stone with a particle size of 28.5mm.

[0137] A preparation method of environmentally friendly high-low-temperature-resistant carbonized concrete is as follows: placing the above solid components in a mixer and mixing and stirring for 30 seconds, mixing 50 parts of water into 250 parts of water glass to form a mixed solution, then adding 30 parts of sodium hydroxide into the mixed solution and stirring to dissolve, cooling and placing, finally placing the cooled mixed solution in an inverted mixer, stirring for 2 minutes to obtain a uniformly stirred environmentally friendly high-low-temperature-resistant carbonized concrete.

[0138] Embodiment 11

[0139] The invention discloses an environmentally friendly high-low temperature carbonization resistance concrete. The components, measured by weight, include 950 parts of gravel, 800 parts of ordinary sand, 300 parts of metakaolin, 200 parts of ground steel slag powder, 30 parts of modified rice husk ash, 50 parts of water, 250 parts of water glass and 25 parts of sodium hydroxide.

[0140] In the above materials, the ground steel slag powder has a CaO content of 58%, a SiO2 content of 13%, a FeO content of 9%, and an average particle diameter of 28 μm.

[0141] The SiO2 content in metakaolin is 45%, the Al2O3 content is 28%, and the CaO content is 1.2%;

[0142] Modified rice husk ash is obtained by calcining rice husk and then modifying it. Its average particle size is about 50μm, it is loosely agglomerated, and has a large number of nano-scale pores. The particle shape is irregular, and the SiO2 content in the chemical composition reaches 86%;

[0143] The modified rice husk ash modification method comprises the following steps: using polyethylene glycol to modify and shape the rice husk ash for 1 day, then adding silicate, and under the action of silicate (water glass) coagulant, rapidly gelling the mixed solution for 12 hours, and finally drying to form a polyethylene glycol / silicon dioxide inorganic-organic composite shaping material;

[0144] The concentration of water glass is 40wt%;

[0145] Sodium hydroxide is industrial grade sodium hydroxide with a purity of 99.50%;

[0146] Ordinary sand is medium-coarse sand with a fineness modulus of 2.6.

[0147] The stone is ordinary granite crushed stone with a particle size of 24.5mm.

[0148] A preparation method of environmentally friendly high-low-temperature-resistant carbonized concrete is as follows: placing the above solid components in a mixer and mixing and stirring for 30 seconds, mixing 50 parts of water into 250 parts of water glass to form a mixed solution, then adding 25 parts of sodium hydroxide to the mixed solution and stirring to dissolve, cooling and placing, finally placing the cooled mixed solution in an inverted mixer, stirring for 2 minutes to obtain a uniformly stirred environmentally friendly high-low-temperature-resistant carbonized concrete.

[0149] Example 12

[0150] The invention discloses an environmentally friendly high-low temperature carbonization resistance concrete. The components, measured by weight, include 950 parts of gravel, 800 parts of ordinary sand, 300 parts of metakaolin, 200 parts of ground steel slag powder, 30 parts of modified rice husk ash, 50 parts of water, 250 parts of water glass and 15 parts of sodium hydroxide.

[0151] In the above materials, the ground steel slag powder has a CaO content of 58%, a SiO2 content of 13%, a FeO content of 9%, and an average particle diameter of 28 μm.

[0152] The SiO2 content in metakaolin is 45%, the Al2O3 content is 28%, and the CaO content is 1.2%;

[0153] Modified rice husk ash is obtained by calcining rice husk and then modifying it. Its average particle size is about 50μm, it is loosely agglomerated, and has a large number of nano-scale pores. The particle shape is irregular, and the SiO2 content in the chemical composition reaches 86%;

[0154] The modified rice husk ash modification method comprises the following steps: using polyethylene glycol to modify and shape the rice husk ash for 1 day, then adding silicate, and under the action of silicate (water glass) coagulant, rapidly gelling the mixed solution for 12 hours, and finally drying to form a polyethylene glycol / silicon dioxide inorganic-organic composite shaping material;

[0155] The concentration of water glass is 40wt%;

[0156] Sodium hydroxide is industrial grade sodium hydroxide with a purity of 99.50%;

[0157] Ordinary sand is medium-coarse sand with a fineness modulus of 2.6.

[0158] The stone is ordinary granite crushed stone with a particle size of 24.5mm.

[0159] A preparation method of environmentally friendly high-low-temperature-resistant carbonized concrete is as follows: placing the above solid components in a mixer and mixing and stirring for 30 seconds, mixing 50 parts of water into 250 parts of water glass to form a mixed solution, then adding 15 parts of sodium hydroxide to the mixed solution and stirring to dissolve, cooling and placing, finally placing the cooled mixed solution in an inverted mixer, stirring for 2 minutes to obtain a uniformly stirred environmentally friendly high-low-temperature-resistant carbonized concrete.

[0160] Embodiment 13

[0161] The invention discloses an environmentally friendly high-low temperature carbonization resistance concrete. The components, measured by weight, include 950 parts of gravel, 800 parts of ordinary sand, 300 parts of metakaolin, 200 parts of ground steel slag powder, 30 parts of modified rice husk ash, 50 parts of water, 250 parts of water glass and 10 parts of sodium hydroxide.

[0162] In the above materials, the ground steel slag powder has a CaO content of 58%, a SiO2 content of 13%, a FeO content of 9%, and an average particle diameter of 28 μm.

[0163] The SiO2 content in metakaolin is 45%, the Al2O3 content is 28%, and the CaO content is 1.2%;

[0164] Modified rice husk ash is obtained by calcining rice husk and then modifying it. Its average particle size is about 50μm, it is loosely agglomerated, and has a large number of nano-scale pores. The particle shape is irregular, and the SiO2 content in the chemical composition reaches 86%;

[0165] The modified rice husk ash modification method comprises the following steps: using polyethylene glycol to modify and shape the rice husk ash for 1 day, then adding silicate, and under the action of silicate (water glass) coagulant, rapidly gelling the mixed solution for 12 hours, and finally drying to form a polyethylene glycol / silicon dioxide inorganic-organic composite shaping material;

[0166] The concentration of water glass is 40wt%;

[0167] Sodium hydroxide is industrial grade sodium hydroxide with a purity of 99.50%;

[0168] Ordinary sand is medium-coarse sand with a fineness modulus of 2.6.

[0169] The stone is ordinary granite crushed stone with a particle size of 24.5mm.

[0170] A preparation method of an environmentally friendly high low-temperature resistant carbonated concrete is as follows: place the above solid components in a blender and mix and stir for 30 s, mix 50 parts of water into 250 parts of water glass to form a mixed solution, then add 10 parts of sodium hydroxide to the mixed solution, stir and dissolve, cool and let stand. Finally, pour the cooled mixed solution into the blender and stir for 2 min to obtain a uniformly stirred environmentally friendly high low-temperature resistant carbonated concrete.

[0171] Comparative Example 1

[0172] The control group is fly ash ordinary concrete: each component is counted by weight, including 950 parts of stones, 800 parts of ordinary sand, 300 parts of PO.425 ordinary Portland cement, 50 parts of Class I fly ash, 200 parts of water and 7 parts of water reducing agent.

[0173] Its preparation method is as follows: first weigh 950 parts of stones and 800 parts of ordinary sand, then add 300 parts of PO.425 ordinary Portland cement and 50 parts of Class I fly ash and mix and stir for 30 s. Finally, pour 200 parts of water mixed with 7 parts of water reducing agent into the blender and mix and stir evenly to obtain C30 ordinary fly ash concrete.

[0174] The raw material dosages of each example are shown in Table 1. The performance characterizations of each example are shown in Table 2.

[0175] Table 1

[0176]

[0177] Table 2

[0178]

[0179]

[0180] By comparing Examples 1-13 and Comparative Example 1, it is found that compared with ordinary fly ash concrete, the high low-temperature resistant carbonated concrete has obvious advantages in carbonation resistance. It shows that the zeolite crystals contained in the hydration products of the alkali-activated metakaolin material and the adsorption effect of the modified rice husk ash effectively improve the carbonation resistance of the alkali-activated concrete; by comparing Example 1, Example 2, Example 3, Example 4 and Example 5, as the ratio of metakaolin to ground steel slag in the alkali-activated raw materials decreases, the strength at different ages (3 d, 7 d, 28 d) and carbonation resistance of the concrete both show a trend of first increasing and then decreasing; but in terms of setting time, the initial and final setting times of the metakaolin alkali-activated concrete are generally longer than those of the ordinary fly ash concrete. Among them, when the mechanical properties and carbonation resistance of the metakaolin alkali-activated concrete are the best (Example 3), its initial and final setting times are 40 min and 37 min longer than those of the ordinary fly ash concrete (Comparative Example 1), which is within the acceptable range.

[0181] It can be seen from Examples 3, 6, 7, 8 and 9 that: with the increase of the incorporation amount of modified rice husk ash, the mechanical properties and carbonation resistance of metakaolin alkali-activated concrete also show a trend of first increasing and then decreasing, indicating that while the modified rice husk ash plays a role in adsorbing CO2, it also promotes the strength development of concrete (the modified rice husk ash in the part where polyethylene glycol hydrolysis occurs participates in the alkali activation reaction); it can be seen from Examples 3, 10, 11, 12 and 13 that with the decrease of the sodium hydroxide content (that is, adjusting the modulus of sodium silicate to decrease), the mechanical properties and carbonation resistance of metakaolin alkali-activated concrete still show a trend of first increasing and then decreasing.

[0182] Based on the above, when the mechanical properties and carbonation resistance of metakaolin alkali-activated concrete are at their best (Example 3), its mechanical properties can reach or even exceed those of ordinary fly ash concrete, and its carbonation resistance is far better than that of ordinary fly ash concrete. Although its initial and final setting times are 40 min and 37 min longer than those of ordinary fly ash concrete (Comparative Example 1), they are still within an acceptable range.

[0183] Although the present invention has been described in detail above with general descriptions and specific examples, based on the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. An environmentally friendly high low-temperature resistant carbonized concrete, characterized in that: By weight parts, it includes 100 - 400 parts of ground steel slag powder, 0 - 400 parts of metakaolin, 10 - 50 parts of modified rice husk ash, 10 - 30 parts of sodium hydroxide, 250 parts of water glass, 800 parts of common sand, 950 parts of stone, and 50 parts of water; the modified rice husk ash is obtained by modifying and shaping rice husk ash with polyethylene glycol, then adding silicate, and under the action of a silicate coagulant, making the mixed solution undergo rapid gelation treatment, and finally drying to form a polyethylene glycol / silica inorganic-organic composite shaped material.

2. The environmentally friendly high low-temperature resistant carbonized concrete according to claim 1, characterized in that: The ground steel slag powder is obtained by calcining and grinding converter slag, with an average particle diameter of 20 - 50 μm. The content of CaO in the ground steel slag powder is 55 - 60%, the content of SiO2 is 10 - 15%, the content of FeO is 5% - 10%, the content of Fe2O3 is 0% - 5%, and the content of Al2O3 is 0% - 5%.

3. An environmentally friendly high low-temperature resistant carbonized concrete according to claim 1, characterized in that: The metakaolin raw material is kaolin, which is dehydrated to form anhydrous aluminum silicate at 600 - 900 °C.

4. An environmentally friendly high low-temperature resistant carbonized concrete according to claim 1 or 3, characterized in that: The content of SiO2 in the metakaolin is 40 - 45%, the content of Al2O3 is 25% - 30%, and the content of CaO is 0 - 2%.

5. An environmentally friendly high low-temperature resistant carbonized concrete according to claim 1, characterized in that: The rice husk ash is obtained by calcining rice husks, with an average particle size of 50 μm and a SiO2 content of 85 - 95%.

6. An environmentally friendly high low-temperature resistant carbonized concrete according to claim 1, characterized in that: The concentration of the water glass is 40 wt%.

7. An environmentally friendly high low-temperature resistant carbonized concrete according to claim 1, characterized in that: The common sand is medium-coarse sand, and its fineness modulus is between 2.1 and 3.

0.

8. An environmentally friendly high low-temperature resistant carbonized concrete according to claim 1, characterized in that: The stone is granite gravel with a particle size range of 5 - 31.5 mm.

9. A preparation method of an environmentally friendly high low-temperature resistant carbonized concrete, characterized in that: It includes the following steps: By weight parts, weigh 850 - 1000 parts of stone, 750 - 900 parts of common sand, 100 - 400 parts of metakaolin, 10 - 50 parts of modified rice husk ash. The modified rice husk ash is obtained by modifying and shaping rice husk ash with polyethylene glycol, then adding silicate, and under the action of a silicate coagulant, making the mixed solution undergo rapid gelation treatment, and finally drying to form a polyethylene glycol / silica inorganic-organic composite shaped material. Place it in a mixer and mix and stir for 30 s. Mix 10 - 60 parts of water into 200 - 250 parts of water glass to form a mixed solution, then add 10 - 30 parts of sodium hydroxide weighed to the mixed solution and stir to dissolve, cool and place. Finally, pour the placed and cooled mixed solution into the mixer and stir for 2 min to obtain evenly stirred environmentally friendly high anti-low temperature carbonization concrete.

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