An eco-friendly high-strength concrete and its preparation method

Abstract

This invention discloses an eco-friendly high-strength concrete and its preparation method, belonging to the field of concrete material technology. The raw materials of the concrete include precursor powder, activator, sand and gravel aggregate, and water in a mass ratio of 1:(0.2-0.4):(0.2-0.4):(0.1-0.2). The precursor powder includes industrial by-product precursor powder, agricultural by-product precursor powder, and kitchen waste by-product precursor powder in a mass ratio of 1:(0.5-1.5):(2.5-3.5). The eco-friendly high-strength concrete provided by this invention mainly uses raw materials derived from solid waste, enriching the types of raw materials used in concrete preparation. It requires no high-temperature curing, and its 3-day compressive strength reaches 75.02 MPa, and its 28-day compressive strength reaches 94.88 MPa, exhibiting characteristics of low carbon emissions, environmental friendliness, simple construction, high early strength, and excellent mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of concrete materials technology, specifically relating to an eco-friendly high-strength concrete and its preparation method. Background Technology

[0002] With the continuous development of society and the economy, the demand for various infrastructure constructions is constantly increasing worldwide, and concrete structures are one of the most widely used structural forms. At the same time, modern concrete structures are increasingly characterized by "complex structural forms and harsh service environments," thus the mechanical properties of concrete itself are showing a trend towards higher strength. Ordinary Portland cement, as one of the most widely used components in concrete, is seeing its production continuously increase, with an estimated annual demand of 3.68-4.38 Gt by 2050. However, due to its unique manufacturing process, the production of ordinary Portland cement inevitably brings many environmental problems. For example, the production of ordinary Portland cement consumes a large amount of energy and emits a large amount of carbon dioxide. Its energy consumption accounts for approximately 5% of natural resources, and its carbon dioxide emissions account for approximately 5-7% of global anthropogenic carbon dioxide emissions. The large-scale emission of greenhouse gases such as carbon dioxide is one of the main causes of global climate change. Therefore, to achieve the goal of carbon peaking and carbon neutrality, it is necessary to further enrich the raw material composition in the building materials sector.

[0003] To address the negative impacts of ordinary Portland cement on natural resources and the environment, an increasing number of researchers are dedicated to developing environmentally friendly cementitious materials to replace ordinary Portland cement-based cementitious materials, thereby preparing eco-friendly concrete. Invention patent CN110407507A discloses a method for preparing all-solid-waste dry-mixed mortar, using gypsum, slag, waste stone chips, and construction waste to replace cement, effectively utilizing solid waste. However, its optimal embodiment has a 28-day compressive strength of only 15.6 MPa. Invention patent CN116606094A discloses a method for preparing geopolymer mortar reinforcement material, using fly ash, slag powder, and other solid waste to replace cement, effectively alleviating the pressure on the building materials industry in terms of energy reduction and emission reduction. However, its optimal embodiment has a 28-day compressive strength of only 45.26 MPa. Furthermore, the high cost of the added polyvinyl alcohol fiber greatly limits its widespread application in engineering practice.

[0004] Therefore, it is necessary to develop a high-strength concrete material with low-carbon and environmentally friendly characteristics to address the shortcomings of existing technologies. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides an eco-friendly high-strength concrete and its preparation method, thereby further improving the utilization rate of solid waste and promoting low-carbon and green development in the field of concrete materials.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides an eco-friendly high-strength concrete, the raw materials of which include precursor powder, activator, sand and gravel aggregate and water in a mass ratio of 1:(0.2~0.4):(0.2~0.4):(0.1~0.2);

[0008] The precursor powder includes industrial by-product precursor powder, agricultural by-product precursor powder and kitchen waste by-product precursor powder in a mass ratio of 1:(0.5~1.5):(2.5~3.5).

[0009] As a preferred embodiment of the present invention, the activator is obtained by mixing sodium silicate solution and sodium hydroxide solution in a volume ratio of (1.3-1.7):1; the sodium silicate is Na2O·nSiO2, where n is 3-3.3, and the mass ratio of H2O to Na2O·nSiO2 in the sodium silicate solution is 7-10; the concentration of the sodium hydroxide solution is 12-16 mol / L.

[0010] As a preferred embodiment of the present invention, the maximum particle size of the sand and gravel aggregate is 1 mm, and the average particle size is 0.6 to 0.7 mm.

[0011] As a preferred embodiment of the present invention, the industrial by-product precursor powder is fly ash, with a SiO2 content of 52-55 wt%, an Al2O3 content of 34-38 wt%, a CaO content of 1.9-2.2 wt%, and an average particle size (d50) of 9-10 μm; the agricultural by-product precursor powder is a precursor powder made from rice husk raw materials, with a SiO2 content of 92-98 wt%, an Al2O3 content of 0.12-0.45 wt%, a CaO content of 0.17-0.57 wt%, and an average particle size of 2-4 μm; the kitchen waste by-product precursor powder is a precursor powder made from eggshell raw materials, with a SiO2 content of 31-33 wt%, an Al2O3 content of 16-18.5 wt%, a CaO content of 33-35 wt%, and an average particle size of 9-10 μm.

[0012] As a preferred embodiment of the present invention, the preparation method of the agricultural by-product precursor powder includes the following steps: firstly, the rice husk ash obtained by burning rice husk is chemically activated by sequentially using chitosan quaternary ammonium salt solution and sodium phosphate solution, then filtered, dried, ground, sieved, and then carbonized to obtain the agricultural by-product precursor powder.

[0013] As a preferred embodiment of the present invention, the concentration of the chitosan quaternary ammonium salt solution is 4.5–5.5 wt%; the mass fraction of the sodium phosphate solution is 0.8–1.2 wt%; the mass ratio of rice husk ash to chitosan quaternary ammonium salt solution is 1:(2.5–3.5), and the mass ratio of rice husk ash to sodium phosphate solution is 1:(2.5–3.5); the carbonization treatment temperature is 600–800°C, and the time is 2–4 hours.

[0014] As a preferred embodiment of the present invention, the preparation method of the precursor powder of kitchen waste by-product includes the following steps: first, crushing, grinding and sieving eggshells to obtain eggshell ash; then, chemically activating the obtained eggshell ash with ethylenediaminetetraacetic acid solution and ethanol solution in sequence, followed by pressure filtration, drying, grinding, sieving and then carbonization treatment to obtain the precursor powder of kitchen waste by-product.

[0015] As a preferred embodiment of the present invention, the concentration of the ethylenediaminetetraacetic acid solution is 0.08-0.12 mol / L, the concentration of the ethanol solution is 90-95 wt%, the mass ratio of eggshell ash to ethylenediaminetetraacetic acid solution is 1:(2-5), and the mass ratio of eggshell ash to ethanol solution is 1:(2-5); the carbonization treatment temperature is 600-800℃, and the time is 2-4 h.

[0016] This invention also provides a method for preparing eco-friendly high-strength concrete as described above, comprising the following steps: weighing each raw material according to the proportion of raw material usage; firstly, dry mixing the industrial by-product precursor powder, agricultural by-product precursor powder, and kitchen waste by-product precursor powder to obtain uniformly dispersed precursor powder; then adding sand and gravel aggregate and dry mixing to obtain dry-mixed material; finally, adding activator and water to the dry-mixed material and continuing to mix.

[0017] As a preferred embodiment of the present invention, after adding the activator and water to the dry mix and continuing to mix, the resulting mixture is then loaded into a mold, cured, demolded, and then moved to a standard curing room for curing, thus obtaining the eco-friendly high-strength concrete.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) This invention enriches the types of raw materials for preparing concrete materials. It uses industrial by-product precursor powder, agricultural by-product precursor powder, kitchen waste by-product precursor powder, activator, sand and gravel aggregate and water as raw materials. By selecting the raw materials and adjusting the dosage, ecological high-strength concrete is obtained.

[0020] (2) In the preferred embodiment of the present invention, by optimizing the treatment method of agricultural by-product precursor powder and kitchen waste by-product precursor powder, and by adopting physical and chemical activation methods, their reactivity is fully utilized, which can effectively improve the mechanical properties of ecological concrete.

[0021] (3) The ecological high-strength concrete raw materials provided by the present invention are mainly derived from solid waste. They do not require high-temperature curing. Their compressive strength can reach 75.02 MPa in 3 days and 94.88 MPa in 28 days, showing the characteristics of low carbon and environmental protection, simple construction, high early strength and excellent mechanical properties. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a flowchart illustrating the preparation process of the eco-friendly high-strength concrete according to Embodiment 1 of the present invention. Detailed Implementation

[0024] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0025] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included within this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0026] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0027] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0028] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0029] The aggregate used in the following examples and comparative examples is fine sand with a particle size range of 0-1 mm and an average particle size of 0.645 mm. The industrial by-product precursor powder used is commercially available Grade 1 fly ash, containing 54.14 wt% SiO2, 36.41 wt% Al2O3, and 2.03 wt% CaO, with an average particle size of 9.475 μm. The chitosan quaternary ammonium salt used was purchased from Guangdong Qianjin Chemical Reagent Co., Ltd. These details will not be repeated below.

[0030] Example 1

[0031] An eco-friendly high-strength concrete mixture was prepared using sand and gravel aggregate, activator, water, and precursor powder in a mass ratio of 0.3:0.3:0.14:1. The precursor powder consisted of industrial by-product precursor powder, agricultural by-product precursor powder, and kitchen waste by-product precursor powder in a mass ratio of 1:1:3. The specific steps are as follows:

[0032] Step 1, Preparation of agricultural by-product precursor powder, the steps are as follows:

[0033] (1) Rice husk ash, which is produced by burning rice husks, a by-product of agricultural production, is used as raw material and is screened through a 200-mesh sieve to obtain ash content;

[0034] (2) The prepared rice husk ash is washed and cleaned, and then filtered by pressure to remove impurities;

[0035] (3) It is then dried at 70°C and then ground and sieved to remove impurities;

[0036] (4) The rice husk ash obtained in step (3) is soaked in a 5 wt% chitosan quaternary ammonium salt solution and a 1 wt% sodium phosphate solution in sequence. The mass ratio of rice husk ash to chitosan quaternary ammonium salt solution is 1:3, and the mass ratio of rice husk ash to sodium phosphate solution is 1:3. The ash reaction activity is activated by chemical activation.

[0037] (5) The chemically activated ash is subjected to pressure filtration, drying, grinding and sieving.

[0038] (6) Then calcined at 700℃ for 2 hours to activate the ash activity using physical methods;

[0039] (7) After final grinding and sieving, an agricultural by-product precursor powder with an average particle size of 2.925 μm was obtained. The content of SiO2 was 97.60 wt%, Al2O3 was 0.37 wt%, and CaO was 0.42 wt%.

[0040] Step 2, Preparation of kitchen waste by-product precursor powder, the steps are as follows:

[0041] (1) Collect eggshells, a by-product of kitchen waste, as a raw material for preparation;

[0042] (2) Thoroughly wash the collected eggshells to remove contaminants and dry them at 70°C.

[0043] (3) The eggshells are crushed manually, then ground in a ball mill and sieved.

[0044] (4) The obtained eggshell ash was soaked in a 0.1 mol / L ethylenediaminetetraacetic acid solution and a 95 wt% ethanol solution in sequence. The mass ratio of eggshell ash to ethylenediaminetetraacetic acid solution was 1:4, and the mass ratio of eggshell ash to ethanol solution was 1:4. The ash reaction activity was activated by chemical activation.

[0045] (5) The chemically activated eggshell ash is subjected to pressure filtration, drying, grinding and sieving to improve its purity;

[0046] (6) Then calcined at 700℃ for 2 hours to activate the ash activity using physical methods;

[0047] (7) After final grinding and sieving, a precursor powder of kitchen waste by-product with an average particle size of 9.284 μm was obtained, wherein the SiO2 content was 32.36 wt%, the Al2O3 content was 17.93 wt%, and the CaO content was 34.11 wt%.

[0048] Step 3, preparation of the activator, the steps are as follows:

[0049] (1) Prepare a 14M sodium hydroxide solution using sodium hydroxide flakes with a purity of 99wt%;

[0050] (2) The sodium silicate solution (wherein the modulus of sodium silicate is 3.2, and the contents of Na2O, SiO2 and H2O in the solution are 8.35wt%, 26.54wt% and 65.11wt% respectively) is mixed with the sodium hydroxide solution prepared in step (1) at a mass ratio of 1.5:1 and cooled to room temperature to obtain the activator.

[0051] Step 4: Preparation of concrete mixture, the steps are as follows:

[0052] Weigh each raw material according to the proportion of raw material usage. First, dry mix the industrial by-product precursor powder, agricultural by-product precursor powder, and kitchen waste by-product precursor powder to obtain a uniformly dispersed precursor powder. Then, add sand and gravel aggregate and dry mix to obtain a dry mix. Finally, add activator and water to the dry mix and continue mixing to obtain an eco-friendly high-strength concrete mix.

[0053] Example 2

[0054] An eco-friendly high-strength concrete mixture was prepared using sand and gravel aggregate, activator, water, and precursor powder in a mass ratio of 0.2:0.4:0.1:1. The precursor powder consisted of industrial by-product precursor powder, agricultural by-product precursor powder, and kitchen waste by-product precursor powder in a mass ratio of 1:0.5:2.5. The specific steps are as follows:

[0055] Step 1, Preparation of agricultural by-product precursor powder, the steps are as follows:

[0056] (1) Rice husk ash, which is produced by burning rice husks, a by-product of agricultural production, is used as raw material and screened to obtain ash content;

[0057] (2) The prepared rice husk ash is washed and cleaned, and then filtered by pressure to remove impurities;

[0058] (3) It is then dried at 70°C and then ground and sieved to remove impurities;

[0059] (4) The rice husk ash obtained in step (3) is soaked in a 4.5 wt% chitosan quaternary ammonium salt solution and a 1.2 wt% sodium phosphate solution in sequence. The mass ratio of rice husk ash to chitosan quaternary ammonium salt solution is 1:2.5, and the mass ratio of rice husk ash to sodium phosphate solution is 1:3.5. The ash reaction activity is activated by chemical activation.

[0060] (5) The chemically activated ash is subjected to pressure filtration, drying, grinding and sieving.

[0061] (6) Subsequently, calcination was carried out at 600℃ for 4 hours to activate the ash activity using physical methods;

[0062] (7) After final grinding and sieving, an agricultural by-product precursor powder with an average particle size of 2.914 μm was obtained. The content of SiO2 was 97.15 wt%, Al2O3 was 0.41 wt%, and CaO was 0.22 wt%.

[0063] Step 2, Preparation of kitchen waste by-product precursor powder, the steps are as follows:

[0064] (1) Collect eggshells, a by-product of kitchen waste, as a raw material for preparation;

[0065] (2) Thoroughly wash the collected eggshells to remove contaminants and dry them at 70°C.

[0066] (3) The eggshells are crushed manually, then ground in a ball mill and sieved.

[0067] (4) The obtained eggshell ash was successively treated with a 0.08 mol / L ethylenediaminetetraacetic acid solution and a 90 wt% ethanol solution. The mass ratio of eggshell ash to ethylenediaminetetraacetic acid solution was 1:2, and the mass ratio of eggshell ash to ethanol solution was 1:5. The ash reaction activity was activated by chemical activation.

[0068] (5) The chemically activated eggshell ash is subjected to pressure filtration, drying, grinding and sieving to improve its purity;

[0069] (6) Then calcined at 800℃ for 2 hours to activate the ash activity using physical methods;

[0070] (7) After final grinding and sieving, a kitchen waste by-product precursor powder with an average particle size of 9.358 μm was obtained, wherein the SiO2 content was 31.45 wt%, the Al2O3 content was 16.85 wt%, and the CaO content was 34.58 wt%.

[0071] Step 3, preparation of the activator, the steps are as follows:

[0072] (1) Prepare a 12M sodium hydroxide solution using sodium hydroxide flakes with a purity of 99wt%;

[0073] (2) A sodium silicate solution consisting of 8.35% Na2O, 26.54% SiO2 and 65.11% H2O (wherein the modulus of sodium silicate is 3.2, and the contents of Na2O, SiO2 and H2O in the solution are 8.35wt%, 26.54wt% and 65.11wt%, respectively) is mixed with the sodium hydroxide solution prepared in step (1) at a mass ratio of 1.3:1 and cooled to room temperature to obtain the activator.

[0074] Step 4: Preparation of concrete mixture, the steps are as follows:

[0075] Weigh each raw material according to the proportion of raw material usage. First, dry mix the industrial by-product precursor powder, agricultural by-product precursor powder, and kitchen waste by-product precursor powder to obtain a uniformly dispersed precursor powder. Then, add sand and gravel aggregate and dry mix to obtain a dry mix. Finally, add activator and water to the dry mix and continue mixing to obtain an eco-friendly high-strength concrete mix.

[0076] Example 3

[0077] An eco-friendly high-strength concrete mixture was prepared using sand and gravel aggregate, activator, water, and precursor powder in a mass ratio of 0.4:0.2:0.2:1. The precursor powder consisted of industrial by-product precursor powder, agricultural by-product precursor powder, and kitchen waste by-product precursor powder in a mass ratio of 1:1.5:3.5. The specific steps are as follows:

[0078] Step 1, Preparation of agricultural by-product precursor powder, the steps are as follows:

[0079] (1) Rice husk ash, which is produced by burning rice husks, a by-product of agricultural production, is used as raw material and screened to obtain ash content;

[0080] (2) The prepared rice husk ash is washed and cleaned, and then filtered by pressure to remove impurities;

[0081] (3) It is then dried at 70°C and then ground and sieved to remove impurities;

[0082] (4) The rice husk ash obtained in step (3) is sequentially treated with a 5.5 wt% chitosan quaternary ammonium salt solution and a 0.8 wt% sodium phosphate solution. The mass ratio of rice husk ash to chitosan quaternary ammonium salt solution is 1:3.5, and the mass ratio of rice husk ash to sodium phosphate solution is 1:2.5. The ash reaction activity is activated by chemical activation.

[0083] (5) The chemically activated ash is subjected to pressure filtration, drying, grinding and sieving.

[0084] (6) Then calcined at 800℃ for 2 hours to activate the ash activity using physical methods;

[0085] (7) After final grinding and sieving, an agricultural by-product precursor powder with an average particle size of 3.130 μm was obtained. The content of SiO2 was 95.15 wt%, the content of Al2O3 was 0.29 wt%, and the content of CaO was 0.38 wt%.

[0086] Step 2, Preparation of kitchen waste by-product precursor powder, the steps are as follows:

[0087] (1) Collect eggshells, a by-product of kitchen waste, as a raw material for preparation;

[0088] (2) Thoroughly wash the collected eggshells to remove contaminants and dry them at 70°C.

[0089] (3) The eggshells are crushed manually, then ground in a ball mill and sieved.

[0090] (4) The obtained eggshell ash was successively treated with a 0.12 mol / L ethylenediaminetetraacetic acid solution and a 95 wt% ethanol solution. The mass ratio of eggshell ash to ethylenediaminetetraacetic acid solution was 1:5, and the mass ratio of eggshell ash to ethanol solution was 1:2. The ash reaction activity was activated by chemical activation.

[0091] (5) The chemically activated eggshell ash is subjected to pressure filtration, drying, grinding and sieving to improve its purity;

[0092] (6) Then calcined at 600℃ for 4 hours to activate the ash activity using physical methods;

[0093] (7) After final grinding and sieving, a kitchen waste by-product precursor powder with an average particle size of 9.417 μm was obtained, wherein the SiO2 content was 31.85 wt%, the Al2O3 content was 16.98 wt%, and the CaO content was 34.83 wt%.

[0094] Step 3, preparation of the activator, the steps are as follows:

[0095] (1) Prepare a 16M sodium hydroxide solution using sodium hydroxide flakes with a purity of 99wt%;

[0096] (2) The sodium silicate solution (wherein the modulus of sodium silicate is 3.2, and the contents of Na2O, SiO2 and H2O in the solution are 8.35wt%, 26.54wt% and 65.11wt% respectively) is mixed with the sodium hydroxide solution prepared in step (1) at a mass ratio of 1.7:1 and cooled to room temperature to obtain the activator.

[0097] Step 4: Preparation of concrete mixture, the steps are as follows:

[0098] Weigh each raw material according to the proportion of raw material usage. First, dry mix the industrial by-product precursor powder, agricultural by-product precursor powder, and kitchen waste by-product precursor powder to obtain a uniformly dispersed precursor powder. Then, add sand and gravel aggregate and dry mix to obtain a dry mix. Finally, add activator and water to the dry mix and continue mixing to obtain an eco-friendly high-strength concrete mix.

[0099] Comparative Example 1

[0100] Similar to Example 1, the only difference is that neither the preparation of the agricultural by-product precursor powder in step 1 nor the preparation of the kitchen waste by-product precursor powder in step 2 involved chemical or physical activation treatment. Specifically:

[0101] Step 1, Preparation of agricultural by-product precursor powder, the steps are as follows:

[0102] (1) Rice husk ash, which is produced by burning rice husks, a by-product of agricultural production, is used as raw material and screened to obtain ash content;

[0103] (2) The prepared rice husk ash is washed and cleaned, and then filtered by pressure to remove impurities;

[0104] (3) The product is then dried at 70°C and then ground and sieved to remove impurities, thus obtaining agricultural by-product precursor powder.

[0105] Step 2, Preparation of kitchen waste by-product precursor powder, the steps are as follows:

[0106] (1) Collect eggshells, a by-product of kitchen waste, as raw materials for preparation;

[0107] (2) Thoroughly wash the collected eggshells to remove contaminants and dry them at 70°C.

[0108] (3) The eggshells are crushed manually, then ground in a ball mill and sieved to obtain the precursor powder of kitchen waste by-product.

[0109] The other steps and the amount of raw materials used are the same as in Example 1.

[0110] Comparative Example 2

[0111] Same as Example 1, except that no physical activation treatment was performed during the preparation of the agricultural by-product precursor powder in step 1. Specifically:

[0112] Step 1, Preparation of agricultural by-product precursor powder, the steps are as follows:

[0113] (1) Rice husk ash, which is produced by burning rice husks, a by-product of agricultural production, is used as raw material and screened to obtain ash content;

[0114] (2) The prepared rice husk ash is washed and cleaned, and then filtered by pressure to remove impurities;

[0115] (3) It is then dried at 70°C and then ground and sieved to remove impurities;

[0116] (4) The rice husk ash obtained in step (3) is soaked in a 5 wt% chitosan quaternary ammonium salt solution and a 1 wt% sodium phosphate solution in sequence. The mass ratio of rice husk ash to chitosan quaternary ammonium salt solution is 1:3, and the mass ratio of rice husk ash to sodium phosphate solution is 1:3. The ash reaction activity is activated by chemical activation.

[0117] (5) The chemically activated ash is subjected to pressure filtration, drying, grinding and sieving to obtain agricultural by-product precursor powder.

[0118] The other steps and the amount of raw materials used are the same as in Example 1.

[0119] Comparative Example 3

[0120] Same as Example 1, except that in step 1, during the preparation of the agricultural by-product precursor powder, the physical activation temperature is 400℃. Specifically:

[0121] Step 1, Preparation of agricultural by-product precursor powder, the steps are as follows:

[0122] (1) Rice husk ash, which is produced by burning rice husks, a by-product of agricultural production, is used as raw material and screened to obtain ash content;

[0123] (2) The prepared rice husk ash is washed and cleaned, and then filtered by pressure to remove impurities;

[0124] (3) It is then dried at 70°C and then ground and sieved to remove impurities;

[0125] (4) The rice husk ash obtained in step (3) is soaked in a 5 wt% chitosan quaternary ammonium salt solution and a 1 wt% sodium phosphate solution in sequence. The mass ratio of rice husk ash to chitosan quaternary ammonium salt solution is 1:3, and the mass ratio of rice husk ash to sodium phosphate solution is 1:3. The ash reaction activity is activated by chemical activation.

[0126] (5) The chemically activated ash is subjected to pressure filtration, drying, grinding and sieving.

[0127] (6) Then calcined at 400℃ for 2 hours to activate the ash activity using physical methods;

[0128] (7) After final grinding and sieving, agricultural by-product precursor powder is obtained.

[0129] The other steps and the amount of raw materials used are the same as in Example 1.

[0130] Comparative Example 4

[0131] Same as Example 1, except that in step 1, during the preparation of the agricultural by-product precursor powder, the physical activation temperature is 1000℃. Specifically:

[0132] Step 1, Preparation of agricultural by-product precursor powder, the steps are as follows:

[0133] (1) Rice husk ash, which is produced by burning rice husks, a by-product of agricultural production, is used as raw material and screened to obtain ash content;

[0134] (2) The prepared rice husk ash is washed and cleaned, and then filtered by pressure to remove impurities;

[0135] (3) It is then dried at 70°C and then ground and sieved to remove impurities;

[0136] (4) The rice husk ash obtained in step (3) is soaked in a 5 wt% chitosan quaternary ammonium salt solution and a 1 wt% sodium phosphate solution in sequence. The mass ratio of rice husk ash to chitosan quaternary ammonium salt solution is 1:3, and the mass ratio of rice husk ash to sodium phosphate solution is 1:3. The ash reaction activity is activated by chemical activation.

[0137] (5) The chemically activated ash is subjected to pressure filtration, drying, grinding and sieving.

[0138] (6) Then calcined at 1000℃ for 2 hours to activate the ash activity using physical methods;

[0139] (7) After final grinding and sieving, agricultural by-product precursor powder is obtained.

[0140] The other steps and the amount of raw materials used are the same as in Example 1.

[0141] Comparative Example 5

[0142] Same as Example 1, except that no chemical activation treatment was performed during the preparation of the agricultural by-product precursor powder in step 1. Specifically:

[0143] Step 1, Preparation of agricultural by-product precursor powder, the steps are as follows:

[0144] (1) Rice husk ash, which is produced by burning rice husks, a by-product of agricultural production, is used as raw material and screened to obtain ash content;

[0145] (2) The prepared rice husk ash is washed and cleaned, and then filtered by pressure to remove impurities;

[0146] (3) It is then dried at 70°C and then ground and sieved to remove impurities;

[0147] (4) Then calcined at 700℃ for 2 hours to activate the ash activity using physical methods;

[0148] (5) After final grinding and sieving, agricultural by-product precursor powder is obtained.

[0149] The other steps and the amount of raw materials used are the same as in Example 1.

[0150] Comparative Example 6

[0151] Same as Example 1, except that in step 1, during the preparation of the agricultural by-product precursor powder, sodium phosphate solution was not used for the chemical activation treatment. Specifically:

[0152] Step 1, Preparation of agricultural by-product precursor powder, the steps are as follows:

[0153] (1) Rice husk ash, which is produced by burning rice husks, a by-product of agricultural production, is used as raw material and screened to obtain ash content;

[0154] (2) The prepared rice husk ash is washed and cleaned, and then filtered by pressure to remove impurities;

[0155] (3) It is then dried at 70°C and then ground and sieved to remove impurities;

[0156] (4) The rice husk ash obtained in step (3) is soaked in a 5 wt% chitosan quaternary ammonium salt solution (the mass ratio of rice husk ash to chitosan quaternary ammonium salt solution is 1:3). The ash reaction activity is activated by chemical activation.

[0157] (5) The chemically activated ash is subjected to pressure filtration, drying, grinding and sieving.

[0158] (6) Then calcined at 700℃ for 2 hours to activate the ash activity using physical methods;

[0159] (7) After final grinding and sieving, agricultural by-product precursor powder is obtained.

[0160] The other steps and the amount of raw materials used are the same as in Example 1.

[0161] Comparative Example 7

[0162] Same as Example 1, except that in step 1, during the preparation of the agricultural by-product precursor powder, the chemical activation treatment did not use chitosan quaternary ammonium salt solution. Specifically:

[0163] Step 1, Preparation of agricultural by-product precursor powder, the steps are as follows:

[0164] (1) Rice husk ash, which is produced by burning rice husks, a by-product of agricultural production, is used as raw material and screened to obtain ash content;

[0165] (2) The prepared rice husk ash is washed and cleaned, and then filtered by pressure to remove impurities;

[0166] (3) It is then dried at 70°C and then ground and sieved to remove impurities;

[0167] (4) The rice husk ash obtained in step (3) is soaked in a sodium phosphate solution with a concentration of 1 wt%. The mass ratio of rice husk ash to sodium phosphate solution is 1:3. The ash reaction activity is activated by chemical activation.

[0168] (5) The chemically activated ash is subjected to pressure filtration, drying, grinding and sieving.

[0169] (6) Then calcined at 700℃ for 2 hours to activate the ash activity using physical methods;

[0170] (7) After final grinding and sieving, agricultural by-product precursor powder is obtained.

[0171] The other steps and the amount of raw materials used are the same as in Example 1.

[0172] Comparative Example 8

[0173] Same as Example 1, except that in step 2, during the preparation of the kitchen waste by-product precursor powder, no physical activation treatment was performed. Specifically:

[0174] Step 2, Preparation of kitchen waste by-product precursor powder, the steps are as follows:

[0175] (1) Collect eggshells, a by-product of kitchen waste, as raw materials for preparation;

[0176] (2) Thoroughly wash the collected eggshells to remove contaminants and dry them at 70°C.

[0177] (3) The eggshells are crushed manually, then ground in a ball mill and sieved.

[0178] (4) The obtained eggshell ash was successively treated with a 0.1 mol / L ethylenediaminetetraacetic acid solution and a 95 wt% ethanol solution. The mass ratio of eggshell ash to ethylenediaminetetraacetic acid solution was 1:4, and the mass ratio of eggshell ash to ethanol solution was 1:4. The ash reaction activity was activated by chemical activation.

[0179] (5) The chemically activated eggshell ash is subjected to pressure filtration, drying, grinding and sieving to improve its purity and obtain kitchen waste by-product precursor powder.

[0180] The other steps and the amount of raw materials used are the same as in Example 1.

[0181] Comparative Example 9

[0182] Same as Example 1, except that in step 2, during the preparation of the kitchen waste by-product precursor powder, the physical activation temperature is 400℃. Specifically:

[0183] Step 2, Preparation of kitchen waste by-product precursor powder, the steps are as follows:

[0184] (1) Collect eggshells, a by-product of kitchen waste, as raw materials for preparation;

[0185] (2) Thoroughly wash the collected eggshells to remove contaminants and dry them at 70°C.

[0186] (3) The eggshells are crushed manually, then ground in a ball mill and sieved.

[0187] (4) The obtained eggshell ash was successively treated with a 0.1 mol / L ethylenediaminetetraacetic acid solution and a 95 wt% ethanol solution. The mass ratio of eggshell ash to ethylenediaminetetraacetic acid solution was 1:4, and the mass ratio of eggshell ash to ethanol solution was 1:4. The ash reaction activity was activated by chemical activation.

[0188] (5) The chemically activated eggshell ash is subjected to pressure filtration, drying, grinding and sieving to improve its purity;

[0189] (6) Then calcined at 400℃ for 2 hours to activate the ash activity using physical methods;

[0190] (7) After final grinding and sieving, the precursor powder of kitchen waste by-products is obtained.

[0191] The other steps and the amount of raw materials used are the same as in Example 1.

[0192] Comparative Example 10

[0193] Same as Example 1, except that in step 2, during the preparation of the kitchen waste by-product precursor powder, the physical activation temperature is 1000℃. Specifically:

[0194] Step 2, Preparation of kitchen waste by-product precursor powder, the steps are as follows:

[0195] (1) Collect eggshells, a by-product of kitchen waste, as raw materials for preparation;

[0196] (2) Thoroughly wash the collected eggshells to remove contaminants and dry them at 70°C.

[0197] (3) The eggshells are crushed manually, then ground in a ball mill and sieved.

[0198] (4) The obtained eggshell ash was successively treated with a 0.1 mol / L ethylenediaminetetraacetic acid solution and a 95 wt% ethanol solution. The mass ratio of eggshell ash to ethylenediaminetetraacetic acid solution was 1:4, and the mass ratio of eggshell ash to ethanol solution was 1:4. The ash reaction activity was activated by chemical activation.

[0199] (5) The chemically activated eggshell ash is subjected to pressure filtration, drying, grinding and sieving to improve its purity;

[0200] (6) Then calcined at 1000℃ for 2 hours to activate the ash activity using physical methods;

[0201] (7) After final grinding and sieving, the precursor powder of kitchen waste by-products is obtained.

[0202] The other steps and the amount of raw materials used are the same as in Example 1.

[0203] Comparative Example 11

[0204] Same as Example 1, except that in step 2, during the preparation of the kitchen waste by-product precursor powder, no chemical activation treatment was performed. Specifically:

[0205] Step 2, Preparation of kitchen waste by-product precursor powder, the steps are as follows:

[0206] (1) Collect eggshells, a by-product of kitchen waste, as raw materials for preparation;

[0207] (2) Thoroughly wash the collected eggshells to remove contaminants and dry them at 70°C.

[0208] (3) The eggshells are crushed manually, then ground in a ball mill and sieved.

[0209] (4) Then calcined at 700℃ for 2 hours to activate the ash activity using physical methods;

[0210] (5) After final grinding and sieving, the precursor powder of kitchen waste by-products is obtained.

[0211] The other steps and the amount of raw materials used are the same as in Example 1.

[0212] Comparative Example 12

[0213] Same as Example 1, except that in step 2, during the preparation of the kitchen waste by-product precursor powder, an ethanol solution was not used during the chemical activation treatment. Specifically:

[0214] Step 2, Preparation of kitchen waste by-product precursor powder, the steps are as follows:

[0215] (1) Collect eggshells, a by-product of kitchen waste, as raw materials for preparation;

[0216] (2) Thoroughly wash the collected eggshells to remove contaminants and dry them at 70°C.

[0217] (3) The eggshells are crushed manually, then ground in a ball mill and sieved.

[0218] (4) The obtained eggshell ash was soaked in a 0.1 mol / L ethylenediaminetetraacetic acid solution with a mass ratio of 1:4. The ash reaction activity was activated by chemical activation.

[0219] (5) The chemically activated eggshell ash is subjected to pressure filtration, drying, grinding and sieving to improve its purity;

[0220] (6) Then calcined at 700℃ for 2 hours to activate the ash activity using physical methods;

[0221] (7) After final grinding and sieving, the precursor powder of kitchen waste by-products is obtained.

[0222] The other steps and the amount of raw materials used are the same as in Example 1.

[0223] Comparative Example 13

[0224] Same as Example 1, except that in step 2, during the preparation of the kitchen waste by-product precursor powder, ethylenediaminetetraacetic acid solution was not used in the chemical activation treatment. Specifically:

[0225] Step 2, Preparation of kitchen waste by-product precursor powder, the steps are as follows:

[0226] (1) Collect eggshells, a by-product of kitchen waste, as raw materials for preparation;

[0227] (2) Thoroughly wash the collected eggshells to remove contaminants and dry them at 70°C.

[0228] (3) The eggshells are crushed manually, then ground in a ball mill and sieved.

[0229] (4) The obtained eggshell ash was soaked in an ethanol solution with a concentration of 95wt%, and the mass ratio of eggshell ash to ethanol solution was 1:4. The ash reaction activity was activated by chemical activation.

[0230] (5) The chemically activated eggshell ash is subjected to pressure filtration, drying, grinding and sieving to improve its purity;

[0231] (6) Then calcined at 700℃ for 2 hours to activate the ash activity using physical methods;

[0232] (7) After final grinding and sieving, the precursor powder of kitchen waste by-products is obtained.

[0233] The other steps and the amount of raw materials used are the same as in Example 1.

[0234] Effect verification

[0235] Referring to the "Test Method for Strength of Cement Mortar" (GB / T 17671-2021), the concrete mixtures prepared in Examples 1-3 and Comparative Examples 1-13 were placed into molds, cured, demolded, and then moved to a standard curing room (temperature 20±3℃, relative humidity 95%) for curing. Mechanical properties were tested at the target ages (3 days, 7 days, and 28 days). The test results are shown in Table 1.

[0236] Table 1. Test results of mechanical properties of concrete specimens in each group.

[0237]

[0238] Comparing the performance test results of Example 1 and Comparative Examples 1-13 in Table 1, it can be seen that the test data of Example 1 is significantly better than that of Comparative Examples 1-13. This indicates that the technical solution adopted in this invention can effectively improve the mechanical strength of solid waste-based concrete.

[0239] This invention physically activates agricultural by-products and kitchen waste by-products at a suitable temperature, which can effectively improve the composition of agricultural by-products and kitchen waste by-products, increase the content of amorphous SiO2 and CaO, and thus achieve efficient utilization.

[0240] This invention activates rice husk ash with a chitosan quaternary ammonium salt solution, which improves its surface morphology. Further soaking in sodium phosphate solution further promotes the densification of its surface morphology, thereby improving the reaction level between it and the alkaline activator, promoting the polymerization reaction of agricultural by-products in an alkaline environment, and thus improving the mechanical strength of concrete materials at the microscopic level.

[0241] Meanwhile, by activating eggshell ash with ethylenediaminetetraacetic acid solution, the present invention can improve its surface morphology. Further soaking in ethanol solution can further improve its surface activity, thereby effectively improving the reaction level between it and alkaline activator, promoting the polymerization reaction of kitchen waste by-products in an alkaline environment, and thus improving the mechanical strength of concrete materials at the microscopic level.

[0242] The above description is merely a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An eco-friendly high-strength concrete, characterized in that, The raw materials include precursor powder, activator, sand and gravel aggregate, and water in a mass ratio of 1:(0.2~0.4):(0.2~0.4):(0.1~0.2); The precursor powder includes industrial by-product precursor powder, agricultural by-product precursor powder and kitchen waste by-product precursor powder in a mass ratio of 1:(0.5~1.5):(2.5~3.5). The preparation method of the agricultural by-product precursor powder includes the following steps: First, the rice husk ash obtained by burning rice husk is chemically activated by chitosan quaternary ammonium salt solution and sodium phosphate solution in sequence. Then, it is filtered, dried, ground, sieved, and then carbonized to obtain the agricultural by-product precursor powder. The preparation method of the kitchen waste by-product precursor powder includes the following steps: first, crushing, grinding, and sieving eggshells to obtain eggshell ash; then, chemically activating the obtained eggshell ash with ethylenediaminetetraacetic acid solution and ethanol solution in sequence, followed by pressure filtration, drying, grinding, sieving, and then carbonization treatment to obtain the kitchen waste by-product precursor powder. The carbonization temperature is 600–800℃.

2. The eco-friendly high-strength concrete according to claim 1, characterized in that, The activator is obtained by mixing sodium silicate solution and sodium hydroxide solution in a volume ratio of (1.3-1.7):1; the sodium silicate is Na2O·nSiO2, where n is 3-3.3, and the mass ratio of H2O to Na2O·nSiO2 in the sodium silicate solution is 7-10; the concentration of the sodium hydroxide solution is 12-16 mol / L.

3. The eco-friendly high-strength concrete according to claim 1, characterized in that, The maximum particle size of the sand and gravel aggregate is 1 mm, and the average particle size is 0.6 to 0.7 mm.

4. The eco-friendly high-strength concrete according to claim 1, characterized in that, The industrial by-product precursor powder is fly ash.

5. The eco-friendly high-strength concrete according to claim 1, characterized in that, The concentration of the chitosan quaternary ammonium salt solution is 4.5–5.5 wt%; the concentration of the sodium phosphate solution is 0.8–1.2 wt%; the mass ratio of rice husk ash to chitosan quaternary ammonium salt solution is 1:(2.5–3.5), and the mass ratio of rice husk ash to sodium phosphate solution is 1:(2.5–3.5).

6. The eco-friendly high-strength concrete according to claim 1, characterized in that, The concentration of the ethylenediaminetetraacetic acid solution is 0.08–0.12 mol / L, the concentration of the ethanol solution is 90–95 wt%, the mass ratio of eggshell ash to ethylenediaminetetraacetic acid solution is 1:(2–5), and the mass ratio of eggshell ash to ethanol solution is 1:(2–5); the carbonization treatment time is 2–4 h.

7. A method for preparing eco-friendly high-strength concrete according to any one of claims 1 to 6, characterized in that, Includes the following steps: Weigh each raw material according to the proportion of raw material usage. First, dry mix the industrial by-product precursor powder, agricultural by-product precursor powder, and kitchen waste by-product precursor powder to obtain a uniformly dispersed precursor powder. Then, add sand and gravel aggregate and dry mix to obtain a dry mix. Finally, add activator and water to the dry mix and continue mixing.

8. The preparation method according to claim 7, characterized in that, After adding the activator and water to the dry mix and continuing to mix, the resulting mixture is then poured into a mold for curing, demolding, and then moved to a standard curing room for further curing to obtain the eco-friendly high-strength concrete.

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