A method for modifying sea sand coarse aggregate and its application in vegetation concrete

Abstract

This invention discloses a method for modifying sea sand coarse aggregate and its application in vegetation concrete. The modified sea sand coarse aggregate is prepared by adding 5-5.34 parts sea sand, 2-2.12 parts red mud, 1.5-1.72 parts cement, and 0.54-0.86 parts waste incineration bottom ash into the disc of a pelletizing machine, and stirring the machine to ensure thorough and uniform mixing of the solid materials. Then, 0.86-1.04 parts water are sprayed onto the materials at a uniform speed and stirred to obtain the modified sea sand coarse aggregate. The vegetation concrete is made from the following raw materials in the following mass fractions: 180-210 parts cement, 50-70 parts bagasse ash, 1080-1180 parts modified sea sand coarse aggregate, and 140-150 parts water. This invention modifies sea sand coarse aggregate by adding red mud, cement, waste incineration bottom ash, and water. The resulting modified sea sand coarse aggregate is then mixed with cement, bagasse ash, and water to prepare vegetated concrete. This fully utilizes the micro-aggregate effect, filling effect, and plant fertilization effect of red mud, waste incineration bottom ash, and bagasse ash from industrial and agricultural by-products. It is low in cost but has good physical properties and durability, and can adapt to plant growth.

Description

Technical Field

[0001] This invention relates to the field of vegetation concrete technology, specifically a method for modifying coarse sea sand aggregate and its application in vegetation concrete. Background Technology

[0002] Vegetated concrete is an eco-friendly type of concrete, typically made from coarse aggregates, cementitious materials, and water. It features a large, interconnected pore structure, enabling it to breathe, permeate water, filter, and absorb nutrients necessary for plant growth. In addition to structural protection, vegetated concrete also enhances ground moisture and heat exchange efficiency, reduces noise pollution, improves groundwater levels, and purifies wastewater. It is currently widely used in ecological construction projects such as ecological seawalls and ecological islands in coastal areas.

[0003] In planted concrete, coarse aggregate typically accounts for 70%–80% of the total volume; therefore, its preparation requires a large amount of coarse aggregate. Due to the enormous consumption of natural coarse aggregate by materials such as ordinary concrete and planted concrete in the construction industry, inland natural coarse aggregate resources are gradually becoming scarce. Furthermore, the extraction of natural coarse aggregate is a complex process that damages the topography and impacts the ecological environment. Coastal areas are even scarcer in coarse aggregate resources; if inland transportation is chosen, construction costs will increase dramatically. In contrast, my country has extremely abundant marine sand resources, with preliminary estimates of approximately 6.796 × 10⁻⁶. 11 The volume of sea sand is relatively small, and its extraction is relatively easy with minimal environmental impact. If sea sand can be processed into low-cost, high-performance artificial coarse aggregate using simple and efficient methods, and then applied to vegetation concrete, it will not only make full use of sea sand resources but also alleviate the shortage of coarse aggregate in coastal areas, thereby greatly promoting the development of ecological construction projects in coastal areas.

[0004] Current methods for preparing artificial coarse aggregates mostly utilize roasting processes. Chinese patent CN 111333404B discloses a method for preparing lightweight porous phosphorus tailings ceramsite. This method uses phosphorus tailings, sludge, cementing materials, and some additives as raw materials, which are then pelletized three times, dried, and finally sintered to obtain phosphorus tailings ceramsite. This method rationally utilizes phosphorus tailings for ceramsite production, avoiding resource waste and environmental problems caused by phosphorus tailings accumulation. However, its granulation process is relatively complex, and the sintering process requires a large amount of energy, making it difficult to control granulation costs effectively. Furthermore, the ceramsite prepared by this method has relatively low strength, limiting its application range.

[0005] Therefore, this invention provides a low-cost, high-performance method for modifying marine sand coarse aggregate, and utilizes the modified marine sand coarse aggregate, supplemented with various industrial and agricultural by-products such as red mud, waste incineration bottom ash, and bagasse ash, to prepare low-cost, high-performance planted concrete. Summary of the Invention

[0006] This invention addresses the technical problems of coarse aggregate scarcity in coastal vegetated concrete and the inability to directly use sea sand as vegetated concrete. It provides a low-cost, high-performance method for modifying sea sand coarse aggregate and its application in vegetated concrete. The invention first adds red mud, cement, waste incineration bottom ash, and water to sea sand coarse aggregate, then modifies it using a pelletizing machine. The resulting modified sea sand coarse aggregate is then mixed with cement, bagasse ash, and water to prepare vegetated concrete. The sea sand coarse aggregate vegetated concrete provided by this invention fully utilizes the micro-aggregate effect, filling effect, and plant fertilization effect of red mud, waste incineration bottom ash, and bagasse ash from industrial and agricultural by-products. It is low in cost but possesses good physical properties and durability, and is adaptable to plant growth.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for modifying coarse aggregate from sea sand includes the following steps:

[0009] Step S1: Add 5-5.34 parts sea sand, 2-2.12 parts red mud, 1.5-1.72 parts cement, and 0.54-0.86 parts waste incineration bottom ash to the pelletizing machine disc, and start the machine to stir for 3-5 minutes to ensure that the solid materials are fully and evenly mixed.

[0010] Step S2: Continuously stir the material and spray 0.86-1.04 parts of water onto the material at a uniform speed through the machine's nozzle. After spraying, stir for another 10-20 minutes to obtain modified sea sand coarse aggregate.

[0011] As a preferred technical solution of the present invention, the red mud particle size is ≤0.1mm.

[0012] As a preferred technical solution of the present invention, the particle size range of the bottom ash from the waste incineration is 1-200μm, and the median particle size is 30-50μm.

[0013] Another object of the present invention is to provide a planted concrete prepared using modified sea sand coarse aggregate, said planted concrete being made from the following raw materials in the indicated mass fractions: 180-210 parts cement, 50-70 parts bagasse ash, 1080-1180 parts modified sea sand coarse aggregate, and 140-150 parts water.

[0014] As a preferred technical solution of the present invention, the bagasse ash has a particle size range of 1 to 150 μm, with a median particle size of 15-40 μm.

[0015] The preparation method of the planted concrete is as follows: Modified sea sand coarse aggregate, cement, bagasse ash and water are put into a mixer and mixed evenly, and then manually molded and tamped to finally obtain modified sea sand coarse aggregate planted concrete.

[0016] Compared with the prior art, the advantages and beneficial effects of the present invention include:

[0017] 1. This invention utilizes sea sand to prepare coarse aggregate for vegetation concrete, fully leveraging my country's abundant sea sand resources and alleviating the shortage of natural coarse aggregate in coastal areas. Red mud and waste incineration ash are added to the coarse aggregate preparation process. These industrial byproducts, represented by red mud and waste incineration ash, modify the sea sand, resulting in a low-cost process containing active components such as silica and alumina. This not only solves the problem of difficult processing of industrial byproducts but also improves the strength of the coarse aggregate while reducing the cost of artificial coarse aggregate. This provides a valuable approach for preparing coarse aggregate for vegetation concrete.

[0018] 2. In order to improve the fertilizer efficiency of modified sea sand coarse aggregate planted concrete, the present invention adds bagasse ash during the preparation process of planted concrete. On the one hand, the pozzolanic activity and filling effect of bagasse ash are used to enhance the strength and durability of planted concrete, and on the other hand, it provides potassium, phosphorus and other elements to plants to promote plant growth.

[0019] 3. The sea sand coarse aggregate vegetated concrete provided by the present invention can make full use of the micro-aggregate effect, filling effect and plant fertilizer effect of red mud, garbage combustion bottom ash and bagasse ash in industrial and agricultural by-products. It is low in cost but has good physical properties and durability. It can adapt to plant growth and is a low-cost, high-performance vegetated concrete with good market prospects. Attached Figure Description

[0020] Figure 1 The process flow diagram for modifying coarse aggregates from sea sand.

[0021] Figure 2 A flowchart illustrating the preparation process of modified sea sand-grown concrete.

[0022] Figure 3 This is a rendering of the vegetation effect of modified sea sand-vegetated concrete.

[0023] Figure 4 This is a rendering of the vegetation effect of modified sea sand-vegetated concrete. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1

[0026] A type of vegetation concrete prepared from modified sea sand coarse aggregate, wherein the vegetation concrete is made from the following raw materials in the indicated mass fractions: 190 parts cement, 65 parts bagasse ash, 1130 parts modified sea sand coarse aggregate, and 142 parts water.

[0027] The preparation method of the modified sea sand coarse aggregate includes the following steps:

[0028] Step S1: Add 5 parts sea sand, 2.05 parts red mud, 1.63 parts cement, and 0.61 parts waste incineration bottom ash to the pelletizing machine disc according to the mass ratio, and start the machine to stir for 5 minutes to ensure that the solid materials are fully mixed evenly.

[0029] Step S2: Continuously stir the material and spray 0.93 parts of water onto the material at a uniform speed through the machine's nozzle. After spraying, stir for another 15 minutes to obtain modified sea sand coarse aggregate.

[0030] Example 2

[0031] A type of vegetation concrete prepared from modified sea sand coarse aggregate, wherein the vegetation concrete is made from the following raw materials in the indicated mass fractions: 205 parts cement, 68 parts bagasse ash, 1180 parts modified sea sand coarse aggregate, and 145 parts water.

[0032] The preparation method of the modified sea sand coarse aggregate includes the following steps:

[0033] Step S1: Add 5.13 parts sea sand, 2.09 parts red mud, 1.68 parts cement, and 0.74 parts waste incineration bottom ash to the pelletizing machine disc according to the mass ratio, and start the machine to stir for 5 minutes to ensure that the solid materials are fully mixed evenly.

[0034] Step S2: Continuously stir the material and spray 1.02 parts of water onto the material at a uniform speed through the machine's nozzle. After spraying, stir for another 10 minutes to obtain modified sea sand coarse aggregate.

[0035] Example 3

[0036] A type of vegetation concrete prepared from modified sea sand coarse aggregate, wherein the vegetation concrete is made from the following raw materials in the indicated mass fractions: 210 parts cement, 70 parts bagasse ash, 1145 parts modified sea sand coarse aggregate, and 150 parts water.

[0037] The preparation method of the modified sea sand coarse aggregate includes the following steps:

[0038] Step S1: Add 5.34 parts sea sand, 2.05 parts red mud, 1.63 parts cement, and 0.73 parts waste incineration bottom ash to the pelletizing machine disc according to the mass ratio, and start the machine to stir for 3 minutes to ensure that the solid materials are fully mixed evenly.

[0039] Step S2: Continuously stir the material and spray 1.04 parts of water onto the material at a uniform speed through the machine's nozzle. After spraying, stir for another 20 minutes to obtain modified sea sand coarse aggregate.

[0040] Example 4

[0041] A type of vegetation concrete prepared from modified sea sand coarse aggregate, wherein the vegetation concrete is made from the following raw materials in the indicated mass fractions: 180 parts cement, 55 parts bagasse ash, 1080 parts modified sea sand coarse aggregate, and 140 parts water.

[0042] The preparation method of the modified sea sand coarse aggregate includes the following steps:

[0043] Step S1: Add 5.25 parts sea sand, 2.12 parts red mud, 1.58 parts cement, and 0.76 parts waste incineration bottom ash to the pelletizing machine disc, and start the machine to stir for 5 minutes to ensure that the solid materials are fully mixed evenly.

[0044] Step S2: Continuously stir the material and spray 0.89 parts of water onto the material at a uniform speed through the machine's nozzle. After spraying, stir for another 15 minutes to obtain modified sea sand coarse aggregate.

[0045] Example 5

[0046] A type of vegetation concrete prepared from modified sea sand coarse aggregate, wherein the vegetation concrete is made from the following raw materials in the indicated mass fractions: 195 parts cement, 70 parts bagasse ash, 1125 parts modified sea sand coarse aggregate, and 146 parts water.

[0047] The preparation method of the modified sea sand coarse aggregate includes the following steps:

[0048] Step S1: Add 5.19 parts sea sand, 2.08 parts red mud, 1.67 parts cement, and 0.78 parts waste incineration bottom ash to the pelletizing machine disc, and start the machine to stir for 3 minutes to ensure that the solid materials are fully mixed evenly.

[0049] Step S2: Continuously stir the material and spray 0.98 parts of water onto the material at a uniform speed through the machine's nozzle. After spraying, stir for another 20 minutes to obtain modified sea sand coarse aggregate.

[0050] Comparative Example 1

[0051] The difference between this comparative example and Example 1 is that the sea sand used in the vegetation concrete is not modified, and the vegetation concrete is made from the following raw materials by mass fraction: 190 parts cement, 65 parts bagasse ash, 1130 parts sea sand coarse aggregate, and 142 parts water.

[0052] Comparative Example 2

[0053] The difference between this comparative example and Example 1 is that the sea sand in this example is only modified with cement. The vegetation concrete is made from the following raw materials by mass fraction: 190 parts cement, 65 parts bagasse ash, 1130 parts modified sea sand coarse aggregate, and 142 parts water.

[0054] The preparation method of the modified sea sand coarse aggregate includes the following steps:

[0055] Step S1: Add 5 parts sea sand and 1.63 parts cement to the pelletizing machine disc according to the mass ratio, and start the machine to stir for 5 minutes to ensure that the solid materials are fully mixed evenly.

[0056] Step S2: Continuously stir the material and spray 0.93 parts of water onto the material at a uniform speed through the machine's nozzle. After spraying, stir for another 15 minutes to obtain modified sea sand coarse aggregate.

[0057] Comparative Example 3

[0058] The difference between this comparative example and Example 1 is that the sea sand is not modified with red mud. The vegetation concrete is made from the following raw materials by mass fraction: 190 parts cement, 65 parts bagasse ash, 1130 parts modified sea sand coarse aggregate, and 142 parts water.

[0059] The preparation method of the modified sea sand coarse aggregate includes the following steps:

[0060] Step S1: Add 5 parts sea sand, 1.63 parts cement, and 0.61 parts waste incineration bottom ash to the pelletizing machine disc according to the mass ratio, and start the machine to stir for 5 minutes to ensure that the solid materials are fully mixed evenly.

[0061] Step S2: Continuously stir the material and spray 0.93 parts of water onto the material at a uniform speed through the machine's nozzle. After spraying, stir for another 15 minutes to obtain modified sea sand coarse aggregate.

[0062] Comparative Example 4

[0063] The difference between this comparative example and Example 1 is that the sea sand is not modified by waste incineration bottom ash. The vegetation concrete is made from the following raw materials by mass fraction: 190 parts cement, 65 parts bagasse ash, 1130 parts modified sea sand coarse aggregate, and 142 parts water.

[0064] The preparation method of the modified sea sand coarse aggregate includes the following steps:

[0065] Step S1: Add 5 parts sea sand, 2.05 parts red mud, and 1.63 parts cement to the pelletizing machine disc according to the mass ratio, and start the machine to stir for 5 minutes to ensure that the solid materials are fully mixed evenly.

[0066] Step S2: Continuously stir the material and spray 0.93 parts of water onto the material at a uniform speed through the machine's nozzle. After spraying, stir for another 15 minutes to obtain modified sea sand coarse aggregate.

[0067] Comparative Example 5

[0068] The difference between this comparative example and Example 1 is that the vegetation concrete does not include bagasse ash, and the vegetation concrete is made from the following raw materials by mass fraction: 190 parts cement, 1130 parts modified sea sand coarse aggregate, and 142 parts water.

[0069] The preparation method of the modified sea sand coarse aggregate includes the following steps:

[0070] Step S1: Add 5 parts sea sand, 2.05 parts red mud, 1.63 parts cement, and 0.61 parts waste incineration bottom ash to the pelletizing machine disc according to the mass ratio, and start the machine to stir for 5 minutes to ensure that the solid materials are fully mixed evenly.

[0071] Step S2: Continuously stir the material and spray 0.93 parts of water onto the material at a uniform speed through the machine's nozzle. After spraying, stir for another 15 minutes to obtain modified sea sand coarse aggregate.

[0072] The vegetation concrete formulations of Examples 1-4 and Comparative Examples 1-5 of the present invention were prepared according to the following steps: modified sea sand coarse aggregate, cement, bagasse ash and water were put into a mixer and mixed evenly, and then manually molded and tamped to finally obtain vegetation concrete.

[0073] The compressive strength and pH value of the vegetation concrete prepared in Example 1 and Comparative Examples 1-5 were determined using conventional methods. The results are shown in the table below:

[0074] Table 1: Strength and pH Measurement Results of the Modified Sea Sand Coarse Aggregate Vegetated Concrete of the Present Invention

[0075]

[0076]

[0077] As shown in Table 1, modifying marine sand coarse aggregate with red mud and waste incineration bottom ash can improve the strength of modified marine sand coarse aggregate vegetated concrete. Simultaneously, the addition of waste incineration bottom ash reduces cement usage and lowers the pH value of the system. Adding bagasse ash to the modified marine sand coarse aggregate vegetated concrete can both improve its strength and reduce its alkalinity. This invention fully utilizes the micro-aggregate effect, filling effect, and plant fertilization effect of red mud, waste incineration bottom ash, and bagasse ash, resulting in modified marine sand coarse aggregate vegetated concrete with excellent mechanical and vegetation properties.

[0078] Figure 3The photos show the growth of alfalfa after it was planted on the vegetated concrete obtained in this embodiment. The alfalfa seeds germinated 6 days after planting and subsequently grew well.

[0079] Figure 4 The photo shows the growth of *Imperata cylindrica* after it was planted on the vegetated concrete obtained in this embodiment. The seeds of *Imperata cylindrica* germinated at an age of 11 days after planting and subsequently grew well.

[0080] The above description, in conjunction with specific / preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the inventive concept, and all such substitutions or modifications should be considered within the scope of protection of the present invention.

Claims

1. A type of vegetation concrete prepared with modified sea sand coarse aggregate, characterized in that: The vegetation concrete is made from the following raw materials in parts by weight: 180-210 parts cement, 50-70 parts bagasse ash, 1080-1180 parts modified sea sand coarse aggregate, and 140-150 parts water. The method for preparing the modified sea sand coarse aggregate includes the following steps: Step S1: Add 5-5.34 parts sea sand, 2-2.12 parts red mud, 1.5-1.72 parts cement, and 0.54-0.86 parts waste incineration bottom ash to the pelletizing machine disc, and start the machine to stir for 3-5 minutes to ensure that the solid materials are fully mixed evenly. Step S2: Continuously stir the material and spray 0.86 to 1.04 parts of water onto the material at a uniform speed through the machine's nozzle. After spraying, stir for another 10 to 20 minutes to obtain modified sea sand coarse aggregate.

2. The vegetation concrete prepared from modified sea sand coarse aggregate according to claim 1, characterized in that: The red mud particle size is ≤0.1mm.

3. The vegetation concrete prepared from modified sea sand coarse aggregate according to claim 1, characterized in that: The particle size range of the waste incineration bottom ash is 1–200 μm, with a median particle size of 30–50 μm.

4. The vegetation concrete prepared from modified sea sand coarse aggregate according to claim 1, characterized in that: The bagasse ash has a particle size range of 1–150 μm, with a median particle size of 15–40 μm.

5. The vegetation concrete prepared from modified sea sand coarse aggregate according to claim 4, characterized in that: The preparation method of the vegetation concrete is as follows: Modified sea sand coarse aggregate, cement, bagasse ash and water are put into a mixer and mixed evenly, and then manually molded and tamped to finally obtain vegetation concrete prepared with modified sea sand coarse aggregate.

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