Bamboo aggregate interface enhancing method for preparing low-carbon concrete

Abstract

The invention discloses a bamboo aggregate interface enhancing method for low-carbon concrete preparation, and aims to solve the problem of poor interface bonding of bamboo aggregate and concrete. Firstly, moso bamboos growing for 3-6 years in a specific area in southern China are selected, the moisture content is accurately controlled to be 10%-15% through an intelligent humidity monitoring and control system in combination with microwave drying, then bamboo aggregate with the particle size being 5-15 mm and the surface being optimized is prepared through a novel double-shaft crusher and an airflow classification technology, for example, the bamboo aggregate is polished through a nanoscale diamond grinding wheel and subjected to plasma treatment, and the bamboo aggregate is obtained. Then preparing a modified solution containing a silane coupling agent, an acrylic emulsion, nano silicon dioxide sol, a polycarboxylic acid water reducer and sodium lignin sulfonate, performing ultrasonic-assisted soaking and online monitoring, and then treating the bamboo aggregate by combining vacuum freeze drying and far infrared drying, so that the mechanical property of the bamboo aggregate concrete is remarkably improved; the method conforms to the concept of high-value utilization and sustainable development of biomass materials, and the application prospect is wide.

Description

Technical Field

[0001] The present invention belongs to the technical field related to building materials, and particularly relates to a method for enhancing the interface of bamboo aggregates that can be used in the preparation of low-carbon concrete. Background Art

[0002] With the development of society, the demand for building materials is increasing day by day, and at the same time, it is facing the pressure of resource shortage and environmental protection. Concrete is one of the most widely used building materials, but its carbon emissions during the production process are serious, which does not meet the requirements of sustainable development under the background of carbon peaking and carbon neutrality. Bamboo, as a renewable biomass resource, has the characteristics of fast growth rate, high strength, and good toughness, but it also has some disadvantages, such as weak dimensional stability of bamboo, susceptibility to alkaline erosion, and weak bonding with mortar. Existing bamboo and wood modification methods include physical modification, chemical modification, etc. However, when applying bamboo to concrete as bamboo aggregates, it is still necessary to further improve the interfacial bonding performance between bamboo aggregates and concrete to improve the comprehensive performance of bamboo aggregate concrete. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for enhancing the interface of bamboo aggregates that can be used in the preparation of low-carbon concrete, so as to solve the problems proposed in the above background art.

[0004] To achieve the above purpose, the present invention provides the following technical solutions:

[0005] A method for enhancing the interface of bamboo aggregates that can be used in the preparation of low-carbon concrete, including: The specific steps of the method are as follows:

[0006] Step 1: Selection and preliminary treatment of bamboo

[0007] Type of bamboo: Select moso bamboo with a growth age of 3 - 6 years as the raw material. Moso bamboo has high strength and toughness, and is rich in resources, which is suitable as the source of bamboo aggregates;

[0008] Control of bamboo moisture content:

[0009] After cutting down the moso bamboo, immediately carry out preliminary treatment to remove the impurities of branches and leaves and the bamboo green and bamboo yellow, and then place the bamboo in a well-ventilated environment for natural drying to reduce the moisture content to 10% - 15%;

[0010] Step 2: Preparation of bamboo aggregates

[0011] Crushing of bamboo aggregates:

[0012] Adopt the method of mechanical crushing to crush the dried bamboo into aggregates with a size of 5 - 15 mm;

[0013] Step 3: Shape optimization and microstructure enhancement of bamboo aggregates

[0014] Bamboo aggregate surface groove and protrusion carving:

[0015] To increase the contact area between bamboo aggregates and concrete and improve the interfacial bonding force, shape optimization treatment is carried out on the crushed bamboo aggregates. Through processes such as screening and grinding, the shape of the bamboo aggregates is made as close as possible to spherical or cubic, reducing sharp edges and corners. At the same time, some tiny grooves and protrusions are created on the surface of the bamboo aggregates, including using laser engraving technology to form grooves and protrusions with a depth of 0.1 - 0.3 mm and a spacing of 2 - 3 mm on the surface of the bamboo aggregates. These microstructures can increase the mechanical bite force between the bamboo aggregates and concrete, thereby enhancing the interfacial bonding performance;

[0016] Step 4: Preparation and immersion treatment of the modified solution

[0017] First, perform anti-corrosion treatment on the bamboo aggregates. Treat the bamboo aggregates with alkaline copper quaternary ammonium salt solution to prevent decay, drain the water, dry, and then prepare the solution;

[0018] Prepare a modified solution, which consists of the following components:

[0019] Silane coupling agent: with a mass fraction of 5% - 10%. The silane coupling agent can form chemical bonds on the surface of the bamboo aggregates, enhancing the chemical bonding force between the bamboo aggregates and concrete;

[0020] Acrylic emulsion: with a mass fraction of 10% - 15%. The acrylic emulsion has good adhesiveness and film-forming properties, and can form a flexible film on the surface of the bamboo aggregates, improving the interfacial compatibility between the bamboo aggregates and concrete;

[0021] Nano-silica sol: with a mass fraction of 5% - 8%. The nano-silica sol can fill the tiny pores on the surface of the bamboo aggregates, improve the density of the bamboo aggregates, and at the same time enhance the physical bonding force of the interface;

[0022] Mix the above components in proportion, add water, stir evenly at room temperature, with a stirring speed of 300 - 500 r / min and a stirring time of 30 - 60 min to obtain a uniform and stable modified solution;

[0023] Bamboo aggregate immersion:

[0024] Put the prepared bamboo aggregates into the prepared modified solution for immersion. Control the immersion temperature at 25℃ - 40℃ and the immersion time at 24 - 48 h. During the immersion process, ensure that the bamboo aggregates are completely immersed in the solution, and stir the solution regularly every 4 - 6 h to make the surface of the bamboo aggregates fully contact with the solution, ensuring uniform impregnation modification effect;

[0025] Step 5: Gradient drying treatment of bamboo aggregates

[0026] Drying method:

[0027] After the soaking is completed, take out the bamboo aggregates, drain the excess solution on the surface, and then perform drying treatment by the gradient drying method. First, place the bamboo aggregates in an environment with a temperature of 30 - 40 °C and a relative humidity of 40% - 50% for 12 - 24 h to preliminarily cure the solution on the surface of the bamboo aggregates. Then, raise the temperature to 50 - 60 °C and reduce the relative humidity to 30% - 40%, and continue drying for 12 - 24 h to gradually drain the moisture inside the bamboo aggregates. At the same time, the modified solution forms a firm modified layer on the surface of the bamboo aggregates;

[0028] Drying time:

[0029] The total time for the entire drying process is 24 - 48 h. By the gradient drying method, it is possible to avoid defects such as cracking of the bamboo aggregates due to too fast drying speed, and at the same time ensure that the modified layer can be fully cured and stably attached to the surface of the bamboo aggregates, thereby effectively enhancing the interfacial bonding performance between the bamboo aggregates and the concrete;

[0030] Step Six: Further optimization of interfacial enhancement performance and recycling treatment

[0031] Recycling treatment: For bamboo aggregates with unqualified interfacial enhancement performance, re - perform the surface optimization, soaking, and drying steps to improve the performance, ensuring the quality consistency and repeatability of the final product.

[0032] Preferably, in the above - mentioned Step One, the moso bamboo selected as the raw material is the moso bamboo growing in the subtropical region in the south of China, at an altitude of 300 - 800 meters.

[0033] Preferably, in the above - mentioned Step One, an intelligent humidity monitoring and control system is introduced during the drying process of bamboo. The moisture content is monitored in real time, and the ventilation and humidity conditions are automatically adjusted to ensure that the moisture content of the bamboo decreases evenly and stably to the target range. At the same time, in the later stage of drying, microwave drying technology is used to uniformly heat the inside of the bamboo, thereby improving the drying efficiency and the overall drying quality.

[0034] Preferably, in the above - mentioned Step Two, a double - shaft crusher is used for bamboo crushing. The rotational speeds and spacings of the two crushing shafts of the crusher are intelligently adjusted according to the characteristics of the bamboo and the required aggregate particle size. During the crushing process, the aggregate particle size is monitored in real time through an internal particle size detection sensor to achieve precise control of the crushing process, ensuring that the crushed particle size is uniformly concentrated at 5 - 15 mm. After crushing, the bamboo aggregates are classified by air classification technology to accurately separate the bamboo aggregates with different particle sizes for targeted use according to different construction requirements.

[0035] Preferably, in the above step two, a nanoscale diamond grinding wheel is also used for fine grinding to make the surface roughness of the bamboo aggregate reach Ra0.5 - 0.8μm, further increasing the contact area with the concrete. Meanwhile, during the grinding process, active groups such as hydroxyl and carboxyl groups are introduced onto the surface of the bamboo aggregate through plasma treatment technology. These active groups can enhance the chemical bonding force between the bamboo aggregate and the subsequent modification solution.

[0036] Preferably, in the above step three, based on the original composition of the modification solution, 2% - 5% of polycarboxylate superplasticizer and 1% - 3% of sodium lignosulfonate are added. The former reduces the surface tension to optimize permeability, and the latter forms hydrogen bond binding with bamboo fibers to enhance strength and toughness. Meanwhile, the addition sequence and stirring process of each component are optimized. First, the silane coupling agent and sodium lignosulfonate are mixed evenly at a high stirring speed of 800 - 1000r / min, then the acrylic emulsion and nano-silica sol are slowly added, and stirring continues for 30 - 60min. Finally, the polycarboxylate superplasticizer and the remaining water are added, and the stirring speed is reduced to 300 - 500r / min, and the stirring time is extended to 60 - 90min to ensure that the solution is uniform and stable and each component fully exerts its synergistic effect.

[0037] Preferably, when the bamboo aggregate is immersed in the modification solution in the above step three, an ultrasonic-assisted immersion technology is also adopted. Ultrasonic waves can generate cavitation effects in the solution, forming tiny bubbles that burst instantly. The generated impact force can prompt the modification solution to penetrate more quickly and deeply into the interior of the bamboo aggregate, shortening the immersion time to 18 - 36h. Meanwhile, an on-line monitoring system is installed to real-time monitor the concentration changes of each component in the solution and the formation of the surface modification layer on the bamboo aggregate, and the immersion time and solution composition are automatically adjusted according to the monitoring results to ensure that the modification effect reaches the best state.

[0038] Preferably, in the above step four, a combination of vacuum freeze-drying and far-infrared drying is also adopted. First, the immersed bamboo aggregate is quickly frozen to -30℃ to -40℃ in a vacuum environment, so that the moisture inside the bamboo aggregate is quickly frozen into ice crystals. Then, it is slowly heated to 0℃ - 10℃ under vacuum conditions to sublime the ice crystals and achieve preliminary drying. This process can effectively avoid the shrinkage and deformation of the bamboo aggregate caused by water evaporation. Then, the bamboo aggregate is subjected to secondary drying using far-infrared drying technology. Far-infrared rays can penetrate the surface of the bamboo aggregate and directly heat the internal moisture, enabling it to evaporate quickly. The drying efficiency is high and the internal and external parts of the bamboo aggregate can be dried evenly. During the far-infrared drying process, the temperature and moisture content of the bamboo aggregate are real-time monitored through temperature sensors and humidity sensors, and the drying temperature is precisely controlled at 40℃ - 60℃, and the relative humidity is at 20% - 30% to ensure that the drying process is stable and efficient, and the total drying time is shortened to 18 - 36h.

[0039] Preferably, the intelligent humidity monitoring and control system includes:

[0040] Humidity sensor:

[0041] Distributed at different positions in the bamboo drying environment, including every corner of the drying chamber and ventilation ducts, for real-time collection of environmental humidity data;

[0042] Common types include capacitive humidity sensors, resistive humidity sensors, etc. Capacitive humidity sensors measure humidity by detecting changes in humidity-sensitive capacitors, with advantages of good linearity and high stability; resistive humidity sensors work based on the principle that the value of the humidity-sensitive resistor changes with humidity and have relatively low costs.

[0043] Data acquisition module:

[0044] Responsible for receiving the analog signals collected by the humidity sensors and converting them into digital signals for subsequent processing and transmission. This module has the ability to collect multiple signals and can process data from multiple sensors simultaneously to ensure data integrity and accuracy;

[0045] It may also have functions such as signal amplification and filtering to remove noise interference and improve data quality.

[0046] Central controller:

[0047] Is the core of the entire system, responsible for processing and analyzing the humidity data from the data acquisition module. According to the preset control algorithm and target humidity value, the central controller issues control instructions to adjust the humidity of the drying environment;

[0048] For example, when the humidity is higher than the set value, the controller will start the ventilation equipment or dehumidification equipment; when the humidity is lower than the set value, the controller will control the humidification equipment to work.

[0049] PLC has advantages such as high reliability, convenient programming, and strong anti-interference ability, and is suitable for complex control in industrial environments; single-chip microcomputers have characteristics such as low cost, small size, and high flexibility, and are often used in small or specific-function control systems.

[0050] Actuator:

[0051] Includes ventilation equipment, dehumidification equipment, and humidification equipment. These devices work according to the instructions of the central controller to achieve humidity adjustment;

[0052] The ventilation equipment affects humidity by changing the air circulation speed and flow rate, the dehumidification equipment removes moisture in the air through physical or chemical methods, and the humidification equipment adds moisture to the air to increase humidity.

[0053] Human-machine interface:

[0054] A touch screen or computer software interface for operators to interact with the system. Through the human-machine interaction interface, operators can set the target humidity value, view real-time humidity data, historical data records, system operation status and other information, and can also perform operations such as system parameter adjustment and fault diagnosis.

[0055] The interface design is simple and intuitive, making it easy for operators to quickly master and use.

[0056] Compared with the prior art, the present invention provides a bamboo aggregate interface enhancement method for the preparation of low-carbon concrete, having the following beneficial effects:

[0057] The compressive strength of the bamboo aggregate concrete after treatment is higher than that of the untreated one. This means that when bearing pressure loads, the structure can better maintain stability and can be applied to building scenarios with higher load-bearing capacity requirements, such as the non-load-bearing structure parts of multi-story buildings, etc.

[0058] The tensile strength is increased, enhancing the ability of the material to resist tensile failure. For structural parts that may bear tensile forces, such as the tensile zones of some flexural members, etc., it can effectively reduce the cracking risk and improve the integrity and safety of the structure.

[0059] The flexural strength is increased, making it less likely to break when bearing bending loads, broadening the application range of bamboo aggregate concrete in flexural structures such as road pavements and bridge decks.

[0060] Adopting a new type of double-shaft crusher combined with an internal particle size detection sensor and air classification technology can not only make the particle size of bamboo aggregates more evenly concentrated in the range of 5-15 mm, but also accurately separate bamboo aggregates of different particle sizes according to different building requirements, improving the standardization degree of bamboo aggregate products, facilitating the use according to needs in different building structures, and enhancing the flexibility and adaptability of material use.

[0061] Introducing an intelligent humidity monitoring and control system during the bamboo drying process, through the coordinated work of its humidity sensor, data acquisition module, central controller and actuator and other components, realizes the precise and stable control of the moisture content of bamboo. It can monitor and automatically adjust the ventilation volume and environmental humidity in real time, and cooperate with microwave drying technology to ensure the overall drying quality of bamboo, avoiding affecting the subsequent performance of bamboo aggregates due to problems such as uneven moisture content, and laying a good foundation for the production of high-quality bamboo aggregates.

[0062] Add polycarboxylate superplasticizer and sodium lignosulfonate to the modified solution, and optimize the addition sequence and stirring process of each component to enable each component to fully exert its synergistic effect, reduce the surface tension of the solution, and improve its penetration ability. This not only allows the modified solution to better penetrate into the tiny pores of bamboo aggregates, ensuring the uniformity of the modification effect, but also further enhances the strength and toughness of the bamboo aggregates themselves, comprehensively improving the comprehensive performance of bamboo aggregates;

[0063] With the help of ultrasonic-assisted soaking technology and an online monitoring system, the modified solution is promoted to quickly and deeply penetrate the bamboo aggregates. While shortening the soaking time, it can also adjust the soaking time and solution composition in real time according to the monitoring results, ensuring that the modification effect reaches the best state, improving production efficiency, and ensuring the stable and reliable quality of the modified bamboo aggregates for each batch;

[0064] Make full use of bamboo, a renewable resource, reduce the dependence on traditional non-renewable building materials, reduce the resource consumption and environmental pressure of the construction industry, and various technical means involved in the entire production process pay attention to energy conservation and environmental protection. In the long run, it has good economic, social and environmental benefits, conforms to the current general trend of green development in the construction industry, and has a positive significance in promoting the application of sustainable building materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 It is a schematic flow chart of the method steps of the present invention.

[0066] Figure 2 It is a schematic diagram of the intelligent humidity monitoring and control system of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0067] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0068] The present invention provides Figure 1-2 as shown

[0069] A method for enhancing the interface of bamboo aggregates that can be used for the preparation of low-carbon concrete, including: The specific steps of the method are as follows

[0070] Step 1: Selection and preliminary treatment of bamboo

[0071] Type of bamboo: Select moso bamboo with a growth age of 3 - 6 years as the raw material. Moso bamboo has high strength and toughness, and is rich in resources, making it suitable as the source of bamboo aggregates;

[0072] Moisture content control of bamboo materials:

[0073] After cutting down the moso bamboo, immediately conduct preliminary treatment to remove the impurities of branches and leaves as well as the bamboo green and bamboo yellow. Then place the bamboo materials in a well-ventilated environment for natural drying to reduce the moisture content to 10%-15%. This moisture content range can not only ensure that the bamboo materials have a certain flexibility, but also facilitate subsequent processing, while reducing the adverse effects of moisture on the interface bonding between bamboo aggregates and concrete;

[0074] Step 2: Preparation of bamboo aggregates

[0075] Crushing of bamboo aggregates:

[0076] Adopt the method of mechanical crushing to crush the dried bamboo materials into aggregates of different sizes. First, use a cutting machine to cut the bamboo materials into small sections with a length of 5-10 cm. Then put the small sections of bamboo materials into a crusher for secondary crushing to obtain bamboo aggregates with a particle size of 5-15 mm. During the crushing process, pay attention to controlling the crushing force and speed to avoid excessive crushing resulting in excessive damage to bamboo fibers and affecting the performance of bamboo aggregates;

[0077] Step 3: Shape optimization and microstructure enhancement of bamboo aggregates

[0078] Engraving of grooves and protrusions on the surface of bamboo aggregates:

[0079] In order to increase the contact area between bamboo aggregates and concrete and improve the interfacial bonding force, conduct shape optimization treatment on the crushed bamboo aggregates. Through processes such as screening and grinding, make the shape of bamboo aggregates as close as possible to spherical or cubic, reducing sharp edges and corners. At the same time, create some tiny grooves and protrusions on the surface of bamboo aggregates, including using laser engraving technology to form grooves and protrusions with a depth of 0.1-0.3 mm and a spacing of 2-3 mm on the surface of bamboo aggregates. These microstructures can increase the mechanical interlocking force between bamboo aggregates and concrete, thereby enhancing the interfacial bonding performance;

[0080] Step 4: Preparation and immersion treatment of the modified solution

[0081] First, conduct anti-corrosion treatment on bamboo aggregates. Treat bamboo aggregates with alkaline copper quaternary ammonium salt solution to prevent decay, drain the moisture, and dry. Then conduct the preparation of the solution;

[0082] Prepare a modified solution, which consists of the following components:

[0083] Silane coupling agent: with a mass fraction of 5%-10%. The silane coupling agent can form chemical bonds on the surface of bamboo aggregates to enhance the chemical bonding force between bamboo aggregates and concrete;

[0084] Acrylic emulsion: with a mass fraction of 10%-15%, the acrylic emulsion has good adhesion and film-forming properties, and can form a flexible film on the surface of bamboo aggregates, improving the interfacial compatibility between bamboo aggregates and concrete;

[0085] Nanosilica sol: with a mass fraction of 5%-8%, the nanosilica sol can fill the tiny pores on the surface of bamboo aggregates, improve the density of bamboo aggregates, and enhance the physical adhesion of the interface at the same time.

[0086] Mix the above components in proportion, add water, and stir evenly at room temperature. The stirring speed is 300-500 r / min, and the stirring time is 30-60 min to obtain a uniform and stable modified solution;

[0087] Soaking of bamboo aggregates:

[0088] Put the prepared bamboo aggregates into the prepared modified solution for soaking. The soaking temperature is controlled at 25°C - 40°C, and the soaking time is 24-48 h. During the soaking process, it is necessary to ensure that the bamboo aggregates are completely immersed in the solution, and stir the solution regularly every 4-6 h to make the surface of the bamboo aggregates fully contact with the solution and ensure uniform modification effect;

[0089] Step Five: Gradient drying treatment of bamboo aggregates

[0090] Drying method:

[0091] After soaking, take out the bamboo aggregates, drain the excess solution on the surface, and then carry out drying treatment by gradient drying method. First, place the bamboo aggregates in an environment with a temperature of 30-40°C and a relative humidity of 40%-50% for 12-24 h to preliminarily solidify the solution on the surface of the bamboo aggregates. Then raise the temperature to 50-60°C and lower the relative humidity to 30%-40%, and continue drying for 12-24 h to gradually discharge the moisture inside the bamboo aggregates. At the same time, the modified solution forms a firm modified layer on the surface of the bamboo aggregates;

[0092] Drying time:

[0093] The total time of the entire drying process is 24-48 h. By the gradient drying method, it is possible to avoid defects such as cracking of bamboo aggregates due to too fast drying speed, and at the same time ensure that the modified layer can be fully cured and stably attached to the surface of bamboo aggregates, thereby effectively enhancing the interfacial bonding performance between bamboo aggregates and concrete;

[0094] Step Six: Re-optimization of interfacial enhancement performance and recycling treatment

[0095] Recycling treatment: For bamboo aggregates with unqualified interfacial enhancement performance, re-perform surface optimization, soaking and drying steps to improve performance, ensuring the quality consistency and repeatability of the final product.

[0096] In the first step above, the moso bamboo selected is grown in the subtropical region in the south of China at an altitude of 300 - 800 meters.

[0097] In the first step above, during the drying process of the bamboo material, an intelligent humidity monitoring and control system is introduced to monitor the moisture content in real time and automatically adjust the ventilation and humidity conditions to ensure that the moisture content of the bamboo material is uniformly and stably reduced to the target range. At the same time, in the later stage of drying, microwave drying technology is used to uniformly heat the inside of the bamboo material, thereby improving the drying efficiency and the overall drying quality.

[0098] In the second step above, a double - shaft crusher is used for bamboo material crushing. The rotational speeds and spacings of the two crushing shafts of this crusher are intelligently adjusted according to the characteristics of the bamboo material and the required aggregate particle size. During the crushing process, the aggregate particle size is monitored in real time through the built - in particle size detection sensor to achieve precise control of the crushing process, ensuring that the crushed particle size is uniformly concentrated between 5 - 15 mm. After crushing, air classification technology is used to classify the bamboo aggregates, and the bamboo aggregates with different particle sizes are accurately separated for subsequent targeted use according to different building requirements.

[0099] In the second step above, a nanoscale diamond grinding wheel is also used for fine grinding to make the surface roughness of the bamboo aggregates reach Ra0.5 - 0.8 μm, further increasing the contact area with concrete. At the same time, during the grinding process, active groups such as hydroxyl and carboxyl groups are introduced onto the surface of the bamboo aggregates through plasma treatment technology, and these active groups can enhance the chemical bonding force between the bamboo aggregates and the subsequent modification solution.

[0100] In the third step above, on the basis of the original modification solution components, 2% - 5% of polycarboxylate superplasticizer and 1% - 3% of sodium lignosulfonate are added. The former reduces the surface tension to optimize permeability, and the latter forms hydrogen - bond binding with bamboo fibers to enhance strength and toughness. At the same time, the addition sequence and stirring process of each component are optimized. First, the silane coupling agent and sodium lignosulfonate are mixed evenly at a high - speed stirring of 800 - 1000 r / min, then the acrylic emulsion and nano - silica sol are slowly added, and stirring continues for 30 - 60 min. Finally, the polycarboxylate superplasticizer and the remaining water are added, and the stirring speed is reduced to 300 - 500 r / min, and the stirring time is extended to 60 - 90 min to ensure that the solution is uniform and stable and each component fully exerts its synergistic effect.

[0101] When the bamboo aggregates are immersed in the modification solution in the third step above, an ultrasonic-assisted immersion technique is also adopted. Ultrasonic waves can generate cavitation effects in the solution, forming tiny bubbles that burst instantaneously. The impact force generated can prompt the modification solution to penetrate more quickly and deeply into the interior of the bamboo aggregates, shortening the immersion time to 18 - 36 h. Meanwhile, an on-line monitoring system is installed to monitor the concentration changes of various components in the solution and the formation of the modified layer on the surface of the bamboo aggregates in real time, and the immersion time and solution components are automatically adjusted according to the monitoring results to ensure that the modification effect reaches the optimal state.

[0102] In the fourth step above, a combination of vacuum freeze-drying and far-infrared drying is also adopted. First, the immersed bamboo aggregates are quickly frozen to -30°C to -40°C in a vacuum environment, causing the moisture inside the bamboo aggregates to freeze rapidly into ice crystals. Then, the temperature is slowly raised to 0°C - 10°C under vacuum conditions to sublimate the ice crystals, achieving preliminary drying. This process can effectively avoid shrinkage and deformation of the bamboo aggregates due to moisture evaporation. Next, the bamboo aggregates are subjected to secondary drying using far-infrared drying technology. Far-infrared rays can penetrate the surface of the bamboo aggregates and directly heat the internal moisture, causing it to evaporate rapidly. The drying efficiency is high and the drying of the interior and exterior of the bamboo aggregates is uniform. During the far-infrared drying process, the temperature and moisture content of the bamboo aggregates are monitored in real time through temperature sensors and humidity sensors, and the drying temperature is precisely controlled at 40°C - 60°C and the relative humidity at 20% - 30% to ensure a stable and efficient drying process, and the total drying time is shortened to 18 - 36 h.

[0103] The intelligent humidity monitoring and control system includes:

[0104] Humidity sensors:

[0105] They are distributed at different positions in the bamboo drying environment, including all corners of the drying chamber and ventilation ducts, and are used to collect environmental humidity data in real time;

[0106] Common types include capacitive humidity sensors, resistive humidity sensors, etc. Capacitive humidity sensors measure humidity by detecting changes in humidity-sensitive capacitors, and their advantages are good linearity and high stability; resistive humidity sensors work based on the principle that the value of the humidity-sensitive resistor changes with humidity, and the cost is relatively low.

[0107] Data acquisition module:

[0108] It is responsible for receiving the analog signals collected by the humidity sensors and converting them into digital signals for subsequent processing and transmission. This module has the ability to collect multiple signals and can process the data of multiple sensors simultaneously to ensure the integrity and accuracy of the data;

[0109] It may also have functions such as signal amplification and filtering to remove noise interference and improve data quality.

[0110] Central controller (such as PLC, single-chip microcomputer, etc.):

[0111] It is the core of the entire system, responsible for processing and analyzing the humidity data from the data acquisition module. According to the preset control algorithm and target humidity value, the central controller issues control instructions to adjust the humidity of the drying environment;

[0112] For example, when the humidity is higher than the set value, the controller will start the ventilation equipment or dehumidification equipment; when the humidity is lower than the set value, the controller will control the humidification equipment to work.

[0113] PLC (Programmable Logic Controller) has the advantages of high reliability, convenient programming, strong anti-interference ability, etc., and is suitable for complex control in industrial environments; the single-chip microcomputer has the characteristics of low cost, small volume, high flexibility, etc., and is often used in small or specific function control systems.

[0114] Actuator:

[0115] It includes ventilation equipment (such as fans, ventilation ducts, etc.), dehumidification equipment (such as dehumidifiers), and humidification equipment (such as humidifiers). These devices work according to the instructions of the central controller to achieve the adjustment of humidity;

[0116] The ventilation equipment affects the humidity by changing the air circulation speed and flow rate. The dehumidification equipment removes moisture in the air through physical or chemical methods, and the humidification equipment adds moisture to the air to increase the humidity.

[0117] Human-machine interface (HMI):

[0118] A touch screen or computer software interface for operators to interact with the system. Through the human-machine interface, operators can set the target humidity value, view real-time humidity data, historical data records, system operation status and other information, and can also perform operations such as system parameter adjustment and fault diagnosis.

[0119] The interface design is simple and intuitive, which is convenient for operators to quickly master and use.

[0120] Humidity data acquisition:

[0121] The humidity sensor continuously monitors the humidity in the drying environment and converts the humidity signal into an electrical signal (such as a voltage or current signal). These electrical signals are transmitted to the data acquisition module through the data line.

[0122] Data processing and analysis:

[0123] After the data acquisition module preprocesses the received analog signals, such as amplification and filtering, it converts them into digital signals and transmits them to the central controller. The central controller analyzes and processes these digital signals, compares them with the preset target humidity value, and calculates the humidity deviation and change trend.

[0124] Control instruction generation and output:

[0125] According to the humidity deviation and change trend, the central controller generates corresponding control instructions according to the built-in control algorithm (such as the PID control algorithm). For example, if the humidity is higher than the target value, the controller will output a control signal to start the dehumidification device or increase the ventilation volume; if the humidity is lower than the target value, the humidification device will be started or the ventilation volume will be reduced.

[0126] Actuator action:

[0127] After receiving the control instruction from the central controller, the actuator immediately performs the corresponding action. The ventilation equipment adjusts the fan speed or the opening degree of the ventilation duct valve, the dehumidification device starts to work to remove moisture in the air, the humidification device sprays water mist into the air, etc., so as to change the humidity of the dry environment.

[0128] Feedback and adjustment:

[0129] The humidity sensor continues to monitor the environmental humidity in real time and feeds the new data back to the central controller. The central controller continuously adjusts the control instruction according to the feedback information, so that the humidity gradually stabilizes near the target value, realizes closed-loop control, and ensures the accuracy and stability of humidity control.

[0130] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A bamboo aggregate interface reinforcement method for preparing low-carbon concrete, characterized in that: include: The specific steps of the method are as follows Step 1: Selection and preliminary processing of bamboo Type of bamboo: Choose bamboo with a growth period of 3-6 years as the raw material. Bamboo has high strength and toughness, and is abundant in resources, making it suitable as a source of bamboo aggregate; Moisture content control of bamboo: After the bamboo is cut down, it is immediately processed to remove impurities and green and yellow bamboo from the branches and leaves, and then placed in a well-ventilated environment to dry naturally to reduce the moisture content to 10%-15%: Step 2: Preparation of bamboo aggregate Crushing of bamboo aggregate: The dried bamboo is crushed into aggregates of 5-15 mm by mechanical crushing; Step 3: Shape optimization and microstructure enhancement of bamboo aggregate Grooved and raised carvings on bamboo aggregate surface: In order to increase the contact area between bamboo aggregate and concrete and improve the interface bonding force, the crushed bamboo aggregate is subjected to shape optimization treatment. Through screening and grinding, the shape of the bamboo aggregate is made as close to sphere or cube as possible, and the sharp edges and corners are reduced. At the same time, some tiny grooves and protrusions are made on the surface of the bamboo aggregate, including the use of laser engraving technology to form grooves and protrusions with a depth of 0.1-0.3mm and a spacing of 2-3mm on the surface of the bamboo aggregate. These microstructures can increase the mechanical bite force between the bamboo aggregate and the concrete, thereby enhancing the interface bonding performance; Step 4: Preparation and soaking of modified solution Firstly, the bamboo aggregate is treated with an alkaline copper quaternary ammonium salt solution to prevent decay, the water is drained, and the solution is then prepared; Prepare a modification solution consisting of the following ingredients: Silane coupling agent: The mass fraction is 5%-10%. The silane coupling agent can form chemical bonds on the surface of bamboo aggregate and enhance the chemical bonding between bamboo aggregate and concrete; Acrylic emulsion: The mass fraction is 10%-15%. Acrylic emulsion has good adhesion and film-forming properties. It can form a flexible film on the surface of bamboo aggregate and improve the interfacial compatibility between bamboo aggregate and concrete. Nano-silica sol: The mass fraction is 5%-8%. Nano-silica sol can fill the tiny pores on the surface of bamboo aggregate, improve the density of bamboo aggregate, and enhance the physical bonding force of the interface; Mix the above ingredients in proportion, add water, and stir evenly at room temperature at a stirring speed of 300-500r / min and a stirring time of 30-60min to obtain a uniform and stable modified solution; Bamboo aggregate soaking: Soak the prepared bamboo aggregate in the prepared modified solution. The soaking temperature is controlled at 25℃-40℃ and the soaking time is 24-48h. During the soaking process, ensure that the bamboo aggregate is completely immersed in the solution and stir the solution regularly every 4-6h to ensure that the surface of the bamboo aggregate can fully contact with the solution to ensure uniform soaking modification effect. Step 5: Gradient drying of bamboo aggregate Drying method: After soaking, the bamboo aggregate is taken out, the excess solution on the surface is drained, and then the bamboo aggregate is dried by gradient drying. First, the bamboo aggregate is placed in an environment with a temperature of 30-40°C and a relative humidity of 40%-50% for 12-24 hours to initially solidify the solution on the surface of the bamboo aggregate. Then, the temperature is increased to 50-60°C and the relative humidity is reduced to 30%-40%. The drying is continued for 12-24 hours to gradually discharge the moisture inside the bamboo aggregate. At the same time, the modified solution forms a firm modified layer on the surface of the bamboo aggregate. Drying time: The total time of the whole drying process is 24-48h. Through the gradient drying method, cracking and other defects of bamboo aggregate caused by too fast drying speed can be avoided. At the same time, the modified layer can be fully cured and stably attached to the surface of bamboo aggregate, thereby effectively enhancing the interface bonding performance between bamboo aggregate and concrete. Step 6: Interface enhancement, performance optimization and loop processing Recycling: Bamboo aggregates that do not meet the interface reinforcement performance standards are re-processed through surface optimization, soaking and drying steps to improve performance and ensure the quality consistency and repeatability of the final product.

2. The method for reinforcing the bamboo aggregate interface that can be used for preparing low-carbon concrete according to claim 1, characterized in that: In the above step 1, the raw materials are bamboo grown in the subtropical region of southern my country at an altitude of 300-800 meters.

3. The method for reinforcing the bamboo aggregate interface that can be used for preparing low-carbon concrete according to claim 1, characterized in that: In the above step 1, an intelligent humidity monitoring and control system is introduced during the bamboo drying process to monitor the moisture content in real time and automatically adjust the ventilation and humidity conditions to ensure that the moisture content of the bamboo is evenly and stably reduced to the target range. At the same time, in the later stage of drying, microwave drying technology is used to evenly heat the inside of the bamboo, thereby improving the drying efficiency and overall drying quality.

4. The method for reinforcing the bamboo aggregate interface that can be used for preparing low-carbon concrete according to claim 1, characterized in that: In the above step 2, a double-shaft crusher is used to crush the bamboo. The two crushing shafts of the crusher intelligently adjust the rotation speed and spacing according to the characteristics of the bamboo and the required aggregate particle size. During the crushing process, the aggregate particle size is monitored in real time through the built-in particle size detection sensor to achieve precise control of the crushing process and ensure that the crushed particle size is evenly concentrated at 5-15mm. After the crushing is completed, the bamboo aggregate is graded using air flow classification technology to accurately separate bamboo aggregates of different particle sizes so that they can be used in a targeted manner according to different construction needs.

5. The method for reinforcing the bamboo aggregate interface that can be used for preparing low-carbon concrete according to claim 1, characterized in that: In the above step 2, a nano-scale diamond grinding wheel is also used for fine grinding to make the surface roughness of the bamboo aggregate reach Ra0.5-0.8μm, further increasing the contact area with the concrete. At the same time, during the grinding process, active groups such as hydroxyl and carboxyl are introduced on the surface of the bamboo aggregate through plasma treatment technology. These active groups can enhance the chemical bonding between the bamboo aggregate and the subsequent modified solution.

6. The method for reinforcing the bamboo aggregate interface that can be used for preparing low-carbon concrete according to claim 1, characterized in that: In the above step three, on the basis of the original modified solution components, 2%-5% of polycarboxylate water reducer and 1%-3% of sodium lignin sulfonate are added, the former reduces the surface tension to optimize the permeability, and the latter forms hydrogen bonds with bamboo fiber to improve the strength and toughness. At the same time, the order of adding each component and the stirring process are optimized. First, the silane coupling agent and sodium lignin sulfonate are mixed evenly under high-speed stirring at 800-1000r / min, and then the acrylic emulsion and nano silica sol are slowly added, and stirring is continued for 30-60min. Finally, the polycarboxylate water reducer and the remaining water are added, the stirring speed is reduced to 300-500r / min, and the stirring time is extended to 60-90min to ensure that the solution is uniform and stable and the components give full play to the synergistic effect.

7. The method for reinforcing the bamboo aggregate interface that can be used for preparing low-carbon concrete according to claim 1, characterized in that: When the bamboo aggregate is immersed in the modified solution in the above step three, ultrasonic-assisted immersion technology is also used. Ultrasonic waves can produce cavitation effect in the solution, forming tiny bubbles and bursting them instantly. The impact force generated can cause the modified solution to penetrate into the bamboo aggregate more quickly and deeply, shortening the immersion time to 18-36 hours. At the same time, an online monitoring system is installed to monitor the concentration changes of each component in the solution and the formation of the modified layer on the surface of the bamboo aggregate in real time. The immersion time and solution composition are automatically adjusted according to the monitoring results to ensure that the modification effect reaches the best state.

8. The method for reinforcing the bamboo aggregate interface that can be used for preparing low-carbon concrete according to claim 1, characterized in that: In the above step 4, a combination of vacuum freeze drying and far-infrared drying is also used. First, the soaked bamboo aggregate is quickly frozen to -30°C to -40°C in a vacuum environment, so that the water inside the bamboo aggregate is quickly frozen into ice crystals, and then slowly heated to 0°C-10°C under vacuum conditions to sublimate the ice crystals to achieve initial drying. This process can effectively avoid the shrinkage and deformation of the bamboo aggregate due to water evaporation. Then, the bamboo aggregate is secondary dried using far-infrared drying technology. Far-infrared rays can penetrate the surface of the bamboo aggregate, directly heat the internal water, and evaporate it quickly. The drying efficiency is high and the inside and outside of the bamboo aggregate can be dried evenly. During the far-infrared drying process, the temperature and moisture content of the bamboo aggregate are monitored in real time by temperature sensors and humidity sensors, and the drying temperature is accurately controlled at 40°C-60°C and the relative humidity is 20%-30%, ensuring that the drying process is stable and efficient, and the total drying time is shortened to 18-36h.

9. The method for reinforcing the bamboo aggregate interface that can be used for preparing low-carbon concrete according to claim 3, characterized in that: Intelligent humidity monitoring and control system includes: Humidity Sensor: Distributed in different locations of the bamboo drying environment, in every corner of the drying room and ventilation ducts, to collect environmental humidity data in real time; Data acquisition module: Responsible for receiving the analog signals collected by the humidity sensor and converting them into digital signals for subsequent processing and transmission. The module has multi-channel signal acquisition capabilities and can process data from multiple sensors at the same time to ensure data integrity and accuracy; Central Controller: It is the core of the whole system, responsible for processing and analyzing the humidity data from the data acquisition module. According to the preset control algorithm and target humidity value, the central controller issues control instructions to adjust the humidity of the drying environment. Actuator: Including ventilation equipment, dehumidification equipment, humidification equipment, these equipment work according to the instructions of the central controller to adjust the humidity; Human-computer interaction interface: The touch screen or computer software interface is used for the operator to interact with the system. Through the human-computer interaction interface, the operator can set the target humidity value, view real-time humidity data, historical data records, system operating status information, and can also adjust system parameters and perform fault diagnosis and other operations.

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