Glass-based fine aggregate, UHPC, and preparation method and application thereof

Abstract

The present invention relates to a glass-based fine aggregate, UHPC and a preparation method and application thereof, and belongs to the technical field of building materials. The preparation method of the glass-based fine aggregate comprises: heating the glass crushed to a set particle size at 500-600°C for 1-2h, adding acetic acid during the heating process; and then using nano-silica sol for surface modification to obtain the glass-based fine aggregate. The UHPC comprises 400-500 parts of cement, 45-135 parts of modified glass powder, 40-50 parts of silica fume, 140-350 parts of glass-based fine aggregate and 165-330 parts of glass-based coarse aggregate; the raw materials for preparing the modified glass powder include glass powder and lithium salt, and the raw materials for preparing the glass-based coarse aggregate include glass particles and silane coupling agent. Waste glass only needs physical crushing, screening and modification to realize functional application in concrete, and all show excellent physical and chemical properties.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and in particular relates to a glass-based fine aggregate, UHPC and a preparation method and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Ultra-High Performance Concrete (UHPC) is a new type of cement-based composite material with ultra-high strength, high toughness and high durability. Although UHPC is widely used due to its excellent mechanical properties, density and durability. However, UHPC production relies on a high amount of ordinary Portland cement, which leads to significant carbon dioxide emissions and resource consumption.

[0004] The accelerated development of urbanization and industrialization has led to the massive generation of waste glass, and the low recycling rate and high landfill rate of waste glass have put serious pressure on the environment. Most of these waste glasses are simply landfilled or discarded, which not only wastes resources but also leads to long-term ecological burdens. Therefore, it is of great significance to recycle waste glass and use it to partially replace traditional materials for UHPC. This can not only reduce the impact of waste glass on the environment, but also reduce the amount of cement used, thereby significantly reducing the carbon footprint. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a glass-based fine aggregate, UHPC and a preparation method and application thereof. After processing such as crushing, grinding and screening, waste glass can be used as a substitute for cementitious materials, fine aggregate and coarse aggregate, which not only reduces the consumption of natural resources, but also significantly reduces the carbon footprint of UHPC production.

[0006] In order to achieve the above object, the technical solution of the present invention is:

[0007] In a first aspect, a method for preparing glass-based fine aggregate comprises the following steps:

[0008] The glass crushed to a set particle size is heated at 500-600°C for 1-2 hours, and acetic acid is added at a mass ratio of 1-2% during the heating process; after cooling, 1-3% by mass of nano-silica sol and 1%-2% by mass of lithium salt are used for surface modification to obtain glass-based fine aggregate.

[0009] In a second aspect, the glass-based fine aggregate is prepared by the above-mentioned method for preparing glass-based fine aggregate.

[0010] In a third aspect, a UHPC based on the above-mentioned glass-based fine aggregate comprises the following components in parts by weight:

[0011] 400-500 parts of cement, 45-135 parts of modified glass powder, 40-50 parts of silica fume, 500-700 parts of fine aggregate, 140-350 parts of the glass-based fine aggregate, 700-900 parts of coarse aggregate, 165-330 parts of glass-based coarse aggregate, 30-50 parts of steel fiber, 120-150 parts of water and 5-8 parts of water reducing agent;

[0012] The raw materials for preparing the modified glass powder include glass powder and lithium salt in a mass ratio of 100:(1-3), and the raw materials for preparing the glass-based coarse aggregate include glass particles and silane coupling agent in a mass ratio of 100:(1-3).

[0013] In a fourth aspect, the method for preparing the UHPC based on the above-mentioned glass-based fine aggregate comprises the following steps:

[0014] S1. Mixing glass powder crushed to a set particle size range with lithium salt in a ratio of 100:(1-2), and calcining at 700-800°C for 0.5-2h to obtain modified glass powder;

[0015] S2, heating the glass particles crushed to a set particle size at 500-600° C. for 0.5-1.5 h, and after cooling, performing surface modification with a silane coupling agent at a mass ratio of 1-2% of the glass particles to obtain a glass-based coarse aggregate;

[0016] S3, mixing cement, modified glass powder, silica fume, fine aggregate, the glass-based fine aggregate, coarse aggregate, the glass-based coarse aggregate, and adding water and a water reducing agent and stirring evenly;

[0017] S4, adding steel fiber while maintaining the stirring state, stirring evenly, and obtaining UHPC slurry;

[0018] S5. Cast the UHPC slurry and cure it to a set age.

[0019] Fifthly, the applications of the above-mentioned UHPC include: applications in bridges, high-rise buildings, nuclear power plants and protective projects.

[0020] Optional, including: core tubes and load-bearing components of high-rise buildings, waterproof and anti-seepage structures of subway tunnels and underground parking lots, marine, underground and cold area projects.

[0021] The beneficial effects of the present invention are:

[0022] 1. The invention proposes a simple and efficient waste glass processing process, which only requires physical crushing, screening and modification to realize the functional application of waste glass in concrete, without complex chemical treatment or expensive chemical additives. Whether as fine aggregate, coarse aggregate, or auxiliary cementitious material, it exhibits excellent physical and chemical properties. Fine aggregate is endowed with an internal curing function by introducing a uniform microbubble structure, effectively reducing the self-shrinkage of concrete; after the coarse aggregate is modified by a silane coupling agent, the interfacial bonding performance with the cement matrix is ​​significantly enhanced; waste glass powder exhibits excellent volcanic ash activity due to its high content of silica, and can react with calcium hydroxide in cement to form dense calcium silicate hydrate (CSH), thereby significantly optimizing the microstructure of UHPC and enhancing its mechanical properties and durability. The UHPC prepared based on the present invention can reach or even exceed 120 MPa in compressive strength at room temperature and pressure, which can meet the requirements of bridges, high-rise buildings and other engineering structures with strict requirements for high strength and high bearing capacity. Glass powder, with its excellent volcanic ash activity, further improves the density and durability of concrete. The low water absorption and excellent particle morphology of waste glass materials can effectively reduce the porosity of concrete and significantly improve its resistance to permeability and chemical erosion. At the same time, through high-temperature calcination and a variety of modification treatments, the alkali-aggregate reaction is effectively inhibited, avoiding the harm caused by expansion and cracks, thereby ensuring the long-term stability of concrete in complex and harsh environments. This further broadens its application scope in the field of high-performance building materials, allowing UHPC based on waste glass to show excellent durability and longer service life in special application scenarios such as marine environments, underground structures, and anti-freeze-thaw cycles. These modified characteristics make the ultra-high performance concrete (UHPC) based on waste glass show higher compressive strength, crack resistance and long-term durability as a whole, meeting the stringent requirements of high-performance building materials.

[0023] 2. The present invention uses waste glass to replace traditional fine aggregate (natural river sand), partially replace cement as an auxiliary cementitious material, and use it as a coarse aggregate to replace traditional coarse aggregate, thereby achieving efficient resource utilization of waste glass, reducing the over-exploitation of natural river sand and mine aggregates, and effectively alleviating natural resource consumption and environmental pressure. At the same time, the present invention reduces the amount of cement, greatly reduces energy consumption and carbon dioxide emissions in the cement production process, and significantly reduces the carbon footprint in the preparation process of ultra-high performance concrete (UHPC). This method not only reduces the complexity and cost of the production process, but also fully realizes the recycling of resources, reduces the impact of waste glass landfill on the environment, and provides a low-cost and sustainable solution for the industrial production of green building materials. The invention conforms to the development trend of green building materials and promotes the in-depth application of circular economy in the construction field. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0025] Figure 1 TEM image of the glass-based fine aggregate prepared in Example 1. DETAILED DESCRIPTION

[0026] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0027] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0028] A method for preparing glass-based fine aggregate comprises the following steps:

[0029] The glass crushed to a set particle size is heated at 500-600°C for 1-2 hours, and acetic acid is added at a mass ratio of 1-2% during the heating process; after cooling, the surface is modified using 1-3% by mass of nano-silica sol and 1%-2% by mass of lithium salt to obtain glass-based fine aggregate.

[0030] A uniform microbubble structure is introduced into the particles through high temperature and acetic acid reaction. This microbubble not only effectively reduces the density of fine aggregate, but also serves as an internal moisture storage point during the concrete hardening process, providing internal curing function, thereby reducing the self-shrinkage of concrete and extending its service life; the surface of fine aggregate is further activated by spraying nano-silica sol to improve its bonding performance with the cement matrix.

[0031] Optionally, the acetic acid is a 2-5 wt % aqueous solution, which is evenly sprayed after being heated to a set temperature.

[0032] Optionally, the nano-silica sol is an aqueous solution with a mass concentration of 20%, a particle size of 10-20 nm, and a pH value of 9.

[0033] Optionally, the coupling agent is allowed to dry naturally on the particle surface for 1-2 hours after spraying to fully solidify it.

[0034] A UHPC based on the above-mentioned glass-based fine aggregate comprises the following components in parts by weight:

[0035] 400-500 parts of cement, 45-135 parts of modified glass powder, 40-50 parts of silica fume, 500-700 parts of fine aggregate, 140-350 parts of the glass-based fine aggregate, 700-900 parts of coarse aggregate, 165-330 parts of glass-based coarse aggregate, 30-50 parts of steel fiber, 120-150 parts of water and 5-8 parts of water reducing agent;

[0036] The raw materials for preparing the modified glass powder include glass powder and lithium oxide in a mass ratio of 100: (1-3), and the raw materials for preparing the glass-based coarse aggregate include glass particles and silane coupling agent in a mass ratio of 100: (1-3).

[0037] Lithium salt modification can utilize the effect of lithium ions to effectively inhibit alkali-aggregate reaction, further improving the long-term stability and durability of concrete; the chemical action of silane coupling agent is used to enhance the interfacial bonding performance between glass aggregate and cement matrix; this modification process significantly improves the toughness and bonding strength of coarse aggregate, effectively reduces stress concentration, and thus improves the overall performance of concrete.

[0038] Optionally, the lithium oxide has a purity of ≥99% and a particle size of ≤100 μm.

[0039] Optionally, the silane coupling agent is γ-aminopropyltriethoxysilane (KH550) with a purity of ≥98%, a colorless or light yellow transparent liquid in appearance, and a specific gravity of 0.94-0.96 g / cm³.

[0040] Optionally, the particle size of the modified glass powder is less than 600 μm, the particle size of the glass-based fine aggregate is 0.15-4.75 mm, and the particle size of the glass-based coarse aggregate is 4.75-8 mm.

[0041] Optionally, the raw materials of the modified glass powder, the glass-based fine aggregate and the glass-based coarse aggregate include waste glass, which is initially crushed by a jaw crusher and then classified according to different uses.

[0042] Optionally, the cement is silicate cement or ordinary silicate cement with strength grade 52.5 or 52.5R.

[0043] Optionally, the mass percentage of silicon dioxide in the silica ash is not less than 95%, and the volcanic ash activity index is greater than 95%.

[0044] Optionally, the fine aggregate is natural river sand.

[0045] Optionally, the coarse aggregate is crushed stone with a particle size of 10-40 mm.

[0046] Optionally, the steel fiber is a straight brass galvanized steel fiber.

[0047] The method for preparing the UHPC based on the above-mentioned glass-based fine aggregate comprises the following steps:

[0048] S1. Mixing glass powder crushed to a set particle size range with lithium oxide in a ratio of 100:(1-2), and calcining at 700-800°C for 0.5-2h to obtain modified glass powder;

[0049] S2, heating the glass particles crushed to a set particle size at 500-600° C. for 0.5-1.5 h, and after cooling, performing surface modification with a silane coupling agent in a proportion of 5-8% by mass of the glass particles to obtain a glass-based coarse aggregate;

[0050] S3, mixing cement, modified glass powder, silica fume, fine aggregate, the glass-based fine aggregate, coarse aggregate, the glass-based coarse aggregate, and adding water and a water reducing agent and stirring evenly;

[0051] S4, adding steel fiber while maintaining the stirring state, stirring evenly, and obtaining UHPC slurry;

[0052] S5. Cast the UHPC slurry and cure it to a set age.

[0053] In the above process, the crystal structure of the glass powder particles is effectively destroyed by high-temperature treatment in S1, and it is converted into an amorphous state, thereby significantly improving the activity and chemical reactivity of the volcanic ash; during the calcination process, lithium oxide is added to effectively inhibit the alkali-aggregate reaction.

[0054] In S2, the glass particles are further optimized through surface modification after cooling to room temperature: the chemical action of the coupling agent can form a strong interfacial bonding force between the glass particles and the cement matrix, while enhancing the durability and shear resistance of the aggregate; to ensure the modification effect, the coupling agent is allowed to dry naturally on the surface of the glass particles for 1-2 hours after spraying to fully solidify it; this process not only improves the toughness and bonding strength of the glass coarse aggregate, but also significantly reduces stress concentration, further optimizing the overall performance of the concrete.

[0055] Optionally, in S1, the modified glass powder is cooled and then classified according to particle size to obtain modified glass powder with a set particle size.

[0056] Optionally, in S2, the silane coupling agent is sprayed on the surface of the glass particles in the form of an aqueous solution with a mass concentration of 5-10%.

[0057] Optionally, in S3, the mixture is stirred at a low speed for 2 to 3 minutes after mixing, and stirred at a low speed for 3 to 5 minutes after adding water.

[0058] Optionally, in S4, steel fibers are sieved in while maintaining the stirring state at a medium speed.

[0059] Optionally, in S5, high-speed stirring is performed for 1 to 2 minutes before pouring, and the curing process is carried out under standard curing conditions.

[0060] The above-mentioned applications of UHPC include: applications in bridges, high-rise buildings, nuclear power plants and protective engineering.

[0061] Example 1

[0062] A glass-based fine aggregate, the preparation method comprising the following steps:

[0063] Collect discarded glass bottles, soak them in water for 24 hours, soften the surface impurities and remove them; air-dry the glass bottles for 24-48 hours to remove surface moisture and avoid particles sticking together during the crushing process; the dried glass bottles are initially crushed by a jaw crusher and sieved to a particle size range of 0.15-4.75 mm for the preparation of glass-based fine aggregate;

[0064] A 5wt% acetic acid aqueous solution is pre-prepared, and the glass raw materials are heated in a high temperature environment of 550°C for 1.5 hours. During the process, the temperature is maintained after heating to 550°C, and the acetic acid aqueous solution is evenly sprayed at a mass ratio of 2% of the glass raw materials. An air atomization spraying device is used during the spraying process, and the acetic acid aqueous solution is atomized into fine droplets with the assistance of compressed air. The spraying duration is 10 to 15 minutes; 60mm is maintained between the nozzle and the glass particles to ensure uniform coverage of the droplets; during the spraying process, a high-temperature rotary stirring device is used to make the glass particles evenly flip at high temperature to maximize the surface reaction effect of acetic acid; after spraying, the heat is continued to be kept until the set 1.5 hours is reached to promote the full reaction of acetic acid and glass and form a stable microbubble structure; after cooling, 3% by mass of nano-silica sol and 2% by mass of lithium chloride are used for surface modification to obtain glass-based fine aggregate.

[0065] The obtained glass-based fine aggregate was subjected to TEM test, such as Figure 1 As shown: there are holes (bubbles) distributed inside the glass-based fine aggregate, and multiple holes are interconnected, and the size of the holes ranges from 1 to 10μm; the reason for using acetic acid is that it can undergo a mild chemical reaction with glass under high temperature conditions to generate a uniform microbubble structure; this structure can not only reduce the density of the glass-based fine aggregate, but also provide internal maintenance functions during the hardening process of concrete, significantly reduce the shrinkage phenomenon and improve the volume stability of the material; in addition, acetic acid, as a weak acid, has moderate reactivity and will not cause excessive corrosion to the glass. At the same time, the generated micropores are evenly distributed, which can optimize the physical properties of the fine aggregate; acetic acid is widely available, inexpensive and relatively environmentally friendly, so it is very suitable as a glass surface modifier, which is in line with the concept of green building materials.

[0066] Comparative Example 1

[0067] A glass-based fine aggregate, the preparation method comprising the following steps:

[0068] Collect discarded glass bottles, soak them in water for 24 hours, soften the surface impurities and remove them; air-dry the glass bottles for 24-48 hours to remove surface moisture and avoid particles sticking together during the crushing process; the dried glass bottles are initially crushed by a jaw crusher and sieved to a particle size range of 0.15-4.75 mm for the preparation of glass-based fine aggregate;

[0069] The glass raw material was heated in a high temperature environment of 550° C. for 1.5 h to obtain glass-based fine aggregate, which was different from Example 1 in that acetic acid, nano-silica sol and lithium salt were not used for modification.

[0070] Example 2

[0071] A modified glass powder, the preparation method comprising the following steps:

[0072] Collect discarded glass bottles, soak them in water for 24 hours, and remove the impurities on the surface after softening; air-dry the glass bottles for 24-48 hours to remove surface moisture and avoid particle adhesion during the crushing process; the dried glass bottles are initially crushed by a jaw crusher and sieved to a particle size range of less than 600 μm for the preparation of modified glass powder;

[0073] The glass powder raw material and lithium oxide were mixed in a ratio of 100:2 and calcined at 750°C for 2h to obtain modified glass powder.

[0074] Comparative Example 2

[0075] A glass powder, the preparation method comprising the following steps:

[0076] Collect discarded glass bottles, soak them in water for 24 hours, and remove the impurities on the surface after softening; air-dry the glass bottles for 24-48 hours to remove surface moisture and avoid particle adhesion during the crushing process; the dried glass bottles are initially crushed by a jaw crusher and sieved to a particle size range of less than 600 μm for the preparation of modified glass powder;

[0077] The glass powder raw material was calcined at 750° C. for 2 hours to obtain modified glass powder, which differs from Example 2 in that lithium oxide is not used for modification.

[0078] Example 3

[0079] A modified glass-based coarse aggregate, the preparation method comprising the following steps:

[0080] Collect discarded glass bottles, soak them in water for 24 hours, soften the surface impurities and remove them; air-dry the glass bottles for 24-48 hours to remove surface moisture and avoid particle adhesion during crushing; the dried glass bottles are initially crushed by a jaw crusher and sieved to a particle size range of 4.75-8 mm for the preparation of modified glass-based coarse aggregate;

[0081] The glass particles crushed to a set particle size are heated at 500-600° C. for 0.5-1.5 hours, and after cooling, the glass particles are surface-modified with a 3% by mass silane coupling agent, and the silane coupling agent is sprayed on the surface of the glass particles in the form of a 5-10% by mass concentration aqueous solution, and naturally dried for 2 hours to fully solidify them to obtain glass-based coarse aggregate.

[0082] Comparative Example 3

[0083] A glass-based coarse aggregate, the preparation method comprising the following steps:

[0084] Collect discarded glass bottles, soak them in water for 24 hours, soften the surface impurities and remove them; air-dry the glass bottles for 24-48 hours to remove surface moisture and avoid particle adhesion during crushing; the dried glass bottles are initially crushed by a jaw crusher and sieved to a particle size range of 4.75-8 mm for the preparation of modified glass-based coarse aggregate;

[0085] The glass particles crushed to a set particle size are heated at 500-600° C. for 0.5-1.5 h, and then cooled to obtain a glass-based coarse aggregate, which is different from Example 3 in that no silane coupling agent is used for modification.

[0086] Example 4

[0087] A HUPC comprising the following components in parts by weight:

[0088] 405 parts of cement, 45 parts of modified glass powder prepared in Example 2, 45 parts of silica fume, 560 parts of natural river sand fine aggregate, 140 parts of glass-based fine aggregate prepared in Example 1, 770 parts of crushed stone coarse aggregate, 330 parts of glass-based coarse aggregate prepared in Example 3, 40 parts of steel fiber, 135 parts of water, and 6 parts of water reducer.

[0089] Among them, the cement is silicate cement with strength grade 52.5, the fine aggregate is natural river sand, the coarse aggregate is crushed stone, the steel fiber is straight brass galvanized steel fiber, and the water reducer is polycarboxylic acid water reducer.

[0090] The preparation method comprises the following steps:

[0091] S3. Mix cement, modified glass powder prepared in Example 2, silica fume, fine aggregate, glass-based fine aggregate prepared in Example 1, coarse aggregate and glass-based coarse aggregate prepared in Example 3, stir at low speed for 3 minutes, then add water and water reducing agent and stir at low speed for 5 minutes until uniform.

[0092] S4. Add steel fiber while maintaining the stirring state, stir evenly, and obtain UHPC slurry.

[0093] S5. Cast the UHPC slurry and cure it to a set age.

[0094] Example 5

[0095] A HUPC comprising the following components in parts by weight:

[0096] 450 parts of cement, 100 parts of modified glass powder prepared in Example 2, 45 parts of silica fume, 500 parts of natural river sand fine aggregate, 250 parts of glass-based fine aggregate prepared in Example 1, 700 parts of crushed stone coarse aggregate, 250 parts of glass-based coarse aggregate prepared in Example 3, 40 parts of steel fiber, 135 parts of water, and 6 parts of water reducer.

[0097] The raw materials and preparation methods are the same as those in Example 4.

[0098] Example 6

[0099] A HUPC comprises the following components in parts by weight: 500 parts of cement, 135 parts of modified glass powder prepared in Example 2, 50 parts of silica fume, 700 parts of natural river sand fine aggregate, 350 parts of glass-based fine aggregate prepared in Example 1, 900 parts of crushed stone coarse aggregate, 330 parts of glass-based coarse aggregate prepared in Example 3, 50 parts of steel fiber, 150 parts of water, and 8 parts of water reducing agent.

[0100] The raw materials and preparation methods are the same as those in Example 4.

[0101] Comparative Example 4

[0102] A UHPC comprises the following components in parts by weight: 450 parts of cement, 45 parts of silica fume, 560 parts of natural river sand fine aggregate, 140 parts of glass-based fine aggregate prepared in Example 1, 1,100 parts of crushed stone coarse aggregate, 40 parts of steel fiber, 135 parts of water, and 6 parts of a water reducing agent.

[0103] The difference from Example 4 is that cement is used instead of the modified glass powder prepared in Example 2, and crushed stone coarse aggregate is used instead of the glass-based coarse aggregate prepared in Example 3; other raw material requirements and preparation methods are the same as those of Example 4.

[0104] Comparative Example 5

[0105] A UHPC comprises the following components in parts by weight: 405 parts of cement, 45 parts of modified glass powder prepared in Example 2, 45 parts of silica fume, 700 parts of natural river sand fine aggregate, 1100 parts of crushed stone coarse aggregate, 40 parts of steel fiber, 135 parts of water, and 6 parts of water reducing agent.

[0106] The difference from Example 4 is that natural river sand fine aggregate is used instead of the glass-based fine aggregate prepared in Example 1, and crushed stone coarse aggregate is used instead of the glass-based coarse aggregate prepared in Example 3; other raw material requirements and preparation methods are the same as those in Example 4.

[0107] Comparative Example 6

[0108] A UHPC comprises the following components in parts by weight: 450 parts of cement, 45 parts of silica fume, 700 parts of natural river sand fine aggregate, 770 parts of crushed stone coarse aggregate, 330 parts of glass-based coarse aggregate prepared in Example 3, 40 parts of steel fiber, 135 parts of water, and 6 parts of a water reducing agent.

[0109] The difference from Example 4 is that cement is used instead of the glass-based fine aggregate prepared in Example 1, and natural river sand fine aggregate is used instead of the modified glass powder prepared in Example 2; other raw material requirements and preparation methods are the same as those of Example 4.

[0110] Comparative Example 7

[0111] A UHPC comprises the following components in parts by mass: 405 parts of cement, 45 parts of modified glass powder prepared in comparative example 2, 45 parts of silica fume, 560 parts of natural river sand fine aggregate, 140 parts of glass-based fine aggregate prepared in comparative example 1, 770 parts of crushed stone coarse aggregate, 330 parts of glass-based coarse aggregate prepared in comparative example 3, 40 parts of steel fiber, 135 parts of water, and 6 parts of water reducing agent.

[0112] The difference from Example 4 is that the glass-based fine aggregate prepared in Comparative Example 1 is used instead of the glass-based fine aggregate prepared in Example 1; and the glass powder prepared in Comparative Example 2 is used instead of the modified glass powder prepared in Example 2, and the glass-based coarse aggregate prepared in Comparative Example 3 is used instead of the modified glass-based coarse aggregate prepared in Example 3; other raw material requirements and preparation methods are the same as those in Example 4.

[0113] Comparative Example 8

[0114] A UHPC comprises the following components in parts by weight: 450 parts of cement, 45 parts of silica fume, 700 parts of natural river sand fine aggregate, 1100 parts of crushed stone coarse aggregate, 40 parts of steel fiber, 135 parts of water, and 6 parts of water reducing agent.

[0115] The difference from Example 4 is that natural river sand fine aggregate is used instead of the glass-based fine aggregate prepared in Example 1, cement is used instead of the modified glass powder prepared in Example 2, and crushed stone coarse aggregate is used instead of the modified glass-based coarse aggregate prepared in Example 3; other raw material requirements and preparation methods are the same as those in Example 4.

[0116] Performance Testing

[0117] The UHPC prepared in Example 4, Example 5, Example 6, Example 7, Comparative Example 4 and Comparative Example 5 were subjected to performance tests, including compressive strength, elastic modulus, flexural strength, autogenous shrinkage, chloride ion diffusion coefficient, freeze-thaw cycle strength retention rate and interface bonding strength. The results are shown in Table 1.

[0118] Table 1 Performance test results

[0119]

[0120] The data in Table 1 show that the performance indicators of Example 4 are better than those of Comparative Examples 7 and 8 in all aspects. The compressive strength reaches 132.6 MPa, which is significantly improved by 11.3% compared with the comparative example without glass aggregate; the flexural strength is increased from 12.6 kN of the comparative example to 16.0 kN, an increase of 26.9%. It shows that the UHPC formula using waste glass-based fine aggregate, modified glass powder and glass-based coarse aggregate has significant improvements in mechanical properties and durability. This performance improvement is mainly attributed to the unique characteristics of glass aggregate and its reasonable dosage distribution. The surface activity of glass aggregate modified by silane coupling agent is significantly enhanced, and the interfacial bonding performance with cement matrix is ​​significantly improved. This enhanced interfacial bonding force effectively alleviates the stress concentration phenomenon of concrete under load, thereby improving the overall compressive and flexural properties.

[0121] In terms of autogenous shrinkage, the autogenous shrinkage values ​​of the embodiments are all lower than those of the comparative examples, especially the 514 μɛ of Example 4 is significantly better than that of Comparative Examples 7 and 8. This performance advantage is due to the introduction of the fine aggregate such as Figure 1 The microbubble structure shown in the figure not only effectively relieves the autogenous shrinkage stress, but also provides a uniform internal moisture reserve, forming a unique internal curing mechanism for glass materials. This mechanism can significantly reduce the autogenous shrinkage phenomenon and greatly improve the long-term volume stability of concrete. In addition, in terms of chloride ion diffusion coefficient, the values ​​of the embodiments are all between 1.5 and 1.85×10 -12 m² / s range, which is lower than the control ratio, indicating that the material has higher impermeability and corrosion resistance, and is suitable for corrosive environments such as oceans and underground.

[0122] The freeze-thaw cycle strength retention rate shows that the retention rates of the embodiments are generally above 92%, which is significantly higher than that of the comparative examples. The retention rate of Example 4 is 96%, which reflects the advantage of the technical solution of jointly modifying fine aggregate and coarse aggregate in enhancing weather resistance. The performance of the interfacial bonding strength further verifies the modification effect of the silane coupling agent. The interface strength in the embodiments is close to or exceeds 4 MPa, which is significantly higher than that of the comparative examples, indicating that UHPC has good overall stability in high-load structures.

[0123] Comprehensive analysis shows that the use of waste glass material modification technology not only effectively improves the mechanical properties and durability of UHPC, but also significantly improves ecological and environmental protection indicators, and reduces resource consumption and carbon emissions. Compared with traditional material systems, waste glass-based UHPC has better crack resistance, impermeability and frost resistance, and is suitable for engineering structure scenarios with high strength and high durability requirements, such as bridges, high-rise buildings and protective projects. At the same time, it promotes the efficient resource utilization of waste glass and realizes the sustainable development of green building materials.

[0124] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing glass-based fine aggregate, characterized in that: The method comprises the following steps: heating glass crushed to a particle size of 0.15-4.75 mm at 500-600° C. for 1-2 hours, maintaining the temperature and uniformly spraying acetic acid at a mass ratio of 1-2% of the glass; after cooling, surface modification is performed at a mass ratio of 1-3% of the glass with nano-silica sol and a mass ratio of 1%-2% of lithium salt to obtain glass-based fine aggregate; the acetic acid is a 2-5wt% aqueous solution; the nano-silica sol is a 20% mass concentration aqueous solution with a pH value of 9.

2. A glass-based fine aggregate prepared by the method for preparing glass-based fine aggregate as claimed in claim 1.

3. A UHPC based on the glass-based fine aggregate as claimed in claim 2, characterized in that: The invention comprises the following components in parts by weight: 400-500 parts of cement, 45-135 parts of modified glass powder, 40-50 parts of silica fume, 500-700 parts of fine aggregate, 140-350 parts of the glass-based fine aggregate, 700- ~900 parts, 165~330 parts of glass-based coarse aggregate, 30~50 parts of steel fiber, 120~150 parts of water and 5~8 parts of water reducer; glass powder crushed to a particle size of less than 600 μm is mixed with lithium salt in a ratio of 100: (1~2), and calcined at 700~800°C for 0.5~2h to obtain modified glass powder; glass particles crushed to a particle size of 4.75~8mm are heated at 500~600°C for 0.5~1.5h, and after cooling, the surface is modified with a silane coupling agent in a proportion of 1~2% by mass of the glass particles to obtain glass-based coarse aggregate; the fine aggregate is natural river sand; and the coarse aggregate is crushed stone.

4. The UHPC according to claim 3, characterized in that The silane coupling agent is KH550, the cement is silicate cement or ordinary silicate cement with strength grade 52.5 or 52.5R; and the steel fiber is straight brass galvanized steel fiber.

5. A method for preparing UHPC as claimed in any one of claims 3 to 4, characterized in that: The following steps are involved: S1. Mix cement, modified glass powder, silica fume, fine aggregate, the glass-based fine aggregate, coarse aggregate, and the glass-based coarse aggregate, add water and a water reducing agent, and stir evenly; S2. Add steel fiber while maintaining the stirring state and stir evenly to obtain UHPC slurry; S3. Cast the UHPC slurry and cure it to the set age.

6. The method for preparing UHPC according to claim 5, characterized in that: The silane coupling agent is sprayed on the surface of the glass particles in the form of an aqueous solution with a mass concentration of 5-10%.

7. The method for preparing UHPC according to claim 5, characterized in that: In S1, the mixture is stirred at a low speed for 2 to 3 minutes after mixing, and stirred at a low speed for 3 to 5 minutes after adding water; in S2, the stirring speed is maintained at a medium speed and steel fibers are sieved in; in S3, the mixture is stirred at a high speed for 1 to 2 minutes before pouring, and the curing process is carried out under standard curing conditions.

8. An application of UHPC as claimed in any one of claims 3 to 4, characterized in that: Including applications in bridges, high-rise buildings, nuclear power plants and protective engineering.

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