Alkali-activated gypsum glass particle concrete and preparation method thereof

Abstract

The invention discloses alkali-activated gypsum glass particle concrete and a preparation method thereof, and belongs to the technical field of building materials. The invention aims to solve the technical problems of poor interface cohesiveness and stockpiling pollution of industrial byproduct gypsum caused by the use of inert aggregate in traditional alkali-activated gypsum concrete. The concrete is prepared from the following raw materials in parts by weight: 10-15 parts of an alkali activator, 30-40 parts of dehydrated gypsum and 50-60 parts of tempered glass particles. In addition, the concrete further comprises a polycarboxylate superplasticizer and a protein gypsum retarder, and the addition amounts of the polycarboxylate superplasticizer and the protein gypsum retarder are respectively determined based on the total mass of the main body material and the mass of the dehydrated gypsum. The core of the invention is that the active aggregate formed by crushing the waste toughened glass is utilized, and amorphous silicon dioxide rich in the active aggregate can react in an alkali excitation environment to generate CSH gel, so that an interface transition region between the aggregate and a rubber material is remarkably reinforced, and the mechanical property of the concrete is improved. Meanwhile, industrial by-product gypsum such as ardealite and the like can be used, and high-added-value resource utilization of the solid waste is achieved.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to an alkali-activated gypsum glass particle concrete and its preparation method, specifically to an alkali-activated gypsum concrete that uses tempered glass particles to completely or partially replace traditional sand and gravel aggregates. Background Technology

[0002] Gypsum, as a widely available air-hardening cementitious material, plays an important role in the construction industry. In particular, with industrial development, a large amount of industrial by-product gypsum has been generated, such as phosphogypsum, a by-product of phosphate chemical production, and desulfurization gypsum produced from flue gas desulfurization in coal-fired power plants. Taking phosphogypsum as an example, it is a major by-product of the production of phosphoric acid-based chemical products, with approximately 3-5 tons of phosphogypsum being emitted for every ton of phosphoric acid produced. Statistics show that the comprehensive utilization rate of phosphogypsum is only about 50%. The large-scale stockpiling of phosphogypsum not only occupies land but also may cause environmental pollution. Therefore, promoting the resource utilization of industrial by-product gypsum such as phosphogypsum has become a critical issue that urgently needs to be addressed by the building materials industry and chemical enterprises.

[0003] Hemihydrate or anhydrous gypsum, obtained by drying and calcining industrial by-product gypsum, can be used as a cementing material in the preparation of various building materials. In recent years, alkali-activated gypsum cementitious materials and alkali-activated gypsum-based concrete have become research hotspots. These materials typically require the addition of siliceous auxiliary cementitious materials rich in amorphous silica, such as silica fume, fly ash, or glass powder. In an alkaline environment, this amorphous silica can dissolve and participate in the reaction, further generating calcium silicate hydrate (CSH) gel, a key product for improving the strength of cementitious materials.

[0004] However, when extending such cementitious systems to concrete, an inherent challenge arises: the coarse and fine aggregates (such as river sand and crushed stone) used extensively in concrete are typically chemically inert. These inert aggregates cannot participate in the hydration reaction of the cementitious materials, resulting in a weak "interfacial transition zone" between the aggregate particles and the cementitious matrix. This region is often loosely structured and highly porosilicated, serving as a stress concentration point and crack initiation site under concrete stress, severely restricting further improvement in the macroscopic mechanical properties of concrete. Therefore, strengthening the interfacial transition zone is key to overcoming the performance bottleneck of alkali-activated gypsum-based concrete.

[0005] Inspired by alkali-activated silica colloids, those skilled in the art would naturally consider that if aggregates could be endowed with certain chemical activity, enabling them to participate in reactions even in alkaline environments, it would be possible to generate cementitious products in situ in the interfacial transition zone, thereby "bridging" and strengthening that area. However, commonly used reactive silica materials, such as silica fume, have particle sizes much smaller than the required aggregate size and cannot be directly used as aggregates. While ordinary glass is rich in amorphous silica, its mechanical strength often fails to meet the high strength requirements (typically 50 MPa-100 MPa) for use as building aggregates. If glass with insufficient strength is used as aggregate, the overall strength of the concrete cannot be guaranteed.

[0006] In summary, the following technical problems urgently need to be solved in the existing technology: (1) Traditional alkali-activated gypsum concrete uses inert aggregates, resulting in weak bonding in the transition zone between aggregates and adhesives, which becomes a performance bottleneck.

[0007] (2) The industrial by-product gypsum has a large stockpile and low utilization rate, and there is an urgent need to develop a high-value-added large-scale disposal method.

[0008] (3) There is a lack of an ideal aggregate material that has both high strength and good chemical activity and can replace traditional sand and gravel, so as to achieve both interface strengthening and solid waste resource utilization. Summary of the Invention

[0009] The main objective of this invention is to propose an alkali-activated gypsum glass particle concrete and its preparation method, thereby solving at least one of the aforementioned problems.

[0010] To achieve the above objectives, in a first aspect, the present invention proposes an alkali-activated gypsum glass particle concrete, which is made from the following raw materials in parts by weight: Alkali activator: 10-15 parts Dehydrated gypsum: 30-40 parts Tempered glass beads: 50-60 parts; In addition, it also includes a concrete admixture, which is composed of a polycarboxylate superplasticizer and a protein-based gypsum retarder; wherein the amount of the polycarboxylate superplasticizer added is 0.5% of the total mass of the alkali activator, dehydrated gypsum and tempered glass particles; and the amount of the protein-based gypsum retarder added is 0.25% of the mass of the dehydrated gypsum.

[0011] Preferably, the tempered glass particles are granules obtained from waste tempered glass products through crushing and screening, with a particle size range of 0.5-2 cm. The particle size range is strictly controlled between 0.5 cm and 2.0 cm to ensure that it can serve as coarse aggregate in concrete to form a good skeletal structure. It is worth emphasizing that the tempered glass used is made from ordinary soda-lime silicate glass through a physical tempering (i.e., rapid cooling) process. This process introduces pre-compressive stress into the glass surface, significantly increasing its compressive strength to 80 MPa to 120 MPa. This strength range fully meets or even exceeds the 50 MPa to 100 MPa strength requirements for building aggregates, providing robust and reliable mechanical support for the concrete.

[0012] Preferably, the alkaline activator is a alkali hydroxide, selected from sodium hydroxide, potassium hydroxide, and calcium hydroxide. These strong or moderately strong bases can provide the alkaline environment required for the activation reaction, thereby activating the active components in the dehydrated gypsum and tempered glass particles.

[0013] Preferably, the dehydrated gypsum is made by uniformly mixing hemihydrate gypsum and anhydrous gypsum in a 1:1 mass ratio and then sealing and aging for 7 days. This specific combination and aging process helps stabilize the phase composition of the gypsum, avoids abnormal setting time, and achieves better long-term strength development.

[0014] Preferably, the hemihydrate gypsum is obtained by drying dihydrate gypsum raw material at 160°C for 5-8 hours; the anhydrous gypsum is obtained by drying dihydrate gypsum raw material at 200°C for 5-8 hours.

[0015] Preferably, the dihydrate gypsum raw material is derived from industrial by-product gypsum, such as phosphogypsum or desulfurized gypsum, or it can be natural dihydrate gypsum. These raw materials need to be crushed and sieved through a 130-mesh screen before use to remove impurities and obtain a suitable fineness.

[0016] Secondly, the present invention also provides a method for preparing alkali-activated gypsum glass particle concrete, which includes the following steps: S1. Raw material preparation: Prepare dehydrated gypsum and tempered glass granules.

[0017] S2. Dry Mixing: According to the designed mix proportions, accurately weighed alkali activator, dehydrated gypsum obtained in step S1, tempered glass granules, and protein-based gypsum retarder are added to the concrete mixer. Start the mixer and perform dry mixing for approximately 30 seconds to ensure that all dry materials, including powdered alkali activator, gypsum, and granular glass aggregate, are thoroughly and evenly mixed.

[0018] S3, Wet Mixing: Add the measured amount of polycarboxylate superplasticizer to the pre-calculated mixing water and stir to dilute it thoroughly. Then, pour this diluted solution into the mixer where dry mixing was carried out in step S2. Continue stirring for 2 to 3 minutes until the entire system forms a concrete slurry with uniform color, suitable fluidity, and no visible dry particles or clumps.

[0019] S4. Molding and Curing: Pour the uniform concrete slurry obtained in step S3 into a pre-prepared mold and compact it using mechanical vibration or manual tamping. After smoothing the surface, place the mold under natural indoor conditions (temperature 20±5℃, relative humidity ≥50%) and let it stand for 24 hours before demolding. After demolding, continue curing the specimens under the same natural indoor conditions for 28 days before conducting various performance tests.

[0020] Preferably, the preparation process of dehydrated gypsum in step S1 is as follows: after crushing dihydrate gypsum, it is sieved through a 130-mesh sieve to obtain dihydrate gypsum raw material; a portion of the dihydrate gypsum raw material is dried at 160℃ for 5-8 hours to obtain hemihydrate gypsum; another portion of the dihydrate gypsum raw material is dried at 200℃ for 5-8 hours to obtain anhydrous gypsum; then the obtained hemihydrate gypsum and anhydrous gypsum are mixed evenly at a mass ratio of 1:1, sealed and aged for 7 days to obtain dehydrated gypsum.

[0021] Preferably, the preparation process of the tempered glass particles in step S1 is as follows: after crushing the waste tempered glass, particles with a particle size in the range of 0.5-2cm are screened out.

[0022] Thirdly, the present invention provides an application of tempered glass particles in alkali-activated gypsum concrete, which uses tempered glass particles to replace sand and gravel aggregates and generates CSH gel through reaction in alkali-activated gypsum-based concrete to strengthen the interfacial transition zone.

[0023] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows: (1) Outstanding strengthening effect in the interface transition zone: Under the action of alkali activator, the amorphous silica in the tempered glass particles generates a large amount of CSH gel. This gel not only fills the gaps between aggregates, but also forms chemical bonds, significantly enhancing the interfacial adhesion and improving the compressive strength of concrete. This active aggregate design solves the drawback of inert aggregates not being able to participate in the cementitious reaction, and realizes the synergistic strengthening of aggregates and cementitious materials.

[0024] (2) Excellent mechanical properties: The compressive strength (80-120 MPa) of tempered glass particles is higher than that of traditional sand and gravel, and the particle shape is regular (rounded edges and high sphericity), which reduces the proportion of flaky and deformed aggregates, thereby improving the density and strength uniformity of concrete.

[0025] (3) Zero water absorption and dense surface: Tempered glass has a dense structure and absorbs almost no water. This characteristic brings two direct benefits: First, when preparing concrete with the same water-cement ratio, the effective water-cement ratio is relatively higher because the aggregate does not compete for mixing water. Therefore, the slurry has greater fluidity, is easier to pump and construct, and has less slump loss and better slump retention. Second, if the same fluidity is required, the total water consumption can be significantly reduced, thereby reducing the actual water-cement ratio. A low water-cement ratio is one of the key factors in obtaining high-strength concrete, which creates conditions for further improving strength. Experiments show that under a water-cement ratio of 0.40, the concrete slump can be maintained above 80 mm, meeting most construction requirements.

[0026] (4) Scientific and precise proportioning, stable and controllable performance: This invention has determined the optimal weight range of each component through numerous experiments, especially clarifying the precise addition ratio of admixtures (polycarboxylate superplasticizer and protein retarder) relative to the main material (based on the total mass of the main material and the mass of dehydrated gypsum, respectively). This scientific proportioning design ensures the stability, repeatability, and predictability of concrete performance. Users can fine-tune the proportions provided by this invention according to different requirements for workability, setting time, and strength in specific engineering application scenarios (such as precast components, cast-in-place structures, etc.), thereby optimizing and customizing the product performance. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram illustrating the cohesive strengthening effect of CSH gel on the aggregate interface. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described in more detail and completely below with reference to five specific embodiments and a comparative example. These embodiments are practices based on the core concept and preferred solutions of this invention, and are intended to demonstrate the specific implementation process and technical effects of this invention, rather than to limit the scope of protection of this invention. Those skilled in the art should understand that various modifications and substitutions can be made to these embodiments without departing from the principles and spirit of this invention, and such modifications and substitutions should all be considered to fall within the scope of protection of this invention.

[0030] To fully demonstrate the environmental value of this invention, the dihydrate gypsum used in all the following embodiments is industrial by-product phosphogypsum provided by Guizhou Kailin Phosphogypsum Comprehensive Utilization Co., Ltd., whose main component is calcium sulfate dihydrate (CaSO4·2H2O); the waste tempered glass used comes from the waste door and window recycling market.

[0031] Example 1: This embodiment details the preparation process of alkali-activated gypsum glass particle concrete.

[0032] I. Raw materials and proportions, as detailed below: Alkali activator: Sodium hydroxide (NaOH), analytical grade, 12 kg.

[0033] Dehydrated gypsum: dosage is 35kg.

[0034] Tempered glass granules: 55 kg.

[0035] Polycarboxylate superplasticizer: This is a solid powder type high-performance polycarboxylate superplasticizer. Its addition amount is 0.5% of the total mass of the alkali activator, dehydrated gypsum, and tempered glass granules (12+35+55=102kg), i.e., 0.51kg. In this embodiment, the polycarboxylate superplasticizer produced by Hunan Zhongyan Building Materials Technology Co., Ltd. is used.

[0036] Protein-based gypsum retarder: This is a commercially available protein-based gypsum retarder, specifically manufactured by Beijing Longtengda Chemical Co., Ltd. Its addition amount is 0.25% of the mass of dehydrated gypsum (35kg), i.e., 0.0875kg.

[0037] Mixing water: Tap water is used, and the water-cement ratio is set to 0.40.

[0038] II. Preparation process: 1. Raw material pretreatment (1) Preparation of dehydrated gypsum: a. Pretreatment: The lumpy industrial by-product phosphogypsum is initially crushed using a jaw crusher, and then finely ground using a ball mill.

[0039] b. Sieving: The finely ground phosphogypsum powder is sieved through a 130-mesh standard sieve, and the residue is collected. This step aims to remove large particles and unground particles to obtain pure dihydrate gypsum raw material with suitable particle size.

[0040] c. Calcination: Dihydrate gypsum raw material obtained from the above screening is divided into two equal portions. The first portion is placed in a forced-air drying oven and dried continuously at a constant temperature of 160℃±5℃ for 5-8 hours. During this process, the dihydrate gypsum loses 1.5 molecules of water of crystallization and transforms into hemihydrate gypsum. The second portion is placed in another forced-air drying oven and dried continuously at a constant temperature of 200℃±5℃ for 5-8 hours. During this process, the dihydrate gypsum is completely dehydrated and transforms into anhydrous gypsum, also known as hard gypsum.

[0041] d. Mixing and Aging: The prepared hemihydrate gypsum and anhydrous gypsum are poured into a double cone mixer at a strict 1:1 mass ratio and mixed for 30 minutes to ensure uniformity. Then, the uniformly mixed gypsum powder is placed into well-sealed polyethylene bags, the bags are tightly sealed, and placed in a dry, cool indoor environment for 7 days of aging. The aging process helps stabilize the phase of the gypsum and improve its gelling properties. After aging, the dehydrated gypsum gelling material required by this invention is obtained.

[0042] (2) Preparation of tempered glass particles: a. Crushing: A jaw crusher is used to crush the collected waste tempered glass. The feed rate and crusher opening are controlled to obtain preliminary particles.

[0043] b. Screening: The crushed glass particles are transferred to a three-layer square-hole vibrating screen. Through screening, particles with a diameter ranging from 0.5 cm to 2.0 cm are precisely selected as coarse aggregate for concrete.

[0044] c. Cleaning and drying: Rinse the sieved tempered glass granules with clean water to remove adhering dust, and then air dry naturally or dry at low temperature for later use.

[0045] 2. Concrete mixing (1) Dry mixing stage: First, check the forced concrete mixer to ensure that its interior is clean and free of residue. Then, add 12 kg of sodium hydroxide, 35 kg of prepared dehydrated gypsum, 55 kg of tempered glass aggregate, and 0.0875 kg of protein-based gypsum retarder to the mixer in the following order according to the mix proportions. Cover the mixer and start the machine, dry mixing at low speed (30 rpm) for 30 seconds. The purpose of this process is to ensure that all powdered materials (alkali, gypsum, retarder) can adhere evenly and disperse on the surface of the granular tempered glass aggregate, forming a preliminary homogeneous mixture.

[0046] (2) Wet mixing stage: While dry mixing is underway, add 0.51 kg of polycarboxylate superplasticizer to the mixing water (tap water) in a separate container and stir until the polycarboxylate superplasticizer is completely dissolved, forming a uniform polycarboxylate superplasticizer diluted solution. The water volume should meet the water-cement ratio of 0.40. Subsequently, while the mixer is running continuously, slowly and evenly pour the polycarboxylate superplasticizer diluted solution into the mixer through the feed port. After all the solution has been added, increase the mixer speed to medium speed (60 rpm) and continue stirring for 2-3 minutes. During this period, closely observe the state of the mixture until the concrete slurry shows a uniform color, good cohesion, no segregation, no bleeding, and good fluidity, indicating that the mixing is complete and the concrete slurry is obtained.

[0047] 3. Shaping and Curing: (1) Molding: Quickly pour the concrete slurry into a cubic mold that has been pre-coated with mineral oil release agent on the inner wall in two layers. After each layer is poured, fix the mold on the concrete test vibration table and vibrate until the surface is covered with full cement slurry and no large air bubbles are released. After the second layer is vibrated, use a trowel to scrape off the excess concrete on the surface of the mold and carefully smooth it to make the surface smooth.

[0048] (2) Standing and demolding: Place the molded test mold stably in the laboratory and let it stand for 24 hours in a natural environment with a temperature of 20±5℃ and a relative humidity of not less than 50%.

[0049] (3) Curing: After 24 hours, carefully loosen the mold bolts and remove the specimen completely. Mark the demolded concrete specimen with a number and then place it in a standard curing room (or continue curing in the same indoor environment). During the curing period, place the specimens at intervals to ensure air circulation. After curing for 28 days, remove the specimens and conduct various physical and mechanical property tests.

[0050] Example 2: This embodiment aims to demonstrate a formulation that uses calcium hydroxide as an alkali activator and adjusts the ratio of dehydrated gypsum to tempered glass particles.

[0051] I. Raw materials and proportions, as detailed below: Alkali activator: Calcium hydroxide Ca(OH)2, analytical grade, is used in a quantity of 10 kg.

[0052] Dehydrated gypsum: 40 kg.

[0053] Tempered glass granules: 50 kg.

[0054] Polycarboxylate superplasticizer: The addition amount is 0.5% of the total mass of the alkali activator, dehydrated gypsum and tempered glass particles (10+40+50=100kg), i.e. 0.50kg.

[0055] Protein-based gypsum retarder: The addition amount is 0.25% of the mass of dehydrated gypsum (40kg), i.e., 0.10kg.

[0056] Mixing water: Tap water is used, and the water-cement ratio is also 0.40.

[0057] II. Preparation Process The preparation process in this embodiment, including all steps such as raw material pretreatment (calcination and aging of dehydrated gypsum; crushing and screening of tempered glass particles), concrete mixing (dry mixing for 30 seconds, wet mixing for 2.5 minutes), molding and curing (indoor static setting for 24 hours before demolding, and natural curing for 28 days), is exactly the same as in Example 1. The only difference is that the types and proportions of raw materials are carried out according to the above-mentioned provisions of this embodiment. Further details will not be elaborated here.

[0058] Example 3: This embodiment aims to demonstrate the formulation effect of using potassium hydroxide as an alkaline activator.

[0059] I. Raw materials and proportions, as detailed below: Alkali activator: Potassium hydroxide (KOH), analytical grade, is used at a dosage of 15 kg.

[0060] Dehydrated gypsum: dosage is 30kg.

[0061] Tempered glass granules: 60kg.

[0062] Polycarboxylate superplasticizer: The addition amount is 0.5% of the total mass of the alkali activator, dehydrated gypsum and tempered glass particles (15+30+60=105kg), that is, 0.525kg.

[0063] Protein-based gypsum retarder: The addition amount is 0.25% of the mass of dehydrated gypsum (30kg), i.e., 0.075kg.

[0064] Mixing water: Tap water is used, and the water-cement ratio is set to 0.40.

[0065] II. Preparation Process The preparation process in this embodiment is exactly the same as in Example 1. The only difference is that the alkaline activator is replaced with potassium hydroxide, and the proportions are performed according to the above-described specifications. Further details will not be repeated here.

[0066] Example 4: This embodiment aims to demonstrate the effect of implementing an intermediate ratio in a calcium hydroxide system.

[0067] I. Raw materials and proportions, as detailed below: Alkali activator: Calcium hydroxide (Ca(OH)2) is used, with a dosage of 13 kg.

[0068] Dehydrated gypsum: dosage is 37 kg.

[0069] Tempered glass granules: 52 kg.

[0070] Polycarboxylate superplasticizer: The addition amount is 0.5% of the total mass of the alkali activator, dehydrated gypsum and tempered glass particles (13+37+52=102kg), that is, 0.51kg.

[0071] Protein-based gypsum retarder: The addition amount is 0.25% of the mass of dehydrated gypsum (37kg), i.e., 0.0925kg.

[0072] Mixing water: Tap water is used, and the water-cement ratio is set to 0.40.

[0073] II. Preparation Process The preparation process in this embodiment is basically the same as that in Example 1. The difference lies in that the raw material ratio is carried out according to the above-mentioned provisions of this embodiment, especially the use of calcium hydroxide as the alkali activator, and the adjustment of the amount, the ratio of dehydrated gypsum and tempered glass particles. Further details will not be elaborated here.

[0074] Example 5: This embodiment aims to demonstrate an implementation case that is close to the upper limit of the formulation range of the present invention (with a higher amount of alkali activator and tempered glass particles).

[0075] I. Raw materials and proportions, as detailed below: Alkali activator: Calcium hydroxide (Ca(OH)2) is used, with a dosage of 15 kg.

[0076] Dehydrated gypsum: 40 kg.

[0077] Tempered glass granules: 60kg.

[0078] Polycarboxylate superplasticizer: The addition amount is 0.5% of the total mass of the alkali activator, dehydrated gypsum and tempered glass particles (15+40+60=115kg), that is, 0.575kg.

[0079] Protein-based gypsum retarder: The addition amount is 0.25% of the mass of dehydrated gypsum (40kg), i.e., 0.10kg.

[0080] Mixing water: Tap water is used, and the water-cement ratio is set to 0.40.

[0081] II. Preparation Process The preparation process in this embodiment is basically the same as that in Example 1. The difference lies in that the raw material ratio is carried out according to the above-mentioned provisions of this embodiment, and a higher amount of alkali activator and tempered glass particles are used. Further details will not be elaborated here.

[0082] Comparative example: To highlight the technical advantages of this invention, a comparative example is provided. This comparative example uses the exact same cementitious system and preparation process, but uses traditional, chemically inert natural river sand instead of the activated tempered glass particles used in this invention as aggregate.

[0083] I. Raw materials and proportions, as detailed below: Alkali activator: Calcium hydroxide (Ca(OH)2) was used, with an amount of 10 kg, consistent with Example 2.

[0084] Dehydrated gypsum: The dosage is 40 kg, consistent with Example 2.

[0085] Aggregate: Ordinary natural river sand, washed, dried and sieved to a particle size range of 0.5-2.0cm, with a dosage of 50kg, replacing the tempered glass particles in Example 2 in equal amounts.

[0086] Polycarboxylate superplasticizer: The addition amount is 0.5% of the total mass of the alkali activator, dehydrated gypsum, and river sand (10+40+50=100kg), i.e., 0.50kg. The calculation basis is consistent with the embodiments of this invention.

[0087] Protein-based gypsum retarder: The addition amount is 0.25% of the mass of dehydrated gypsum (40kg), i.e., 0.10kg. The calculation basis is consistent with the various embodiments of this invention.

[0088] Mixing water: Tap water was used, and the water-cement ratio was set to 0.40, the same as in Example 2.

[0089] II. Preparation Process The preparation process for the comparative example was exactly the same as that for Example 2. The only difference was that 50 kg of tempered glass particles were replaced with 50 kg of ordinary river sand of the same particle size. The specific process will not be described in detail here.

[0090] Performance testing and results analysis: To more intuitively illustrate the raw material ratios of Examples 1 to 5 and the comparative examples, a summary is shown in the table below: Table 1. Raw material ratios for Examples 1 to 5 and comparative examples. For the concrete specimens prepared in Examples 1 to 5 and the comparative examples above, the slump of the fresh concrete was tested according to the national standard "Standard for Test Methods of Performance of Ordinary Concrete Mixtures" (GB / T 50080) to directly characterize its workability. Simultaneously, the cube compressive strength after 28 days of standard curing was tested according to the standard "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GB / T 50081-2019), which is the most critical indicator for evaluating the mechanical properties of concrete. The details are shown in the table below: Table 2. Concrete performance test results for each embodiment and comparative example. Results analysis and discussion: 1. Performance (slump) analysis: As can be clearly seen from the data in Table 2, the slump measurements of Examples 1 to 5 of this invention are all between 83 mm and 91 mm, exhibiting excellent flowability and workability, and meeting the requirements of most construction scenarios. In contrast, the slump of the comparative example (using river sand) is only 76 mm, significantly lower than that of the embodiments of this invention. This result strongly demonstrates the advantages of tempered glass aggregate as an aggregate in improving the workability of concrete. This is mainly attributed to the smooth and dense surface of the tempered glass aggregate, its non-absorbent nature, and its more rounded particle shape, which effectively reduces the frictional resistance inside the concrete mixture.

[0091] 2. Mechanical properties (28-day compressive strength) analysis: Mechanical properties are the core advantage of this invention. Test results show that the 28-day compressive strength of all five embodiments is significantly higher than that of the comparative example. The strength of the embodiments ranges from 41.5 MPa to 46.5 MPa, while the strength of the comparative example (using inert river sand) is only 31.2 MPa. The strength improvement is as high as approximately 33% to 49%. This huge performance difference eloquently demonstrates the significant effect and necessity of using activated tempered glass particles instead of traditional inert aggregates in improving the strength of alkali-activated gypsum concrete. The fundamental reason lies in the interface strengthening mechanism described in this invention: the amorphous SiO2 on the surface of the tempered glass particles participates in the reaction in an alkaline environment, generating CSH gel in situ, which greatly strengthens the aggregate-matrix interface transition zone, resulting in better overall integrity and stronger load-bearing capacity of the concrete.

[0092] Comparison of different alkaline activators: Comparing Example 1 (NaOH), Example 2 (Ca(OH)2), and Example 3 (KOH), with similar aggregate and gypsum dosages, Example 2 using Ca(OH)2 exhibited the highest strength (45.8 MPa), followed by KOH (43.2 MPa), while NaOH was slightly lower (41.5 MPa). This indicates that in this system, calcium hydroxide may provide a more favorable alkaline environment and calcium ion source for interfacial reactions and CSH gel formation.

[0093] Effects of Proportion Optimization: Example 4 (Ca(OH)2 13 kg, dehydrated gypsum 37 kg, glass granules 52 kg) exhibited the highest strength (46.5 MPa) in this series of experiments, indicating that the synergistic effect between the alkali activator, cementitious material, and reactive aggregate was optimal at this proportion. Although Example 5 had higher alkali content and aggregate dosage, resulting in the best flowability, its strength was slightly lower than Examples 2 and 4. This suggests that excessively high alkali content or aggregate volume fraction may require a more precise water-cement ratio and admixture system to match, otherwise it may have some impact on the final strength development. However, this is still within the high strength range and is far superior to the comparative examples.

[0094] 3. Overall Conclusion: Through a systematic comparison of the above five embodiments and a comparative example, a clear conclusion can be drawn: the alkali-activated gypsum concrete provided by this invention, which uses tempered glass particles to replace sand and gravel, successfully transforms industrial solid waste into high-performance building materials. It not only effectively solves the key technical problem of weak interfacial transition zones in traditional concrete, significantly improving mechanical properties, but also enhances the workability of fresh concrete. Furthermore, it opens up a practical new path for the large-scale, high-value-added resource utilization of phosphogypsum and waste tempered glass. This invention possesses significant technological advancements, environmental benefits, and market application potential.

[0095] This invention fundamentally improves the weakest link in concrete—the interface transition zone. Tempered glass particles are not inert aggregates; their surface and near-surface regions are rich in amorphous (glassy) silica. This amorphous SiO2 has extremely high chemical activity. In the strongly alkaline porous solution environment formed after concrete mixing, this SiO2 rapidly depolymerizes and dissolves, generating active silicate ions. These silicate ions react with calcium ions (Ca) provided by the dissolution of dehydrated gypsum. 2+ The process involves a series of complex chemical reactions between the aggregate particles and the metal cations introduced by the alkali activator, ultimately resulting in the in-situ formation of a large amount of fibrous, network, or amorphous hydrated calcium silicate (CSH) gel on the surface of the tempered glass particles and in the surrounding cementitious matrix. This process is equivalent to "welding" a reinforcing layer composed of high-strength cementitious products around each aggregate particle. This CSH gel reinforcing layer plays multiple positive roles: First, it transforms the physical contact point between the aggregate and the matrix into a chemical bonding point, significantly enhancing the adhesion; second, it effectively fills the inherent micropores and microcracks in the interface region, making the structure of this area denser; and finally, it improves the efficiency of stress transfer from the relatively flexible matrix to the high-rigidity aggregate, reducing stress concentration. The ultimate macroscopic manifestation is a significant improvement in the mechanical properties of concrete, such as compressive strength and flexural strength.

[0096] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An alkali-activated gypsum glass particle concrete, characterized in that, Made from the following parts by weight of raw materials: Alkali activator: 10-15 parts Dehydrated gypsum: 30-40 parts Tempered glass beads: 50-60 parts; It also includes concrete admixtures, which are composed of polycarboxylate superplasticizer and protein-based gypsum retarder; the amount of polycarboxylate superplasticizer added is 0.5% of the total mass of alkali activator, dehydrated gypsum and tempered glass particles; the amount of protein-based gypsum retarder added is 0.25% of the mass of dehydrated gypsum.

2. The alkali-activated gypsum glass particle concrete according to claim 1, characterized in that, The tempered glass particles are particulate matter obtained from waste tempered glass products through crushing and screening, with a particle size range of 0.5-2cm.

3. The alkali-activated gypsum glass particle concrete according to claim 1, characterized in that, The alkaline activator is a alkali hydroxide, selected from sodium hydroxide, potassium hydroxide, and calcium hydroxide.

4. The alkali-activated gypsum glass particle concrete according to claim 1, characterized in that, The dehydrated gypsum is made by uniformly mixing hemihydrate gypsum and anhydrous gypsum in a mass ratio of 1:1 and then sealing and aging for 7 days.

5. The alkali-activated gypsum glass particle concrete according to claim 4, characterized in that, The hemihydrate gypsum is obtained by drying dihydrate gypsum raw material at 160℃ for 5-8 hours; the anhydrous gypsum is obtained by drying dihydrate gypsum raw material at 200℃ for 5-8 hours.

6. The alkali-activated gypsum glass particle concrete according to claim 5, characterized in that, The raw material for the dihydrate gypsum is obtained by crushing natural dihydrate gypsum, phosphogypsum, or desulfurized gypsum and then screening it through a 130-mesh sieve.

7. A method for preparing alkali-activated gypsum glass particle concrete, used to prepare the alkali-activated gypsum glass particle concrete according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Raw material preparation: Preparation of dehydrated gypsum and tempered glass granules; S2. Dry mixing: Add the alkali activator, the dehydrated gypsum obtained in step S1, tempered glass particles, and protein-based gypsum retarder into a mixer and mix. S3. Wet mixing: Dilute the polycarboxylate superplasticizer in the mixing water, pour it into the mixer of step S2, and continue mixing for 2-3 minutes to obtain concrete slurry; S4. Molding and Curing: Pour the concrete slurry obtained in step S3 into a mold for molding, and then cure it indoors under natural conditions for 28 days.

8. The preparation method according to claim 7, characterized in that: The preparation process of dehydrated gypsum in step S1 is as follows: after crushing the dihydrate gypsum, it is sieved through a 130-mesh sieve to obtain the dihydrate gypsum raw material; Hemihydrate gypsum is prepared by drying a portion of dihydrate gypsum raw material at 160℃ for 5-8 hours. Another portion of the dihydrate gypsum raw material was dried at 200℃ for 5-8 hours to obtain anhydrous gypsum; The prepared hemihydrate gypsum and anhydrous gypsum are then mixed evenly at a mass ratio of 1:1, sealed and aged for 7 days to obtain dehydrated gypsum.

9. The preparation method according to claim 7, characterized in that: The preparation process of the tempered glass particles in step S1 is as follows: after crushing the waste tempered glass, particles with a particle size in the range of 0.5-2cm are screened out.

10. The application of tempered glass particles in alkali-activated gypsum concrete, characterized in that, Tempered glass particles were used to replace sand and gravel aggregates, and CSH gel was generated in alkali-activated gypsum-based concrete to strengthen the interfacial transition zone.

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