Muck-based baking-free brick and preparation method thereof

Abstract

The invention discloses a muck-based baking-free brick and a preparation method thereof, and relates to the technical field of baking-free bricks. The muck-based baking-free brick is prepared from the following raw materials in parts by weight: 80 to 100 parts of engineering muck, 10 to 12 parts of cement, 30 to 50 parts of deionized water, 10 to 12 parts of alkali activator, 1 to 2 parts of defoaming agent, 1 to 3 parts of basalt fiber and 5 to 10 parts of curing agent. The preparation method comprises the following steps: reacting magnesium chloropropene with phenyl trichlorosilane to obtain trialkenyl (phenyl) silane; the preparation method comprises the following steps: firstly, preparing hyperbranched organic silicon resin, then adding 1, 5-pentanediol in batches to prepare hyperbranched organic silicon resin, then grafting the hyperbranched organic silicon resin onto epoxy resin to prepare hyperbranched organic silicon modified epoxy resin, and then grafting gamma-aminopropyltriethoxysilane to obtain the curing agent. The muck-based baking-free brick prepared by the invention has the characteristics of good compressive strength, low water absorption rate and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of non - fired bricks, and particularly to a construction waste - based non - fired brick and a preparation method thereof. Background Art

[0002] With the acceleration of the urbanization process, the demand for building materials in the construction industry is increasing continuously. However, the production method of traditional sintered bricks faces problems such as resource waste, high energy consumption, and environmental pollution. In recent years, non - fired bricks, as a kind of green building materials, have gradually attracted attention. The production of non - fired bricks does not require high - temperature firing, which can effectively reduce energy consumption and carbon emissions. At the same time, using engineering construction waste, construction waste, etc. as raw materials realizes the recycling of resources. Among various types of non - fired bricks, the development of construction waste - based non - fired bricks has important practical significance. Construction waste is a large amount of waste generated during urban construction and infrastructure construction. Its accumulation not only occupies land resources but also may pollute the environment. Converting construction waste into raw materials for non - fired bricks can not only solve the problem of construction waste disposal but also reduce the production cost of building materials.

[0003] However, the existing technology of construction waste - based non - fired bricks still has some deficiencies. For example, the composition of construction waste is complex, and construction waste from different sources may contain different impurities, which poses a challenge to the quality stability of non - fired bricks. In addition, how to further improve the utilization rate of construction waste while ensuring the high strength and low water absorption of non - fired bricks is also the focus of current research. To sum up, developing a high - strength and environmentally friendly construction waste - based non - fired brick and its preparation method not only helps to solve the problem of construction waste disposal but also promotes the sustainable development of the building materials industry, having important economic and social significance.

[0004] Chinese invention patent with publication number CN110835245A discloses a non - fired brick and a preparation method thereof. The preparation method of the non - fired brick includes the following steps: adding a coagulant and a flocculant to pipeline sludge, stirring to concentrate it, and dehydrating and air - drying to obtain dehydrated sludge with a weight water content of 25 - 35%; after removing impurities from construction waste through a separation process, crushing and screening it to obtain recycled fine aggregate with a particle size of 0 - 4.75 mm; mixing according to the weight ratio of 25 - 40% of dehydrated sludge, 30 - 45% of recycled fine aggregate, 5 - 15% of blast furnace slag, 5 - 15% of steel slag, and 9 - 13% of cementitious material, adding water and stirring to obtain a slurry; pouring the slurry into a mold, pressing to form; and curing for at least 28 days after demolding to obtain a non - fired brick. This non - fired brick has good water absorption, but its compressive strength is poor. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a construction waste - based non - fired brick and a preparation method thereof.

[0006] To achieve the above object, the present invention is implemented through the following technical solutions: A kind of construction waste-based non-fired brick, comprising raw materials in the following weight parts: Construction waste: 80 - 100 parts, Cement: 10 - 12 parts, Deionized water: 30 - 50 parts, Alkali activator: 10 - 12 parts, Defoamer: 1 - 2 parts, Basalt fiber: 1 - 3 parts, Curing agent: 5 - 10 parts; The curing agent is prepared by the following method: S1: Under ice bath, phenyltrichlorosilane is slowly added to the tetrahydrofuran solution of allylmagnesium chloride, and the reaction is carried out for 20 - 24 h to obtain triallyl(phenyl)silane; S2: Under nitrogen protection, DMF and triallyl(phenyl)silane are stirred and mixed evenly, heated to 95 - 105 °C, and 1,5 - pentanediol, catalyst C - 94, and 1 - butyl - 3 - methylimidazolium methanesulfonate ionic liquid are added in sequence, and the reaction is carried out for 3 - 4 h to obtain hyperbranched organosilicon resin; S3: Under nitrogen protection, DMSO, hyperbranched organosilicon resin, and epoxy resin are stirred and mixed evenly, heated to 50 - 60 °C, and phosphoric acid is added, and the reaction is carried out for 2 - 4 h to obtain hyperbranched organosilicon - modified epoxy resin; S4: DMF, hyperbranched organosilicon - modified epoxy resin, and γ - aminopropyltriethoxysilane are stirred and mixed evenly, heated to 80 - 120 °C for reaction for 4 - 6 h, and the curing agent is obtained.

[0007] In step S1, the molar ratio of the feed of allylmagnesium chloride to phenyltrichlorosilane is (3.2 - 4):1.

[0008] In step S1, the concentration of the tetrahydrofuran solution of allylmagnesium chloride is 0.5 - 1.2 mol / L.

[0009] In step S2, the mass ratio of the feed of triallyl(phenyl)silane, 1,5 - pentanediol, catalyst C - 94, and 1 - butyl - 3 - methylimidazolium methanesulfonate ionic liquid is (6 - 8):(10 - 16):(0.6 - 0.8):(0.8 - 1).

[0010] In step S3, the mass ratio of the feed of DMSO, hyperbranched organosilicon resin, and epoxy resin is 100:(8 - 10):(12 - 14).

[0011] In step S3, the concentration of phosphoric acid is 75 - 85 wt%.

[0012] In step S4, the feeding mass ratio of DMF, hyperbranched organosilicon modified epoxy resin and γ-aminopropyltriethoxysilane is 100:(12-20):(4-6).

[0013] The alkali activator is one of sodium silicate, sodium carbonate and potassium sulfate.

[0014] The defoamer is one of sodium dodecyl sulfate, fatty alcohol polyoxyethylene ether sulfate and sodium fatty acid methyl ester sulfonate.

[0015] A preparation method of construction waste-based non-fired bricks includes the following steps: (1) Weigh by weight: construction waste: 80-100 parts, cement: 10-12 parts, deionized water: 30-50 parts, alkali activator: 10-12 parts, defoamer: 1-2 parts, basalt fiber: 1-3 parts, curing agent: 5-10 parts; (2) Screen the construction waste to remove impurities such as steel wires and plastics, use a crusher to crush it into fine powder with a particle size ≤ 0.1 mm, add cement and alkali activator and mix evenly, then add curing agent, defoamer, basalt fiber and deionized water and stir and mix. Spread the mixed material in a mold, place the mold in a press and vibrate and press it to obtain a semi-finished non-fired brick. Steam-cure the semi-finished non-fired brick at 60-90 °C and a humidity ≥ 95% for 12-24 h; then cure it at room temperature to obtain the construction waste-based non-fired brick.

[0016] Due to the above technical solutions, the beneficial effects of the present invention include: (1) In the present invention, trienyl(phenyl)silane is obtained by reacting allylmagnesium chloride with phenyltrichlorosilane; hyperbranched organosilicon resin is obtained by reacting trienyl(phenyl)silane with 1,5-pentanediol, and then it is grafted onto epoxy resin to prepare hyperbranched organosilicon modified epoxy resin. Finally, a curing agent is obtained by grafting with γ-aminopropyltriethoxysilane.

[0017] (2) The present invention uses industrial construction waste to replace natural raw materials to process non-fired bricks, reducing the pollution caused by waste to the environment, reducing the exploitation of natural resources, saving energy, and reducing the production cost of non-fired bricks.

[0018] (3) Flexible Si-O bonds are introduced into the curing agent prepared in the present invention. The Si-O bonds can make the polymer chain segments rotate more easily, reduce the internal stress of the resin, and thus improve the fracture toughness of the resin well, making the prepared non-fired bricks have good mechanical strength.

[0019] (4) The curing agent prepared by the present invention has a dendritic structure of hyperbranched organosilicon. The three-dimensional network structure of hyperbranched organosilicon is crosslinked by multi-functional groups to form high-density crosslinking points, which synergistically enhances the rigidity and toughness of epoxy resin, and improves the compressive strength and flexural strength of non-fired bricks. Moreover, the hyperbranched structure can evenly disperse stress and reduce internal cracks. At the same time, the hyperbranched structure can seal pores, reduce the water vapor penetration path, lower the water absorption rate, and extend the freeze-thaw cycle life. Specific Embodiments

[0020] The following is further described in conjunction with embodiments, but the present invention is not limited to these embodiments.

[0021] Example 1 Preparation of Curing Agent: S1: Under ice bath, 0.1 mol of phenyltrichlorosilane was slowly added dropwise to 630 ml of 0.5 mol / L tetrahydrofuran solution over 40 min. After reacting for 20 h, 200 ml of saturated ammonium chloride solution was added, mixed evenly, and left to stand for layering at 0 °C. The organic phase was dried with 50 g of anhydrous sodium sulfate for 2 h and then distilled under reduced pressure at 70 °C for 3 h to obtain trienyl(phenyl)silane. The reaction equation is shown as follows: 。

[0022] S2: Under nitrogen protection, 500 g of DMF and 60 g of trienyl(phenyl)silane were added to the reactor, stirred, and heated to 95 °C. Then, 100 g of 1,5-pentanediol was added in batches (20 g per batch, with a batch interval of 20 min). Subsequently, 6 g of catalyst C-94 and 8 g of 1-butyl-3-methylimidazolium methanesulfonate ionic liquid were added in sequence. After reacting for 4 h, the temperature was lowered to room temperature, 400 g of deionized water was added and stirred evenly, followed by centrifugal filtration. Then, it was washed with 100 g of absolute ethanol and then with 100 g of deionized water, and dried under vacuum at 50 °C for 5 h to obtain hyperbranched organosilicon resin. The reaction equation is shown as follows: 。

[0023] S3: Under nitrogen protection, 1000 g of DMSO, 80 g of hyperbranched organosilicon resin, and 120 g of epoxy resin were added to the reactor, stirred and mixed evenly, and heated to 50 °C. Then, 20 g of 75 wt% phosphoric acid was added, and after reacting for 4 h, rotary evaporation was carried out at 40 °C for 3 h. Then, it was recrystallized three times with acetone (300 g of acetone was used each time), and dried under vacuum at 60 °C for 4 h to obtain hyperbranched organosilicon-modified epoxy resin. During this reaction process, the hydroxyl groups on the hyperbranched organosilicon resin react with the epoxy groups on the epoxy resin. When the epoxy resin is grafted onto the hyperbranched organosilicon resin through the epoxy groups, some epoxy resins react with the hyperbranched organosilicon resin through one epoxy group, and some epoxy resins react with the hyperbranched organosilicon resin through both epoxy groups.

[0024] S4: Add 1000 g of DMF, 120 g of hyperbranched organosilicon-modified epoxy resin, and 40 g of γ-aminopropyltriethoxysilane into the reactor in sequence. Stir, heat up to 80 °C, react for 6 h, cool to 40 °C, add 300 g of triethylamine for neutralization, carry out vacuum distillation at 50 °C for 3 h, and carry out vacuum drying at 60 °C for 3 h to obtain the curing agent. The reaction in this step is the reaction between the epoxy groups on the hyperbranched organosilicon-modified epoxy resin and the amino groups of γ-aminopropyltriethoxysilane. The structural formula of the product is shown as follows: 。

[0025] Among them represents: ; n is a natural number.

[0026] It should be noted that the reaction processes of hyperbranching and grafting reactions are relatively complex. The above structures are only used to understand the reaction sites of this application and are all used to illustrate the reaction sites between the epoxy groups and amino groups in step S4.

[0027] Example 2 Preparation of the curing agent: S1: Under ice bath, slowly drop 0.12 mol of phenyltrichlorosilane into 520 ml of 0.8 mol / L tetrahydrofuran solution. The dropping takes 40 min. After reacting for 22 h, add 250 ml of saturated ammonium chloride solution, mix evenly, let it stand for layer separation at 0 °C, dry the organic phase with 50 g of anhydrous sodium sulfate for 2 h, and carry out vacuum distillation at 70 °C for 3 h to obtain trienyl(phenyl)silane; S2: Under nitrogen protection, add 500 g of DMF and 70 g of trienyl(phenyl)silane into the reactor, stir, heat up to 100 °C, then add 130 g of 1,5-pentanediol in batches (10 g each time, with a batch interval of 10 min), then add 7 g of catalyst C-94 and 9 g of 1-butyl-3-methylimidazolium methanesulfonate ionic liquid in sequence. After reacting for 3.5 h, cool to room temperature, add 400 g of deionized water and stir evenly, carry out centrifugal filtration, then wash with 100 g of absolute ethanol and then wash with 100 g of deionized water, and carry out vacuum drying at 60 °C for 4 h to obtain hyperbranched organosilicon resin; S3: Under nitrogen protection, add 1000 g of DMSO, 90 g of hyperbranched organosilicon resin, and 130 g of epoxy resin into the reactor, stir and mix evenly, heat up to 55 °C, then add 20 g of 80 wt% phosphoric acid, react for 3 h, carry out rotary evaporation at 50 °C for 2 h, then carry out recrystallization with acetone three times (300 g of acetone each time), and carry out vacuum drying at 70 °C for 3 h to obtain hyperbranched organosilicon-modified epoxy resin; S4: Sequentially add 1000 g of DMF, 160 g of hyperbranched organosilicon-modified epoxy resin, and 50 g of γ-aminopropyltriethoxysilane into the reactor, stir, heat up to 100 °C, react for 5 h, cool to 40 °C, add 300 g of triethylamine for neutralization, perform vacuum distillation at 60 °C for 2 h, and conduct vacuum drying at 70 °C for 2 h to obtain the curing agent.

[0028] Example 3 Preparation of the curing agent: S1: Under an ice bath, slowly drop 0.16 mol of phenyltrichlorosilane into 530 ml of a 1.2 mol / L tetrahydrofuran solution over 40 min. After reacting for 24 h, add 250 ml of saturated ammonium chloride solution, mix evenly, let it stand for liquid separation at 0 °C, dry the organic phase with 50 g of anhydrous sodium sulfate for 2 h, and perform vacuum distillation at 70 °C for 3 h to obtain trienyl(phenyl)silane; S2: Under nitrogen protection, add 500 g of DMF and 80 g of trienyl(phenyl)silane into the reactor, stir, heat up to 105 °C, then add 160 g of 1,5-pentanediol in batches (20 g per batch, with a 10-min interval between batches), then sequentially add 8 g of catalyst C-94 and 10 g of 1-butyl-3-methylimidazolium methanesulfonate ionic liquid. After reacting for 3 h, cool to room temperature, add 400 g of deionized water and stir evenly, perform centrifugal filtration, then wash with 100 g of absolute ethanol and then with 100 g of deionized water, and conduct vacuum drying at 70 °C for 3 h to obtain hyperbranched organosilicon resin; S3: Under nitrogen protection, add 1000 g of DMSO, 100 g of hyperbranched organosilicon resin, and 140 g of epoxy resin into the reactor, stir and mix evenly, heat up to 60 °C, then add 20 g of 85 wt% phosphoric acid, react for 2 h, perform rotary evaporation at 60 °C for 1 h, then recrystallize three times with acetone (300 g of acetone each time), and conduct vacuum drying at 80 °C for 2 h to obtain hyperbranched organosilicon-modified epoxy resin; S4: Sequentially add 1000 g of DMF, 200 g of hyperbranched organosilicon-modified epoxy resin, and 60 g of γ-aminopropyltriethoxysilane into the reactor, stir, heat up to 120 °C, react for 4 h, cool to 40 °C, add 300 g of triethylamine for neutralization, perform vacuum distillation at 70 °C for 1 h, and conduct vacuum drying at 80 °C for 1 h to obtain the curing agent.

[0029] Example 4 Preparation of construction waste-based non-fired bricks: (1) Weigh: 800 g of construction waste, 100 g of cement, 300 g of deionized water, 100 g of alkali activator (sodium silicate, modulus 1.2), 10 g of defoamer (sodium dodecyl sulfate), 10 g of basalt fiber, and 50 g of curing agent (prepared in Example 1); (2) The construction waste soil was sieved (pore size 5 mm) to remove impurities such as steel wire and plastic, and crushed into fine powder with a particle size of ≤0.1 mm using a crusher. Cement and alkali activator were added and mixed evenly. The mixture was stirred for 20 min at a stirring speed of 200 r / min. Then, curing agent, defoaming agent, basalt fiber and deionized water were added and mixed. The mixture was stirred for 10 min at a stirring speed of 300 r / min. The mixed material was spread in a mold, and the mold was placed in a press for vibration pressing. The pressure was 20 MPa, the pressing time was 10 s, and the vibration frequency was 60 Hz to obtain a semi-finished unfired brick. The semi-finished unfired brick was steam-cured at 60 ° C and humidity 98% for 24 h. Then, the semi-finished unfired brick was cured at room temperature for 7 days to obtain a waste soil-based unfired brick with a size of 200 mm × 100 mm × 60 mm.

[0030] Example 5 Preparation of unburned bricks based on slag: (1) Weigh: 900 g of construction waste, 110 g of cement, 400 g of deionized water, 110 g of alkali activator (sodium silicate, modulus 1.2), 150 g of defoaming agent (sodium fatty alcohol polyoxyethylene ether sulfate), 20 g of basalt fiber, and 80 g of curing agent (prepared in Example 2); (2) The construction waste soil was sieved (pore size 5 mm) to remove impurities such as steel wire and plastic, and crushed into fine powder with a particle size of ≤0.1 mm using a crusher. Cement and alkali activator were added and mixed evenly. The mixture was stirred for 20 min at a stirring speed of 200 r / min. Then, curing agent, defoaming agent, basalt fiber and deionized water were added and stirred for 10 min at a stirring speed of 300 r / min. The mixed material was spread in a mold, and the mold was placed in a press for vibration pressing at a pressure of 20 MPa, a pressing time of 10 s, and a vibration frequency of 60 Hz to obtain a semi-finished unfired brick. The semi-finished unfired brick was steam-cured at 80°C and a humidity of 95% for 18 h. The semi-finished unfired brick was then cured at room temperature for 7 days to obtain a waste soil-based unfired brick with a size of 200 mm×100 mm×60 mm.

[0031] Example 6 Preparation of unburned bricks based on slag: (1) Weigh: 1000 g of construction waste, 120 g of cement, 500 g of deionized water, 120 g of alkali activator (sodium carbonate), 20 g of defoaming agent (sodium fatty acid methyl ester sulfonate), 30 g of basalt fiber, and 100 g of curing agent (prepared in Example 3); (2) The construction waste soil was sieved (pore size 5 mm) to remove impurities such as steel wire and plastic, and crushed into fine powder with a particle size of ≤0.1 mm using a crusher. Cement and alkali activator were added and mixed evenly. The mixture was stirred for 20 min at a stirring speed of 200 r / min. Then, curing agent, defoaming agent, basalt fiber and deionized water were added and stirred for 10 min at a stirring speed of 300 r / min. The mixed material was spread in a mold, and the mold was placed in a press for vibration pressing at a pressure of 20 MPa, a pressing time of 10 s, and a vibration frequency of 60 Hz to obtain a semi-finished unfired brick. The semi-finished unfired brick was steam-cured at 90°C and a humidity of 95% for 12 h. Then, the semi-finished unfired brick was cured at room temperature for 7 days to obtain a waste soil-based unfired brick with a size of 200 mm×100 mm×60 mm.

[0032] Comparative Example 1 The raw material composition and process of the slag-based unfired bricks are basically the same as those in Example 5, except that no curing agent is added to the components.

[0033] Comparative Example 2 The raw material composition and process of the slag-based unfired bricks are basically the same as those in Example 5, except that the curing agent added to the components is replaced with an epoxy curing agent of equal weight.

[0034] Comparative Example 3 The raw material composition and process of the slag-based unfired bricks are basically the same as those in Example 5, except that the curing agent added to the components is replaced by an equal weight of the hyperbranched silicone-modified epoxy resin prepared in step S3.

[0035] Comparative Example 4 The raw material composition and process of the slag-based unburned bricks are basically the same as those in Example 5, except that the curing agent added to the components is replaced by a curing agent prepared by the following method: The preparation method of the curing agent in this comparative example is basically the same as that in Example 2, except that the phenyltrichlorosilane in step S1 is replaced by 0.25 mol of triethylvinylsilane.

[0036] Comparative Example 5 The raw material composition and process of the slag-based unburned bricks are basically the same as those in Example 5, except that the curing agent added to the components is replaced by a curing agent prepared by the following method: The preparation method of the curing agent in this comparative example is basically the same as that in Example 2, except that the phenyltrichlorosilane in step S1 is replaced by 0.25 mol of triphenylvinylsilane.

[0037] Comparative Example 6 The raw material composition and process of the slag-based unburned bricks are basically the same as those in Example 5, except that the curing agent added to the components is replaced by a curing agent prepared by the following method: The preparation method of the curing agent in this comparative example is basically the same as that in Example 2, except that the 130 g of 1,5-pentanediol added in step S2 is replaced by 70 g of 1,5-pentanediol.

[0038] Comparative Example 7 The raw material composition and process of the slag-based unburned bricks are basically the same as those in Example 5, except that the curing agent added to the components is replaced by a curing agent prepared by the following method: The preparation method of the curing agent in this comparative example is basically the same as that in Example 2, except that the 130 g 1,5-pentanediol added in step S2 is replaced by 130 g 1,2-propylene glycol.

[0039] Comparative Example 8 The raw material composition and process of the slag-based unburned bricks are basically the same as those in Example 5, except that the curing agent added to the components is replaced by a curing agent prepared by the following method: The preparation method of the curing agent in this comparative example is basically the same as that in Example 2, except that the 50 g of γ-aminopropyltriethoxysilane added in step S4 is replaced by 50 g of (3-aminopropyl)dimethylethoxysilane.

[0040] Comparative Example 9 The raw material composition and process of the slag-based unfired bricks are basically the same as those in Example 5, except that the 80g curing agent (prepared in Example 2) added in the components is changed to 30g.

[0041] Comparative Example 10 The unfired bricks are made by using the raw material composition and process of Example 2 of the Chinese invention patent with publication number CN110835245A.

[0042] The main components of the construction slag used in the embodiments and comparative examples of the present application are broken concrete blocks: 41.6%, bricks and tiles: 23.5wt%, ceramic fragments: 15.1wt%, crushed stone: 10.4wt%, lime: 6.2wt%, and the moisture content is ≤5%; the cement is road silicate cement grade 42.5 (codenamed P.R7.5), purchased from Shanxi Excellence Cement Co., Ltd.; the basalt fiber length is 1-3mm, purchased from Shandong Oude Chemical Fiber Products Co., Ltd.; the model of the epoxy resin is E-51; the model of the epoxy curing agent is HMA-2300, purchased from Complex High-tech Materials (Shanghai) Co., Ltd.

[0043] The compressive strength, flexural strength and water absorption performance of the slag-based unfired bricks prepared in Examples 4-6 of the present application and Comparative Examples 1-10 were tested. The test results are shown in Table 1.

[0044] According to GB / T 2542-2012 "Test Methods for Burnt Clay Bricks", compressive strength, flexural strength and water absorption tests were carried out.

[0045] Table 1 Performance Test Table

[0046] It can be seen from Table 1 that the waste soil-based non-fired bricks prepared in Examples 4-6 of this application have excellent compressive strength, flexural properties and water absorption.

[0047] Comparative Example 1 is a comparative example prepared without adding a curing agent. It can be seen from the data in Table 1 that its compressive strength is 9.1 MPa, its flexural strength is 2.72 MPa, and its water absorption is 10.5%. The compressive strength and water absorption are poor.

[0048] In Comparative Example 2, the added curing agent was replaced with an equal weight of epoxy curing agent. It can be seen from Table 1 that its compressive strength is 15.3 MPa, its flexural strength is 3.65 MPa, and its water absorption is 9.3%. This shows that the mechanical strength of the non-fired bricks prepared with commercially available epoxy curing agents is inferior to that of this application.

[0049] In Comparative Example 3, the added curing agent was replaced with the hyperbranched organosilicon modified epoxy resin prepared in step S3. It can be seen from Table 1 that its compressive strength is 16.4 MPa, its flexural strength is 4.18 MPa, and its water absorption is 8.8%. This is because the curing agent grafted with γ-aminopropyltriethoxysilane contains Si-O-Si bonds, which can provide hydrophobicity and chemical corrosion resistance, reduce the pulverization of the brick body caused by the migration of metal ions in the waste soil. At the same time, the amino group of γ-aminopropyltriethoxysilane reacts with the epoxy group to form a chemical bond, and the silanol (-Si-OH) generated after the hydrolysis of its ethoxy group combines with inorganic aggregates (such as waste soil particles), enhancing the organic-inorganic interfacial bonding force and reducing internal cracks, thereby improving the compressive performance.

[0050] In Comparative Example 4 and Comparative Example 5, trialkenyl(phenyl)silane prepared in step S1 during the preparation of the curing agent was replaced with triethylvinylsilane and triphenylvinylsilane respectively. As can be seen from Table 1, both the compressive strength and water absorption are inferior to those of the present application. This is because the curing agents prepared from triethylvinylsilane and triphenylvinylsilane have a low hyperbranched structure, while the curing agent prepared in the present application has a dendritic structure of hyperbranched organosilicon. The three-dimensional network structure of hyperbranched organosilicon is crosslinked by multi-functional groups to form high-density crosslinking points, which synergistically enhance the rigidity and toughness of the epoxy resin, improving the compressive strength and flexural strength of the non-fired brick. Moreover, the hyperbranched structure can evenly disperse stress and reduce internal cracks; the hyperbranched structure seals pores, reduces the water vapor penetration path, lowers the water absorption, and improves the freeze-thaw cycle life; the epoxy resin with a low-branched structure has fewer crosslinking points, poor compressive strength, uneven stress dispersion, and is prone to crack due to interfacial peeling.

[0051] In Comparative Example 6, the addition method of 1,5-pentanediol in step S2 of the curing agent preparation process was different, and in Comparative Example 7, 1,5-pentanediol in step S2 of the curing agent preparation process was replaced with 1,2-propanediol; as can be seen from Table 1, both the compressive strength and water absorption are inferior to those of the present application.

[0052] In Comparative Example 8, γ-aminopropyltriethoxysilane in step S4 of the curing agent preparation process was replaced with (3-aminopropyl)dimethylethoxysilane. As can be seen from Table 1, its compressive strength is 20.3 MPa, flexural strength is 4.80 MPa, and water absorption is 7.3%.

[0053] Comparative Example 9 is a comparative example different from Example 5, and the difference lies in the different addition amounts of the curing agent. As can be seen from Table 1, its compressive strength is 18.6 MPa, flexural strength is 4.69 MPa, and water absorption is 6.9%, indicating that the addition of the curing agent also has a certain impact on the performance of the non-fired brick in various aspects.

[0054] Comparative Example 10 is a non-fired brick prepared with the raw material composition and process of Example 2 of the Chinese invention patent with the publication number CN110835245A, and both its compressive strength and water absorption are inferior to those of the non-fired brick prepared in the present application.

[0055] The room temperature curing time of the construction waste-based non-fired brick prepared in Example 5 is 7 days. Table 2 shows the performance test of the construction waste-based non-fired bricks prepared with different room temperature curing times (other process conditions remain unchanged).

[0056] Table 2 Performance data of construction waste-based non-fired bricks prepared with different room temperature curing times

[0057] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. However, for those of ordinary skill in the art, within the scope of the technical solution of the present invention, any minor changes, modifications, and equivalent variations made using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any changes, modifications, and equivalent variations made to the above embodiments based on the essential technology of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A slag-based unburned brick, characterized in that: The invention comprises the following raw materials in parts by weight: Construction waste: 80-100 parts, Cement: 10-12 parts, Deionized water: 30-50 parts, Alkali activator: 10-12 parts, Defoaming agent: 1-2 parts, Basalt fiber: 1-3 parts, Curing agent: 5-10 parts; The curing agent is prepared by the following method: S1: Slowly add phenyltrichlorosilane to a tetrahydrofuran solution of magnesium chloride under ice bath, and react for 20-24h to obtain trienyl (phenyl) silane; S2: Under nitrogen protection, DMF and trienyl (phenyl) silane were stirred and mixed, the temperature was raised to 95-105°C, 1,5-pentanediol, catalyst C-94, and 1-butyl-3-methylimidazolium methane sulfonate ionic liquid were added in sequence, and the reaction was carried out for 3-4 hours to obtain a hyperbranched silicone resin; S3: Under nitrogen protection, DMSO, hyperbranched silicone resin and epoxy resin are stirred and mixed, the temperature is raised to 50-60° C., phosphoric acid is added and reacted for 2-4 hours to obtain a hyperbranched silicone-modified epoxy resin; S4: DMF, hyperbranched silicone-modified epoxy resin and γ-aminopropyltriethoxysilane are stirred and mixed, and the mixture is heated to 80-120° C. and reacted for 4-6 hours to obtain a curing agent.

2. The slag-based unburned brick according to claim 1, characterized in that: In step S1, the molar ratio of the magnesium chloride to phenyltrichlorosilane is (3.2-4):

1.

3. The slag-based unburned brick according to claim 1, characterized in that: In step S1, the concentration of the tetrahydrofuran solution of allyl magnesium chloride is 0.5-1.2 mol / L.

4. The slag-based unburned brick according to claim 1, characterized in that: In the step S2, the feed mass ratio of trienyl (phenyl) silane, 1,5-pentanediol, catalyst C-94, and 1-butyl-3-methylimidazolium methane sulfonate ionic liquid is (6-8):(10-16):(0.6-0.8):(0.8-1).

5. The slag-based unburned brick according to claim 1, characterized in that: In the step S3, the mass ratio of DMSO, hyperbranched silicone resin and epoxy resin is 100:(8-10):(12-14).

6. The slag-based unburned brick according to claim 1, characterized in that: The concentration of phosphoric acid in step S3 is 75-85 wt %.

7. The slag-based unburned brick according to claim 1, characterized in that: In the step S4, the feed mass ratio of DMF, hyperbranched organosilicon-modified epoxy resin and γ-aminopropyltriethoxysilane is 100:(12-20):(4-6).

8. The slag-based unburned brick according to claim 1, characterized in that: The alkaline activator is one of sodium silicate and sodium carbonate.

9. The slag-based unburned brick according to claim 1, characterized in that: The defoaming agent is one of sodium lauryl sulfate, sodium fatty alcohol polyoxyethylene ether sulfate and sodium fatty acid methyl ester sulfonate.

10. A method for preparing slag-based unburned bricks according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) Weigh by weight: construction waste soil: 80-100 parts, cement: 10-12 parts, deionized water: 30-50 parts, alkali activator: 10-12 parts, defoamer: 1-2 parts, basalt fiber: 1-3 parts, curing agent: 5-10 parts; (2) The construction waste soil is sieved to remove impurities such as steel wire and plastic, and crushed into fine powder with a particle size of ≤0.1 mm using a crusher. Cement and alkali activator are added and mixed evenly. Then, a curing agent, a defoaming agent, basalt fiber and deionized water are added and stirred. The mixed material is spread in a mold, and the mold is placed in a pressing machine for vibration pressing to obtain a semi-finished unburned brick. The semi-finished unburned brick is steam-cured at 60-90°C and humidity ≥95% for 12-24 hours. Then, it is cured at room temperature to obtain a waste soil-based unburned brick.

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