Dry-mixed solidified soil mortar material

Abstract

The invention discloses a dry-mixed solidified soil mortar material. Mud is subjected to mud-water separation to form a mud cake, the mud cake is dried, the water content of the mud cake is reduced to 1%-10%, the mud cake is crushed and dried to form a crushed mud cake material, and the crushed mud cake material is mixed with a curing agent to form the dry-mixed solidified soil mortar material. According to the invention, complete resourceful treatment of the shield muck and even building waste soil materials is realized. Waste soil of a construction site is sieved through a sieve with overlarge particles removed, water is added for uniform stirring, shield muck (slurry) can be added in the process to form slurry, the slurry is subjected to mud-water separation to form a mud cake, the mud cake is dried, and the water content is reduced to the required standard. And uniformly mixing with a curing agent to obtain the dry-mixed solidified soil mortar material which can be directly utilized. Therefore, the vast majority of building waste which is prepared to be transported outwards for waste treatment in a construction site becomes available substances, the cost of due building waste treatment is eliminated, and the cost is converted into earnings.

Description

Technical Field

[0001] The present invention relates to the field of building materials or environmental protection technologies, and more specifically, to a dry-mixed solidified soil mortar material. Background Art

[0002] Building materials such as cement and concrete are precisely formulated at professional production sites to produce standardized finished materials. After these building materials are transported to the construction site, construction workers only need to add sufficient water in a predetermined proportion and simply stir to put them into use. The required operation process is simple and clear, and the required equipment and site are extremely limited, greatly streamlining the complexity of on-site construction.

[0003] Solidified soil is a new type of environmental protection building material. Its original main material of solidified soil comes from waste building materials that need to be transported out, such as shield muck, etc. Its formation process is carried out by temporary preparation and processing at the construction site, and a special area needs to be set aside to place the preparation equipment and preparation.

[0004] Compared with ready-made materials such as cement and concrete that can be taken and used at any time, the characteristic of solidified soil relying on on-site temporary processing undoubtedly slows down the construction progress and increases the input of labor and equipment costs. In addition, not all construction sites that produce solidified soil raw materials can use solidified soil as a building material. Therefore, the performance of the on-site preparation of solidified soil reduces the application scenarios of solidified soil. Summary of the Invention

[0005] In order to solve the problem that the on-site preparation of solidified soil limits the application scenarios, the present invention provides a dry-mixed solidified soil mortar material, so that the use of solidified soil is no longer limited by the production site, can be arbitrarily allocated to the required place, and realizes the complete resource utilization of waste soil materials such as shield muck that need to be transported out.

[0006] The technical solution of the present invention is as follows:

[0007] A dry-mixed solidified soil mortar material is formed by separating mud and water from slurry to form a mud cake, drying the mud cake to reduce the moisture content of the mud cake to 1%-10%, crushing the dried mud cake to form a crushed mud cake, and mixing the crushed mud cake with a curing agent.

[0008] For the above dry-mixed solidified soil mortar material, the moisture content of the dried mud cake is 10%.

[0009] For the above dry-mixed solidified soil mortar material, the moisture content of the dried mud cake is 1%.

[0010] The above dry-mixed solidified soil mortar material forms a fluidized solidified soil after being mixed with water, and the fluidized solidified soil is used for synchronous grouting of shield segments, post-grouting behind the lining of a mined tunnel, plugging grouting, backfilling of foundation trenches, backfilling of underground prefabricated stations, and construction of road and floor structural layers.

[0011] The above dry-mixed solidified soil mortar material is evenly laid on the construction surface, water is sprayed on the surface of the dry-mixed solidified soil mortar material, and after the dry-mixed solidified soil mortar material is evenly mixed by a mixing device, a stable structural layer is formed.

[0012] For the above dry-mixed solidified soil mortar material, the curing agent consists of cement, sodium sulfate and calcium carbonate with a mass ratio of (6-9):(0.5-2):(0.5-2).

[0013] For the above dry-mixed solidified soil mortar material, the mixing mass ratio of the mud cake pulverized matter to the curing agent is mud cake pulverized matter:curing agent=(1-4):(8-10).

[0014] For the above dry-mixed solidified soil mortar material, the determination test of the water content of the mud cake includes the adhesion test of the mud cake, the dispersion test of the mud cake pulverized matter and the compressive strength loss rate test.

[0015] Furthermore, the adhesion test of the mud cake includes a pipeline transportation test, a mixer stirring test and a crusher crushing test. The mud cake is respectively placed into a pipeline transportation simulation device, a small mixer and a small crusher, and the pipeline transportation simulation device, the small mixer and the small crusher are respectively made to work for a certain period of time. The adhered soil is scraped at each test point of the pipeline transportation simulation device, the small mixer and the small crusher, weighed respectively, and the total adhered weight of the pipeline transportation simulation device, the small mixer and the small crusher is calculated.

[0016] Furthermore, the process of the dispersion test of the mud cake pulverized matter includes: preparing mud cake pulverized matter with different water contents; taking several grams of mud cake pulverized matter with different water contents, putting them into a colorimetric dish containing a fixed amount of deionized water, using a magnetic stirrer to stir at a fixed speed for a certain number of minutes to fully disperse the mud cake in water; putting the colorimetric dish containing the dispersion liquid into a spectrophotometer, measuring the transmitted light intensity at a wavelength of 550 nm, and recording the data.

[0017] Further, the compressive strength loss rate test includes: preparing crushed mud cake; taking equal amounts of crushed mud cake and curing agent, mixing them evenly in a mixer according to a certain ratio to make a dry-mixed mortar material sample; taking equal amounts of materials from the dry-mixed mortar material sample and making initial specimens of standard size respectively; placing the initial specimens in a curing box for 28 hours, using a pressure testing machine with a suitable range to conduct an initial compressive strength test on the cured initial specimens to obtain the initial compressive strength of each initial specimen; placing the remaining dry-mixed mortar material sample in a simulated environment with constant temperature and humidity and storing it for a certain period of time; taking equal amounts of dry-mixed mortar material sample at regular intervals and making test specimens of standard size; after the test specimens are cured under the same curing conditions and curing time as the initial specimens, using a pressure testing machine under the same conditions to conduct a compressive strength test on the cured test specimens to obtain the compressive strength of the specimens; calculating the compressive strength loss rate based on the initial compressive strength and the compressive strength of the specimens.

[0018] Tests such as the adhesion test of the mud cake, the dispersibility test of the crushed mud cake, and the compressive strength loss rate test evaluate and determine the moisture content of the mud cake from different dimensions. The adhesion test focuses on the characteristics of mud cakes with different moisture contents during transportation and processing. The dispersibility test focuses on the dispersibility of the crushed mud cake in liquid. The compressive strength loss rate test focuses on the performance stability of the final product of the dry-mixed solidified soil mortar material in the actual environment. On the contrary, in the process of determining the moisture content of the mud cake, at the level of transportation and processing of the dry-mixed solidified soil mortar material, only the adhesion performance corresponding to the amount of moisture content of the mud cake needs to be tested; in the level of solidified soil forming, only the dispersibility of the crushed mud cake needs to be tested (the greater the dispersibility, the faster the mud cake forms solidified soil); and the quality of the mud cake forming solidified soil and the shelf life of the dry-mixed solidified soil mortar material only need to be determined through the compressive strength loss rate test. Through comprehensive analysis of the test results from multiple dimensions, the appropriate moisture content range of the mud cake can be determined more comprehensively and accurately to meet various requirements from mud cake treatment to the application of the final product.

[0019] The present invention according to the above solution has the beneficial effect that the present invention realizes the complete resource treatment of shield muck and even construction waste soil materials. The waste soil materials at the construction site are sieved to remove oversized particles, and then evenly stirred with water. During this process, shield muck (in slurry form) can be added to form slurry. After the slurry is separated by sedimentation, a mud cake is formed. The moisture content of the mud cake is reduced to the required standard by drying, and then it can be directly used as dry-mixed solidified soil mortar material after being evenly mixed with a curing agent. In this way, most of the construction waste that was originally prepared to be transported out of the construction site for waste treatment becomes reusable materials, eliminating the cost of disposing of this part of the construction waste and turning it into revenue. The present invention forms a new variety of building materials, re-establishes a material chain for waste building materials, makes the waste building materials that cannot be digested at the construction site resourceful, and enables them to be transferred to the construction site for floors, roads, etc., forming a new building industrial chain. Detailed implementation mode

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clear and understandable, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] The slurry is separated by sedimentation to form a mud cake, the mud cake is dried, the moisture content of the mud cake is reduced to 1%-10%, the dried mud cake is crushed to form a mud cake powder, and the mud cake powder is mixed with a curing agent to form a dry-mixed solidified soil mortar material. The curing agent consists of cement, sodium sulfate and calcium carbonate with a mass ratio of (6-9):(0.5-2):(0.5-2). The mixing mass ratio of the mud cake powder to the curing agent is mud cake powder:curing agent = (1-4):(8-10).

[0022] The waste soil materials generated at existing construction sites are usually discarded because they cannot meet the required properties of building materials, and these soil materials cannot be used as raw materials for ordinary building materials. Therefore, the only way for the construction party to deal with these waste soil materials is to transport them out for landfill. In order to avoid the pollution and occupation of the environment by waste building materials, the state has a series of regulations on the treatment methods of waste building materials. Currently, the common treatment method of the construction party is to transport the waste soil materials to the designated place. The costs incurred include transportation costs, labor costs, treatment costs, etc., and the calculation unit of these costs is vehicle.

[0023] In order to reduce costs, some construction parties will separate the muddy water from the waste soil to form mud cakes, reducing the transportation volume and treatment weight. Usually, the mud cakes formed by the muddy water separation through extrusion technology have a moisture content of 30%-50%. However, some construction parties want to further compress the volume of the mud cakes and will further dry them. The moisture content control standard for the dried mud cakes is 20%-30%. For some mud cakes such as sludge with more microorganisms, the moisture content may be lower, but the standard line is around 20%. Because too low moisture content will increase the brittleness of the mud cakes, causing the originally compressed volume to redisperse and increase the volume, which is not conducive to efficient transportation and stacking (and the transportation cost is calculated by the vehicle. Even if the moisture content is relatively high, the weight of the mud cakes filling the transportation vehicle will not exceed the load of the transportation vehicle, nor will it increase the energy cost additionally). Additionally, the mud cakes with too low moisture content also have problems such as dust flying, which are not conducive to transportation either.

[0024] The present invention does not directly transport the mud cakes out, but further dries them on this basis, reducing the moisture content of the mud cakes to 1%-10%, and then crushing and adding a curing agent to stir at the construction site to form dry-mixed solidified soil mortar materials. Compared with the mud cakes transported out, the moisture content control is more strict and lower.

[0025] For mud cakes with a moisture content higher than 20%, the mud cakes will adhere to the pipelines, crushing equipment and mixing equipment. While for mud cakes with a moisture content below 20%, the adhesion phenomenon is greatly improved. Among them, setting the moisture content of the mud cakes to 10% is the best consideration based on cost, performance and shelf life. While ensuring a sufficient shelf life, the dried mud cakes should be easy to stir, quickly made into dry-mixed solidified soil or fluidized solidified soil, and the cost needs to be controlled (since the power of the drying equipment is very high, during the process of reducing the moisture content of the mud cakes from 30% to 1%, usually the power consumption for evaporating 1 kg of water will increase from 0.3 / 0.4 kW (the power consumption for evaporating 1 kg of water when the moisture content is reduced from 80% to 30%) to 0.5 / 0.6 kW, and the energy consumption increases significantly. Therefore, it is not that the lower the moisture content of the mud cakes, the better).

[0026] Experiment 1: Mud cake adhesion test.

[0027] Pour the waste soil into an extrusion type muddy water separator to obtain a preliminarily formed wet mud cake. Randomly select 3-5 small mud cake samples, accurately weigh them with an electronic balance, record as m1, put them into a drying oven, dry them to a constant weight at 105°C ± 5°C, and weigh them again, record as m2. If you want to obtain a mud cake with a moisture content of 35%, assuming the initial mud cake weight m1 = 1000 grams and the moisture content ω0 = 30%, first calculate the dry soil mass ω d = m1×(1 - ω0)= 1000×0.7 = 700 grams. Let the mass of water to be added be x. According to the target moisture content formula: (m1 + x - m d) / (m1 + x) = 0.35, and by solving, x ≈ 77 grams.

[0028] According to the calculation result, slowly add the required amount of water to the preliminary mud cake, and fully stir with tools while adding water to ensure uniform distribution of moisture, obtaining a mixed material. Put the mixed material into the extrusion type mud - water separator (with unchanged parameters) again to extrude a formed mud cake. Select at least 5 samples from different parts of the new mud cake, each sample weighing about 50 grams, and measure the wet weight m 湿 and the dry weight m after drying 干 , and calculate the moisture content ω = (m 湿 - m 干 ) / m 湿 ×100%. If the calculated moisture content is not equal to 35%, recalculate the required increase or decrease in the amount of water and soil according to the deviation, and repeat the steps of adding water and stirring, secondary forming, and measurement until the average moisture content of the mud cake samples reaches the standard.

[0029] Finally, the actual moisture content of the mud cake for the test only needs to meet the standard of the target moisture content ±0.5%. According to this standard, prepare mud cakes with moisture contents of 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, and 45% respectively. Conduct pipeline transportation tests, mixer stirring tests, and crusher crushing tests on the above mud cakes with different moisture contents.

[0030] Pipeline transportation test: Put the mud cake into the feed inlet of the pipeline transportation simulation device, set a fixed transportation flow rate, pipe diameter, and pipe inclination angle. After transporting a fixed length (such as 5 meters), stop the transportation, open the pipeline, and observe and record the thickness and weight of the mud cake adhered to the inner wall of the pipeline at 3 equally - spaced measurement points (starting section, middle section, end section) of the pipeline, and then clean the pipeline to restore it to its original state. (The total mass of the test mud cake sample is 500 grams)

[0031] Mixer stirring test: Put the mud cake into a small mixer and stir at a fixed speed for 5 minutes. After stopping the machine, observe the adhesion conditions at 6 different positions such as the mixer blades and the inner wall (3 positions on the blades and 3 positions on the inner wall, and the sampling position is fixed). Scrape off the adhered mud cake and weigh it separately, and then sum up to obtain the total adhesion weight. (The total mass of the test mud cake sample is 500 grams)

[0032] Crusher crushing test: Put the mud cake into a small crusher (similar to the crushers commonly used at the construction site, such as a hammer crusher, etc.) and crush it for 3 minutes. After pouring out the crushed material, carefully weigh the mud cake weight at 8 key positions (4 test points in the inner cavity and 4 test points on the crusher hammer head) remaining in the crusher hammer head and the inner cavity, and sum them up to obtain the total adhesion weight. (The total mass of the test mud cake sample is 100 grams)

[0033] The data of the above three tests are shown as follows.

[0034]

[0035]

[0036]

[0037]

[0038]

[0039] It can be seen from the above data that as the water content of the mud cake increases, the average adhesion weight generally shows an upward trend, but not a linear growth. In the water content range of 1% - 10%, the total adhesion weight increases relatively smoothly; in the water content range of 10% - 15%, the total adhesion weights are relatively close, and the adhesion performance is relatively stable, without significant differences in adhesion weight due to small changes in water content. In the water content range of 15% - 20%, the average adhesion weight increases significantly. When the water content exceeds 20%, the total adhesion weight increases significantly, and the adhesion performance deteriorates severely at high water contents.

[0040] Test 2: Mud cake dispersion test.

[0041] Prepare mud cakes with different water contents as in Test 1, and use a hammer mill to crush the mud cakes into crushed mud cake materials with the same average particle size. Take 10 grams of the crushed mud cake materials with different water contents and put them into a colorimetric dish containing a fixed amount (100 ml) of deionized water. Use a magnetic stirrer to stir at a fixed speed (500 r / min) for 15 minutes to fully disperse the crushed mud cake materials in the water. Put the colorimetric dish containing the dispersion liquid into a spectrophotometer and measure the transmitted light intensity at a wavelength of 550 nm, and record the data. Each sample is measured 3 times, and the average value is taken as the measurement result of the sample.

[0042]

[0043]

[0044] It can be seen that in the water content range of 1% - 15% of the mud cake, the transmitted light intensity gradually decreases, and the dispersibility increases. After the water content is greater than 15%, the transmitted light intensity rises, and the dispersibility decreases. At about 25%, the transmitted light intensity rises significantly, and the dispersibility deteriorates sharply. After the water content is greater than 25%, the transmitted light intensity continues to rise, and the decrease in dispersibility is greater than that between 15% - 25%.

[0045] Test 3: Compressive strength loss rate test.

[0046] Prepare mud cakes with different water contents in the same way as in Experiment 1, and use a hammer mill to crush the mud cakes into crushed mud cake materials with the same average particle size. According to the same preset ratio, take equal amounts of the crushed mud cake materials and the curing agent and mix them evenly in a mixer according to a certain ratio to make dry-mixed mortar material samples. Subsequently, take equal amounts of materials from the dry-mixed mortar material samples and make initial specimens of standard size respectively. When making the initial specimens, it is necessary to ensure that the forming quality of the initial specimens, such as uniform vibration and smooth surface, is the same. Place the initial specimens in a curing box for 28 hours, and use a pressure testing machine with an appropriate range to conduct an initial compressive strength test on the cured initial specimens to obtain the initial compressive strength of each initial specimen. The remaining dry-mixed mortar material samples are placed in a simulated environment with a constant temperature and humidity of (20±2)°C and a relative humidity of (60±5)%. Store for 1-8 months. Every full month, take out equal amounts of dry-mixed mortar material samples and make test specimens of standard size. After the test specimens are cured under the same curing conditions and curing time as the initial specimens, use a pressure testing machine under the same conditions to conduct a compressive strength test on the cured test specimens to obtain the compressive strength of the specimens. Calculate the compressive strength loss rate according to the initial compressive strength and the compressive strength of the specimens, that is

[0047]

[0048] Among them, the compressive strength at the current time is the compressive strength of the test specimens at each time point.

[0049]

[0050]

[0051] Water in the mud cake will act as a solvent or reaction medium inside. Excessive water will trigger some physical or chemical reactions that are not conducive to the stability of the material, such as dissolving some gelling substances and causing changes in the internal pore structure. A low water content means a low degree of these negative effects, and the material structure is relatively more stable, so the compressive strength loss rate is smaller. When the water content reaches 10% or more, more water makes the internal structure of the material be affected more significantly in a short time. Water will damage some connection structures formed between the curing agent and the mud cake particles, reduce the cohesion of the material, and thus cause the compressive strength loss rate to increase rapidly.

[0052] In this way, the water content of the mud cake is reduced to 10% or less, enabling the mud cake to have a certain shelf life (ranging from 1 month to 6 months, with a 10% loss rate of compressive strength as the criterion) after being crushed and uniformly mixed with a curing agent, so as to be transported to the required construction site and maintain the performance of the dry-mixed solidified soil mortar material made from the mud cake. Compared with directly applying the mud cake on-site to make solidified soil, although there is a certain loss in the compressive performance of the finally formed solidified soil after transportation, storage and other placements, the loss rate is still within a reasonable range of 10%-20%, and it can also ensure that the application of the solidified soil is not limited by the construction site, enabling better utilization of these soil materials and reducing the waste treatment cost at the construction site.

[0053] In actual use, when the water content of the mud cake is 10%, the shelf life of the dry-mixed solidified soil mortar material made from the mud cake is 1 month, and when the water content of the mud cake is 1%, the shelf life of the dry-mixed solidified soil mortar material made from the mud cake is 6 months.

[0054] The dry-mixed solidified soil mortar material of the present invention can be moved from a construction site where waste soil materials overflow (due to technical requirements, on-site construction materials do not support the use of solidified soil, etc.) to another construction site where there are no waste soil materials or insufficient waste soil materials, such as construction sites for floor and road construction, etc., so as to realize resource allocation of waste soil materials and improve resource utilization rate.

[0055] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A dry-mixed solidified soil mortar material, characterized in that: The mud is separated into mud cakes through mud and water separation, and the mud cakes are dried to reduce the moisture content of the mud cakes to 1%-10%. The mud cakes are crushed and dried to form mud cake crushed materials, and the mud cake crushed materials are mixed with a curing agent to form a dry-mixed cured soil mortar material.

2. A dry-mixed solidified soil mortar material according to claim 1, characterized in that: The moisture content of the mud cake after drying is 10%.

3. The dry-mixed solidified soil mortar material according to claim 1, characterized in that: The moisture content of the mud cake after drying is 1%.

4. The dry-mixed solidified soil mortar material according to claim 1, characterized in that: The dry-mixed solidified soil mortar material is stirred with water to form fluidized solidified soil, which is used for synchronous grouting of shield segments, grouting behind the mining tunnel wall, plugging grouting, backfilling of fertilizer troughs, backfilling of underground prefabricated stations, and construction of road and floor structure layers.

5. The dry-mixed solidified soil mortar material according to claim 1, characterized in that: The curing agent comprises cement, sodium sulfate and calcium carbonate in a mass ratio of (6-9):(0.5-2):(0.5-2).

6. The dry-mixed solidified soil mortar material according to claim 1, characterized in that: The mixing mass ratio of the mud cake crushed material and the curing agent is mud cake crushed material: curing agent = (1-4): (8-10).

7. The dry-mixed solidified soil mortar material according to claim 1, characterized in that: The tests for determining the moisture content of mud cake include the adhesion test of mud cake, the dispersion test of mud cake crushed material and the compressive strength loss rate test.

8. The dry-mixed solidified soil mortar material according to claim 7, characterized in that: The adhesion test of the mud cake includes a pipeline transportation test, a mixer stirring test and a pulverizer crushing test. The mud cake is placed in a pipeline transportation simulation device, a small mixer and a small pulverizer respectively. The pipeline transportation simulation device, the small mixer and the small pulverizer are respectively operated for a certain period of time. The adhered soil is scraped off at each test point of the pipeline transportation simulation device, the small mixer and the small pulverizer, and weighed respectively. The total adhesion weight of the pipeline transportation simulation device, the small mixer and the small pulverizer is calculated.

9. The dry-mixed solidified soil mortar material according to claim 7, characterized in that: The process of the dispersibility test of the mud cake crushed material includes: preparing mud cake crushed materials with different moisture contents; taking several grams of mud cake crushed materials with different moisture contents, putting them into a cuvette filled with a certain amount of deionized water, and using a magnetic stirrer to stir at a fixed speed for several minutes to fully disperse the mud cake in the water; placing the cuvette containing the dispersion into a spectrophotometer, measuring the intensity of the transmitted light at a wavelength of 550nm, and recording the data.

10. The dry-mixed solidified soil mortar material according to claim 7, characterized in that: The compressive strength loss rate test includes: preparing mud cake crushed material; taking equal amounts of mud cake crushed material and curing agent in a certain proportion and mixing them evenly in a mixer to make dry-mixed mortar material samples; taking equal amounts of materials from the dry-mixed mortar material samples and making them into initial test pieces of standard size respectively; placing the initial test pieces in a curing box for curing for 28 hours, using a pressure testing machine with a suitable range to perform an initial compressive strength test on the cured initial test pieces, and obtaining the initial compressive strength of each initial test piece; placing the remaining dry-mixed mortar material samples in a constant temperature and humidity simulated environment for a certain period of time; taking out equal amounts of dry-mixed mortar material samples at regular intervals to make test pieces of standard size; after the test pieces have been subjected to the same curing conditions and curing time as the initial test pieces, using a pressure testing machine under the same conditions to perform a compressive strength test on the cured test pieces, and obtaining the compressive strength of the test pieces; calculating the compressive strength loss rate based on the initial compressive strength and the compressive strength of the test pieces.

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