Landfill-type lightweight high-strength concrete material and method for preparing the same

Abstract

The application provides a kind of stack type light weight high strength concrete material and its preparation method.The application is filled in the mold by stacking ceramsite, and the ceramsite fills the mold in a close-packed manner;Then, according to the preset weight fraction, the cement, silica fume, saw mud, fly ash floating bead, hollow glass microsphere, fly ash, water reducing agent and water are weighed, and the high fluid light weight high strength mortar is obtained after fully mixing, and it is poured into the mold filled with ceramsite, so that the high fluid light weight high strength mortar fills the gap between the ceramsite, and the light weight high strength concrete material is obtained after curing. Through the above-mentioned manner, the application can prepare the high fluid light weight high strength mortar with slightly lower density than the ceramsite, to ensure that the pouring process will not appear the phenomenon of ceramsite floating, and effectively utilize the space skeleton formed by the mutual lap of ceramsite in the stacking process to effectively improve the strength of the concrete, so that the prepared stack type light weight high strength concrete material has low bulk density and high strength.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete preparation, and in particular to a filling-type lightweight high-strength concrete material and a preparation method thereof. Background Art

[0002] With the advancement of science and technology and the demands of economic and social development, the drawback of ordinary concrete, whose deadweight accounts for a large proportion of the total building load, has become more prominent. The demand for lightweight, high-strength materials in the engineering field has become increasingly apparent. Lightweight, high-strength concrete is one of the current hot development directions in concrete technology. It has the advantages of high strength, light weight, good durability, good volume stability, and excellent thermal insulation properties. It has broad application prospects in super high-rise buildings, long-span structures, bridge engineering, marine engineering and other fields.

[0003] Currently, the quality of traditional lightweight aggregates is generally low, limiting the strength and bulk density of the lightweight, high-strength concrete they produce. When it comes to creating lightweight, high-strength materials with even lower bulk densities, the strength drops significantly, making it difficult to meet the required standards. Therefore, balancing strength with low bulk density—ensuring sufficient strength while minimizing bulk density—is a top priority for lightweight, high-strength materials.

[0004] Patent publication number CN115557801A provides a lightweight, high-strength, low-shrinkage concrete and its preparation method. The lightweight concrete is prepared using glass microspheres, coarse lightweight aggregate, and discarded hard plastic particles. The close-packing theory is employed to prepare a high-strength concrete system of cement, mineral admixtures, quartz sand, and glass microspheres. An optimized construction process is then used to produce the lightweight, high-strength, low-shrinkage concrete. However, to ensure high strength, the concrete produced by this method has a relatively high bulk density, which limits its application. Achieving a low bulk density while maintaining high strength remains a pressing issue.

[0005] Furthermore, existing concrete preparation methods typically involve premixing all raw materials to form a slurry before pouring and molding. This approach requires ensuring the concrete slurry's fluidity meets usage requirements, and this limitation also limits the design of the raw material composition.

[0006] In view of this, it is necessary to design an improved lightweight high-strength concrete material and a preparation method thereof to solve the above problems. Summary of the Invention

[0007] In response to the shortcomings of the prior art, the present invention aims to provide a novel concrete preparation method for producing lightweight, high-strength concrete with low bulk density and high strength. By pre-packing ceramsite into a mold, then preparing a high-flow, lightweight, high-strength mortar with a density slightly lower than that of the ceramsite, and pouring this mortar into the mold already packed with ceramsite, the present invention can produce concrete with both low bulk density and high strength, achieving the combined advantages of lightweight and high strength in cement-based materials.

[0008] To achieve the above object, the present invention provides a method for preparing a landfill-type lightweight high-strength concrete material, comprising the following steps:

[0009] S1, filling the ceramsite into a mold so that the ceramsite fills the mold in a tightly packed manner;

[0010] S2. Weigh cement, silica fume, sawdust, fly ash beads, hollow glass microspheres, fly ash coarse ash, water reducer, and water according to preset weight proportions, and mix thoroughly to obtain a highly fluid, lightweight, and high-strength mortar;

[0011] S3, pouring the high-flow, lightweight, high-strength mortar into the mold filled with ceramsite obtained in step S1, so that the high-flow, lightweight, high-strength mortar fully fills the gaps between the ceramsite, and obtaining a lightweight, high-strength concrete material after curing.

[0012] As a further improvement of the present invention, in step S2, the preset weight proportions of the raw materials are as follows:

[0013] Cement, 15-25 parts;

[0014] Silica fume, 5-10 parts;

[0015] Sawdust, 5-8 parts;

[0016] Fly ash beads, 5-10 parts;

[0017] Hollow glass microspheres, 2-4 parts;

[0018] Fly ash coarse ash, 8-12 parts;

[0019] Water reducing agent, 1 to 2 parts;

[0020] Water, 6-10 parts.

[0021] As a further improvement of the present invention, in step S1, the ceramsite is shale ceramsite with a bulk density of 700-800 kg / m 3 , apparent density is 1300~1400kg / m 3 .

[0022] As a further improvement of the present invention, the mass ratio of the ceramsite to the high-fluidity, lightweight, high-strength mortar is 1 to 1.6:1.

[0023] As a further improvement of the present invention, the apparent density of the hollow glass microspheres is 350 to 450 kg / m 3 , particle size is 150 ~ 200μm; the fly ash coarse ash particle size greater than 45μm particles account for 70%, the apparent density is 1800 ~ 2000kg / m 3 The fly ash floating beads are light floating beads separated from fly ash in power plants, with a particle size of 20 to 40 mesh and an apparent density of 500 to 520 kg / m 3 .

[0024] As a further improvement of the present invention, the saw mud is the original wet saw mud produced by granite cutting, with a moisture content of 10% to 30%, and the specific surface area of ​​the saw mud after drying is 620 to 700 m 2 / kg.

[0025] As a further improvement of the present invention, the cement is ordinary Portland cement with a strength of ≥52.5 MPa.

[0026] As a further improvement of the present invention, the specific surface area of ​​the silica fume is ≥15000m 2 / kg, the SiO2 content in the silica ash is greater than 92% to 95%.

[0027] As a further improvement of the present invention, the water reducer is a polycarboxylic acid water reducer powder with a water reduction rate of 35% to 40%.

[0028] As a further improvement of the present invention, in step S3, the curing method is curing under standard conditions for 28 days or curing in 70°C water for 5 days.

[0029] To achieve the above objectives, the present invention further provides a backfill-type lightweight high-strength concrete material, which is prepared according to the method described in any of the above technical solutions.

[0030] The bulk density of the reclaimed lightweight high-strength concrete is 1250-1400 kg / m 3 , the compressive strength is 60~75MPa.

[0031] The beneficial effects of the present invention are:

[0032] 1、The present application prepares the stacked type light-weight high-strength concrete simply and efficiently by pre-stacking the ceramsite into the mold, then preparing the high-fluidity light-weight high-strength mortar with a density slightly lower than the ceramsite, and pouring it into the mold stacked with the ceramsite. Through the method provided by the present application, the ceramsite tightly stacked in the mold can form a spatial framework by overlapping each other during the stacking process, which plays a role of mutual support, is conducive to the strength development of the concrete, and can effectively improve the strength of the finally obtained concrete. At the same time, the preparation method provided by the present application is simpler than the traditional preparation method, only needs to stir the high-fluidity light-weight high-strength mortar, the mortar does not contain ceramsite, has good fluidity and filling property, not only facilitates the stirring and pouring process, can omit the traditional vibrating process, but also is conducive to improving the compactness of the concrete, and further improving the strength of the concrete.

[0033] 2、The present application successfully prepares the high-fluidity light-weight high-strength mortar with a density slightly lower than the ceramsite by designing a specific raw material composition and ratio. In the process of preparing the high-fluidity light-weight high-strength mortar, the present application uses hollow glass microspheres as high-strength light-weight powder, which greatly reduces the bulk density of the mortar while ensuring the strength of the mortar, and then uses fly ash floating beads and coarse fly ash together as light-weight concrete fine aggregate, which not only makes up for the shortcomings of low strength and high water absorption of traditional light-weight aggregate, but also further achieves higher strength under the premise of reducing the bulk density of the concrete mortar, and stimulates the pozzolanic effect under the action of calcium hydroxide generated by cement hydration, enhances the interfacial bonding strength between the cementitious material matrix and the aggregate, and fully improves the mechanical properties of the concrete. It is based on the use of hollow glass microspheres, fly ash floating beads and coarse fly ash with specific particle size and ratio in the present application that the wet density of the concrete mortar can be reduced to slightly lower than the density of the ceramsite, so as to ensure that the ceramsite does not float during the pouring process, and the homogeneity of the concrete is guaranteed, which is more conducive to the strength development of the concrete. In addition, the coarse fly ash, as a bulk solid waste, can improve its application added value when applied in light-weight high-strength concrete, which has important economic and environmental benefits.

[0034] 3、The application introduces the saw mud with high water content as the raw material for preparing the concrete in the process of preparing the high-flow lightweight high-strength mortar, can fill the gap between the cement and silica fume with the superfine powder in the saw mud, effectively enhances the compactness of the lightweight high-strength concrete structure, and improves the strength of the prepared lightweight concrete. Meanwhile, the main component of the saw mud powder is siliceous material, which can be further hydrated in the high-strength concrete to generate calcium silicate hydrate, further improving the strength of the concrete. Moreover, the saw mud is a solid waste generated in the cutting and polishing process of natural stone, and it is difficult to be treated by the conventional method due to its high water content and sticky texture. The application of the saw mud in the preparation process of the lightweight high-strength concrete also improves the applicability of the saw mud, and has important guiding significance for the resource utilization of the saw mud.

[0035] 4、The preparation method of the stack type lightweight high-strength concrete material provided by the application can reduce the bulk density of the finally prepared concrete by improving the conventional concrete preparation method and adjusting the composition, particle size and amount of each raw material, improve the bulk density by using the particle size distribution of each raw material, make the concrete have high compactness, improve the homogeneity and mechanical properties of the concrete by using the synergistic effect of each raw material, and finally prepare the stack type lightweight high-strength concrete with a bulk density of 1250-1400 kg / m 3 , and a compressive strength of 60-75 MPa, which has low bulk density and high strength, and realizes the unity of lightweight and high strength of the cement-based material. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is the real object diagram of the stack type lightweight high-strength concrete material prepared in Example 1.

[0037] Figure 2 It is the internal structure diagram of the stack type lightweight high-strength concrete material prepared in Example 1.

[0038] Figure 3 It is the internal structure diagram of the lightweight high-strength concrete material prepared in Comparative Example 8. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the application clearer, the application will be described in detail below with reference to the drawings and specific examples.

[0040] Here, it also needs to be explained that, in order to avoid the unnecessary details from blurring the application, only the structures and / or processing steps closely related to the scheme of the application are shown in the drawings, and other details not closely related to the application are omitted.

[0041] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0042] The present invention provides a method for preparing a landfill-type lightweight high-strength concrete material, comprising the following steps:

[0043] S1, filling the ceramsite into a mold so that the ceramsite fills the mold in a tightly packed manner;

[0044] S2. Weigh cement, silica fume, sawdust, fly ash beads, hollow glass microspheres, fly ash coarse ash, water reducer, and water according to preset weight ratios, and mix thoroughly to obtain a highly fluid, lightweight, and high-strength mortar;

[0045] S3, pouring the high-flow, lightweight, high-strength mortar into the mold filled with ceramsite obtained in step S1, so that the high-flow, lightweight, high-strength mortar fully fills the gaps between the ceramsite, and obtaining a lightweight, high-strength concrete material after curing.

[0046] Through the above-mentioned method, during the filling process, the ceramsite tightly stacked in the mold can overlap with each other to form a spatial skeleton, playing a role of mutual support, which is beneficial to the strength development of the concrete and can effectively improve the strength of the final concrete. At the same time, the preparation method provided by the present invention is simpler than the traditional preparation method. It only requires stirring a high-flow, lightweight, high-strength mortar. The mortar does not contain ceramsite and has good fluidity and filling properties. It not only facilitates the mixing and pouring process, but also can omit the traditional vibration process, and is also beneficial to improving the density of the concrete, thereby improving the strength of the concrete.

[0047] In step S2, the preset weight proportions of the raw materials are as follows:

[0048] Cement, 15-25 parts;

[0049] Silica fume, 5-10 parts;

[0050] Sawdust, 5-8 parts;

[0051] Fly ash beads, 5-10 parts;

[0052] Hollow glass microspheres, 2-4 parts;

[0053] Fly ash coarse ash, 8-12 parts;

[0054] Water reducing agent, 1 to 2 parts;

[0055] Water, 6-10 parts.

[0056] The ceramsite is shale ceramsite with a bulk density of 700-800 kg / m 3 , apparent density is 1300~1400kg / m 3 The mass ratio of the ceramsite to the high-flow lightweight high-strength mortar is 1 to 1.6:1; the apparent density of the hollow glass microspheres is 350 to 450 kg / m 3 , particle size is 150 ~ 200μm; the fly ash coarse ash particle size greater than 45μm particles account for 70%, the apparent density is 1800 ~ 2000kg / m 3 The fly ash floating beads are light floating beads separated from fly ash in power plants, with a particle size of 20 to 40 mesh and an apparent density of 500 to 520 kg / m 3 .

[0057] With this arrangement, hollow glass microspheres, as a high-strength, lightweight powder, significantly reduce the bulk density of the slurry while maintaining its strength. Furthermore, the use of fly ash buoyant beads and coarse fly ash as fine aggregates for lightweight concrete not only compensates for the shortcomings of traditional lightweight aggregates, such as low strength and high water absorption, but also achieves higher strength while reducing the bulk density of the concrete slurry. Furthermore, the volcanic ash effect generated by cement hydration, which produces calcium hydroxide, enhances the interfacial bond strength between the cementitious material matrix and the aggregate, and fully improves the mechanical properties of the concrete. Furthermore, the synergistic effect of the hollow glass microspheres, coarse fly ash, and buoyant fly ash can effectively reduce the amount of hollow glass microspheres added, which is more expensive, achieving a balance between low bulk density and high strength while reducing costs.

[0058] At the same time, by combining hollow glass microspheres of specific particle sizes and proportions with fly ash floating beads and coarse fly ash, the wet density of the concrete paste can be reduced to slightly below that of ceramsite, preventing the ceramsite from floating during the pouring process. This ensures the overall homogeneity of the concrete and further enhances its strength development. Furthermore, the use of coarse fly ash, a major solid waste, in lightweight, high-strength concrete can increase its added value, providing significant economic and environmental benefits.

[0059] The cement is ordinary Portland cement with a strength of ≥52.5MPa; the specific surface area of ​​the silica fume is ≥15000m 2 / kg, the SiO2 content in the silica fume is greater than 92% to 95%; the saw mud is the original wet saw mud produced by granite cutting, with a moisture content of 10% to 30%, and the specific surface area of ​​the saw mud after drying is 620 to 700m 2This arrangement allows the ultrafine powder in sawdust to fully fill the gaps between cement and silica fume, effectively enhancing the density of lightweight, high-strength concrete structures and improving the strength of the resulting lightweight concrete. Furthermore, sawdust powder, primarily composed of siliceous materials, further hydrates in high-strength concrete to form hydrated calcium silicate, further increasing the concrete's strength.

[0060] The water reducing agent is a polycarboxylic acid water reducing agent powder with a water reducing rate of 35% to 40%.

[0061] The curing method is curing under standard conditions for 28 days or curing in 70°C water for 5 days.

[0062] The present invention also provides a reclaimed lightweight high-strength concrete material, which is prepared according to the method described in any of the above technical solutions; the bulk density of the reclaimed lightweight high-strength concrete is 1250-1400 kg / m 3 , the compressive strength is 60~75MPa.

[0063] The following describes the lightweight high-strength concrete material and its preparation method provided by the present invention in detail with reference to specific embodiments and comparative examples.

[0064] Example 1

[0065] This embodiment provides a method for preparing a landfill-type lightweight high-strength concrete material, comprising the following steps:

[0066] S1, filling the ceramsite into a mold so that the ceramsite fills the mold in a tightly packed manner;

[0067] S2. Weigh cement, silica fume, sawdust, fly ash beads, hollow glass microspheres, fly ash coarse ash, water reducer, and water according to preset weight ratios, and mix thoroughly to obtain a highly fluid, lightweight, and high-strength mortar;

[0068] S3. Pouring the high-flow, lightweight, high-strength mortar into the mold filled with ceramsite obtained in step S1, so that the high-flow, lightweight, high-strength mortar fully fills the gaps between the ceramsite, and curing under standard conditions for 28 days to obtain a lightweight, high-strength concrete material.

[0069] Specifically, in step S1, the ceramsite used is commercially available lightweight aggregate shale ceramsite with a bulk density of 750 kg / m 3 , the apparent density is 1350kg / m 3 The ceramsite was piled in a 10 cm×10 cm×cm mold. When the ceramsite was tightly piled, the mass of the ceramsite was 741 g.

[0070] In step S2, the preset weight proportions of the raw materials are as follows:

[0071] cement, 21 parts;

[0072] Silica fume, 7.5 parts;

[0073] Sawdust, 6 parts;

[0074] Fly ash beads, 7.5 parts;

[0075] hollow glass microspheres, 2.5 parts;

[0076] fly ash coarse ash, 10 parts;

[0077] Water reducing agent, 1.5 parts;

[0078] Water, 8 parts.

[0079] Among them, the sources and performance parameters of each raw material are as follows:

[0080] The cement used is PO 52.5 type Portland cement produced by Wuhan Huaxin Cement Co., Ltd., with an apparent density of 3140kg / m 3 Silica fume adopts semi-densified silica fume with an apparent density of 2200kg / m 3 , SiO2 content 94%, specific surface area 18000m 2 / kg; Saw mud is the tailings of Macheng granite cutting, with a moisture content of 19.3%. After drying, the powder with a particle size of less than 45μm accounts for 88%, and the specific surface area (powder below 45μm) is 660m 2 / kg, the apparent density is 2620kg / m 3 The powder fluidity ratio is 102%; the fineness of the fly ash beads is 20-40 mesh, and the apparent density is 510kg / m 3 ; The apparent density of hollow glass microspheres is 400kg / m 3 The particle size is 150-200 μm. The fly ash raw material is produced by Yangluo Power Plant. The particles with a particle size greater than 45 μm account for 70% of the fly ash coarse ash. The apparent density is 1900 kg / m 3 , 28d activity index is 60%; the water reducer is polycarboxylate water reducer, which is a white powder with a water reduction rate of 40% and an apparent density of 1060kg / m 3 .

[0081] After testing the density of the high-flow, lightweight, high-strength mortar prepared in step S2, it was found to be 1321 kg / m 3 The mortar was poured into a mold and the weight of the poured mortar was measured to be 587 g. The mass ratio of ceramsite to mortar was calculated to be approximately 1.26:1.

[0082] The performance of the landfill-type lightweight high-strength concrete obtained in this example was tested. The wet bulk density and compressive strength of the lightweight high-strength concrete were measured in accordance with JGJ / T70-2009 "Standard for Test Methods for Basic Properties of Building Concrete". The results are shown in Table 1:

[0083] Table 1 Performance parameters of the landfill type lightweight high-strength concrete material prepared in Example 1

[0084] Container weight (kg / m 3 ) Compressive strength (MPa) 1336 68.9

[0085] It can be seen from the above table that the reclaimed lightweight high-strength concrete prepared in this embodiment has both low bulk density and high strength, achieving the unity of light weight and high strength of cement-based materials.

[0086] The actual image and cross-sectional view of the reclaimed lightweight high-strength concrete prepared in this embodiment are shown in FIG. Figure 1 、 Figure 2 shown. Figure 1 In the figure, the upper and lower figures correspond to the top and side surfaces of two concrete specimens, respectively. Figure 1 It can be seen that the uneven surface formed by the ceramsite filling can still be seen on the top surface, while the side surface has a better flatness. Figure 2 It can be seen that the concrete has good density and homogeneity, and a large amount of expanded clay is densely packed in the concrete.

[0087] Examples 2 to 9 and Comparative Examples 1 to 4

[0088] Examples 2 to 9 and Comparative Examples 1 to 4 respectively provide a method for preparing a reclaimed lightweight high-strength concrete material. Compared with Example 1, the only difference is that the weight proportions of each raw material when preparing the high-fluidity lightweight high-strength mortar in step S2 are changed. The raw material proportions corresponding to each embodiment and comparative example are shown in Table 2. The remaining steps and parameters are the same as those in Example 1 and are not repeated here.

[0089] Table 2 Raw material ratios of Examples 2 to 9 and Comparative Examples 1 to 4 (unit: parts by weight)

[0090]

[0091] The bulk density and 28d compressive strength of the reclaimed lightweight high-strength concrete materials prepared in the above embodiments and comparative examples were tested, and the results are shown in Table 3.

[0092] Table 3 Performance data of Examples 2 to 9 and Comparative Examples 1 to 9

[0093]

[0094]

[0095] It can be seen from Table 3 that the change of the raw material composition of the mortar has an important influence on the bulk density and compressive strength of the prepared concrete.

[0096] More specifically, a comparison of Examples 1-3 and Comparative Example 1 shows that the amount of sawdust used has a relatively significant impact on concrete strength, with either too much or too little leading to reduced strength in the resulting concrete. This is primarily because the sawdust in the present invention primarily serves as a filler, and too little of it makes it difficult to achieve effective filling, resulting in more voids between the cement and silica fume, leading to reduced strength. However, sawdust itself is not highly active, and if too much sawdust is added, the proportion of the more active cement and silica fume decreases, further reducing strength. Therefore, by adjusting the sawdust dosage to a specific ratio, optimal strength can be achieved.

[0097] By comparing Example 1, Examples 4 to 9, and Comparative Examples 2 to 4, it can be seen that the addition of fly ash floating beads and hollow glass microspheres is beneficial to effectively reduce the bulk density, but will lead to a decrease in strength, while the change in the amount of fly ash coarse ash has little effect on the bulk density, and too much or too little fly ash coarse ash will lead to a decrease in the strength of the concrete. However, if any of the fly ash floating beads, hollow glass microspheres, and fly ash coarse ash are not added at all, not only will the final bulk density be affected by the change in raw material density, but the concrete strength will also be reduced due to the impact on the particle grading effect and the homogeneity of the concrete. Therefore, fly ash floating beads, hollow glass microspheres, and fly ash coarse ash are indispensable, and the amount of each raw material needs to be controlled within a specific range.

[0098] Comparative Examples 5-6

[0099] Comparative Examples 5 to 6 provide a method for preparing a landfill type lightweight high strength concrete material. Compared with Example 1, Comparative Example 5 changes the specifications of the hollow glass microspheres used, and selects an apparent density of 500 kg / m 3 , hollow glass microspheres with a particle size range of 50 to 100 μm; Comparative Example 6 is to replace the fly ash coarse ash and fly ash floating beads with conventional fly ash (apparent density of 2700 kg / m 3 , particle size <45 μm), and the remaining raw materials and their weight proportions are the same as those in Example 1 and will not be repeated here.

[0100] The bulk density and 28d compressive strength of the reclaimed lightweight high-strength concrete material prepared in the above comparative example were tested, and the results are shown in Table 4.

[0101] Table 4 Performance data of comparative examples 5 to 6

[0102] Example / Comparative Example <![CDATA[容重(kg / m 3 )]]> Compressive strength (MPa) Comparative Example 5 1351 59.1 Comparative Example 6 1603 63.5

[0103] As can be seen in Table 4, the particle size of the raw materials has a significant impact on the bulk density and compressive strength of the resulting lightweight, high-strength concrete. Even under the same composition, changes in the particle size of the raw materials can affect the overall density and the gradation between the raw materials, thereby affecting the bulk density and compressive strength of the lightweight, high-strength concrete. By selecting hollow glass microspheres, fly ash coarse ash, and fly ash floating beads of specific sizes, the present invention can simultaneously reduce the bulk density and improve the overall gradation, resulting in a low bulk density and high strength, achieving the goal of combining lightweight and high strength in cement-based materials.

[0104] Comparative Example 7

[0105] Comparative Example 7 provides a method for preparing a slurry, comprising the following steps:

[0106] S1. Weigh cement, silica fume, sawdust, fly ash beads, hollow glass microspheres, fly ash coarse ash, and ceramsite, mix them, add 80% of the total water, and stir for 2 minutes to mix evenly to obtain a raw material mixture;

[0107] S2. Add 20% of the total amount of water and a polycarboxylate water-reducing agent weighed in parts by weight to the raw material mixture obtained in step S1, and continue stirring for 5 minutes. After stirring evenly, a concrete slurry with good fluidity is obtained.

[0108] The composition and amount of each raw material are exactly the same as those in Example 1 and will not be repeated here.

[0109] The experiment found that due to the large amount of expanded clay mixed in the slurry, its fluidity could not meet the casting requirements and could not be used in practice, indicating that conventional mixing methods were simply unable to achieve the addition of large amounts of expanded clay.

[0110] Comparative Example 8

[0111] Comparative Example 8 provides a method for preparing a lightweight and high-strength concrete material. Compared with Comparative Example 7, the difference is that the amount of ceramsite is changed, and the weight of the ceramsite is adjusted to 36 parts to ensure that the fluidity of the slurry meets the casting requirements (the slump of the slurry is measured to be 260 mm and the expansion is 710 mm). The slurry is then poured into a mold, vibrated to remove bubbles, and then allowed to stand for molding. It is then cured under standard conditions for 28 days to obtain a lightweight and high-strength concrete material.

[0112] The properties of the lightweight high-strength concrete obtained in this comparative example were tested. The wet density and compressive strength of the lightweight high-strength concrete were measured in accordance with JGJ / T70-2009 "Standard for Test Methods for Basic Properties of Building Concrete". The results are shown in Table 1:

[0113] Table 5 Performance parameters of lightweight high-strength concrete materials prepared in Comparative Example 8

[0114] <![CDATA[容重(kg / m 3 )]]> Compressive strength (MPa) 1324 62.1

[0115] The cross-sectional view of the lightweight high-strength concrete prepared in this comparative example is as follows: Figure 3 As shown, Figure 3 and Figure 2 By comparison, it can be seen that in order to ensure the fluidity of the slurry, the conventional preparation method must significantly reduce the amount of ceramsite. The ceramsite in the concrete produced is in a dispersed state and cannot overlap with each other to form a spatial skeleton. Therefore, its compressive strength is significantly lower than that of Example 1.

[0116] In summary, the present invention provides a heap-type lightweight high-strength concrete material and a preparation method thereof. The present invention heaps ceramsite into a mold so that the ceramsite fills the mold in a tightly stacked manner; then cement, silica fume, sawdust, fly ash floating beads, hollow glass microspheres, fly ash coarse ash, water reducer and water are weighed according to preset weight proportions, and after fully mixing, a high-flow lightweight high-strength mortar is obtained, and the mortar is poured into the mold filled with ceramsite so that the high-flow lightweight high-strength mortar fully fills the gaps between the ceramsite, and a lightweight high-strength concrete material is obtained after curing. Through the above-mentioned method, the present invention can prepare a high-flow lightweight high-strength mortar with a density slightly lower than that of ceramsite, so as to ensure that the ceramsite does not float during the pouring process, and at the same time effectively utilize the spatial skeleton formed by the overlapping of the ceramsite during the heaping process to effectively improve the strength of the concrete, so that the obtained heap-type lightweight high-strength concrete material has both low bulk density and high strength.

[0117] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a landfill-type lightweight high-strength concrete material, characterized in that: Includes the following steps S1, filling the ceramsite into the mold so that the ceramsite fills the mold in a tightly packed manner; the bulk density of the ceramsite is 700-800 kg / m 3 , apparent density is 1300~1400kg / m 3 ; S2. Weigh cement, silica fume, sawdust, fly ash floating beads, hollow glass microspheres, fly ash coarse ash, water reducer and water according to the preset weight ratio, and mix them thoroughly to obtain a high-flow, lightweight and high-strength mortar; the apparent density of the hollow glass microspheres is 350-450 kg / m 3 , particle size is 150 ~ 200μm; the fly ash coarse ash particle size greater than 45μm particles account for 70%, the apparent density is 1800 ~ 2000kg / m 3 The fly ash floating beads are light floating beads separated from fly ash in power plants, with a particle size of 20 to 40 mesh and an apparent density of 500 to 520 kg / m 3 In step S2, the preset weight portions of each raw material are as follows: Cement, 15-25 parts; Silica fume, 5-10 parts; Sawdust, 5-8 parts; Fly ash beads, 5-10 parts; Hollow glass microspheres, 2-4 parts; Fly ash coarse ash, 8-12 parts; Water reducing agent, 1 to 2 parts; Water, 6-10 parts; S3, pouring the high-flow lightweight high-strength mortar into the mold filled with ceramsite obtained in step S1, wherein the mass ratio of the ceramsite to the high-flow lightweight high-strength mortar is 1-1.6:1; the high-flow lightweight high-strength mortar is made to fully fill the gaps between the ceramsite, and a lightweight high-strength concrete material can be obtained after curing; the bulk density of the filling type lightweight high-strength concrete is 1250-1400 kg / m 3 .

2. The method for preparing a landfill-type lightweight high-strength concrete material according to claim 1, characterized in that: In step S1, the ceramsite is shale ceramsite.

3. The method for preparing a landfill-type lightweight high-strength concrete material according to claim 1, wherein the saw mud is original wet saw mud produced by cutting granite, has a moisture content of 10% to 30%, and has a specific surface area of ​​620 to 700 m2 after drying. 2 / kg.

4. The method for preparing a landfill-type lightweight high-strength concrete material according to claim 1, wherein the cement is ordinary Portland cement with a strength of ≥52.5 MPa.

5. The method for preparing a landfill-type lightweight high-strength concrete material according to claim 1, wherein the specific surface area of ​​the silica fume is ≥ 15000 m 2 / kg, SiO2 content is greater than 92% to 95%.

6. The method for preparing a landfill-type lightweight high-strength concrete material according to claim 1, wherein in step S3, the curing method is curing for 28 days under standard conditions or curing in 70°C water for 5 days.

7. A landfill-type lightweight high-strength concrete material, characterized in that: The compound is prepared by the preparation method described in any one of claims 1 to 6.

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