Low-pumping-resistance lightweight aggregate concrete preventing aggregate floating and preparation method thereof

Abstract

The application relates to the technical field of building materials, in particular to low-pumping-resistance lightweight aggregate concrete capable of preventing aggregate from floating and a preparation method thereof. The low-pumping-resistance lightweight aggregate concrete comprises aggregate and paste, the aggregate comprises coarse aggregate and fine aggregate, the coarse aggregate comprises gravel-type shale ceramsite, the paste comprises cementitious material, additive and water, the cementitious material is composed of cement and fly ash, and the ratio of the volume of the paste to the bulk volume of the aggregate is 1.05-1.10. The system effectively improves the flow degree and anti-segregation stability of the lightweight aggregate concrete mixture, guarantees excellent compactness of a structure after hardening, and significantly improves long-term mechanical strength and overall durability.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a low-pumping-resistance lightweight aggregate concrete that prevents aggregate from floating and its preparation method. Background Technology

[0002] Lightweight aggregate concrete, due to its characteristics of light weight, thermal insulation, good seismic resistance, fire resistance, and excellent durability, can effectively reduce the structural self-weight, decrease foundation load, and control foundation deformation, making it a preferred material for the construction of super high-rise buildings and large-span structures. Shale ceramsite, as a commonly used artificial lightweight aggregate, forms a hard outer shell and a dense honeycomb-like microporous structure after high-temperature calcination, which can significantly reduce the density of concrete while meeting the structural stress requirements, and is widely used in engineering.

[0003] Currently, there are still significant technical problems in the preparation and pumping of ceramsite lightweight aggregate concrete. On the one hand, ceramsite aggregate has a low density, which differs significantly from that of cement paste. During mixing, transportation, and pumping, aggregate floating and segregation are prone to occur, resulting in uneven internal structure of the concrete, large strength dispersion after hardening, and poor interfacial bonding performance, affecting structural safety and durability. On the other hand, ceramsite particles are porous and have a high water absorption rate. During pumping, they easily absorb moisture from the paste, leading to decreased fluidity of the mixture, increased pumping resistance, and a tendency to clog pipes, making it difficult to guarantee construction efficiency and quality.

[0004] CN107673693A discloses a lightweight concrete method for suppressing aggregate floating, which uses mineral thickeners and fibers to inhibit aggregate floating. However, this method is costly and requires sophisticated mixing techniques. Patent document CN108689658A discloses a pumpable lightweight aggregate concrete and its preparation method, using pumice instead of fly ash ceramsite as coarse aggregate. This method focuses on improving the flowability and pumpability of the concrete, but its effect on suppressing ceramsite floating is limited, making it difficult to simultaneously ensure the stability and structural strength of the mixture with low cementitious material content.

[0005] In summary, existing technologies struggle to simultaneously address the two core issues of ceramsite's tendency to float and high pumping resistance. Furthermore, they generally suffer from drawbacks such as excessive cement usage and difficulty in balancing the workability and density of the mixture, failing to meet the demands of modern high-rise construction for high-performance, low-energy-consumption, and easily constructible lightweight aggregate concrete. Therefore, developing a lightweight aggregate concrete preparation technology that effectively suppresses aggregate floating, reduces pumping resistance, provides stable strength, and offers excellent economic efficiency has become a critical issue urgently needing to be addressed. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the present invention provides a lightweight aggregate concrete with anti-aggregate floating and low pumping resistance and its preparation method. By accurately selecting raw materials, optimizing the mix proportion and synergistically combining segmented mixing process, the invention achieves the dual effects of anti-buoyancy of ceramsite and pumping resistance reduction, ensuring the strength and workability of concrete with low cement content.

[0007] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a low-pumping-resistance lightweight aggregate concrete that prevents aggregate from floating, comprising aggregate and slurry. The aggregate includes coarse aggregate and fine aggregate, wherein the coarse aggregate includes crushed shale ceramsite. The slurry comprises cementitious material, admixture and water, wherein the cementitious material is composed of cement and fly ash. The volume ratio of the slurry to the bulk volume of the aggregate is 1.05 to 1.10, for example, it can be 1.05, 1.06, 1.07, 1.08, 1.09 or 1.10, etc.

[0008] The present invention preferably uses crushed shale ceramsite as coarse aggregate, optimizes the ratio of slurry volume to aggregate bulk volume, and the multi-component synergistic system ensures that the slurry fully fills the gaps between aggregates and completely coats the aggregate surface. During pumping, a continuous and stable lubricating layer is formed on the inner wall of the pump pipe, which not only significantly reduces the frictional resistance between aggregates and pump pipe, but also inhibits aggregate floating by the coating and viscosity of the slurry. It eliminates the need for multiple complex cementing materials and achieves a synergistic effect of anti-float and drag reduction.

[0009] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0010] As a preferred embodiment of the present invention, the mass ratio of coarse aggregate to fine aggregate is 0.34 to 0.36, for example, it can be 0.34, 0.35 or 0.36.

[0011] The coarse aggregate is 5-25mm continuously graded crushed shale ceramsite, wherein by mass percentage: 5-10mm particle size accounts for 35%-45%, 10-20mm particle size accounts for 45%-55%, and 20-25mm particle size accounts for 5%-10%.

[0012] This invention, by limiting the mass ratio of ceramsite to river sand, can further optimize the gradation of coarse and fine aggregates, improve aggregate packing density, reduce aggregate packing void ratio, reduce internal frictional resistance of the mixture, and at the same time reduce the density difference between ceramsite and slurry, thereby improving the overall stability of the mixture from the aggregate structure level.

[0013] The following is a preferred embodiment of the present invention, wherein the bulk density of the crushed shale ceramsite is 750~850 kg / m³. 3Compressive strength ≥ 4.0 MPa, water absorption ≤ 3.5%.

[0014] As a preferred embodiment of the present invention, the water-cement ratio of the slurry to the cementitious material is 0.35 to 0.40, for example, it can be 0.35, 0.36, 0.37, 0.38, 0.39 or 0.40, etc.

[0015] As a preferred embodiment of the present invention, the amount of cement used is 300~320 kg / m³. 3 For example, it could be 300 kg / m 3 305kg / m 3 310kg / m 3 315kg / m 3 Or 320kg / m 3 The amount of fly ash used is 30-35% of the cement mass, for example, it can be 30%, 31%, 32%, 33%, 34% or 35%, etc.

[0016] The optimized water-cement ratio range of this invention can take into account both the development of concrete strength and the fluidity of the paste. Too high a water-cement ratio can easily cause bleeding, segregation and aggregate floating, while too low a water-cement ratio will lead to dryness of the mixture and a sharp increase in pumping resistance. It can achieve a good balance between strength and workability.

[0017] Preferably, the cement comprises P.O42.5 ordinary Portland cement.

[0018] Preferably, the fly ash includes Class II fly ash.

[0019] The following is a preferred embodiment of the present invention, wherein the viscosity of the slurry η ≥ 0.8 dny•s / cm 2 .

[0020] The following is a preferred embodiment of the present invention, wherein the admixture includes SDC8860 water-reducing agent.

[0021] The following is a preferred embodiment of the present invention, wherein the amount of the additive is 0.8 to 1.2% of the mass of the cementitious material, for example, it can be 0.8%, 0.9%, 1.0%, 1.1% or 1.2%, etc.

[0022] The following is a preferred embodiment of the present invention: the slurry forms a slurry film of 0.1 to 0.2 mm on the surface of the aggregate, for example, it can be 0.10 mm, 0.12 mm, 0.14 mm, 0.16 mm, 0.18 mm or 0.20 mm.

[0023] This invention uses SDC8860 water-reducing agent, which is specially matched to the rough surface of crushed shale ceramsite. It can form a dense slurry film of 0.1~0.2mm on the aggregate surface, which not only prevents the ceramsite from floating, but also reduces the frictional resistance between the aggregate and the pump pipe.

[0024] The fine aggregate includes river sand, such as Yangtze River sand with a mud content of less than 3%, and a volumetric sand ratio of 35-45%. The particle size distribution of the river sand meets the requirements of the "Standard for Quality and Testing Methods of Sand and Stone for Ordinary Concrete" JGJ52-2006. By accurately filling the gaps between the ceramsite with sand particles, the aggregate porosity is reduced, laying the foundation for subsequent low-resistance pumping.

[0025] In a second aspect, the present invention provides a method for preparing low-pumping-resistance lightweight aggregate concrete as described in the first aspect, the method comprising: (1) Mix the pretreated coarse aggregate and fine aggregate and stir to obtain premixed aggregate; (2) Mix the cementitious material with the premixed aggregate and stir to obtain the mixture; (3) After adding water and admixtures to the mixture, stir to obtain the low pumping resistance lightweight aggregate concrete that prevents aggregate from floating.

[0026] This invention employs a step-by-step progressive mixing process, which differs from traditional one-time or simple two-time feeding. First, aggregates are pre-mixed to form a densely packed skeleton. Then, cementitious materials are pre-adsorbed to establish an initial bonding interface. Finally, water and admixtures are added to form a complete encapsulating slurry film. The entire process strengthens the bonding state between aggregates and slurry, and completely solves problems such as ceramsite floating, uneven mixing, and high pumping resistance from the preparation process.

[0027] The stirring time in step (1) of this invention is 30s~60s, so that the river sand can fully fill the gaps between the crushed shale ceramsite particles, forming a uniform and dense aggregate skeleton, reducing the aggregate porosity and improving the overall density.

[0028] The stirring time in step (2) of this invention is 30s~60s, so that cement and fly ash are evenly adsorbed on the surface of ceramsite and river sand, forming a continuous pre-adsorption layer of cementitious material, which strengthens the initial bonding force between aggregate and paste, and further inhibits the floating tendency of ceramsite.

[0029] The stirring time in step (3) of this invention is 120s~240s, so that the slurry forms a uniform thickness and dense structure on the surface of the aggregate, ensuring the cohesiveness, fluidity and anti-segregation performance of the mixture, and finally obtaining lightweight aggregate concrete with no aggregate floating, low pumping resistance and stable strength.

[0030] The pretreatment method for coarse aggregate described in this invention is as follows: the coarse aggregate is pre-wetted in clean water, then drained naturally until the ceramsite is saturated with water and the surface is dry, ensuring stable slurry viscosity and interfacial bonding strength.

[0031] Compared with the prior art, the present invention has at least the following beneficial effects: (1) This invention uses the synergistic combination of component ratio and three-stage segmented mixing process to jointly suppress the floating of ceramsite from multiple aspects such as aggregate gradation, paste viscosity and encapsulation structure, thus solving the problem of easy stratification and segregation of lightweight aggregate concrete. The mixture has stronger stability and no obvious aggregate floating phenomenon during construction. (2) The present invention can form a uniform and dense continuous slurry film on the surface of ceramsite, effectively reducing the internal friction between aggregates and the resistance of the pumping pipe wall, making pumping smoother and with lower resistance. At the same time, the key indicators such as workability, density and mechanical strength of concrete mixture meet the engineering requirements, and the molding quality is stable, making it suitable for long-distance and ultra-high-rise pumping construction. (3) The present invention uses all readily available raw materials in construction engineering, without using special additives, modified materials or special auxiliaries. The components are widely available and low in cost. They can be implemented with conventional mixing equipment. The process is simple and easy to operate, with good economic efficiency and practicality, and is easy to promote and apply on a large scale on site. Attached Figure Description

[0032] Figure 1 This is a flowchart of the preparation method of low pumping resistance lightweight aggregate concrete with anti-aggregate floating provided in Embodiment 1 of the present invention. Detailed Implementation

[0033] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0034] The raw materials used in the following examples are all conventional commercially available products: crushed shale ceramsite with a continuous gradation of 5~25mm, a particle size composition of 35%~45% for 5~10mm, 45%~55% for 10~20mm, and 5%~10% for 20~25mm, and a bulk density of 750~850kg / m³. 3 The compressive strength of the sand should be ≥4.0MPa and the water absorption rate should be ≤3.5%. The river sand should be Yangtze River sand with a mud content of less than 3% and a volumetric sand ratio of 35~45%. The particle size distribution of the river sand should meet the requirements of the "Standard for Quality and Testing Methods of Sand and Stone for Ordinary Concrete" JGJ52-2006.

[0035] Example 1 This embodiment provides a lightweight aggregate concrete with low pumping resistance that prevents aggregate from floating. It includes, by weight parts: 310 parts crushed shale ceramsite, 890 parts river sand, 320 parts P.O42.5 grade ordinary Portland cement, 168 parts tap water, 100 parts grade II fly ash, and 4.24 parts SDC8860 water-reducing agent. The low-pumping-resistance lightweight aggregate concrete with anti-aggregate floating properties is prepared using the following steps: (1) Immerse crushed shale ceramsite in clean water and drain until the surface is dry, then mix it with river sand and stir for 30 seconds to obtain premixed aggregate; (2) Add cement and fly ash, mix with the pre-mixed aggregate, and stir for 30 seconds; (3) Add tap water and SDC8860 water-reducing agent, stir for 120s to obtain the low pumping resistance lightweight aggregate concrete with anti-aggregate floating; after stirring, let stand for 5 minutes, and there is no obvious bleeding, stratification and lightweight aggregate floating phenomenon.

[0036] Example 2 This embodiment provides a lightweight aggregate concrete with low pumping resistance that prevents aggregate from floating, comprising, by weight parts: 306 parts crushed shale ceramsite, 900 parts river sand, 300 parts P.O42.5 grade ordinary Portland cement, 137 parts tap water, 90 parts grade II fly ash, and 4.68 parts SDC8860 water-reducing agent. The low-pumping-resistance lightweight aggregate concrete with anti-aggregate floating properties is prepared using the following steps: (1) Immerse crushed shale ceramsite in clean water and drain until the surface is dry, then mix it with river sand and stir for 30 seconds to obtain premixed aggregate; (2) Add cement and fly ash, mix with the pre-mixed aggregate, and stir for 30 seconds; (3) Add tap water and SDC8860 water-reducing agent, stir for 120s to obtain the low pumping resistance lightweight aggregate concrete with anti-aggregate floating; after stirring, let stand for 5 minutes, and there is no obvious bleeding, stratification and lightweight aggregate floating phenomenon.

[0037] Example 3 This embodiment provides a lightweight aggregate concrete with low pumping resistance that prevents aggregate from floating. By mass fraction, it includes: 324 parts crushed shale ceramsite, 900 parts river sand, 320 parts P.O42.5 grade ordinary Portland cement, 160 parts tap water, 112 parts grade II fly ash, and 3.46 parts SDC8860 water-reducing agent. The low-pumping-resistance lightweight aggregate concrete with anti-aggregate floating properties is prepared using the following steps: (1) Immerse crushed shale ceramsite in clean water and drain until the surface is dry, then mix it with river sand and stir for 30 seconds to obtain premixed aggregate; (2) Add cement and fly ash, mix with the pre-mixed aggregate, and stir for 30 seconds; (3) Add tap water and SDC8860 water-reducing agent, stir for 120s to obtain the low pumping resistance lightweight aggregate concrete with anti-aggregate floating; after stirring, let stand for 5 minutes, and there is no obvious bleeding, stratification and lightweight aggregate floating phenomenon.

[0038] Example 4 This embodiment provides a low-pumping-resistance lightweight aggregate concrete that prevents aggregate floating. The proportion of river sand is 850 parts, and the proportion of crushed shale ceramsite is 320 parts, resulting in a coarse-to-fine aggregate ratio of 0.38. All other aspects are the same as in Example 1. After the mixture is left to stand for 5 minutes, a slight tendency for aggregate floating occurs, indicating a slight tendency for segregation.

[0039] Example 5 This embodiment provides a low-pumping-resistance lightweight aggregate concrete that prevents aggregate floating. The amount of river sand is 910 parts, and the amount of crushed shale ceramsite is 300 parts, so that the coarse-fine aggregate ratio is 0.33. The rest are the same as in Example 1. After the mixture is left to stand for 5 minutes, a slight tendency for aggregate to float is observed, and there is a slight tendency for segregation.

[0040] Example 6 This embodiment provides a lightweight aggregate concrete with low pumping resistance that prevents aggregate from floating. Except for replacing the SDC8860 water-reducing agent with the SDC8861 water-reducing agent, everything else is the same as in Example 1. After standing for 5 minutes, there is no obvious bleeding, stratification or aggregate floating phenomenon.

[0041] Example 7 This embodiment provides a low-pumping-resistance lightweight aggregate concrete that prevents aggregate floating. Except for replacing the SDC8860 water-reducing agent with the RP325 water-reducing agent, everything else is the same as in Example 1. After standing for 5 minutes, obvious bleeding and lightweight aggregate floating occur, and segregation is severe.

[0042] Example 8 This embodiment provides a low-pumping-resistance lightweight aggregate concrete that prevents aggregate from floating. Except for the one-step full mixing process and stirring for 180 seconds, the rest is the same as in Example 1. The slurry does not coat the aggregate evenly, and local aggregate aggregation and slight segregation occur after standing for 5 minutes.

[0043] Comparative Example 1 This comparative example provides a lightweight aggregate concrete. Based on Example 1, the amount of grout is reduced proportionally. The volume of the grout that is reduced is made up by the aggregate components being increased proportionally, so that the ratio of the volume of the grout to the bulk volume of the aggregate is 0.9. All other aspects are the same as in Example 1. The grout volume is insufficient and cannot fully wrap and fill the gaps between the aggregates. After standing for 5 minutes, a large amount of aggregate floats to the surface, and the mixture is severely segregated.

[0044] Comparative Example 2 This comparative example provides a lightweight aggregate concrete. Based on Example 1, the amount of slurry is increased proportionally. The excess slurry volume is matched by reducing the aggregate components proportionally according to the original proportions, so that the ratio of slurry volume to aggregate bulk volume is 1.2. All other aspects are the same as in Example 1. After standing for 5 minutes, obvious bleeding and segregation phenomena appear.

[0045] Comparative Example 3 This comparative example provides a lightweight aggregate concrete in which the crushed shale ceramsite in Example 1 is replaced with an equal mass of clay ceramsite, and all other aspects are the same as in Example 1. After standing for 5 minutes, obvious aggregate floating phenomenon occurs.

[0046] Comparative Example 4 This comparative example provides a lightweight aggregate concrete in which the crushed shale ceramsite in Example 1 is replaced with an equal mass of fly ash ceramsite, and all other aspects are the same as in Example 1. After standing for 5 minutes, obvious aggregate floating phenomenon occurs.

[0047] Comparative Example 5 This comparative example provides a lightweight aggregate concrete. In Example 1, 100 parts of Class II fly ash were replaced with 60 parts of Class II fly ash and 40 parts of silica fume. The mixing time in step (2) was increased to 120s. The rest was the same as in Example 1. After standing for 5 minutes, there was no segregation or aggregate floating.

[0048] Test method: Referring to the "Standard for Test Methods of Performance of Ordinary Concrete Mixtures" GB / T 50080, "Standard for Test Methods of Mechanical Properties of Ordinary Concrete" GB / T 50081, and "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete" GB / T 50082, the spreadability (initial state, 1.5h, 3.0h) and compressive strength (3D, 7D, 28D) of the lightweight aggregate concrete prepared in the examples and comparative examples were tested. The test results are shown in Table 1. After the concrete was prepared, it was left to stand for 5 minutes, and the bleeding, segregation and floating of the lightweight aggregate were observed by visual inspection to qualitatively evaluate the anti-segregation performance.

[0049] Test results: Table 1 The test results show that: (1) As can be seen from Examples 1 to 3, the present invention uses crushed shale ceramsite as the core coarse aggregate and controls the ratio of slurry volume to aggregate bulk volume in the range of 1.05 to 1.10. Through the synergistic effect of multiple components, the prepared lightweight aggregate concrete has excellent workability and low segregation rate, which solves the problem of easy aggregate floating of lightweight aggregate. At the same time, the compressive strength at each age increases steadily, and the 28-day compressive strength fully meets the requirements of engineering use. It achieves the synergistic technical effect of preventing aggregate floating, low pumping resistance and stable mechanical properties.

[0050] (2) As can be seen from Examples 4-8, by further limiting the mass ratio of coarse and fine aggregates to 0.34-0.36 and using SDC8860 water-reducing admixture, the present invention can achieve better anti-segregation performance and more stable mechanical properties. When the mass ratio of coarse and fine aggregates deviates from the preferred range of the present invention, the risk of aggregate floating increases significantly and the segregation rate increases substantially. When a non-preferred admixture is used, the concrete spreadability and 28D compressive strength are both lower than in Example 1. When a one-step mixing preparation method is used, the segregation rate increases, verifying the synergistic optimization effect of the preferred formulation range and preparation method of the present invention on the comprehensive performance of concrete.

[0051] (3) As can be seen from Example 1 and Comparative Examples 1 and 2, when the paste-aggregate ratio is lower than the lower limit of the present invention, the paste cannot fully coat the aggregate and fill the gaps in the skeleton, the aggregate floats up severely, and the segregation rate increases significantly; when the paste-aggregate ratio is higher than the upper limit of the present invention, the apparent density increases and the stability decreases. As can be seen from Example 1 and Comparative Examples 3 and 4, when clay ceramsite, fly ash ceramsite, etc. are used as substitutes, the risk of aggregate floating increases, and the workability and compressive strength both decrease significantly. As can be seen from Example 1 and Comparative Example 5, the cementitious material system of the present invention, which uses a mixture of cement and fly ash, can simplify the preparation process and reduce the cost of raw materials while fully meeting the engineering strength requirements; although the compressive strength can be slightly improved after replacing fly ash with silica fume in Comparative Example 5, the stirring time needs to be greatly extended, and the complexity of the preparation process and the cost of raw materials are significantly increased, while the cementitious material system of the present invention can fully meet the engineering needs and has better economy and practicality.

[0052] In summary, this invention, through specific coarse aggregate selection, control of the slurry volume to aggregate bulk volume ratio, and optimized cementitious material system, water-cement ratio, coarse and fine aggregate proportions, and admixture selection, synergistically solves the problems of easy aggregate floating and high pumping resistance in lightweight aggregate concrete. The resulting lightweight aggregate concrete possesses excellent anti-segregation and anti-floating properties, pumpable construction performance, and stable mechanical properties. At the same time, the preparation process is simple, the raw material cost is controllable, and it can be widely applied to complex construction scenarios such as ultra-high-rise pumping, demonstrating excellent engineering application value.

[0053] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A lightweight aggregate concrete with low pumping resistance and anti-aggregate floating properties, characterized in that, The mixture includes aggregates and slurry. The aggregates include coarse aggregates and fine aggregates. The coarse aggregates include crushed shale ceramsite. The slurry includes cementitious materials, admixtures, and water. The cementitious materials are composed of cement and fly ash. The volume ratio of the slurry to the bulk volume of the aggregates is 1.05 to 1.

10.

2. The low pumping resistance lightweight aggregate concrete according to claim 1, characterized in that, The mass ratio of coarse aggregate to fine aggregate is 0.34 to 0.

36.

3. The low pumping resistance lightweight aggregate concrete according to claim 1, characterized in that, The bulk density of the crushed shale ceramsite is 750~850 kg / m³. 3 Compressive strength ≥ 4.0 MPa, water absorption ≤ 3.5%.

4. The low pumping resistance lightweight aggregate concrete according to claim 1, characterized in that, The water-cement ratio of the slurry to the cementitious material is 0.35~0.

40.

5. The low pumping resistance lightweight aggregate concrete according to claim 1, characterized in that, The amount of cement used is 300~320 kg / m³. 3 The amount of fly ash used is 30-35% of the cement mass.

6. The low pumping resistance lightweight aggregate concrete according to claim 1, characterized in that, The viscosity of the slurry η ≥ 0.8 dny•s / cm 2 .

7. The low pumping resistance lightweight aggregate concrete according to claim 1, characterized in that, The admixture includes SDC8860 water-reducing agent.

8. The low pumping resistance lightweight aggregate concrete according to claim 1, characterized in that, The amount of the admixture added is 0.8 to 1.2% of the mass of the cementitious material.

9. The low pumping resistance lightweight aggregate concrete according to claim 1, characterized in that, The slurry forms a 0.1-0.2 mm slurry film on the surface of the aggregate.

10. A method for preparing low-pumping-resistance lightweight aggregate concrete as described in any one of claims 1 to 9, characterized in that, The preparation method includes: (1) Mix the pretreated coarse aggregate and fine aggregate and stir to obtain premixed aggregate; (2) Mix the cementitious material with the premixed aggregate and stir to obtain the mixture; (3) After adding water and admixtures to the mixture, stir to obtain the low pumping resistance lightweight aggregate concrete that prevents aggregate from floating.

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