Super close packing structure design method for 500-800 MPa super high-strength concrete

Abstract

The invention provides a design method of a super close packing structure for 500-800MPa super high-strength concrete. The design method mainly comprises the following steps: 1) calculating the close packing blending proportion of powder in a dry state; 2) establishing a quantitative relation between the concrete forming pressure and the water film thickness through the wet stacking density; (3) determining initial maintenance conditions of the concrete and the thickness of a hydration product layer on the outer layer of the cement particles under the corresponding conditions; 4) super close packing design based on matching of the thickness of the water film and the thickness of the outer hydration product; and (5) ensuring the uniformity of the powder by adopting an ultrasonic dispersion technology, and preparing the super high-strength concrete by adopting a later composite curing process according to the forming pressure under the specific water film thickness and the initial curing condition under the corresponding product layer thickness. Based on the physical and chemical synergistic effect, the ultra-close packing structure design method is provided for optimizing the hydration product growth space, and the method has great significance in promoting breakthrough of the frontier strategic engineering construction technology.

Description

Technical Field

[0001] The present invention relates to the technical field of high-strength concrete performance design methods, and in particular to a method for designing an ultra-compact stacking structure for 500-800 MPa super high-strength concrete. Background Art

[0002] Concrete, thanks to its numerous advantages, has become the most widely used building material in the world today, playing an irreplaceable role in the construction industry. Strength, as the key to concrete's ability to withstand pressure and provide support, directly impacts its usability and safety in buildings and infrastructure. At the same time, with the rapid development of the national economy and the acceleration of urbanization, guided by various forward-looking major national projects, modern concrete structures face complex application scenarios and need to adapt to the development of lightweight, high-rise, long-span, and heavy-load structural forms. Faced with complex structural load-bearing requirements and extreme environmental challenges, the development of high-strength, high-performance concrete is crucial to achieving breakthroughs in strategic engineering construction technology.

[0003] A significant increase in concrete strength is often accompanied by superior durability, meaning it possesses outstanding performance for handling a variety of complex structures and extreme environments. Typically, a substantial increase in concrete strength is accompanied by a reduction in the water-cement ratio. However, existing models for dense packing of concrete cannot achieve dense packing design at extremely low water-cement ratios while taking into account cement hydration. This is because as cement hydration proceeds, the water in the system is gradually consumed, and the hydration products gradually fill the volume occupied by water, thereby forming gel and pore regions, which affects the packing system of the concrete material. Furthermore, the disruptive effect of cement hydration on particle packing in the mix design of cement-based materials requires further study. In particular, as the cement hydration process proceeds, the particle size distribution of the cement changes.

[0004] Therefore, the technical problem that needs to be solved urgently is: how to directionally select the optimal water film thickness at an extremely low water-binder ratio to achieve ultra-dense stacking of the structure, so that the concrete can break through the strength bottleneck of 200-500 MPa. Summary of the Invention

[0005] The present invention is made to solve the above-mentioned problem and aims to provide a method for designing an ultra-dense packing structure for 500-800 MPa super high strength concrete.

[0006] The present invention provides a method for designing an ultra-dense packing structure for 500-800 MPa super-high-strength concrete, which has the following characteristics and specifically comprises the following steps: S1, calculating the mixing ratio of the dense packing of initial material powders in a dry state, thereby determining the volume ratio of cement, silica fume, mineral powder, quartz powder, fine aggregate, and nanopowder; S2, establishing a quantitative relationship between the concrete forming pressure and the water film thickness through the wet bulk density based on the volume ratio of the cement, silica fume, mineral powder, quartz powder, fine aggregate, and nanopowder; S3, determining the initial curing conditions of the concrete and the thickness of the external hydration product layer of the cement particles under the corresponding conditions; S4, based on the ultra-dense packing design in which the water film thickness matches the thickness of the external hydration product layer, re-determining the volume ratio of cement, silica fume, mineral powder, quartz powder, fine aggregate, and nanopowder; and S5, using ultrasonic dispersion technology to ensure the uniformity of the initial material powders, and using a post-curing process according to the forming pressure under a specific water film thickness and the initial curing conditions under the corresponding product layer thickness to prepare the super-high-strength concrete.

[0007] The ultra-dense packing structure design method for 500-800 MPa super-high-strength concrete provided by the present invention may also have the following features: wherein step S1 specifically includes the following sub-steps: calculating the blending ratio of each material for dense packing in a dry state using a modified Anderson model based on the particle size distribution of the initial material powder:

[0008]

[0009] Where P(D) is the fraction of solid particles smaller than particle size D; D max is the maximum particle size in the solid; D min is the minimum particle size; q is the distribution modulus; the initial material powder includes cement, silica fume, mineral powder, quartz powder, fine aggregate and nanopowder. The mass ratio of the solid particles is adjusted using the least squares method according to the above formula so that the mixture of the solid particles reaches the best fitting position of the target curve, thereby determining the volume ratio of cement, silica fume, mineral powder, quartz powder, fine aggregate and nanopowder.

[0010] The ultra-dense packing structure design method for 500-800 MPa super-high-strength concrete provided by the present invention may also have the following features: wherein step S2 specifically includes the following sub-steps: establishing a quantitative relationship between the concrete forming pressure and the water film thickness based on the wet packing density:

[0011] Where τ is the wet bulk density; M is the weight of the mixture; V is the volume under pressure; ρ w , ρ c , ρ f , ρ m , ρ q, ρ a , ρ n are the densities of water, cement, silica fume, mineral powder, quartz powder, fine aggregate, and nano powder respectively; Y w 、Y c 、Y f 、Y m 、Y q 、Y a 、Y n are the volume ratios of water, cement, silica fume, mineral powder, quartz powder, fine aggregate, nano powder and the total mixture,

[0012]

[0013] Where λ is the porosity of the concrete after mixing; A is the specific surface area of the gelling material component, and the gelling material is a mixture of cement, silica fume and mineral powder, and A c 、A f 、A m are the specific surface areas of cement, silica fume and mineral powder respectively; R c 、R f 、R m are the volume ratios of cement, silica fume, mineral powder and the cementitious material respectively, d is the thickness of the water film, and the relationship between the wet bulk density of the mixture under pressure is described according to the Heckel equation: τ(P) = ae -kP +b

[0014] Combined with the obtained fitting formula, the relationship between the ultra-dense packing coefficient and the water-binder ratio-molding pressure is obtained. Combined with the above obtained fitting formula, the relationship between the water film thickness and the molding pressure-water-binder ratio is obtained, d(P,w)=ae -kP +bw+c

[0015] Where P is the molding pressure, w is the water-binder ratio, which refers to the ratio of water to the gel material, and a, b, and c are the density constants of the powder under pressure. These parameters are calculated by MATLAB fitting the porosity results under different water-binder ratios and molding pressures.

[0016] The ultra-dense packing structure design method for 500-800 MPa super-high-strength concrete provided by the present invention may also have the following features: wherein step S3 specifically includes the following sub-steps: establishing the thickness of the external hydration product layer of the cement particles under initial curing conditions of the concrete: the initial curing conditions are a temperature of 30-90° C. and a humidity of 40-95%, and establishing a functional relationship between the cement particles and the external hydration product layer by measuring the hydration degree of the cement particles at different water-binder ratios under standard curing conditions when the external hydration product layer has completed growth. The time required for the external hydration product layer to complete growth is 2 days:

[0017] DoH'=DoH(w)*T*RH

[0018]

[0019] Where, DoH is the hydration degree of cement particles under standard curing conditions for 2 days at different water-binder ratios. The functional relationship is fitted by MATLAB. DoH' is the hydration degree after considering temperature and humidity. T is the temperature influence coefficient, t is the temperature, RH is the humidity influence coefficient, and h is the humidity. The volume of cement particles after two days of curing and the volume of hydration products V are established. product and the volume of unhydrated product V unreact Functional relationship: V 2d =V unreact +V product

[0020] Where V 2d is the volume of cement particles after two days of curing, which is calculated from the volume of hydrated products V product and the volume of unhydrated product V unreact Composition and, and considered when 1cm 3 When cement particles are hydrated, they produce about 2.2 cm 3 The hydration products are used to calculate the initial cement particle volume V initial With V unreact 、V product Relationship:

[0021] V unreact =(1-DoH)*V initial

[0022] V product =2.2*DoH*V initial

[0023] V 2d =(1+1.2DoH)*V initial

[0024] The radius R of the outer hydration product layer thickness is then calculated by the initial cement particle volume. outer The radius R of the initial cement particle initial Relationship:

[0025]

[0026] The ultra-dense packing structure design method for 500-800 MPa super high strength concrete provided by the present invention may also have the following features: wherein step S4 specifically includes the following sub-steps: ultra-dense packing design based on matching the water film thickness with the thickness of the external hydration product layer: matching the water film thickness d with the thickness of the cement particle external hydration product layer R outerWhen the water film thickness is consistent, it is defined as the critical water film thickness d critical And match the parameter, d=d critical =R outer The corrected cement particle size is reintroduced into the close packing equation, and the mass ratio of solid particles is redesigned using the least squares method to determine the volume ratio of cement, silica fume, mineral powder, quartz powder, fine aggregate, and nanopowder.

[0027] The ultra-compact packing structure design method for 500-800 MPa super-high-strength concrete provided by the present invention may also have the following characteristics: wherein, in step S5, the curing process includes high-temperature curing, autoclave curing, hot water curing and composite curing process.

[0028] Functions and effects of the invention

[0029] According to the ultra-dense packing structure design method for 500-800 MPa super-high-strength concrete involved in the present invention, ultra-dense packing of concrete structures is achieved by directional optimization of water film thickness at an extremely low water-binder ratio. Specifically:

[0030] 1) The present invention achieves ultra-dense packing of concrete structures close to the setting and hardening stage by applying pressure to directionally control the thickness of the water film at an extremely low water-binder ratio, thus solving the problem of the inability to mix and form materials when water demand is insufficient, and further achieving a breakthrough in concrete strength.

[0031] 2) The present invention realizes ultra-tight packing of the entire concrete hydration stage by adopting a process flow of pre-pressing followed by combined curing.

[0032] 3) The present invention achieves a close integration of the crystalline and amorphous phases in the concrete microstructure. The simultaneous effects of physical stacking and cement hydration further enhance the bonding between hydration products, which was originally dominated by van der Waals forces, thereby achieving a significant increase in strength.

[0033] 4) This invention achieves a dense packing of the concrete's submicroscopic structure. The application of pressure reduces the inter-aggregate porosity, allowing the cement paste, which originally filled the inter-aggregate pores, to fully envelop the particles, thereby forming a bond and generating strength. Furthermore, the sustained pressure eliminates defects often caused by early shrinkage cracking in concrete, further preventing the localized stress concentrations that can result from early cracking. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a flow chart of design steps in an embodiment of the present invention;

[0035] Figure 2is a schematic diagram showing a large number of voids caused by agglomeration between ultrafine particles at an extremely low water-to-binder ratio in an embodiment of the present invention;

[0036] Figure 3 This is a schematic diagram of the oscillating state of solid particles and water after ultrasonic dispersion in an embodiment of the present invention, i.e., the presence of liquid bridges between particles and a large number of pores between the particles;

[0037] Figure 4 This is a schematic diagram showing that under the action of pre-pressure, the number of pores between solid particles decreases and excess water forms a water film on the surface of the particles in the mix ratio designed in the embodiment of the present invention;

[0038] Figure 5 is a schematic diagram of the hydration process of a sample placed at a certain temperature after pre-pressing in an embodiment of the present invention; and

[0039] Figure 6 Schematic diagram of the compact state of a sample under pressure and composite curing in an embodiment of the present invention.

[0040] Description of the marks in the figure:

[0041] 1—solid particles; 2—liquid bridges; 3—pores between particles; 4—critical water film thickness; 5—applied pressure; 6—volume before preloading; 7—volume after pressure application; 8—ettringite; 9—defects in cement particles; 10—applied high temperature; 11—early hydration products between particles; 12—high-density hydrated calcium silicate; 13—calcium hydroxide; 14—late hydration products. DETAILED DESCRIPTION

[0042] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0043] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the following embodiments and accompanying drawings specifically illustrate the ultra-dense packing structure design method for 500-800 MPa super-high-strength concrete of the present invention.

[0044] Example 1

[0045] Figure 2Schematic diagram showing a large number of voids caused by agglomeration of ultrafine particles at an extremely low water-to-binder ratio in an embodiment of the present invention. Figure 3 This is a schematic diagram of the oscillating state of solid particles and water after ultrasonic dispersion in an embodiment of the present invention, that is, the existence of liquid bridges between particles and a large number of pores between particles. Figure 4 This is a schematic diagram showing that under the action of pre-pressure, the number of pores between solid particles is reduced and excess water forms a water film on the surface of the particles in the mix ratio designed in the embodiment of the present invention. Figure 5 Schematic diagram of the hydration process of a sample placed at a certain temperature after pre-pressing in an embodiment of the present invention. Figure 6 Schematic diagram of the compact state of a sample under pressure and composite curing in an embodiment of the present invention.

[0046] like Figure 2-6 It can be seen that the key factors affecting the strength of ice concrete are the agglomeration of ultrafine particles under extremely low water-binder ratios; the presence of liquid bridges and a large number of pores between particles; the reduction in the number of pores between solid particles under pre-pressure, and the formation of a water film on the surface of the particles by excess water; the hydration process at a certain temperature after pre-pressure; and the compact state of the sample under pressure and composite curing conditions. Based on this, this embodiment provides a design method for an ultra-compact packing structure for 500-800 MPa super-high-strength concrete.

[0047] Figure 1 is a flow chart of design steps in an embodiment of the present invention.

[0048] like Figure 1 As shown, this embodiment specifically includes the following steps:

[0049] S1, calculate the mixing ratio of the initial material powder in a tightly packed state in a dry state, thereby determining the volume ratio of cement, silica fume, mineral powder, quartz powder, fine aggregate, and nano powder.

[0050] According to the particle size distribution of the initial materials, the modified Anderson model is used to calculate the mixing ratio of each powder material tightly packed in a dry state. The initial materials are cement, silica fume, mineral powder, quartz powder, fine aggregate, and nanopowder, among which the gel materials are cement, silica fume, and mineral powder.

[0051] The particle size of P·O525 cement is 1 to 25 μm, and the specific surface area is 378 m 2 / kg, density is 3140kg / m 3 The particle size of silica fume is 0.2-0.7 μm, and the specific surface area is 25400 m 2 / kg, density is 2450kg / m 3 The particle size of the mineral powder is 70-90 μm, and the specific surface area is 790 m 2 / kg, density is 337kg / m3 The particle size of quartz powder is 2-8 μm, and the specific surface area is 21800 m 2 / kg, density is 2730kg / m 3 The nano powder material is nano SiO2 with a particle size of 0.005 to 0.05 μm and a specific surface area of 850,000 to 1,100,000 m 2 / kg, density is 121kg / m 3 The fine aggregate is metal steel aggregate with a particle size of 100 to 900 μm and a specific surface area of 89 m 2 / kg, density is 7790kg / m 3 The steel fiber is an ultra-high strength steel fiber with a diameter of 0.08-0.4mm and a length of 2-12mm, and a density of 7860kg / m 3 ; During the mixing process of the powder components, 2% of a special ultra-high surfactant admixture is added, and the water reduction efficiency is 40-45%.

[0052] The modified Anderson model is used to calculate the blending ratio of each powder material tightly packed in a dry state based on the particle size distribution of the initial material:

[0053]

[0054] Where P(D) is the fraction of solid particles smaller than particle size D; D max is the maximum particle size in the solid; D min is the minimum particle size; q is the distribution modulus. Based on the above formula, the least squares method is used to adjust the mass ratio of the solid particles so that the solid particle mixture reaches the optimal fit position of the target curve, thereby determining the volume ratio of cement, silica fume, mineral powder, quartz powder, fine aggregate, and nanopowder.

[0055] S2, based on the volume ratio of cement, silica fume, mineral powder, quartz powder, fine aggregate, and nanopowder, a quantitative relationship between concrete molding pressure and water film thickness is established through wet bulk density.

[0056] Ultrasonic dispersion is used to ensure uniformity during mixing with water, and a quantitative relationship between water film thickness, molding pressure, and water-binder ratio is established:

[0057]

[0058] Where τ is the wet bulk density; M is the weight of the mixture; V is the volume under pressure; ρ w , ρ c , ρ f , ρ m , ρ q , ρ a , ρ nare the densities of water, cement, silica fume, mineral powder, quartz powder, fine aggregate, and nano powder respectively; Y w 、Y c 、Y f 、Y m 、Y q 、Y a 、Y n are the volume ratios of water, cement, silica fume, mineral powder, quartz powder, fine aggregate, nano powder and the total mixture, respectively.

[0059]

[0060] Where λ is the porosity of the concrete after mixing; A is the specific surface area of the cementitious material component, A c 、A f 、A m are the specific surface areas of cement, silica fume and mineral powder respectively; R c 、R f 、R m are the volume ratios of cement, silica fume, mineral powder and cementitious materials respectively, and d is the thickness of water film.

[0061] The relationship between the wet bulk density of the mixture under pressure is described by the Heckel equation:

[0062] τ(P)=ae -kP +b

[0063] The relationship between the ultra-close packing coefficient and the water-binder ratio-pressure is obtained by combining the obtained fitting formula. The relationship between the water film thickness and the molding pressure-water-binder ratio is obtained by combining the obtained fitting formula. The water-binder ratio refers to the ratio of water to gel material.

[0064] d(P,w)=ae -kP +bw+c

[0065] Where P is the molding pressure, w is the water-binder ratio, and a, b, and c are the density constants of the powder under pressure. These parameters are calculated by fitting the porosity results of some powders under different water-binder ratios and molding pressures using MATLAB.

[0066] S3, determine the initial curing conditions of concrete and the thickness of the outer hydration product layer of cement particles under the corresponding conditions.

[0067] Establishing the thickness of the outer hydration product layer of cement particles under initial concrete curing conditions: Initial curing conditions are a temperature of 30-90°C and a humidity of 40-95%. According to literature, the increase in the thickness of the outer hydration product layer primarily occurs from the end of the induction phase to the middle of the acceleration phase of the exotherm curve, and the subsequent hydration process primarily involves changes in the inner hydration product layer. Therefore, when the outer hydration product layer stops growing, it indicates the maximum particle size of the hydrated cement particles. The present invention assumes that the outer layer product growth is complete after 2 days. By measuring the hydration degree of cement at different water-binder ratios under standard curing conditions at 2 days, a functional relationship between the outer hydration product layer and the outer hydration product layer is established:

[0068] DoH'=DoH(w)*T*RH

[0069]

[0070] Where DoH is the degree of hydration of cement particles at different water-binder ratios under standard curing conditions for two days, and this functional relationship was fitted using MATLAB. DoH' is the degree of hydration after accounting for temperature and humidity, where T is the temperature influence coefficient, t is the temperature, RH is the humidity influence coefficient, and h is the humidity. The functional relationship between the degree of hydration of cement particles at different water-binder ratios under standard curing conditions after two days and the external hydration product layer was established:

[0071] V 2d =V unreact +V product

[0072] Where V 2d is the volume of cement after two days of curing, mainly composed of the volume of hydration products V product and the volume of unhydrated product V unreact Composition and, and considered when 1cm 3 When cement particles are hydrated, they produce about 2.2 cm 3 The initial cement particle volume V can be calculated. initial With V unreact 、V product relationship.

[0073] V unreact =(1-DoH)*V initial

[0074] V product =2.2*DoH*V initial

[0075] V 2d =(1+1.2DoH)*V initial

[0076] Then the radius R of the external product is obtained by volume calculation outerWith the initial radius R initial relationship.

[0077]

[0078] S4. Based on the ultra-dense packing design in which the thickness of the water film matches the thickness of the external hydration product layer, the volume ratio of cement, silica fume, mineral powder, quartz powder, fine aggregate, and nano powder is re-determined.

[0079] Based on the ultra-tight packing design that matches the thickness of the water film with the thickness of the outer hydration product, the water film thickness d is matched with the thickness of the outer hydration product layer R of the cement particles. outer When the water film thickness is consistent, it is defined as the critical water film thickness d critical and match the parameter.

[0080] d=d critical =R outer

[0081] The corrected cement particle size is reintroduced into the close packing equation, and the mass ratio of solid particles is redesigned using the least squares method to determine the volume ratio of cement, silica fume, mineral powder, quartz powder, fine aggregate, and nanopowder.

[0082] S5, uses ultrasonic dispersion technology to ensure the uniformity of the initial material powder, and adopts a post-curing process to prepare super high-strength concrete based on the molding pressure under a specific water film thickness and the initial curing conditions under the corresponding product layer thickness.

[0083] The materials were mixed and stirred, then subjected to ultrasonic dispersion. The water-binder ratio was calculated according to the above formula, and the samples were then formed under pressure. The samples were then cured at 30°C and 50% humidity for two days, followed by curing in 90°C hot water for five days, and then heat-curing at 200°C for seven days to produce the super-high-strength concrete.

[0084] A super high-strength concrete material prepared according to this embodiment has a 28-day performance test showing that the concrete has a compressive strength of 572 MPa, a tensile strength of 58 MPa, an elastic modulus of 74.1 GPa, a porosity of 0.07%, and an impermeability grade ≥ P12.

[0085] Example 2

[0086] This embodiment provides a method for designing an ultra-dense packing structure for 500-800 MPa super-high-strength concrete. Based on Example 1, step S5 is replaced by: S5: The materials are mixed and stirred and subjected to ultrasonic dispersion. The water-binder ratio and pressure molding are then calculated according to the above formula. The sample is then cured at 60°C and 90% humidity for 2 days, then cured in 90°C hot water for 5 days, and finally cured in an autoclave for 28 days to obtain the super-high-strength concrete.

[0087] A super high-strength concrete material prepared according to this embodiment has a 28-day performance test showing that the concrete has a compressive strength of 646 MPa, a tensile strength of 63 MPa, an elastic modulus of 74.9 GPa, a porosity of 0.03%, and an impermeability grade ≥ P12.

[0088] For the sake of convenience, the same symbols are given to the same structures in this embodiment as in the first embodiment, and the same descriptions are omitted.

[0089] Those skilled in the art will appreciate that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for designing an ultra-dense packing structure for 500-800 MPa super high strength concrete, characterized in that: The specific steps include: S1, calculate the mixing ratio of the initial material powder in a tightly packed state in a dry state, thereby determining the volume ratio of cement, silica fume, mineral powder, quartz powder, fine aggregate, and nano powder; S2, based on the volume ratio of the cement, silica fume, mineral powder, quartz powder, fine aggregate, and nano powder, a quantitative relationship between the concrete forming pressure and the water film thickness is established through wet bulk density; S3, determine the initial curing conditions of concrete and the thickness of the outer hydration product layer of cement particles under the corresponding conditions; S4, based on the ultra-dense packing design in which the thickness of the water film matches the thickness of the external hydration product layer, re-determining the volume ratio of cement, silica fume, mineral powder, quartz powder, fine aggregate, and nano powder; and S5, uses ultrasonic dispersion technology to ensure the uniformity of the initial material powder, and adopts a post-curing process to prepare super high-strength concrete based on the molding pressure under a specific water film thickness and the initial curing conditions under the corresponding product layer thickness.

2. The method for designing an ultra-dense packing structure for 500-800 MPa super high strength concrete according to claim 1, characterized in that: in, The step S1 specifically includes the following sub-steps: The modified Anderson model is used to calculate the blending ratio of each material in a dry state based on the particle size distribution of the initial material powder: Where P(D) is the fraction of solid particles smaller than particle size D; D max is the maximum particle size in the solid; D min is the minimum particle size; q is the distribution modulus; the initial material powder includes cement, silica fume, mineral powder, quartz powder, fine aggregate and nanopowder. The mass ratio of the solid particles is adjusted using the least squares method according to the above formula so that the mixture of the solid particles reaches the best fitting position of the target curve, thereby determining the volume ratio of cement, silica fume, mineral powder, quartz powder, fine aggregate and nanopowder.

3. The method for designing an ultra-dense packing structure for 500-800 MPa super high strength concrete according to claim 1, characterized in that: in, The step S2 specifically includes the following sub-steps: The quantitative relationship between concrete forming pressure and water film thickness is established through wet bulk density: Where τ is the wet bulk density; M is the weight of the mixture; V is the volume under pressure; ρ w , ρ c , ρ f , ρ m , ρ q , ρ a , ρ n are the densities of water, cement, silica fume, mineral powder, quartz powder, fine aggregate, and nano powder respectively; Y w 、Y c 、Y f 、Y m 、Y q 、Y a 、Y n are the volume ratios of water, cement, silica fume, mineral powder, quartz powder, fine aggregate, nano powder and the total mixture, Where λ is the porosity of the concrete after mixing; A is the specific surface area of the gelling material component, and the gelling material is a mixture of cement, silica fume and mineral powder, and A c 、A f 、A m are the specific surface areas of cement, silica fume and mineral powder respectively; R c 、R f 、R m are the volume ratios of cement, silica fume, mineral powder and the cementitious material, d is the thickness of the water film, The relationship between the wet bulk density of the mixture under pressure is described by the Heckel equation: τ(P)=ae -kP +b Combined with the obtained fitting formula, the relationship between the ultra-close packing coefficient and the water-binder ratio-molding pressure is obtained. Combined with the above obtained fitting formula, the relationship between the water film thickness and the molding pressure-water-binder ratio is obtained. d(P,w)=ae -kP +bw+c Where P is the molding pressure, w is the water-binder ratio, which refers to the ratio of water to the gel material, and a, b, and c are the density constants of the powder under pressure. These parameters are calculated by MATLAB fitting the porosity results under different water-binder ratios and molding pressures.

4. The method for designing an ultra-dense packing structure for 500-800 MPa super high strength concrete according to claim 1, characterized in that: in, The step S3 specifically includes the following sub-steps: Establish the thickness of the outer hydration product layer of the cement particles under initial concrete curing conditions: The initial curing conditions are a temperature of 30-90°C and a humidity of 40-95%. By measuring the hydration degree of cement particles at different water-binder ratios under standard curing conditions when the external hydration product layer has grown, a functional relationship between the cement particles and the external hydration product layer is established. The time for the external hydration product layer to grow is 2 days: DoH'=DoH(w)*T*RH Where, DoH is the hydration degree of cement particles under standard curing conditions for 2 days at different water-binder ratios. The functional relationship is fitted by MATLAB. DoH' is the hydration degree after considering temperature and humidity. T is the temperature influence coefficient, t is the temperature, RH is the humidity influence coefficient, and h is the humidity. Establish the volume of cement particles and the volume of hydration products V after two days of curing product and the volume of unhydrated product V unreact Functional relationship: V 2d =V unreact +V product Where V 2d is the volume of cement particles after two days of curing, which is calculated from the volume of hydrated products V product and the volume of unhydrated product V unreact Composition and, and considered when 1cm 3 When cement particles are hydrated, they produce about 2.2 cm 3 The hydration products are used to calculate the initial cement particle volume V initial With V unreact 、V product Relationship: In unreact =(1-DoH)*V initial In product =2.2*DoH*V initial In 2d =(1+1.2DoH)*V initial The radius R of the outer hydration product layer thickness is then calculated by the initial cement particle volume. outer The radius R of the initial cement particle initial Relationship:

5. The method for designing an ultra-dense packing structure for 500-800 MPa super high strength concrete according to claim 1, characterized in that: in, The step S4 specifically includes the following sub-steps: Ultra-dense packing design based on matching the water film thickness with the thickness of the external hydration product layer: The water film thickness d is related to the thickness of the hydration product layer outside the cement particles R outer When the water film thickness is consistent, it is defined as the critical water film thickness d critical And match the parameter, d=d critical =R outer The corrected cement particle size is reintroduced into the close packing equation, and the mass ratio of solid particles is redesigned using the least squares method to determine the volume ratio of cement, silica fume, mineral powder, quartz powder, fine aggregate, and nanopowder.

6. The method for designing an ultra-dense packing structure for 500-800 MPa super high strength concrete according to claim 1, characterized in that: in, In step S5, the curing process includes high temperature curing, autoclave curing, hot water curing and composite curing process.

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