Low-strength pumping concrete construction method

Abstract

The invention discloses a low-strength pump concrete construction method which is characterized by comprising the steps of aggregate gradient treatment, interface nanometer strengthening, dynamic gel proportioning, two-parameter feedback control, pulsating pumping control, thermodynamic layering control and gas-solid coupling maintenance.

Description

Technical Field

[0001] The present invention relates to the field of concrete construction, and particularly to a construction method for low-strength pumped concrete. Background Art

[0002] In the fields of building structure reinforcement and lightweight filling projects, low-strength pumped concrete is widely used due to its economic advantages. However, this type of concrete faces a key technical contradiction in pumping construction: to meet the fluidity requirements for pumping, the dosage of cementitious materials needs to be significantly reduced, but this measure directly leads to insufficient cohesion of the paste, causing aggregate segregation and paste bleeding. In the prior art, although the conventional methods of using a single thickening agent or optimizing the gradation can partially alleviate segregation, they will increase the pumping resistance, resulting in an increase in the pipe blockage rate and a decrease in the bonding strength of the structural interface. This contradiction severely restricts the engineering applicability of low-strength concrete under complex working conditions such as high-rise pumping and long-distance transportation. Summary of the Invention

[0003] To achieve the above object and other related objects, the present invention discloses a construction method for low-strength pumped concrete, which is characterized by including the following steps: S1. Aggregate gradient treatment: The coarse aggregate is screened into two grades of 5 - 20 mm and 20 - 40 mm, and the pre-wetting time is calculated according to the formula: ; Wherein: is the water absorption rate of the aggregate, is the total mass of the aggregate, is the water pump flow rate; S2. Interface nano-strengthening: Spray nano-SiO2 sol on the surface of the aggregate treated in S1, and the spraying amount satisfies: ; Wherein: is the maximum particle size of the coarse aggregate, is the same as the aggregate mass in S1; S3. Gel dynamic ratio: Based on the bulk density of the aggregate treated in S2, adjust the mass ratio of cement to fly ash according to the relationship: ; And synchronously calculate the initial dosage of the water reducer, where is the total amount of cementitious materials; S4. Two-parameter feedback control: Real-time monitor the slump (tested according to GB / T 50080) and the pumping pressure , and dynamically correct the water-binder ratio: ; When or When triggered, the proportion recombination of S3 occurs; S5. Pulsating pumping control, setting the pulsating frequency of the variable-frequency pump: ; Wherein: is the horizontal pipe length; is the vertical height (m); S6. Thermodynamic stratification control, based on the concrete viscosity and the pumping flow rate , calculate the pouring layer thickness: ; Wherein: is the initial setting time; ; is the concrete temperature value, is the ambient temperature value; S7. Gas-solid coupling curing, alternately executed during the curing of each layer of concrete: Steam stage: Control the steam pressure , with a cycle ; Atomization stage: Maintain the humidity , and the droplet size .

[0004] Furthermore, the preparation parameters of the nano-sol in S2 include: The concentration of sodium silicate ; The hydrolysis time ; The dispersant is a polycarboxylic acid series, with a dosage .

[0005] Furthermore, in the pulsating pumping of S5, a damper is set in the vertical pipe section, and its damping coefficient: Wherein: is the concrete density, is the pump pipe diameter.

[0006] Furthermore, in the gas-solid coupling curing of S7: A CO2 / N2 mixed gas is introduced in the steam stage, with a volume ratio ; The gas flow rate (L / min), where is the curing area (m 2 ).

[0007] By adopting the above technical solutions, the wetting requirement of the paste is reduced through aggregate gradient treatment and nano-interface strengthening, combined with the dynamic ratio optimization of two-parameter feedback and the energy dissipation control of pulsating pumping, to achieve the coordinated adaptation of the rheological properties of the paste and the pumping stability while maintaining a low binder dosage. At the same time, the thermodynamic stratification algorithm and gas-solid coupling curing are used to regulate the directional growth of the hydration phase, systematically solving the mutually exclusive contradictions of fluidity, cohesiveness and segregation resistance in the pumping construction of low-strength concrete. Brief Description of the Drawings

[0008] In combination with the accompanying drawings and with reference to the following detailed description, the above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent. The drawings are used to better understand the solution and do not constitute a limitation to the present disclosure. In the drawings, the same or similar reference numerals denote the same or similar elements, wherein: Figure 1 is a flowchart of the present invention. Detailed Description of the Embodiments

[0009] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present invention.

[0010] Referring to Figure 1 , the embodiments of the present invention provide a construction method for low-strength pumped concrete, which is characterized by including the following steps: S1. Aggregate gradient treatment: The coarse aggregate is screened into two grades of 5-20 mm and 20-40 mm, and the pre-wetting time is calculated according to the formula: ; Wherein: is the water absorption rate of the aggregate, is the total mass of the aggregate, is the water pump flow rate; Above, through the immersion control of hierarchical pre-wetting and water absorption rate adaptation, the negative pressure adsorption effect of the pores inside the aggregate is eliminated, and the fluidity attenuation caused by the excessive absorption of the paste water by the aggregate during the pumping process is reduced.

[0011] S2. Interface nano-strengthening: Spray nano-SiO2 sol on the surface of the aggregate treated in S1, and the spraying amount satisfies: ; Wherein: is the maximum particle size of the coarse aggregate, is the same as the aggregate mass in S1.

[0012] As described above, the nano-sol forms a dense coating layer on the surface of the aggregate, enhancing the bond strength at the aggregate-paste interface and inhibiting the displacement segregation of coarse aggregates under the pumping shear force.

[0013] S3. Gel dynamic ratio, based on the bulk density of the aggregate after S2 treatment , adjust the mass ratio of cement to fly ash according to the relationship: ; And synchronously calculate the initial dosage of the water reducer , where is the total amount of cementitious materials.

[0014] As described above, based on the real-time feedback of the aggregate bulk density, dynamically adjust the proportion of cementitious materials to avoid the sharp increase in viscosity caused by excessive cementitious materials while ensuring the paste coating thickness.

[0015] S4. Two-parameter feedback control, real-time monitor the slump (tested by GB / T 50080) and the pumping pressure , dynamically correct the water-binder ratio: ; When or , trigger the ratio recombination of S3.

[0016] As described above, the collaborative correction mechanism coupling the slump and pump pressure breaks through the hysteresis of traditional single-parameter regulation and realizes the synchronous optimization of the water-binder ratio and pumping resistance.

[0017] S5. Pulsating pumping control, set the pulsation frequency of the variable-frequency pump: ; Where: is the length of the horizontal pipe; is the vertical height.

[0018] As described above, the periodic shear stress generated by the variable-frequency pulsating flow destroys the flocculated structure in the paste, maintains the dynamic stability of the suspension system, and reduces the risk of pipe blockage.

[0019] S6. Thermodynamic stratification control, based on the concrete viscosity and the pumping flow rate , calculate the pouring layer thickness: ; Where: is the initial setting time; ; is the concrete temperature value, is the ambient temperature value.

[0020] The above-mentioned layer thickness algorithm with temperature difference compensation offsets the difference in setting time caused by the temperature gradient, ensuring that the interlayer bonding surface is poured under the best plastic state.

[0021] S7. Gas-solid coupling curing, which is alternately executed during the curing of each layer of concrete: Steam stage: Control the steam pressure , with a cycle ; Atomization stage: Maintain the humidity , and the droplet size .

[0022] The above-mentioned alternating action of steam and atomization forms a hydration environment driven by humidity gradient, accelerating the oriented growth of ettringite and improving the density of the interfacial transition zone.

[0023] Furthermore, the preparation parameters of the nano-sol in S2 include: The concentration of sodium silicate ; The hydrolysis time ; The dispersant is a polycarboxylic acid series, with a dosage .

[0024] Furthermore, in the pulsating pumping of S5, a damper is set in the vertical pipe section, and its damping coefficient: Where: is the density of the concrete, is the diameter of the pump pipe.

[0025] Furthermore, in the gas-solid coupling curing of S7: In the steam stage, a CO2 / N2 mixed gas is introduced, with a volume ratio ; The gas flow rate (L / min), where is the curing area (m 2 ).

[0026] This solution reduces the wetting demand of the paste through aggregate gradient treatment and nano-interface strengthening, combines the dynamic ratio optimization with two-parameter feedback and the energy dissipation control of pulsating pumping, realizes the coordinated adaptation of the rheological properties of the paste and the pumping stability while maintaining a low cementitious material dosage, and at the same time uses the thermodynamic stratification algorithm and gas-solid coupling curing to regulate the oriented growth of the hydration phase, systematically solving the mutually exclusive contradictions of fluidity, cohesion and segregation resistance in the pumping construction of low-strength concrete, and achieving the unity of material economy and engineering reliability.

[0027] Those skilled in the art can understand that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those of ordinary skill in the field to which the present invention belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the context of the prior art, and will not be interpreted in an idealized or overly formal sense unless specifically defined.

[0028] For method embodiments, for the sake of simplicity of description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the embodiments of the present invention are not limited by the described order of actions, because according to the embodiments of the present invention, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily essential to the embodiments of the present invention.

[0029] From the description of the above embodiments, it can be clearly understood by those skilled in the art that the present application can be implemented by means of software plus a necessary general hardware platform. Based on this understanding, the technical solution of the present application, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server or a network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of the present application.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A construction method for low-strength pumped concrete, characterized in that It includes the following steps: S1. Aggregate gradient treatment: screening the coarse aggregate into two grades of 5-20 mm and 20-40 mm, and calculating the pre-wetting time according to the formula: ； Wherein: is the water absorption rate of the aggregate, is the total mass of the aggregate, is the pump flow rate; S2. Interface nano-strengthening: spraying nano-SiO2 sol on the surface of the aggregate treated in S1, and the spraying amount meets: ； Wherein: is the maximum particle size of coarse aggregate, which is consistent with the aggregate quality in S1; S3. Gelation dynamic ratio, based on the bulk density of the aggregate after S2 treatment , adjust the mass ratio of cement to fly ash according to the relationship: ； and synchronously calculate the initial dosage of water reducer , where is the total amount of cementitious materials; S4. Dual-parameter feedback control to monitor the slump in real time (tested according to GB / T 50080) and the pumping pressure , dynamically correct the water-binder ratio: ； When or occurs, trigger the ratio recombination of S3; S5. Pulsating pumping control: setting the pulsating frequency of the variable-frequency pump: ； Wherein: is the length of the horizontal pipe; is the vertical height (m); S6. Thermodynamic stratification control, based on the concrete viscosity and the pumping flow rate , calculate the pouring layer thickness: ； Wherein: is the initial setting time; ； is the concrete temperature value, is the ambient temperature value; S7. Gas-solid coupling curing: alternately executing during the curing of each layer of concrete: Steam stage: Control steam pressure , cycle ; Atomization stage: Maintain humidity , droplet size .

2. The method according to claim 1, wherein The nano-sol preparation parameters of S2 include: Sodium silicate concentration ; Hydrolysis time ; The dispersant is a polycarboxylic acid series, dosage .

3. The method according to claim 1, wherein For the pulsating pumping in S5, a damper is set in the vertical pipe section, and its damping coefficient: ； Wherein: is the density of concrete, is the diameter of the pump pipe.

4. The method according to claim 1, wherein In the gas-solid coupling curing of S7: A CO2 / N2 mixed gas is introduced in the steam stage, with a volume ratio ; Gas flow rate (L / min), where is the curing area (m 2 ).

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