Phase change temperature control internal curing functional aggregate for high-strength concrete and preparation method thereof

Abstract

The application provides a phase change temperature control internal curing function aggregate for high-strength concrete and a preparation method thereof, and relates to the technical field of building materials. A phase change material paraffin is arranged in an inner layer, and a heat conduction water storage layer composed of carbon fibers, graphite powder, superabsorbent resin, fly ash, phosphorus slag powder, slag powder, quicklime, polyacrylamide, clear lime water and an additive is coated on the outside to form aggregate granulation and molding. The carbon fibers are connected to the dispersed graphite powder to form a heat conduction net structure with line connection points, improve the heat conduction performance, promote the heat conduction between the internal paraffin and the external environment, and the clear lime water activates the fly ash, the phosphorus slag powder and the slag powder in the ingredients to generate a hydration reaction, thereby constructing the strength of the external structure. When the temperature in the concrete is low, heat is released, the whole process is accompanied by slow water release, the double internal curing functions of temperature control and moisture are realized, the cracking of high-strength concrete caused by high hydration heat and large shrinkage is avoided, and the durability of the high-strength concrete is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building materials, in particular to a phase change temperature control internal curing functional aggregate for high-strength concrete and a preparation method thereof. BACKGROUND

[0002] With the development of high-strength concrete technology, high-strength concrete is increasingly widely used in high-rise buildings, bridge engineering, port engineering and prefabricated components. Concrete with a mark of C70 to C150 has been applied in domestic engineering. However, in order to achieve higher strength in design, more cement and lower water-binder ratio have to be used, resulting in the problems of large shrinkage and high hydration heat of high-strength concrete.

[0003] The above patent documents and prior art cannot effectively avoid the cracking problem caused by high temperature and large shrinkage under the surface curing conditions of existing engineering. In addition, phase change temperature control materials and superabsorbent polymers are difficult to be directly added and applied to concrete due to their volume instability. SUMMARY

[0004] Technical problems to be solved

[0005] In view of the deficiencies of the prior art, the present application provides a phase change temperature control internal curing functional aggregate for high-strength concrete and a preparation method thereof, which solves the problems of high hydration heat and large shrinkage of high-strength concrete.

[0006] Technical scheme

[0007] To achieve the above purpose, the present application is implemented by the following technical scheme: a phase change temperature control internal curing functional aggregate for high-strength concrete and a preparation method thereof, the preparation method of the aggregate is as follows:

[0008] Sp1: preparation of raw material liquid and raw material powder, the preparation of raw material liquid and raw material powder is to prepare raw material powder by proportioning carbon fiber, graphite powder, superabsorbent polymer, fly ash, phosphorous slag powder, slag powder and quicklime, prepare raw material liquid by proportioning polyacrylamide, clear lime water and admixture, and prepare granular paraffin for standby;

[0009] Sp2: mixing of aggregate, the mixing of aggregate is to proportion the raw material powder and paraffin in step Sp1 and then put them into a disc balling machine, and adjust the inclination angle;

[0010] Sp3: mixing of raw material liquid, the mixing of raw material liquid is to adjust the water output and angle of the water spraying device of the disc balling machine, and add the prepared raw material liquid in step Sp1 into the water storage tank;

[0011] Sp4: Aggregate granulation and molding, wherein the aggregate granulation and molding is to adjust the rotation speed of the disc pelletizer, start the disc pelletizer, the raw material powder and paraffin rotate in the disc, the raw material liquid is sprayed out through atomization, and the granular paraffin gradually agglomerates the raw material powder and raw material liquid, and rolls into pellets;

[0012] Sp5: Aggregate curing, wherein the aggregate curing is to dry the spherical aggregate from step Sp4 and then move it into a curing room for curing.

[0013] Preferably, in the preparation of the raw material liquid and raw material powder, the mass percentage of each component in the raw material powder is as follows: carbon fiber 0.5%-0.7%, graphite powder 3%-5%, superabsorbent resin 0.5%-0.7%, fly ash 12%-16%, phosphorus slag powder 22%-26%, slag powder 44%-48%, and quicklime 9%-11%.

[0014] Preferably, in the preparation of the raw material liquid and raw material powder, the mass percentage of each component in the raw material liquid is: 2.4%-3% polyacrylamide, 90%-96% clear lime water, and 3.4%-4.2% additives.

[0015] Preferably, the mass ratio of raw material powder and raw material liquid in the mixture of raw material liquid is 13%-17% raw material liquid and 83%-87% raw material powder.

[0016] Preferably, the paraffin particles in the aggregate mixture are particles with a particle size of 8mm-15mm, accounting for 11%-13% of the total mass of all raw materials.

[0017] Preferably, the disc pelletizer used in the aggregate mixing process is equipped with an atomizing device, and the disc tilt angle is 40° during the mixing process.

[0018] Preferably, the stirring speed in the aggregate granulation process is 25 r / min and the stirring time is 30 s.

[0019] Preferably, the curing temperature of the aggregate is 20±1℃, the curing humidity is greater than 90%, and the curing time is 3 days.

[0020] Preferably, the disc pelletizer in the aggregate pelletizing process adopts a control method of first adjusting the rotation speed to mix and pelletize the materials, and then adjusting the rotation speed to agglomerate the pellets.

[0021] Preferably, the aggregate consists of an inner layer of paraffin wax and an outer layer of heat-conducting and water-retaining material, and the heat-conducting and water-retaining layer includes carbon fiber, graphite powder, superabsorbent resin, fly ash, phosphorus slag powder, slag powder, quicklime, polyacrylamide, clarified lime water, and additives.

[0022] Beneficial effects

[0023] This invention provides a phase change temperature-controlled internal curing functional aggregate for high-strength concrete and its preparation method. It has the following beneficial effects:

[0024] This invention employs an inner layer of paraffin wax (a phase change material) and an outer coating of a thermally conductive and water-retaining layer composed of carbon fiber, graphite powder, superabsorbent resin, fly ash, phosphorus slag powder, slag powder, quicklime, polyacrylamide, clarified lime water, and additives for aggregate granulation. When used in concrete, the dispersed graphite powder, connected by carbon fiber, forms a thermally conductive network structure with interconnected points, significantly improving the thermal conductivity of the outer aggregate layer and promoting heat transfer between the internal paraffin wax and the external environment. The clarified lime water alkali-activated the fly ash, phosphorus slag powder, and slag powder in the mix, inducing a hydration reaction and strengthening the external structure, thus preventing... During the firing process, a stable superabsorbent resin is added to the ingredients. In the aggregate state, water exists in the superabsorbent resin layer on the outer layer of the aggregate in a stable bound water form. When applied to high-strength concrete, water is slowly released into the concrete as the pH rises, achieving internal curing. When this functional aggregate is applied to high-strength concrete, it can absorb heat when the internal temperature of the concrete is high and release heat when the internal temperature of the concrete is low. The whole process is accompanied by the slow release of water, achieving a dual internal curing function of temperature control and humidification. This avoids the risk of cracking caused by high heat of hydration and large shrinkage in high-strength concrete, and improves the durability of high-strength concrete. Attached Figure Description

[0025] Figure 1 This is a diagram of the aggregate preparation method of the present invention;

[0026] Figure 2 This is a schematic diagram of the aggregate structure of the present invention;

[0027] Figure 3 This is a diagram showing the mixing state of aggregates and high-strength concrete according to the present invention.

[0028] Figure 4 This is a graph showing the change in self-shrinkage rate when using aggregate and when not using aggregate in this invention;

[0029] Figure 5 This is a graph showing the adiabatic temperature rise changes when using aggregate and when not using aggregate in this invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Specific Implementation Example 1:

[0032] likeFigures 1-5 As shown, a phase change temperature-controlled internal curing functional aggregate for high-strength concrete and its preparation method are disclosed. The preparation method of the aggregate is as follows:

[0033] Sp1: Preparation of raw material liquid and raw material powder. The preparation of raw material liquid and raw material powder involves mixing carbon fiber, graphite powder, superabsorbent resin, fly ash, phosphorus slag powder, slag powder and quicklime in proportion to form raw material powder, mixing polyacrylamide, clear lime water and additives to form raw material liquid, and preparing granular paraffin for later use.

[0034] Sp2: Aggregate mixing. Aggregate mixing involves mixing the raw material powder and paraffin wax from step Sp1, then feeding them into the disc pelletizer and adjusting the tilt angle.

[0035] Sp3: Mixing of raw material liquid. The mixing of raw material liquid involves adjusting the water output and angle of the spray device of the disc pelletizer and adding the raw material liquid prepared in step Sp1 to the water storage tank.

[0036] Sp4: Aggregate granulation and molding. Aggregate granulation and molding involves adjusting the speed of the disc pelletizer, starting the disc pelletizer, rotating the raw material powder and paraffin wax in the disc, and spraying the raw material liquid through atomization. The granular paraffin wax gradually condenses the raw material powder and raw material liquid, and rolls into pellets.

[0037] Sp5: Aggregate curing. Aggregate curing involves drying the spherical aggregates from step Sp4 and then transferring them to a curing room for curing.

[0038] In the preparation of raw material liquid and raw material powder, the mass percentage of each component in the raw material powder is as follows: carbon fiber 0.5%-0.7%, graphite powder 3%-5%, superabsorbent resin 0.5%-0.7%, fly ash 12%-16%, phosphorus slag powder 22%-26%, slag powder 44%-48%, and quicklime 9%-11%. In the preparation of raw material liquid and raw material powder, the mass percentage of each component in the raw material liquid is as follows: polyacrylamide 2.4%-3%, clarified lime water 90%-96%, and admixtures 3.4%-4.2%. In the mixing of raw material liquid, the mass percentage of raw material powder and raw material liquid is 13%-17% for raw material liquid and 83%-87% for raw material powder. In the mixing of aggregates, the paraffin particles are particles with a particle size of 8mm-15mm, accounting for 11%-13% of the total mass of raw materials.

[0039] In the aggregate mixing process, the disc pelletizer is equipped with an atomizing device, and the disc tilt angle is 40° during mixing. The mixing speed during aggregate granulation is 25 r / min, and the mixing time is 30 s. During aggregate curing, the aggregate is placed in a tray and placed in a drying room for 1 day, then cured in an anti-corrosion curing room at a temperature of 20±1℃ and a humidity greater than 90% for 3 days. The disc pelletizer in the aggregate granulation process uses a control method of first adjusting the rotation speed for mixing and pelletizing, and then adjusting the rotation speed to condense the pellets. The disc pelletizer condenses granulated paraffin wax into specially prepared raw material powder and atomized raw material liquid, gradually rolling them into pellets. After drying and curing, a phase change temperature-controlled internally cured aggregate with a certain particle size range is obtained. Through special raw material formulation design and production process design, a comprehensive functional aggregate is formed, with an internal phase change temperature-controlled material and an external structure possessing thermal conductivity, water retention, and high strength. Specific Implementation Example 2:

[0041] like Figures 1-5 As shown, the aggregate consists of an internal paraffin layer and an external thermally conductive and water-retaining layer. The thermally conductive and water-retaining layer includes carbon fiber, graphite powder, superabsorbent resin, fly ash, phosphorus slag powder, slag powder, quicklime, polyacrylamide, clarified lime water, and admixtures. When used in concrete, the dispersed graphite powder, connected by carbon fiber, forms a thermally conductive network structure with interconnected points, significantly improving the thermal conductivity of the outer layer of the aggregate and promoting heat transfer between the internal paraffin and the external environment. The clarified lime water alkali-activated the fly ash, phosphorus slag powder, and slag powder in the mix, causing a hydration reaction that strengthens the external structure and prevents over-firing. The process involves adding a stable superabsorbent polymer (SAP) to the aggregate mix. Water exists as stable bound water within the SAP layer in the aggregate's outer layer. When applied to high-strength concrete, this SAP slowly releases water into the concrete as the pH rises, achieving internal curing. This functional aggregate absorbs heat when the concrete's internal temperature is high and releases heat when the internal temperature is low, all while water is slowly released. This achieves dual internal curing functions of temperature control and humidification, preventing cracking risks caused by high heat of hydration and large shrinkage in high-strength concrete, and improving its durability. Specific Implementation Example 3:

[0043] like Figures 1-5 As shown, in the entire aggregate preparation process, carbon fiber, graphite powder, superabsorbent resin, fly ash, phosphorus slag powder, slag powder, and quicklime will be prepared into raw material powder according to the proportion, and polyacrylamide, clear lime water, and additives will be prepared into raw material liquid. The preparation amount is 500 kg, and the formula is shown in Table 1 below.

[0044]

[0045] Table 1

[0046] The apparent density and barrel compressive strength of the aggregate after molding are shown in Table 2.

[0047] Apparent density / kg / m 3 ]] Barrel pressure intensity / Mpa 2060 24

[0048] Table 2

[0049] The functional aggregate was used to replace crushed stone in C90 high-strength concrete at volumes of 10%, 20%, and 30%, and the design formula is shown in Table 3.

[0050]

[0051]

[0052] Table 3

[0053] The working performance, 28-day compressive strength, shrinkage rate (non-contact method), and adiabatic temperature rise of each test group were tested.

[0054] High-strength concrete with added functional aggregates is in the following state: Figure 3 As shown in Table 4, the working performance and 28-day compressive strength are as follows.

[0055]

[0056] Table 4

[0057] As shown in Table 4, the addition of functional aggregates has virtually no effect on the workability of concrete, and when the aggregate content is within the range of 25%, it has no effect on the concrete strength.

[0058] The comparison chart of shrinkage rate changes over time is shown below. Figure 4 As shown in the figure, the shrinkage rate of concrete decreased at all time periods with the addition of functional aggregates, especially after 3 days. The shrinkage rate decreased more significantly with the increase of functional aggregate content, proving that the addition of functional aggregates effectively reduced the shrinkage of high-strength concrete.

[0059] Temperature changes over time in ordinary high-strength concrete and high-strength concrete with 20% functional aggregate are as follows: Figure 5 As shown, by Figure 5 It can be seen that the incorporation of functional aggregates effectively reduces the peak temperature of high-strength concrete, makes the temperature change more gradual, reduces the temperature difference between high-strength concrete and the environment, and reduces temperature stress.

[0060] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a reference structure" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0061] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a phase change temperature-controlled internal curing functional aggregate for high-strength concrete, characterized in that: The method for preparing the aggregate is as follows: Sp1: Preparation of raw material liquid and raw material powder, wherein the raw material liquid and raw material powder are prepared by mixing carbon fiber, graphite powder, super absorbent resin, fly ash, phosphorus slag powder, slag powder and quicklime in proportion to form raw material powder, mixing polyacrylamide, clear lime water and water reducing agent to form raw material liquid, and preparing granular paraffin for later use. Sp2: Aggregate mixing, wherein the aggregate mixing is to mix the raw material powder and paraffin wax in step Sp1 and then put them into the disc pelletizing machine and adjust the tilt angle; Sp3: Mixing of raw material liquid, wherein the mixing of raw material liquid is to adjust the water output and angle of the water spray device of the disc pelletizer and add the raw material liquid prepared in step Sp1 to the water storage tank. Sp4: Aggregate granulation and molding, wherein the aggregate granulation and molding is to adjust the rotation speed of the disc pelletizer, start the disc pelletizer, the raw material powder and paraffin rotate in the disc, the raw material liquid is sprayed out through atomization, and the granular paraffin gradually agglomerates the raw material powder and raw material liquid, and rolls into pellets; Sp5: Aggregate curing, wherein the aggregate curing involves drying the spherical aggregates from step Sp4 and then transferring them to a curing room for curing; The aggregate consists of an inner layer of paraffin wax and an outer layer of heat-conducting and water-retaining material. The heat-conducting and water-retaining layer is composed of carbon fiber, graphite powder, superabsorbent resin, fly ash, phosphorus slag powder, slag powder, quicklime, polyacrylamide, clarified lime water, and water-reducing agent.

2. The method for preparing a phase change temperature-controlled internal curing functional aggregate for high-strength concrete according to claim 1, characterized in that: In the preparation of the raw material liquid and raw material powder, the mass percentage of each component in the raw material powder is as follows: carbon fiber 0.5%-0.7%, graphite powder 3%-5%, superabsorbent resin 0.5%-0.7%, fly ash 12%-16%, phosphorus slag powder 22%-26%, slag powder 44%-48%, and quicklime 9%-11%.

3. The method for preparing a phase change temperature-controlled internal curing functional aggregate for high-strength concrete according to claim 1, characterized in that: In the preparation of the raw material liquid and raw material powder, the mass of each component in the raw material liquid is: 2.5 kg of polyacrylamide, 85 kg of clear lime water, and 3.5 kg of water-reducing agent.

4. The method for preparing a phase change temperature-controlled internal curing functional aggregate for high-strength concrete according to claim 1, characterized in that: The paraffin particles in the aggregate mixture are particles with a diameter of 8mm-15mm, accounting for 11%-13% of the total mass of all raw materials.

5. The method for preparing a phase change temperature-controlled internal curing functional aggregate for high-strength concrete according to claim 1, characterized in that: The aggregate mixing process involves a disc pelletizing machine equipped with an atomizing device, and the disc tilts at a 40° angle during the mixing process.

6. The method for preparing a phase change temperature-controlled internal curing functional aggregate for high-strength concrete according to claim 1, characterized in that: The stirring speed during aggregate granulation is 25 r / min, and the stirring time is 30 s.

7. The method for preparing a phase change temperature-controlled internal curing functional aggregate for high-strength concrete according to claim 1, characterized in that: The curing temperature for the aggregate is 20±1℃, the curing humidity is greater than 90%, and the curing time is 3 days.

8. The method for preparing a phase change temperature-controlled internal curing functional aggregate for high-strength concrete according to claim 1, characterized in that: The disc pelletizer used in the aggregate granulation process employs a control method that first adjusts the rotation speed to mix and pelletize the materials, and then adjusts the rotation speed to agglomerate the pellets.

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