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

Abstract

The application discloses a phase change temperature control internal curing function aggregate for high-strength concrete and a preparation method thereof, and belongs to the technical field of building materials. The steps are as follows: carbon fibers, graphite powder, superabsorbent resin, fly ash, phosphorous slag powder, slag powder and quicklime are proportioned to prepare raw material powder, polyacrylamide, saturated clear limewater and admixture are proportioned to prepare raw material liquid; the inclination angle is adjusted, the prepared raw material powder and granular paraffin are put into a disc balling machine; the water discharge and angle of a water spraying device are adjusted, the prepared raw material liquid is added into a water storage tank; the number of revolutions is adjusted, the disc balling machine is started, the raw material powder and particles rotate in the disc, the raw material liquid is sprayed through atomization, the granular paraffin gradually agglomerates the raw material powder and the raw material liquid, and the balling is rolled; the prepared spherical objects are dried and then moved into a curing chamber for curing. The application is applied to high-strength concrete and effectively solves the problem of cracks caused by shrinkage and high temperature.

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, and concrete with a mark of C70 to C150 has been applied in domestic engineering. However, in order to achieve higher strength, high-strength concrete has to use more cement and lower water-binder ratio, resulting in the problems of large shrinkage and high hydration heat of high-strength concrete. Under the existing surface curing conditions of engineering, the cracking problem caused by high temperature and large shrinkage cannot be effectively avoided. At the same time, phase change temperature control materials and superabsorbent polymers are difficult to be directly added and applied to concrete due to their volume instability. In view of the above problems, the present application provides a functional aggregate which can replace part of the aggregate and be applied to high-strength concrete, gradually release bound water during the hydration process of concrete, and gradually absorb heat when the temperature of concrete rises, and gradually release heat at low temperature, so as to realize the dual internal curing effect of wetting and temperature control.

[0003] For example, the prior art, application number: CN201210416369.1, publication number: CN102923983B, discloses a fibrous concrete aggregate of attapulgite andesite, and the technical scheme is as follows:

[0004] "Provided is a fibrous concrete aggregate of attapulgite andesite.

[0005] The fibrous concrete aggregate of attapulgite andesite is composed of attapulgite clay tailings, andesite mixture, opal, montmorillonite tailings and rock wool.

[0006] The production method of the fibrous concrete aggregate of attapulgite andesite is as follows: the ingredients of the fibrous concrete aggregate of attapulgite andesite are added to a mixer for stirring, and after uniform stirring, the fibrous concrete aggregate of attapulgite andesite is packaged as a finished product.

[0007] During the mining process of attapulgite clay, a certain amount of gravel and soil is mixed, which is abandoned as a kind of tailings, resulting in a large amount of resource waste. The present application selects attapulgite clay tailings with a particle size of ≤2.0 mm.

[0008] The volcanic fragmentary rock is a transitional type of rock between lava and sedimentary rock, wherein more than 50% of the components are composed of materials ejected by volcanic fragment flow, and the volcanic fragments are mainly early solidified lava on the volcano, and rocks around the channel are cracked during volcanic eruption. The volcanic fragmentary rock mixture includes rock fragments, crystal fragments, glass fragments, slurry fragments, volcanic blocks, volcanic gravels and volcanic ashes, and the volcanic fragmentary rock can increase the strength of the attapulgite volcanic fragmentary rock fiber concrete aggregate.

[0009] The opal and the attapulgite clay are symbiotic, and the opal is a kind of hard rock which is difficult to remove in the mining process of the attapulgite clay, and is accumulated in large quantities in the attapulgite clay mining area as a kind of waste, and the particle size of the opal is less than or equal to 2.0 mm.

[0010] The montmorillonite tailings selected by the application are mostly distributed in the lower layer of the attapulgite clay mine, and are difficult to be independently mined, but the montmorillonite tailings are hard in texture and are suitable for producing aggregate, and the particle size of the montmorillonite tailings is less than or equal to 2.0 mm.

[0011] The rock wool is an inorganic fiber made of natural rocks such as basalt, gabbro, dolomite, iron ore and bauxite as main raw materials through high-temperature melting and fiberization.

[0012] In combination with the above prior art, the following problems are obtained:

[0013] Through testing, the mechanical property is general, and effective temperature control cannot be realized. SUMMARY

[0014] In view of the problems of high hydration heat and large shrinkage of the existing high-strength concrete, a phase change temperature control internal curing functional aggregate for high-strength concrete is particularly invented, which gradually releases combined water in the hydration process of the concrete, and gradually absorbs heat when the temperature of the concrete rises, and gradually releases heat at low temperature, realizing double internal curing of wetting and temperature control, and effectively solving the problem of cracks caused by shrinkage and high temperature of the high-strength concrete.

[0015] The technical scheme of the application is:

[0016] A phase change temperature control internal curing functional aggregate for high-strength concrete, wherein the raw materials include raw material powder and raw material liquid, and the mass ratio between the raw material powder and the raw material liquid is (13-17):(83-87).

[0017] The raw material powder includes the following components in parts by weight:

[0018] Carbon fiber 0.5-0.7 parts, graphite powder 3-5 parts,

[0019] 0.5-0.7 parts of super absorbent resin, 12-16 parts of fly ash,

[0020] 22-26 parts of phosphorous slag powder, 44-48 parts of slag powder, 9-11 parts of quicklime;

[0021] The raw material liquid comprises the following components by weight:

[0022] 2.4-3 parts of polyacrylamide,

[0023] 90-96 parts of saturated clear lime water, 3.4-4.2 parts of admixture.

[0024] The phase change temperature control internal curing functional aggregate for high-strength concrete,

[0025] The raw material of the phase change temperature control internal curing functional aggregate for high-strength concrete further comprises granular paraffin wax;

[0026] The granular paraffin wax accounts for 11-13% of the total raw material.

[0027] The phase change temperature control internal curing functional aggregate for high-strength concrete, wherein the particle size of the granular paraffin wax is 8-15 mm.

[0028] The phase change temperature control internal curing functional aggregate for high-strength concrete,

[0029] The super absorbent resin comprises grafted acrylamide, high-substitution degree cross-linked carboxymethyl cellulose, cross-linked carboxymethyl cellulose grafted acrylamide, and cross-linked hydroxyethyl cellulose grafted acrylamide polymer.

[0030] The phase change temperature control internal curing functional aggregate for high-strength concrete,

[0031] The phosphorous slag powder is mainly granulated electric furnace phosphorous slag, and a small amount of gypsum is co-milled to form a powder of a certain fineness; the main components include SiO2, P2O5, Al2O3, CaO, and MgO, wherein the ratio of the sum of the mass fractions of Al2O3, CaO, and MgO to the sum of the mass fractions of SiO2 and P2O5 is greater than 1.0, the mass fraction of P2O5 is less than or equal to 3.2%, and the 28d activity index is greater than 70%.

[0032] The phase change temperature control internal curing functional aggregate for high-strength concrete,

[0033] The slag powder is prepared by using granulated blast furnace slag as main raw material and adding a small amount of gypsum to grind into a powder of a certain fineness; the main components include Al2O3, CaO, MgO, SiO2, TiO2 and MnO, wherein the ratio of the sum of the mass fractions of Al2O3, CaO and MgO to the sum of the mass fractions of SiO2, TiO2 and MnO is greater than 1.1%, the content of MnO is less than 2.5%, and the 28d activity index should be greater than 75%.

[0034] The 28d activity index should be greater than 75%.

[0035] The high-strength concrete phase-change temperature control internal curing functional aggregate,

[0036] The additive component comprises 20 parts of polycarboxylic acid water reducer, 0.05 parts of sodium alkyl sulfonate, 0.05 parts of polyether defoaming agent, 8 parts of calcium chloride and 71.9 parts of water.

[0037] A preparation method of a high-strength concrete phase-change temperature control internal curing functional aggregate, comprising the following steps:

[0038] (1) proportionally prepare carbon fiber, graphite powder, superabsorbent resin, fly ash, phosphorous slag powder, slag powder and quicklime into raw material powder, and prepare polyacrylamide, saturated clear limewater and additive into raw material liquid;

[0039] (2) use a PQ22W type disc balling machine, which comprises a disc body, a vertical scraper, a water spraying device, a support, an adjustable rack, a transmission device and a water storage tank, and the water spraying device can spray water under pressure and atomization; adjust the inclination angle of the disc, and put the prepared raw material powder and granular paraffin into the disc balling machine;

[0040] (3) adjust the water output and angle of the water spraying device, and add the prepared raw material liquid into the water storage tank;

[0041] (4) adjust the rotation speed, start the disc balling machine, and the raw material powder and particles rotate in the disc, the raw material liquid is sprayed out through atomization, and the granular paraffin gradually agglomerates the raw material powder and the raw material liquid to roll into balls;

[0042] (5) after the prepared spherical objects are dried, they are moved into a curing chamber for curing.

[0043] The preparation method of the high-strength concrete phase-change temperature control internal curing functional aggregate, wherein the inclination angle of the disc during the stirring process in step (4) is 40°, and the stirring speed is 25r / min.

[0044] In step (4), the stirring is stopped after the balls are basically formed and stirred for 30s.

[0045] The preparation method of the phase change temperature control internal curing functional aggregate for high-strength concrete has the curing temperature of the curing chamber of 20 DEG C+ / -1 DEG C and the curing humidity of greater than 90%.

[0046] It should be noted that special paraffin particle condensation raw material powder and raw material liquid are designed to form a special structure with paraffin inside and heat conduction water storage layer outside. The heat conduction water storage layer outside has the following characteristics: first, the special heat conduction net structure is formed by connecting the dispersed graphite powder through carbon fibers; second, the saturated clear lime water has an alkali-activating effect on the fly ash, phosphorus slag powder and slag powder, which can make them hydrate and provide strength support; third, the high water absorption resin in the outer layer can store stable combined water, which is slowly released to the high-strength concrete to play the internal curing effect and reduce shrinkage; and fourth, the melting point of paraffin inside the aggregate is 45-50 DEG C, and when the aggregate is applied to high-strength concrete, the internal temperature of the aggregate rises to the range, the aggregate starts to absorb heat and store heat, so that the high-strength concrete passes through the high temperature peak, the internal temperature development of the concrete becomes gentle, the internal and external temperature difference is effectively reduced, and the temperature stress is reduced.

[0047] It should be noted that when applied to high-strength concrete, 10%-25% of the amount of ordinary coarse aggregate in the original design formula can be replaced by the same volume, and the working performance and mechanical properties are not affected, and the durability is improved.

[0048] The beneficial effects of the present application are as follows:

[0049] A phase change temperature control internal curing functional aggregate for high-strength concrete and a preparation method thereof are provided. The aggregate is obtained by condensing paraffin particles into powder through a disc-type balling machine, and the production process and the design of the ingredients form a functional aggregate with paraffin inside and a heat conduction water storage layer outside. The ingredients of the outer layer are composed of carbon fibers, graphite powder, high water absorption resin, fly ash, phosphorus slag powder, slag powder, quicklime, polyacrylamide, saturated clear lime water and admixture. The aggregate has the following characteristics: first, the heat conduction net structure with linear connection points is formed by connecting the dispersed graphite powder through carbon fibers, which greatly improves the heat conduction performance of the outer layer of the aggregate and promotes the heat conduction between the internal paraffin and the external environment; second, the alkali-activating effect of the saturated clear lime water on the fly ash, phosphorus slag powder and slag powder in the ingredients causes a hydration reaction, which builds the strength of the external structure and avoids the baking process; third, the stable high water absorption resin is added to the ingredients, and the water exists in the outer layer of the aggregate in the form of stable combined water, which is slowly released to the concrete to achieve internal curing under the condition of ph increase when the functional aggregate is applied to high-strength concrete. When the 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 slow water release, which realizes the dual internal curing functions of temperature control and moisture, avoids the cracking risk of high-strength concrete caused by high hydration heat and large shrinkage, and improves the durability of high-strength concrete.

[0050] Further, for the first time, a functional aggregate structure with a phase change temperature control material inside and a heat conducting water storage layer outside is designed in a phase change temperature control internal curing functional aggregate for high-strength concrete and its preparation method. Its application in high-strength concrete can realize dual curing of moisture release and temperature control, effectively avoiding the problems of high internal temperature and large shrinkage deformation of high-strength concrete.

[0051] Further, for the first time, a heat conducting net structure of carbon fiber connecting graphite powder line connection points is designed in the aggregate external structure in a phase change temperature control internal curing functional aggregate for high-strength concrete and its preparation method. When applied to high-strength concrete, it greatly improves the heat transfer between the internal phase change material and the external concrete, and greatly improves the heat exchange efficiency between the internal phase change material of the aggregate and the high-strength concrete.

[0052] Further, for the first time, a heat conducting net structure of carbon fiber connecting graphite powder line connection points is designed in the aggregate external structure in a phase change temperature control internal curing functional aggregate for high-strength concrete and its preparation method. When applied to high-strength concrete, it greatly improves the heat transfer between the internal phase change material and the external concrete, and greatly improves the heat exchange efficiency between the internal phase change material of the aggregate and the high-strength concrete. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 The figure is a schematic diagram of the phase change temperature control internal curing functional aggregate for high-strength concrete of the present application.

[0054] Figure 2 The figure is a finished product diagram of the phase change temperature control internal curing functional aggregate for high-strength concrete in the present application.

[0055] Figure 3 The figure is a mixing state diagram of high-strength concrete mixed with functional aggregate in the present application.

[0056] Figure 4 The figure is a self-shrinkage change diagram of high-strength concrete using the phase change temperature control internal curing functional aggregate for high-strength concrete and not using the aggregate in the present application.

[0057] Figure 5 The figure is an adiabatic temperature rise change diagram of high-strength concrete using the phase change temperature control internal curing functional aggregate for high-strength concrete and not using the aggregate in the present application. DETAILED DESCRIPTION

[0058] The technical solutions of the present application will be further described below through examples, which are an explanation of the present application rather than a limitation.

[0059] The present application relates to a kind of high-strength concrete phase change temperature control internal curing function aggregate and its preparation method, the aggregate preparation method: by disc-type balling machine, the granular paraffin condensation preparation ready-made raw powder and atomized raw material liquid, gradually rolling into ball, after drying, curing obtain certain particle size range spherical phase change temperature control internal curing function aggregate.The raw powder includes: carbon fiber, graphite powder, superabsorbent resin, fly ash, phosphorus slag powder, slag powder, quicklime.The raw material liquid includes: polyacrylamide, saturated clear limewater, admixture.Formed by formula design and preparation process design the special structure aggregate structure with paraffin inside and heat-conducting water storage layer outside.In the scheme, carbon fiber is provided to connect the heat-conducting net structure of graphite powder, the stress matrix structure of saturated clear limewater alkali-activated fly ash, phosphorus slag powder and slag powder, and the double internal curing function aggregate with internal temperature control and external water storage is provided.

[0060] Embodiment

[0061] The present application relates to a kind of high-strength concrete phase change temperature control internal curing function aggregate and its preparation method.The method is: by disc-type balling machine, the granular paraffin condensation preparation ready-made special raw powder and atomized raw material liquid, gradually rolling into ball, after drying, curing obtain certain particle size range phase change temperature control internal curing function aggregate.Formed by special raw material formula design and production process design the comprehensive function aggregate with phase change temperature control material inside and the structure of heat-conducting, water storage, high strength outside.

[0062] Aggregate preparation:

[0063] The high-strength concrete phase change temperature control internal curing function aggregate and its preparation method are as follows:

[0064] The carbon fiber, graphite powder, crosslinked carboxymethyl cellulose grafted acrylamide, fly ash, phosphorus slag powder, slag powder and quicklime are prepared into raw powder in proportion, and the polyacrylamide, saturated clear limewater and admixture are prepared into raw material liquid.The preparation amount is 500kg, and the formula is shown in Table 1.

[0065] Table 1

[0066]

[0067] The PQ22W type disc-type balling machine of Henan Zhengkuang Machinery Co., Ltd. is used, the inclination angle is adjusted, and the prepared raw powder and granular paraffin are put into the disc-type balling machine.

[0068] The particle size of the paraffin is 10mm, and the paraffin and the raw powder are put into the disc-type balling machine together, and the disc inclination angle is adjusted to 40.

[0069] The water output and angle of the water spraying device are adjusted, and the prepared raw material liquid is added to the water storage tank.

[0070] Add the prepared raw material solution to the water storage tank, and adjust the water flow rate and angle according to the rotation state of the raw material powder to ensure that the atomized raw material solution contacts the raw material powder as much as possible.

[0071] Adjust the rotation speed and start the disc pelletizer. The raw material powder and granules rotate in the disc, and the raw material liquid is sprayed out through atomization. The granular paraffin gradually condenses the raw material powder and raw material liquid and rolls into pellets.

[0072] Adjust the rotation speed to 25 r / min, start the disc pelletizer, and the particles gradually agglomerate and roll into pellets.

[0073] A high-strength concrete aggregate with phase change temperature-controlled internal curing function was dried and then moved into a curing room for curing.

[0074] The aggregate was placed in a tray and left in a drying room for one day, then moved to a curing room for three days at a temperature of 20°C and a humidity of 95%. The finished aggregate product is as follows: Figure 2 As shown.

[0075] The apparent density and barrel compressive strength of the aggregate were tested, as shown in Table 2.

[0076] Table 2

[0077] Apparent density / kg / m3 Barrel strength / MPa 2060 24

[0078] Application of this aggregate in high-strength concrete:

[0079] 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.

[0080] Table 3

[0081] Test number Water kg / m3 Cement kg / m3 GGBS kg / m3 Silica fume kg / m3 Machine-made sand kg / m3 Macadam 5-16 mm Functional aggregate Admixture kg / m3 1 136 483 103 58 591 1051 0 16 2 136 483 103 58 591 946 80 16 3 136 483 103 58 591 841 160 16 4 136 483 103 58 591 736 240 16

[0082] The working performance, 28-day compressive strength, shrinkage rate (non-contact method), and adiabatic temperature rise of each test group were tested.

[0083] 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.

[0084] Table 4

[0085] Test number Slump / mm Spread / mm 28-day compressive strength / MPa 1 250 710 106 2 255 705 107.5 3 250 715 105 4 250 715 98

[0086] As shown in the table, 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.

[0087] The comparison chart of shrinkage rate changes over time is shown below. Figure 4As shown in the figure, the shrinkage rate of concrete decreased at all time points with the addition of functional aggregates, especially after 3 days, and the decrease in shrinkage rate was more significant with the increase of functional aggregate dosage. This proves that the addition of functional aggregates effectively reduces the shrinkage of high-strength concrete.

[0088] Temperature changes over time in ordinary high-strength concrete and high-strength concrete with 10% and 20% functional aggregates 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.

[0089] The above description, in conjunction with specific embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered to fall within the scope of protection defined by the claims submitted herein.

Claims

1. A phase change temperature-controlled internal curing aggregate for high-strength concrete, characterized in that: The raw materials of the high-strength concrete phase change temperature-controlled internal curing functional aggregate include raw material powder, raw material liquid and granular paraffin, and the mass ratio between the raw material powder and the raw material liquid is (13-17):(83-87). The raw material powder, by weight, comprises the following components: Carbon fiber 0.5-0.7 parts, 3-5 parts graphite powder 0.5-0.7 parts of superabsorbent polymer, 12-16 parts fly ash 22-26 parts of phosphorus slag powder, wherein the phosphorus slag powder is mainly composed of granulated electric furnace phosphorus slag, which is ground together with a small amount of gypsum to form a powder of a certain fineness; The slag powder consists of 44-48 parts, wherein the slag powder is made from granulated blast furnace slag as the main raw material, with a small amount of gypsum added and ground into a powder of a certain fineness; 9-11 parts quicklime; The raw material liquid, by weight, comprises the following components: 2.4-3 parts polyacrylamide, 90-96 parts saturated clear limewater The additive is 3.4 to 4.2 parts, and the additive does not contain polyacrylamide.

2. The phase change temperature-controlled internal curing functional aggregate for high-strength concrete according to claim 1, characterized in that: The particle size of the granular paraffin is 8mm-15mm.

3. The phase change temperature-controlled internal curing functional aggregate for high-strength concrete according to claim 1, characterized in that: The superabsorbent polymers include grafted acrylamide, highly substituted cross-linked carboxymethyl cellulose, cross-linked carboxymethyl cellulose grafted acrylamide, and cross-linked hydroxyethyl cellulose grafted acrylamide polymers.

4. The phase change temperature-controlled internal curing functional aggregate for high-strength concrete according to claim 1, characterized in that: The main components of the phosphorus slag powder include SiO2, P2O5, Al2O3, CaO, and MgO. The ratio of the sum of the mass fractions of Al2O3, CaO, and MgO to the sum of the mass fractions of SiO2 and P2O5 is greater than 1.0, and the mass fraction of P2O5 is less than or equal to 3.2%. The 28-day activity index should be greater than 70%.

5. The phase change temperature-controlled internal curing functional aggregate for high-strength concrete according to claim 1, characterized in that: The main components of the slag powder include Al2O3, CaO, MgO, SiO2, TiO2, and MnO. The ratio of the sum of the mass fractions of Al2O3, CaO, and MgO to the sum of the mass fractions of SiO2, TiO2, and MnO is greater than 1.1%, and the MnO content is less than 2.5%. The 28-day activity index is greater than 75%.

6. The phase change temperature-controlled internal curing functional aggregate for high-strength concrete according to claim 1, characterized in that: The additive components, by weight, include 20 parts polycarboxylate superplasticizer, 0.05 parts sodium alkyl sulfonate, 0.05 parts polyether defoamer, 8 parts calcium chloride, and 71.9 parts water.

7. The method for preparing phase change temperature-controlled internal curing functional aggregate for high-strength concrete according to any one of claims 1-6, characterized in that: The steps are as follows: (1) Prepare raw material powder by mixing carbon fiber, graphite powder, superabsorbent resin, fly ash, phosphorus slag powder, slag powder and quicklime in proportion, and prepare raw material liquid by mixing polyacrylamide, saturated clear lime water and additives. (2) The PQ22W model disc pelletizer from Henan Zhengkuang Machinery Co., Ltd. is used. The device includes a disc body, vertical scraper, water spraying device, support, adjustable frame, transmission device, and water storage tank. The water spraying device can pressurize and atomize water and spray it out. Adjust the tilt angle of the disc and put the prepared raw material powder and granular paraffin into the disc pelletizer. (3) Adjust the water output and angle of the atomizing spray device, and add the prepared raw material liquid into the water storage tank; (4) Adjust the speed and start the disc pelletizing machine. The raw material powder and granular paraffin rotate in the disc, and the raw material liquid is atomized and sprayed out through the water spraying device. The granular paraffin gradually condenses the raw material powder and raw material liquid and rolls into pellets. (5) After drying the prepared spheres, move them into the curing room for curing.

8. The method for preparing phase change temperature-controlled internal curing functional aggregate for high-strength concrete according to claim 7, characterized in that: In step (4), the disc tilt angle is 40° and the stirring speed is 25 r / min. In step (4), after the balls have basically formed, stir for 30 seconds and then stop stirring.

9. The method for preparing phase change temperature-controlled internal curing functional aggregate for high-strength concrete according to claim 8, characterized in that: In step (5), the curing temperature in the curing room is 20℃±1℃ and the curing humidity is greater than 90%.

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