Ultra-high performance concrete and preparation method thereof
By leveraging the synergistic effects of functional composite admixtures, composite fibers, and water-retaining phase change resins, the problems of early cracking and temperature difference cracking in ultra-high performance concrete in large-volume structures have been solved. This has resulted in the preparation of ultra-high performance concrete with low heat of hydration and low shrinkage, which is suitable for the field of large-volume concrete and improves the mechanical properties and durability of concrete.
Patent Information
- Application Number
- CN202510789717.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-13
- Publication Date
- 2025-11-04
AI Technical Summary
Ultra-high performance concrete in large-volume structures has the problem of high risk of early cracking and easy generation of temperature difference cracks, mainly due to high heat of hydration and large shrinkage.
By employing the synergistic effect of functional composite admixtures, composite fibers, and water-retaining phase change resins, and through reasonable material proportions and preparation processes, ultra-high performance concrete with low heat of hydration and low shrinkage is prepared. Functional composite admixtures reduce early heat of hydration, composite fibers enhance bonding ability, and water-retaining phase change resins release water to fill defects in the later stages of hydration.
It achieves ultra-high performance concrete with low heat of hydration and low shrinkage, reduces temperature difference cracks, is suitable for the field of large-volume concrete, and improves the mechanical properties and durability of concrete.
Smart Images
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of building materials, and particularly relates to an ultra-high performance concrete and a preparation method thereof. BACKGROUND
[0002] Ultra-high performance concrete, in English, is Ultra-High Performance Concrete, for short, UHPC, which is a new type of cement-based structural engineering material with clear performance indicators, new constitutive relations and structural life. Based on particle size design and particle distribution design, UHPC has higher compactness and fewer micro-defects compared with ordinary concrete. The "ultra-high performance" can be summarized as the following four points: ultra-high mechanical performance, ultra-high structural performance, ultra-high durability performance and ultra-high work performance.
[0003] However, due to the characteristics of large dosage of UHPC cementitious materials and high hydration heat, there are great limitations in large volume structures. On the one hand, UHPC is accompanied by large shrinkage during hardening and service after hardening, and the risk of early cracking is high; on the other hand, the temperature rises too fast in a short time, and the internal and external temperature difference is too large, which is easy to cause temperature difference cracks or temperature shrinkage effect of UHPC.
[0004] In view of this, the application is proposed. SUMMARY
[0005] The purpose of the application is to provide a brand new ultra-high performance concrete and a preparation method. Through the synergistic effect of three materials of functional composite admixture, composite fiber and water storage phase change resin, the shortcomings brought by the addition of a single material are made up. In the reasonable material ratio and preparation process, the ultra-high performance concrete with low hydration heat, low shrinkage and internal curing is prepared, and then it is suitable for the field of mass concrete.
[0006] Specifically, the application provides the following technical scheme:
[0007] An ultra-high performance concrete, the preparation raw materials of which comprise cement, fly ash, silica fume, functional composite admixture, composite fiber, water storage phase change resin, graded quartz sand, water reducing agent and water;
[0008] The functional composite admixture comprises phosphorous slag powder and magnesium slag powder.
[0009] The composite fiber comprises high-strength polypropylene fiber and steel fiber.
[0010] The preparation method of the water storage phase change resin comprises the following steps:
[0011] S1, a cross-linked hydroxyethyl cellulose grafted acrylamide polymer resin is immersed in water to obtain a water storage resin;
[0012] S2, heating the phase change paint to a liquid state;
[0013] S3, immersing the water storage resin surface obtained in S1 in a layer of liquid phase change paint, standing and cooling for a period of time to obtain a water storage phase change resin.
[0014] In the present application, the high-strength polypropylene fiber refers to a polypropylene fiber with a breaking strength of ≥6.0 cN / dtex and an elongation at break of <30%.
[0015] As a preferred, the preparation raw materials include, by weight: cement 350-380 parts, fly ash 130-150 parts, silica ash 140-170 parts, functional composite admixture 390-440 parts, composite fiber 100-140 parts, water storage phase change resin 10-15 parts, graded quartz sand 990-1060 parts, water reducing agent 15-19 parts, and water 155-165 parts.
[0016] As a preferred, the mass ratio of phosphorus slag powder and magnesium slag powder in the functional composite admixture is 3.5-4.5:1. Research has found that if the mass ratio of phosphorus slag powder and magnesium slag powder is too high, there are disadvantages of long concrete setting time and low early strength; if the mass ratio is too low, the performance advantage of low hydration heat cannot be achieved.
[0017] Further preferably, the phosphorus slag powder is L95 grade, and the specific surface area is not less than 450 m 2 / kg, and the content of phosphorus pentoxide in the phosphorus slag powder is 2.5-3.5 wt%;
[0018] The content of dicalcium silicate in the magnesium slag powder is not less than 90 wt%, and the content of magnesium oxide is not less than 5 wt%.
[0019] As a preferred, the mass ratio of high-strength polypropylene fiber and steel fiber in the composite fiber is 1:16-19.
[0020] Further preferably, the steel fiber is an end-hook-shaped steel fiber, and the surface is roughened by high manganic acid or high chloric acid.
[0021] As a preferred, in S2, the heating temperature for heating the phase change paint to a liquid state is 70-80℃, and the heating time is 25-30 min;
[0022] In S3, the temperature for standing and cooling is room temperature, and the time is 3-4 h.
[0023] As a preferred, the graded quartz sand is four-grade quartz sand, and the specific ratio is 18-26 mesh quartz sand: 26-44 mesh quartz sand: 44-90 mesh quartz sand: 90-150 mesh quartz sand = 2.5-3.5:1.5-2.5:2.5-3.5:1.5-2.5. In the present application, the above graded quartz sand can make the ultra-high performance concrete tightly packed.
[0024] The application also provides a preparation method of the super high performance concrete.
[0025] (1) mixing and stirring cement, fly ash, silica fume and functional composite admixture for a period of time to obtain dry mixture;
[0026] (2) adding graded quartz sand, water reducing agent and water to the dry mixture and stirring for a period of time to obtain first slurry;
[0027] (3) adding composite fiber to the first slurry and stirring for a period of time to obtain second slurry;
[0028] (4) adding water storage phase change resin to the second slurry and stirring for a period of time to obtain third slurry;
[0029] (5) pouring the third slurry into a mold for curing, and surrounding the mold with thermal insulation material for insulation;
[0030] (6) removing the thermal insulation material after curing for 21-23 days, continuing to cure for 5-7 days and then removing the mold to obtain the super high performance concrete.
[0031] Preferably, in step (5), the thermal insulation material is an organic thermal insulation material with a thermal conductivity of ≤0.05 W / m·K.
[0032] The specific feeding sequence described above is adopted in the preparation, which can ensure the uniform distribution of the composite fiber and the water storage phase change resin in the concrete and fully play their roles.
[0033] The application has the following advantages:
[0034] (1) the functional composite admixture is used to reduce early hydration heat and control early shrinkage of cement stone matrix;
[0035] (2) the addition of the composite fiber improves the bonding capacity between the cement stone matrix and the aggregate, solves the problem of weak interface transition zone between the early cement stone matrix and the aggregate caused by the functional composite admixture, and reduces temperature shrinkage;
[0036] (3) the water storage phase change resin releases water at the later hydration stage of the super high performance concrete, which makes the un-hydrated cement in the concrete continue to hydrate, and the generated hydration products not only reduce the pores of the cement stone matrix, but also fill the defects between the two fibers caused by the addition of the composite fiber;
[0037] (4) The synergistic effect of the three materials of functional composite admixture, composite fiber and water storage phase change resin makes up for the shortcomings of single material, and under the reasonable material ratio and preparation process, the super high performance concrete with low hydration heat, low shrinkage and internal curing is prepared, and then is used in the field of mass concrete. DETAILED DESCRIPTION
[0038] The following examples are used to illustrate the present application, but not to limit the scope of the present application.
[0039] Unless otherwise specified, the techniques or conditions in the examples are carried out according to the techniques or conditions described in the literature in the art, or according to the product instructions. Unless otherwise specified, the reagents or instruments used are conventional products that can be purchased through regular channels.
[0040] In the following examples, the cement is sourced from Anhui Conch Cement Co., Ltd., and the model is Conch P.O 42.5;
[0041] The phosphorous slag powder is sourced from Mabian Changhe Power;
[0042] The magnesium slag powder is sourced from Ruige Magnesium Industry;
[0043] The high-strength polypropylene fiber is sourced from Jiangsu Hongfa New Material Co., Ltd., and the model is HF-PP;
[0044] The steel fiber is sourced from Yutian County Chetai Steel Fiber Manufacturing Co., Ltd., and the model is CACL 0.2 / 13;
[0045] The cross-linked hydroxyethyl cellulose grafted acrylamide polymer resin is sourced from Nolinge, and the model is FC 370.
[0046] Example 1
[0047] In this example, the super high performance concrete with low hydration heat, low shrinkage and internal curing is prepared by adding the three materials of functional composite admixture, composite fiber and water storage phase change resin, and the specific steps are as follows:
[0048] (1) 370 parts by weight of cement, 130 parts by weight of fly ash, 150 parts by weight of silica ash and 440 parts by weight of functional composite admixture are mixed and stirred for 1 min to obtain a dry mixture;
[0049] (2) 1000 parts by weight of graded quartz sand, 17 parts by weight of water reducing agent and 160 parts by weight of water are added and stirred for 3 min to obtain a first slurry;
[0050] (3) 110 parts by weight of composite fiber is added and stirred for 1 min to obtain a second slurry;
[0051] (4) adding the water storage phase change resin and stirring for 30s to obtain a third slurry;
[0052] (5) pouring the third slurry into a mold for curing, and using an organic thermal insulation material with a thermal conductivity of 0.04 W / m·K around the mold for insulation;
[0053] (6) removing the insulation material after 21 days of curing, continuing to cure for 7 days, and removing the mold to obtain the ultra-high performance concrete.
[0054] In this embodiment, the water storage phase change resin is prepared as follows: S1, immersing the cross-linked hydroxyethyl cellulose grafted acrylamide polymer resin in water to obtain a water storage resin; S2, heating the phase change paint to a liquid state, the heating temperature is 95℃, and the heating time is 27 min; S3, immersing the water storage resin obtained in S1 in the phase change paint for one layer, and cooling at room temperature for 3h to obtain the water storage phase change resin.
[0055] In this embodiment, the functional composite admixture 440 parts by weight includes phosphorous slag powder 350 parts by weight and magnesium slag powder 90 parts by weight; the composite fiber 110 parts by weight includes high-strength polypropylene fiber 6 parts by weight and steel fiber 104 parts by weight, wherein the steel fiber is end-hook-shaped and the surface is roughened by immersion in perchloric acid.
[0056] In this embodiment, the graded quartz sand is four-grade, specifically 20 mesh: 40 mesh: 70 mesh: 150 mesh = 3:2:3:2.
[0057] The internal temperature rise and shrinkage of the ultra-high performance concrete during the curing process were monitored, and the mechanical properties of the ultra-high performance concrete obtained after the mold was removed were tested, and the results are shown in Tables 1 and 2.
[0058] Comparative Example 1
[0059] Different from Example 1, only the functional composite admixture was added, and no composite fiber and water storage phase change resin were added.
[0060] Comparative Example 2
[0061] Different from Example 1, only the composite fiber was added, and no functional composite admixture and water storage phase change resin were added.
[0062] Comparative Example 3
[0063] Different from Example 1, only the water storage phase change resin was added, and no functional composite admixture and composite fiber were added.
[0064] Comparative Example 4
[0065] Different from Example 1, only the functional composite admixture and the composite fiber were added, and no water storage phase change resin was added.
[0066] Comparative Example 5
[0067] Different from example 1, only functional composite admixture and water storage phase change resin were added, and no composite fiber was added.
[0068] Comparative example 6
[0069] Different from example 1, only composite fiber and water storage phase change resin were added, and no functional composite admixture was added.
[0070] Table 1: Mechanical properties and shrinkage development of ultra-high performance concrete
[0071]
[0072]
[0073] Table 2: Internal temperature development of ultra-high performance concrete (℃)
[0074]
[0075] As can be seen from table 1 and table 2, the synergy of functional composite admixture, composite fiber and water storage phase change resin can realize low hydration heat, low shrinkage, high tensile strength and high compressive strength of concrete. The addition of functional composite admixture alone can reduce the hydration heat of concrete, but cause the strength to decrease; the addition of composite fiber alone only improves the tensile strength of concrete; the addition of water storage phase change resin alone has no obvious improvement on the performance of concrete.
[0076] The above examples only describe the preferred embodiments of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements of the technical solutions of the present application made by the ordinary engineering technicians in the art shall fall within the protection scope determined by the claims of the present application.
Claims
1. A type of ultra-high performance concrete, characterized in that, The raw materials for preparation include: cement, fly ash, silica fume, functional composite admixtures, composite fibers, water-storing phase change resin, graded quartz sand, water-reducing agent and water; The functional composite admixture includes phosphorus slag powder and magnesium slag powder; The composite fiber includes high-strength polypropylene fiber and steel fiber; The preparation method of the water-storing phase change resin includes the following steps: S1, cross-linked hydroxyethyl cellulose grafted acrylamide polymer resin is soaked in water to obtain water-retaining resin; S2, heating the phase change coating to a liquid state; S3. Impregnate the surface of the water-storing resin obtained in S1 with a layer of liquid phase change coating, and let it stand and cool for a period of time to obtain water-storing phase change resin.
2. The ultra-high performance concrete according to claim 1, characterized in that, The raw materials for preparation, by weight, include: 350-380 parts cement, 130-150 parts fly ash, 140-170 parts silica fume, 390-440 parts functional composite admixture, 100-140 parts composite fiber, 10-15 parts water-storing phase change resin, 990-1060 parts graded quartz sand, 15-19 parts water-reducing agent, and 155-165 parts water.
3. The ultra-high performance concrete according to claim 1 or 2, characterized in that, The mass ratio of phosphorus slag powder to magnesium slag powder in the functional composite admixture is 3.5–4.5:
1.
4. The ultra-high performance concrete according to claim 3, characterized in that, The phosphorus slag powder is L95 grade, with a specific surface area of not less than 450 m². 2 / kg, the phosphorus pentoxide content in phosphorus slag powder is 2.5-3.5wt%; The magnesium slag powder contains no less than 90 wt% dicalcium silicate and no less than 5 wt% magnesium oxide.
5. The ultra-high performance concrete according to claim 1 or 2, characterized in that, The mass ratio of high-strength polypropylene fiber to steel fiber in the composite fiber is 1:16 to 19.
6. The ultra-high performance concrete according to claim 5, characterized in that, The steel fibers are hook-shaped steel fibers, and their surfaces are roughened using high manganese acid or perchloric acid.
7. The ultra-high performance concrete according to claim 1 or 2, characterized in that, In step S2, the heating temperature for heating the phase change coating to a liquid state is 70-80°C, and the heating time is 25-30 minutes. In step S3, the temperature for static cooling is room temperature, and the time is 3 to 4 hours.
8. The ultra-high performance concrete according to claim 1 or 2, characterized in that, The graded quartz sand is a four-graded quartz sand, with a specific ratio of 18-26 mesh quartz sand: 26-44 mesh quartz sand: 44-90 mesh quartz sand: 90-150 mesh quartz sand = 2.5-3.5: 1.5-2.5: 2.5-3.5: 1.5-2.
5.
9. A method for preparing ultra-high performance concrete according to any one of claims 1-8, comprising the following steps: (1) Mix cement, fly ash, silica fume and functional composite admixture for a period of time to obtain dry mix; (2) Add graded quartz sand, water-reducing agent and water to the dry mixture, stir for a period of time to obtain the first slurry; (3) Add composite fibers to the first slurry and stir for a period of time to obtain the second slurry; (4) Add water-storage phase change resin to the second slurry and stir for a period of time to obtain the third slurry; (5) Pour the third slurry into the mold for curing, and use insulation material to keep the mold warm. (6) After curing for 21 to 23 days, remove the insulation material, continue curing for another 5 to 7 days, and then remove the formwork to obtain the ultra-high performance concrete.
10. The preparation method according to claim 9, characterized in that, In step (5), the insulation material is an organic insulation material with a thermal conductivity ≤0.05W / m·K.