UHPC viscosity reducer with ultrafine powder-small molecule alcohol dual-phase synergy and preparation method thereof

Abstract

The application discloses a superfine powder-micromolecule alcohol dual-phase synergistic UHPC viscosity reducer and a preparation method thereof, and belongs to the technical field of admixtures for building materials. The superfine powder is used to prepare the viscosity reducing admixture, dense packing is realized through multi-scale particle filling, the friction between particles is reduced, a graded continuous particle system is formed, the demand for free water is reduced, and the slurry fluidity is significantly improved. Meanwhile, through the dispersion of the polycarboxylic acid high-performance water reducing agent, the lubrication and hydration regulation of the micromolecule alcohol, the synergistic optimization of the air entraining agent and the defoaming agent on the bubble system, and the retardation of the setting retarder on the hydration process, a multi-scale synergistic viscosity reduction mechanism is formed, the slurry yield stress and plastic viscosity are significantly reduced, high strength and durability are maintained, and the application is suitable for the efficient viscosity reduction and working performance optimization of the low water-binder ratio UHPC system.

Description

Technical Field

[0001] This invention belongs to the field of building material admixtures technology, and particularly relates to a UHPC viscosity reducer with dual-phase synergy of ultrafine powder and small molecule alcohol and its preparation method. Background Technology

[0002] UHPC (Ultra-High Performance Concrete) is a new type of building material with ultra-high strength, ultra-high toughness, and excellent durability. The compressive strength of UHPC typically exceeds 100 MPa, far surpassing that of ordinary concrete. Furthermore, its tensile strength, modulus of elasticity, and durability are also significantly superior to traditional concrete. With advancements in technology and increasing engineering demands, UHPC has a very promising future. Its excellent mechanical properties and durability meet the higher requirements of modern engineering for structural safety and durability, leading to its increasingly widespread application in bridges, high-rise buildings, water conservancy projects, marine engineering, rail transit, and new energy fields.

[0003] The high viscosity of UHPC is a significant drawback, primarily due to its low water-cement ratio, high cementitious material content, and enhanced interparticle interactions. These factors significantly reduce the fluidity of the UHPC slurry, making it difficult to flow and spread freely during casting. Poor fluidity affects the casting efficiency and quality of UHPC, especially in complex structures requiring precise control of shape and dimensions, increasing construction difficulty and even impacting the overall structural performance. High UHPC viscosity also leads to difficulties in pumping and vibration, resulting in material waste, extended construction periods, and reduced economic viability.

[0004] To address the aforementioned issues, patent CN117902847A provides a viscosity-reducing admixture, an ultra-high performance concrete material, its preparation method, and its application. The viscosity-reducing admixture provided by this invention, by mass parts, comprises the following raw materials: 19-21 parts gypsum, 19-21 parts lime, 29-31 parts slag, 14-16 parts calcium carbonate, 4-6 parts glass microspheres, 3-5 parts nano-alumina, 5-7 parts nano-calcium silicate, and 5-7 parts additives; the additives are triethanolamine, sodium hexametaphosphate, and potassium silicate. The ultra-high performance concrete material prepared using this viscosity-reducing admixture exhibits lower mixture viscosity and less slump loss. However, the viscosity-reducing admixture of this invention uses nanomaterials such as nano-alumina and nano-calcium silicate, and the preparation process of nanomaterials is complex and costly, increasing the production cost of the viscosity-reducing admixture, making it uneconomical and hindering its widespread application. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a dual-phase synergistic UHPC viscosity reducer composed of ultrafine powder and small molecule alcohol, along with its preparation method. The raw materials for preparing this dual-phase synergistic UHPC viscosity reducer are abundant, the preparation process is simple, and it maintains excellent viscosity-reducing effects even under conditions of high silica fume content and extremely low water-cement ratio.

[0006] To achieve the above objectives, the present invention provides a UHPC viscosity reducer with dual-phase synergy of ultrafine powder and small molecule alcohol, which is composed of viscosity reducer admixture and viscosity reducer water-reducing agent;

[0007] The viscosity-reducing admixture is composed of ultrafine fly ash and at least two of the following raw materials: ultrafine limestone powder, ultrafine slag powder, and ultrafine quartz powder;

[0008] The viscosity-reducing and water-reducing agent is composed of the following raw materials: polycarboxylate high-performance water-reducing agent, small molecule alcohol, defoamer, air-entraining agent and retarder;

[0009] The ultrafine fly ash is FⅠ grade fly ash that meets the national standard GB / T 1596-2017, with an average particle size of less than 5μm and a sphericity of >95%.

[0010] The ultrafine limestone powder conforms to the national standard GB / T 35164-2017 and has an average particle size of less than 10μm.

[0011] The ultrafine slag powder is granulated blast furnace slag powder of grade S95 or above that meets the national standard GB / T 18046-2017, and the average particle size is less than 10μm.

[0012] The ultrafine quartz powder is quartz powder that conforms to the national standard GB / T 31387-2015, and has an average particle size of less than 10μm.

[0013] Furthermore, in the raw materials of the UHPC viscosity reducer with dual-phase synergy of ultrafine powder and small molecule alcohol, by mass parts, the ultrafine fly ash is 200-600 parts, the ultrafine limestone powder is 0-400 parts, the ultrafine slag powder is 0-400 parts, the ultrafine quartz powder is 0-400 parts, the polycarboxylate high-performance water-reducing agent is 21-27 parts, and the small molecule alcohol is 3-9 parts, and the total number of ultrafine fly ash, ultrafine limestone powder, ultrafine slag powder and ultrafine quartz powder is 1000 parts;

[0014] The amount of defoamer is 0.01 to 0.04 wt% of the amount of polycarboxylate superplasticizer, the amount of air-entraining agent is 0.01 to 0.04 wt% of the amount of polycarboxylate superplasticizer, and the amount of retarder is 0.5 to 2 wt% of the amount of polycarboxylate superplasticizer.

[0015] Furthermore, the polycarboxylate high-performance water-reducing agent has a solid content of 40% and a water reduction rate of over 30%.

[0016] Furthermore, the air-entraining agent is selected from rosin-based air-entraining agents or saponin-based air-entraining agents.

[0017] Furthermore, the defoamer is selected from polyether defoamers, silicone defoamers, or phosphate ester defoamers.

[0018] Furthermore, the retarder is selected from sodium gluconate, citric acid, or hydroxyethylidene diphosphonic acid.

[0019] Furthermore, the small molecule alcohol is selected from neopentyl glycol, 1,6-hexanediol, or isohexanediol.

[0020] This invention also provides a method for preparing the above-mentioned ultrafine powder-small molecule alcohol biphase synergistic UHPC viscosity reducer, comprising the following steps:

[0021] Accurately weigh each raw material according to the above-mentioned mass proportions;

[0022] Ultrafine fly ash, ultrafine limestone powder, ultrafine slag powder and ultrafine quartz powder are mixed and stirred evenly to prepare a viscosity-reducing admixture;

[0023] A viscosity-reducing water-reducing agent is prepared by compounding polycarboxylate high-performance water-reducing agent, small molecule alcohol, defoamer, air-entraining agent and retarder and stirring until uniformly dissolved.

[0024] This invention also provides an application of the UHPC viscosity reducer, as described above, which is a dual-phase synergistic agent of ultrafine powder and small molecule alcohol, in the preparation of ultra-high performance concrete.

[0025] When preparing ultra-high performance concrete using the UHPC viscosity reducer of the present invention, which is a dual-phase synergistic agent of ultrafine powder and small molecule alcohol, the viscosity reducer admixture and viscosity reducer water-reducing agent can be mixed with other raw materials of ultra-high performance concrete.

[0026] The present invention also provides an ultra-high performance concrete, the raw materials of which contain the above-mentioned ultrafine powder-small molecule alcohol dual-phase synergistic UHPC viscosity reducer.

[0027] Furthermore, the viscosity-reducing admixture accounts for 10-20 wt% of the ultra-high performance concrete adhesive, and the viscosity-reducing water-reducing agent accounts for 3 wt% of the ultra-high performance concrete adhesive.

[0028] Compared with the prior art, the present invention has the following advantages and technical effects:

[0029] 1. The raw materials for the UHPC viscosity reducer of the present invention, which is a dual-phase synergistic process of ultrafine powder and small molecule alcohol, are abundant, and the ultrafine powder for preparing viscosity reducer admixtures is inexpensive and easy to obtain.

[0030] 2. The preparation method of the UHPC viscosity reducer of the present invention, which is a dual-phase synergistic agent of ultrafine powder and small molecule alcohol, is simple and only requires simple compounding.

[0031] 3. The UHPC viscosity reducer of the present invention, which is a dual-phase synergistic agent of ultrafine powder and small molecule alcohol, has excellent viscosity reduction effect on UHPC formulations with extremely low water-binder ratio and high silica fume content. Detailed Implementation

[0032] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0033] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0034] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0035] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0036] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0037] An embodiment of the present invention provides a UHPC viscosity reducer with dual-phase synergy of ultrafine powder and small molecule alcohol, which is composed of viscosity reducer admixture and viscosity reducer water-reducing agent;

[0038] The viscosity-reducing admixture is composed of ultrafine fly ash and at least two of the following raw materials: ultrafine limestone powder, ultrafine slag powder, and ultrafine quartz powder;

[0039] Viscosity reducing and water-reducing agents are composed of the following raw materials: polycarboxylate high-performance water-reducing agent, small molecule alcohol, defoamer, air-entraining agent and retarder;

[0040] The ultrafine fly ash is FⅠ grade fly ash that meets the national standard GB / T 1596-2017, with an average particle size of less than 5μm, preferably 1μm < fly ash particle size < 5μm, and sphericity > 95%.

[0041] The ultrafine limestone powder conforms to the national standard GB / T 35164-2017 and has an average particle size of less than 10μm, preferably 5μm < ultrafine limestone powder particle size < 10μm;

[0042] The ultrafine slag powder is granulated blast furnace slag powder of grade S95 or above that meets the national standard GB / T 18046-2017, and the average particle size is less than 10μm, preferably 5μm < ultrafine slag powder particle size < 10μm.

[0043] The ultrafine quartz powder conforms to the national standard GB / T 31387-2015 and has an average particle size of less than 10μm, preferably 5μm < quartz powder particle size < 10μm.

[0044] The principle of this invention is as follows:

[0045] 1. The viscosity-reducing admixture uses a combination of ultrafine fly ash (particle size <5μm, spherical), ultrafine limestone powder (<10μm), ultrafine slag powder (<10μm), and ultrafine quartz powder (<10μm), achieving dense packing through multi-scale particle filling. The spherical particles of ultrafine fly ash can exert a "ball bearing effect," reducing inter-particle friction. Simultaneously, its particle size is smaller than cement particles, filling the pores between cement particles and reducing slurry viscosity. The ultrafine limestone powder, ultrafine slag powder, and ultrafine quartz powder further refine and fill the slurry, forming a continuously graded particle system, reducing free water requirements and significantly improving slurry fluidity.

[0046] 2. The UHPC viscosity reducer of this invention, which combines ultrafine powder and small molecule alcohol in a two-phase synergistic process, forms a multi-scale synergistic viscosity reduction mechanism through the dispersing effect of polycarboxylic acid high-performance water-reducing agent, the lubrication and hydration regulation of small molecule alcohol, the synergistic optimization of the bubble system by air-entraining agent and defoamer, and the delay of the hydration process by retarder. This mechanism significantly reduces the yield stress and plastic viscosity of the slurry while maintaining high strength and durability. It is suitable for efficient viscosity reduction and performance optimization of UHPC systems with low water-binder ratio.

[0047] In the embodiments of the present invention, in the raw materials of the UHPC viscosity reducer with biphase synergy of ultrafine powder and small molecule alcohol, the following proportions by mass are: 200-600 parts of ultrafine fly ash, 0-400 parts of ultrafine limestone powder, 0-400 parts of ultrafine slag powder, 0-400 parts of ultrafine quartz powder, 21-27 parts of polycarboxylate high-performance water-reducing agent, and 3-9 parts of small molecule alcohol, and the total proportions of ultrafine fly ash, ultrafine limestone powder, ultrafine slag powder and ultrafine quartz powder are 1000 parts;

[0048] The dosage of defoamer is 0.01 to 0.04 wt% of the dosage of polycarboxylate superplasticizer, the dosage of air-entraining agent is 0.01 to 0.04 wt% of the dosage of polycarboxylate superplasticizer, and the dosage of retarder is 0.5 to 2 wt% of the dosage of polycarboxylate superplasticizer.

[0049] In the embodiments of the present invention, the polycarboxylate high-performance water-reducing agent has a solid content of 40% and a water reduction rate of over 30%; preferably, the polycarboxylate high-performance water-reducing agent is a high-water-reducing and viscosity-reducing polycarboxylate high-performance water-reducing agent conforming to the national standard GB 8076-2008, with a solid content of 40% and a water reduction rate of over 50%. For example, the water-reducing agent is UHPC-specific water-reducing agent-S5 produced by Sichuan Tongdao Technology Co., Ltd.

[0050] In embodiments of the present invention, the air-entraining agent is selected from rosin-based air-entraining agents or saponin-based air-entraining agents. Exemplary examples include rosin thermal polymer air-entraining agents, sodium rosinate air-entraining agents, rosin saponin air-entraining agents, or modified rosin thermal polymer air-entraining agents; saponin-based air-entraining agents include triterpenoid saponin air-entraining agents, modified saponin air-entraining agents, or composite saponin air-entraining agents.

[0051] In embodiments of the present invention, the defoamer is selected from polyether defoamers, silicone defoamers, or phosphate ester defoamers. For example, polyether defoamers include GP-type polyether defoamers, GPE-type polyether defoamers, or GPES-type polyether defoamers; silicone defoamers include silicone oil-type defoamers, polyether-modified silicone defoamers, emulsion-type silicone defoamers, solid powder-type silicone defoamers, or self-emulsifying and self-dispersing silicone defoamers; phosphate ester defoamers include tributyl phosphate (TBP) or triisobutyl phosphate (TIBP).

[0052] In embodiments of the present invention, the small molecule alcohol is selected from neopentyl glycol, 1,6-hexanediol, or isohexanediol. The small molecule alcohol reduces viscosity by weakening intermolecular forces such as van der Waals forces and hydrogen bonds between cement particles, thereby altering the surface properties of the cement particles, reducing interparticle interactions, lowering the surface tension of the system, and increasing the fluidity of the system.

[0053] In embodiments of the present invention, the retarder is selected from sodium gluconate, citric acid, or hydroxyethylidene diphosphonic acid (HEDP), which has no significant side effect on the viscosity of UHPC mixtures.

[0054] The embodiments of the present invention also provide a method for preparing the above-mentioned ultrafine powder-small molecule alcohol biphase synergistic UHPC viscosity reducer, comprising the following steps:

[0055] Accurately weigh each raw material according to the above-mentioned mass proportions;

[0056] Ultrafine fly ash, ultrafine limestone powder, ultrafine slag powder and ultrafine quartz powder are mixed and stirred evenly to prepare a viscosity-reducing admixture;

[0057] A viscosity-reducing water-reducing agent is prepared by compounding, dissolving, and stirring polycarboxylate high-performance water-reducing agent, small molecule alcohol, defoamer, air-entraining agent, and retarder evenly.

[0058] Embodiments of the present invention also provide an application of the UHPC viscosity reducer, as described above, which is a dual-phase synergistic agent of ultrafine powder and small molecule alcohol, in the preparation of ultra-high performance concrete.

[0059] When preparing ultra-high performance concrete using the UHPC viscosity reducer of the present invention, which is a dual-phase synergistic agent of ultrafine powder and small molecule alcohol, the viscosity reducer admixture and viscosity reducer water-reducing agent can be mixed with other raw materials of ultra-high performance concrete.

[0060] Embodiments of the present invention also provide an ultra-high performance concrete, the raw materials of which contain the above-mentioned ultrafine powder-small molecule alcohol dual-phase synergistic UHPC viscosity reducer.

[0061] In embodiments of the present invention, the viscosity-reducing admixture accounts for 10-20 wt% of the ultra-high performance concrete adhesive, and the viscosity-reducing water-reducing agent accounts for 3 wt% of the ultra-high performance concrete adhesive.

[0062] In a preferred embodiment of the present invention, the raw materials for ultra-high performance concrete include: water, cement, silica fume, quartz sand, steel fiber, viscosity-reducing admixtures, and viscosity-reducing water-reducing agents.

[0063] In a preferred embodiment of the present invention, the mix proportion of ultra-high performance concrete raw materials is: cement 600-750 kg / m³. 3 Silica fume 100-200 kg / m³ 3 Quartz sand 1180kg / m 3 156 kg / m of steel fiber 3 Viscosity-reducing admixture 100-200 kg / m³ 3 Viscosity reducing and water reducing agent 30kg / m 3The water-cement ratio of ultra-high performance concrete is 0.14 to 0.16. For example, the cement is PO 52.5R cement; the silica fume is grade 90 silica fume; the quartz sand is a mixture of 20-40 mesh, 40-70 mesh and 70-120 mesh quartz sand in a mass ratio of 5:3:2; the water-reducing agent is UHPC special water-reducing agent-S5 produced by Sichuan Tongdao Technology Co., Ltd.; and the steel fiber is a straight copper-plated micro-fine steel fiber with a diameter of 0.2 mm and a length of 13 mm.

[0064] In concrete, adhesives typically refer to materials that act as a binder, holding aggregates and other components together to form a cohesive whole. In this invention, adhesives refer to cement, silica fume, and viscosity-reducing admixtures.

[0065] Unless otherwise specified, the room temperature in this invention is 25±2℃.

[0066] Unless otherwise specified, "parts" in this invention refers to parts by mass.

[0067] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0068] The technical solution of the present invention will be further illustrated by the following embodiments.

[0069] Example 1

[0070] This embodiment provides a dual-phase synergistic UHPC viscosity reducer composed of ultrafine powder and small molecule alcohol, comprising the following raw materials: ultrafine fly ash, ultrafine limestone powder, ultrafine slag powder, ultrafine quartz powder, polycarboxylate high-performance water-reducing agent (UHPC-specific water-reducing agent-S5 produced by Sichuan Tongdao Technology Co., Ltd.), neopentyl glycol (industrial grade), polyether defoamer (polyether defoamer WT-355 produced by Shandong Aichino Environmental Protection Technology Co., Ltd.), rosin-based air-entraining agent (industrial grade sodium rosinate (liquid) produced by Henan Wanshan New Material Technology Co., Ltd.), and retarder ( Sodium gluconate (industrial grade); by weight, 400 parts ultrafine fly ash, 200 parts ultrafine limestone powder, 200 parts ultrafine slag powder, 200 parts ultrafine quartz powder, 27 parts polycarboxylate superplasticizer, and 3 parts neopentyl glycol; the amount of polyether defoamer is 0.01 wt% of the amount of polycarboxylate superplasticizer, the amount of rosin-based air-entraining agent is 0.01 wt% of the amount of polycarboxylate superplasticizer, the amount of retarder is 0.5 wt% of the amount of polycarboxylate superplasticizer, and the ultrafine fly ash conforms to the national standard GB / T The fly ash is of grade FⅠ according to 1596-2017, with an average particle size of 1μm to 5μm and a sphericity >95%; the ultrafine limestone powder is limestone powder that meets the national standard GB / T 35164-2017, with an average particle size of 5μm to 10μm; the ultrafine slag powder is granulated blast furnace slag powder of grade S95 or above that meets the national standard GB / T 18046-2017, with an average particle size of 5μm to 10μm; the ultrafine quartz powder is quartz powder that meets the technical indicators of the national standard GB / T31387-2015, with an average particle size of 5μm to 10μm.

[0071] The preparation method of the above-mentioned UHPC viscosity reducer with synergistic effect of ultrafine powder and small molecule alcohol is as follows:

[0072] Accurately weigh each raw material according to the above-mentioned mass proportions;

[0073] Ultrafine fly ash, ultrafine limestone powder, ultrafine slag powder and ultrafine quartz powder are mixed and stirred evenly to prepare a viscosity-reducing admixture;

[0074] A viscosity-reducing water-reducing agent is prepared by compounding polycarboxylate high-performance water-reducing agent, neopentyl glycol, polyether defoamer, rosin-based air-entraining agent and retarder, and stirring until uniformly dissolved.

[0075] The method for preparing UHPC using the above-mentioned ultrafine powder-small molecule alcohol biphase synergistic UHPC viscosity reducer is as follows:

[0076] S1. Determine the UHPC raw material ratio, as shown in Table 1;

[0077] S2. Accurately weigh water, cement, silica fume, viscosity-reducing admixture, viscosity-reducing water-reducing agent, quartz sand and steel fiber according to the mix proportion, and set aside.

[0078] S3. Dry mixing stage: Pour cement, silica fume, viscosity-reducing admixture and quartz sand into a concrete forced mixer for dry mixing. The dry mixing time is 5 minutes, until all materials are evenly distributed.

[0079] S4. Wet mixing stage: Add tap water and viscosity reducer to the dry mixture and stir thoroughly for 10 minutes. During the stirring process, ensure that all materials are fully mixed to form a uniform mixture.

[0080] S5. When the mixture changes from granular to agglomerated, add steel fibers and continue stirring. Add the steel fibers in 3 batches to avoid clumping and ensure that they are evenly dispersed in the concrete. After stirring evenly, the UHPC mixture is obtained.

[0081] S6. Pour the UHPC mixture into a mold for casting, and compact it by vibration to remove internal air bubbles. The vibration time is 15 seconds to obtain a UHPC test block.

[0082] S7. Cover the UHPC test block with plastic wrap and let it stand at room temperature for 24 hours. Then remove the mold and cure it. The curing regime is standard curing. Cure it for 28 days (in this embodiment, when preparing UHPC, the amount of viscosity reducing admixture is 10 wt% of the adhesive material and the amount of viscosity reducing water reducing agent is 3 wt% of the adhesive material) to obtain UHPC.

[0083] Example 2

[0084] This embodiment provides a dual-phase synergistic UHPC viscosity reducer composed of ultrafine powder and small molecule alcohol, comprising the following raw materials: ultrafine fly ash, ultrafine limestone powder, ultrafine slag powder, ultrafine quartz powder, polycarboxylate high-performance water-reducing agent (UHPC-specific water-reducing agent-S5 produced by Sichuan Tongdao Technology Co., Ltd.), isohexyl glycol (industrial grade), polyether defoamer (polyether defoamer WT-355 produced by Shandong Aicino Environmental Protection Technology Co., Ltd.), rosin-based air-entraining agent (industrial grade sodium rosinate (liquid) produced by Henan Wanshan New Material Technology Co., Ltd.), and retarder (sodium gluconate (industrial grade)). The composition, by weight, is as follows: 200 parts ultrafine fly ash, 400 parts ultrafine limestone powder, 400 parts ultrafine slag powder, 0 parts ultrafine quartz powder, 21 parts polycarboxylate superplasticizer, and 9 parts isohexyl glycol; the amount of polyether defoamer is 0.02 wt% of the amount of polycarboxylate superplasticizer, the amount of rosin-based air-entraining agent is 0.02 wt% of the amount of polycarboxylate superplasticizer, and the amount of retarder is 1 wt% of the amount of polycarboxylate superplasticizer; the performance requirements of ultrafine fly ash, ultrafine limestone powder, ultrafine slag powder, and ultrafine quartz powder are the same as in Example 1.

[0085] The preparation method of the UHPC viscosity reducer with ultrafine powder-small molecule alcohol synergy in this embodiment is the same as that in Example 1.

[0086] The raw material formulation of UHPC in this embodiment is shown in Table 1. The method for preparing UHPC using the above-mentioned ultrafine powder-small molecule alcohol dual-phase synergistic UHPC viscosity reducer is the same as in Example 1. The only difference is that when preparing UHPC, the amount of viscosity reducer admixture is 20wt% of the adhesive material and the amount of viscosity reducer and water reducer is 3wt% of the adhesive material.

[0087] Example 3

[0088] This embodiment provides a UHPC viscosity reducer with a synergistic effect of ultrafine powder and small molecule alcohol, composed of the following raw materials: ultrafine fly ash, ultrafine limestone powder, ultrafine slag powder, ultrafine quartz powder, polycarboxylate high-performance water-reducing agent (UHPC-specific water-reducing agent-S5 produced by Sichuan Tongdao Technology Co., Ltd.), 1,6-hexanediol (industrial grade), and organosilicon defoamer (self-dispersing organosilicon defoamer SILFOAM SD produced by Wacker Chemie International Ltd., Germany). 860), saponin-based air-entraining agent (triterpenoid saponins (liquid) produced by Chongqing Boruida Building Materials Co., Ltd.) and retarder (citric acid (industrial grade)); by mass parts, ultrafine fly ash is 400 parts, ultrafine limestone powder is 200 parts, ultrafine slag powder is 0 parts, ultrafine quartz powder is 400 parts, polycarboxylate high-performance water-reducing agent is 24 parts, and 1,6-hexanediol is 6 parts; the amount of organosilicon defoamer is 0.03 wt% of the amount of polycarboxylate high-performance water-reducing agent, the amount of saponin-based air-entraining agent is 0.03 wt% of the amount of polycarboxylate high-performance water-reducing agent, and the amount of retarder is 1.5 wt% of the amount of polycarboxylate high-performance water-reducing agent; the performance requirements of ultrafine fly ash, ultrafine limestone powder, ultrafine slag powder, and ultrafine quartz powder are the same as in Example 1.

[0089] The preparation method of the UHPC viscosity reducer with ultrafine powder-small molecule alcohol synergy in this embodiment is the same as that in Example 1.

[0090] The raw material formulation of UHPC in this embodiment is shown in Table 1. The method for preparing UHPC using the above-mentioned ultrafine powder-small molecule alcohol biphase synergistic UHPC viscosity reducer is the same as in Example 1. The only difference is that when preparing UHPC, the amount of viscosity reducer admixture is 15wt% of the adhesive material and the amount of viscosity reducer and water reducer is 3wt% of the adhesive material.

[0091] Example 4

[0092] This embodiment provides a UHPC viscosity reducer with a synergistic effect of ultrafine powder and small molecule alcohol, composed of the following raw materials: ultrafine fly ash, ultrafine limestone powder, ultrafine slag powder, ultrafine quartz powder, polycarboxylate high-performance water-reducing agent (UHPC-specific water-reducing agent-S5 produced by Sichuan Tongdao Technology Co., Ltd.), neopentyl glycol (industrial grade), and organosilicon defoamer (self-dispersing organosilicon defoamer SILFOAM SD produced by Wacker Chemie International Ltd., Germany). 860), saponin-based air-entraining agent (triterpenoid saponins (liquid) produced by Chongqing Boruida Building Materials Co., Ltd.) and retarder (citric acid (industrial grade)); by mass parts, ultrafine fly ash is 600 parts, ultrafine limestone powder is 0 parts, ultrafine slag powder is 200 parts, ultrafine quartz powder is 200 parts, polycarboxylate high-performance water-reducing agent is 24 parts, neopentyl glycol is 6 parts; the amount of organosilicon defoamer is 0.04 wt% of the amount of polycarboxylate high-performance water-reducing agent, the amount of saponin-based air-entraining agent is 0.04 wt% of the amount of polycarboxylate high-performance water-reducing agent, and the amount of retarder is 2 wt% of the amount of polycarboxylate high-performance water-reducing agent; the performance requirements of ultrafine fly ash, ultrafine limestone powder, ultrafine slag powder, and ultrafine quartz powder are the same as in Example 1.

[0093] The preparation method of the UHPC viscosity reducer with ultrafine powder-small molecule alcohol synergy in this embodiment is the same as that in Example 1.

[0094] The raw material formulation of UHPC in this embodiment is shown in Table 1. The method for preparing UHPC using the above-mentioned ultrafine powder-small molecule alcohol biphase synergistic UHPC viscosity reducer is the same as in Example 1. The only difference is that when preparing UHPC, the amount of viscosity reducer admixture is 15wt% of the adhesive material and the amount of viscosity reducer and water reducer is 3wt% of the adhesive material.

[0095] Example 5

[0096] This embodiment provides a dual-phase synergistic UHPC viscosity reducer composed of ultrafine powder and small molecule alcohol, comprising the following raw materials: ultrafine fly ash, ultrafine limestone powder, ultrafine slag powder, ultrafine quartz powder, polycarboxylate high-performance water-reducing agent (UHPC-specific water-reducing agent-S5 produced by Sichuan Tongdao Technology Co., Ltd.), 1,6-hexanediol (industrial grade), phosphate ester defoamer (tributyl phosphate defoamer produced by Jinan Guobang Chemical Co., Ltd.), saponin air-entraining agent (triterpenoid saponins (liquid) produced by Chongqing Boruida Building Materials Co., Ltd.), and retarder (hydroxyethylidene diphosphonic acid (HEDP, industrial grade)). The composition, by weight, is as follows: 400 parts ultrafine fly ash, 0 parts ultrafine limestone powder, 200 parts ultrafine slag powder, 400 parts ultrafine quartz powder, 24 parts polycarboxylate superplasticizer, and 6 parts 1,6-hexanediol; the dosage of phosphate ester defoamer is 0.04 wt% of the dosage of polycarboxylate superplasticizer, the dosage of saponin air-entraining agent is 0.04 wt% of the dosage of polycarboxylate superplasticizer, and the dosage of retarder is 2 wt% of the dosage of polycarboxylate superplasticizer; the performance requirements of ultrafine fly ash, ultrafine limestone powder, ultrafine slag powder, and ultrafine quartz powder are the same as in Example 1.

[0097] The preparation method of the UHPC viscosity reducer with ultrafine powder-small molecule alcohol synergy in this embodiment is the same as that in Example 1.

[0098] The raw material formulation of UHPC in this embodiment is shown in Table 1. The method for preparing UHPC using the above-mentioned ultrafine powder-small molecule alcohol biphase synergistic UHPC viscosity reducer is the same as in Example 1. The only difference is that when preparing UHPC, the amount of viscosity reducer admixture is 15wt% of the adhesive material and the amount of viscosity reducer and water reducer is 3wt% of the adhesive material.

[0099] Comparative Example 1

[0100] In this comparative example, no viscosity-reducing admixtures or viscosity-reducing water-reducing agents were used when preparing the concrete. That is, in this comparative example, P.O52.5R cement was used in an equal amount to replace the viscosity-reducing admixtures in Example 1, and high-performance polycarboxylate superplasticizer (UHPC special superplasticizer-S5 produced by Sichuan Tongdao Technology Co., Ltd.) was used in an equal amount to replace the viscosity-reducing water-reducing agent in Example 1. Everything else was the same as in Example 1.

[0101] Comparative Example 2

[0102] In this comparative example, no viscosity-reducing admixture was used when preparing the concrete. That is, the viscosity-reducing admixture in Example 4 was replaced with an equal amount of PO 52.5R cement in this comparative example, and everything else was the same as in Example 4.

[0103] Comparative Example 3

[0104] In this comparative example, no viscosity-reducing water-reducing agent was used when preparing concrete. That is, the viscosity-reducing water-reducing agent in Example 4 was replaced with an equal amount of high-performance polycarboxylate superplasticizer (UHPC special water-reducing agent-S5 produced by Sichuan Tongdao Technology Co., Ltd.). Everything else was the same as in Example 4.

[0105] Comparative Example 4

[0106] In this comparative example, the fly ash used to prepare the viscosity reducer had a particle size of 40 μm, the slag powder had a particle size of 30 μm, the limestone powder had a particle size of 50 μm, and the quartz powder had a particle size of 40 μm. Other parameters were the same as in Example 1. The method for preparing UHPC using the viscosity reducer of this comparative example was also the same as in Example 1.

[0107] Comparative Example 5

[0108] The preparation process of the viscosity reducer in this comparative example is the same as in Example 1, except that a small molecule alcohol (neopentyl glycol) is not added. The method for preparing UHPC using the viscosity reducer in this comparative example is also the same as in Example 1.

[0109] Comparative Example 6

[0110] The process for preparing the viscosity reducer in this comparative example is the same as in Example 1, except that the small molecule alcohol (neopentyl glycol) is replaced with an equal mass of polycarboxylate high-performance water-reducing agent (UHPC-specific water-reducing agent-S5 produced by Sichuan Tongdao Technology Co., Ltd.). The method for preparing UHPC using the viscosity reducer in this comparative example is also the same as in Example 1.

[0111] The compressive and flexural strengths of the ultra-high performance concrete specimens prepared in Examples 1 to 5 and Comparative Examples 1 to 6 were tested according to GB / T 31387-2015. The air void time and spread of the ultra-high performance concrete specimens prepared in Examples 1 to 5 and Comparative Examples 1 to 6 were tested according to GB / T 50080-2016. The UHPC raw material mix proportions of each test group are shown in Table 1, and the test results are shown in Table 2.

[0112] Table 1. UHPC raw material proportions for Examples 1-5 and Comparative Examples 1-6 (kg / m³) 3 )

[0113] Group number cement silica ash Viscosity-reducing admixtures Viscosity reducer and water reducer Quartz sand Water reducing agent Water-to-glue ratio steel fiber Example 1 700 200 100 30 1180 / 0.16 156 Example 2 600 200 200 30 1180 / 0.16 156 Example 3 650 200 150 30 1180 / 0.16 156 Example 4 750 100 150 30 1180 / 0.14 156 Example 5 750 100 150 30 1180 / 0.14 156 Comparative Example 1 800 200 / / 1180 30 0.16 156 Comparative Example 2 900 100 / 30 1180 / 0.14 156 Comparative Example 3 750 100 150 / 1180 30 0.14 156 Comparative Example 4 700 200 100 30 1180 / 0.16 156 Comparative Example 5 700 200 100 30 1180 / 0.16 156 Comparative Example 6 700 200 100 30 1180 / 0.16 156

[0114] Note: In Table 1, the cement is PO 52.5R cement; the silica fume is grade 90 silica fume; the quartz sand is a mixture of 20-40 mesh, 40-70 mesh and 70-120 mesh quartz sand in a mass ratio of 5:3:2; the water-reducing agent is UHPC special water-reducing agent-S5 produced by Sichuan Tongdao Technology Co., Ltd.; and the steel fiber is a straight copper-plated micro steel fiber with a diameter of 0.2 mm and a length of 13 mm.

[0115] Table 2. UHPC performance test results of Examples 1-5 and Comparative Examples 1-6

[0116]

[0117]

[0118] Table 2 shows that the ultra-high performance concrete of Examples 1 to 5 all had a voiding time of less than 10.0 s, a spread of more than 720 mm, a 28-day flexural strength of more than 24.3 MPa, and a 28-day compressive strength of more than 185.9 MPa. Under high silica fume content and a water-cement ratio of 0.16, Comparative Example 1 (without viscosity-reducing admixtures or water-reducing agents) showed a significantly increased voiding time compared to Examples 1 to 3, and significantly decreased spread, 28-day compressive strength, and 28-day flexural strength. Under an extremely low water-cement ratio of 0.14, Comparative Example 2 (without viscosity-reducing admixtures) and Comparative Example 3 (without viscosity-reducing agents) showed a significantly increased voiding time, and significantly decreased spread, 28-day compressive strength, and 28-day flexural strength. In Comparative Example 4, replacing the ultrafine powder of the viscosity reducer with a non-ultrafine powder significantly increased the evaporation time and substantially reduced the spread, 28-day compressive strength, and 28-day flexural strength. In Comparative Example 5, no small molecule alcohol was added when preparing the viscosity reducer and water-reducing agent; the evaporation time increased slightly, and the spread decreased slightly. In Comparative Example 6, replacing the small molecule alcohol with an equal mass of polycarboxylate high-performance water-reducing agent slightly increased the evaporation time and slightly decreased the spread. This indicates that the ultrafine powder-small molecule alcohol synergistic UHPC viscosity reducer prepared in this invention has excellent viscosity-reducing effects, improving both the flowability of freshly mixed UHPC and significantly enhancing its mechanical properties.

[0119] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A UHPC viscosity reducer with a dual-phase synergistic effect of ultrafine powder and small molecule alcohol, characterized in that, It consists of viscosity-reducing admixtures and viscosity-reducing water-reducing agents; The viscosity-reducing admixture is composed of ultrafine fly ash and at least two of the following raw materials: ultrafine limestone powder, ultrafine slag powder, and ultrafine quartz powder; The viscosity-reducing and water-reducing agent is composed of the following raw materials: polycarboxylate high-performance water-reducing agent, small molecule alcohol, defoamer, air-entraining agent and retarder; The ultrafine fly ash is FⅠ grade fly ash, with an average particle size of less than 5μm and a sphericity >95%; The average particle size of the ultrafine limestone powder is less than 10 μm; The ultrafine slag powder is granulated blast furnace slag powder of grade S95 or above, and the average particle size is less than 10μm. The average particle size of the ultrafine quartz powder is less than 10 μm; Based on the mass fractions, the ultrafine fly ash comprises 200-600 parts, the ultrafine limestone powder comprises 0-400 parts, the ultrafine slag powder comprises 0-400 parts, the ultrafine quartz powder comprises 0-400 parts, the polycarboxylate high-performance water-reducing agent comprises 21-27 parts, the small molecule alcohol comprises 3-9 parts, and the total mass fraction of the ultrafine fly ash, ultrafine limestone powder, ultrafine slag powder and ultrafine quartz powder is 1000 parts; The amount of defoamer is 0.01~0.04 wt% of the amount of polycarboxylate superplasticizer, the amount of air-entraining agent is 0.01~0.04 wt% of the amount of polycarboxylate superplasticizer, and the amount of retarder is 0.5~2 wt% of the amount of polycarboxylate superplasticizer. The retarder is selected from sodium gluconate, citric acid or hydroxyethylidene diphosphonic acid; The ultrafine powder-small molecule alcohol dual-phase synergistic UHPC viscosity reducer is used in ultra-high performance concrete with a water-cement ratio of 0.14 to 0.

16.

2. The UHPC viscosity reducer with synergistic effects of ultrafine powder and small molecule alcohol as described in claim 1, characterized in that, The polycarboxylate high-performance water-reducing agent has a solid content of 40% and a water reduction rate of over 30%.

3. The UHPC viscosity reducer with synergistic effects of ultrafine powder and small molecule alcohol as described in claim 1, characterized in that, The air-entraining agent is selected from rosin-based air-entraining agents or saponin-based air-entraining agents.

4. The UHPC viscosity reducer with synergistic effects of ultrafine powder and small molecule alcohol as described in claim 1, characterized in that, The defoamer is selected from polyether defoamers, silicone defoamers, or phosphate ester defoamers.

5. A method for preparing a UHPC viscosity reducer with a dual-phase synergistic effect of ultrafine powder and small molecule alcohol as described in any one of claims 1 to 4, characterized in that, Includes the following steps: Accurately weigh each raw material according to the above-mentioned mass proportions; Ultrafine fly ash, ultrafine limestone powder, ultrafine slag powder and ultrafine quartz powder are mixed and stirred evenly to prepare a viscosity-reducing admixture; A viscosity-reducing water-reducing agent is prepared by compounding polycarboxylate high-performance water-reducing agent, small molecule alcohol, defoamer, air-entraining agent and retarder and stirring until uniformly dissolved.

6. The application of the UHPC viscosity reducer with dual-phase synergy of ultrafine powder and small molecule alcohol as described in any one of claims 1 to 4 in the preparation of ultra-high performance concrete.

7. A type of ultra-high performance concrete, characterized in that, The raw material contains the UHPC viscosity reducer with a dual-phase synergistic effect of ultrafine powder and small molecule alcohol as described in any one of claims 1 to 4.

8. The ultra-high performance concrete according to claim 7, characterized in that, The viscosity-reducing admixture accounts for 10-20 wt% of the ultra-high performance concrete adhesive, and the viscosity-reducing water-reducing agent accounts for 3 wt% of the ultra-high performance concrete adhesive.

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