CN-122010449-A - Phosphogypsum-based UHPC special excitant and preparation method and application thereof

Abstract

The invention discloses a phosphogypsum-based UHPC special excitant, a preparation method and application thereof, belonging to the technical field of concrete, and comprising the following raw materials, by mass, 60-80 wt% of activated phosphogypsum, 5-15 wt% of alkaline excitation component, 5-15 wt% of aluminum sulfate active component, 2-10 wt% of early emphasis control component and 3-5 wt% of aluminum lignin sulfonate. The exciting agent provided by the invention can obviously promote the early strength development of a UHPC system, improve the compactness of a microstructure, promote the stability of fresh mixing performance, realize the high-value utilization of solid waste phosphogypsum, and the obtained ultra-high performance concrete can be used in fabricated concrete members, bridge structure reinforcement, ocean engineering or service concrete in severe environments, and has obvious social benefit and engineering application value.

Inventors

• YANG JUN
• YU KUN
• ZOU YANG
• LONG YU
• ZHANG ZHONGYA
• CAO SAIJUN
• DU JIANG
• RAN HONGYU
• ZHOU JIANTING
• JIANG ZHIMEI
• He Yuexiao
• CHEN RUI
• YU XIANG

Assignees

• 重庆交通大学

Dates

Publication Date

20260512

Application Date

20260211

Claims (10)

1. 1. The UHPC special excitant based on phosphogypsum is characterized by comprising the following raw materials in parts by mass: 60-80 wt% of activated phosphogypsum, 5-15 wt% of alkaline excitation component, 5-15 wt% of aluminum sulfate active component, 2-10 wt% of early strength control component and 3-5 wt% of aluminum lignin sulfonate.
2. 2. The phosphogypsum-based UHPC special activator according to claim 1, wherein the content of CaSO 4 in the activated phosphogypsum is 60-90 wt%, the content of water-soluble impurities is not more than 1.5 wt%, and the specific surface area is not less than 300 m 2 /kg.
3. 3. The phosphogypsum-based UHPC special activator according to claim 1, wherein the aluminum lignosulfonate has a lignosulfonate sulfonation degree of 70% -90% and a solubility in water of not less than 30 g/L.
4. 4. The phosphogypsum-based UHPC special activator of claim 1, wherein the alkaline exciting component is sodium metasilicate.
5. 5. The phosphogypsum-based UHPC special activator according to claim 1, wherein the active component of aluminum sulfate is aluminum sulfate.
6. 6. The phosphogypsum-based UHPC special activator of claim 1, wherein the early strength controlling component is sodium sulfate.
7. 7. A method for preparing the phosphogypsum-based special excitant for UHPC according to any one of claims 1-6, characterized in that the raw materials are weighed, and the obtained mixture is dry-mixed, dried and ground to obtain the phosphogypsum-based special excitant for UHPC.
8. 8. Use of the phosphogypsum-based UHPC special activator according to any one of claims 1-6 in ultra-high performance concrete.
9. 9. An ultra-high performance concrete, characterized by comprising the phosphogypsum-based UHPC special activator as set forth in any one of claims 1-6, wherein the mixing amount of the UHPC special activator is 3-8 wt% of the mass of the cementing material.
10. 10. Use of the ultra-high performance concrete of claim 9 in fabricated concrete structures, bridge construction reinforcements, marine engineering or service concrete in harsh environments.

Description

Phosphogypsum-based UHPC special excitant and preparation method and application thereof Technical Field The invention belongs to the technical field of concrete, and particularly relates to a phosphogypsum-based UHPC special excitant, and a preparation method and application thereof. Background Ultra-high performance concrete (UHPC) is widely used in concrete engineering for bridges, high-rise buildings, fabricated components, and extreme service environments due to its high compactness, high strength, and excellent durability. However, the traditional UHPC relies on a large amount of cement clinker, silica fume and other high-energy materials, and the emission amount of CO 2 is huge in the production process, and the material cost is also increased, so that the development of a UHPC system with low carbon, economy and excellent performance becomes an important research direction in the field of international concrete. The main flow thought for reducing the carbon emission of UHPC comprises the use of mineral powder, fly ash, metakaolin and other industrial solid waste parts to replace cement clinker, but the hydration environment is limited and the early activation is difficult in UHPC with low water-gel ratio because of the low reactivity of the solid waste materials, so that the strength development of UHPC in 1 day and 7 days is often insufficient, and the popularization of the UHPC in bridge engineering and quick construction is limited. On the other hand, phosphogypsum, a by-product of the phosphorus chemical industry, is one of industrial solid wastes with huge reserves in China, the annual output exceeds 7,000 ten thousand tons, and the main component of phosphogypsum is CaSO 4·2H2 O, but contains a certain amount of water-soluble impurities (such as P, F and soluble salts), and the untreated phosphogypsum is difficult to directly use in a gelling system. However, a great deal of researches show that after proper pretreatment, phosphogypsum can release sulfate radical, and react with a silicon-aluminum source to generate early structural products such as AFt (ettringite) and the like, thereby providing potential early activation capability for a cement-based system. Phosphogypsum is therefore considered as a low-carbon excitation material with potential high-value utilization prospect. However, the direct application of phosphogypsum to a UHPC system still has the following problems that (1) the phosphogypsum has low activity, if the phosphogypsum is not pretreated, the internal impurities can influence the stability of hydration reaction, (2) the low water-gel ratio of the UHPC leads to limited dissolution of sulfate radical, so that the coagulation accelerating effect of the phosphogypsum is difficult to fully exert, (3) the dissolution rate of a silicon-aluminum source is insufficient, so that the synergistic reaction efficiency with the phosphogypsum is low, and (4) the design of a composite activator which can be synergistic with the phosphogypsum is lacking, so that the composite activator is difficult to meet the dual requirements of the UHPC on early strength and flow retention. In the prior art, although the application of desulfurized gypsum, metasilicate and aluminate compounds to early hydration promotion of ordinary concrete or alkali-activated cementing materials has been attempted, a set of special excitant system which takes phosphogypsum as a core and is adapted to a UHPC low-water-gel-ratio system has not been established, and particularly, the integrated composite excitation technology which has the capabilities of early strength promotion, fluidity regulation and carbon emission reduction is lacking. Therefore, how to provide a composite activator with the capability of early strength promotion, fluidity regulation and carbon emission reduction is a technical problem to be solved by those skilled in the art. Disclosure of Invention In order to solve the technical problems, the invention provides a UHPC special excitant based on phosphogypsum, and a preparation method and application thereof. In order to achieve the above purpose, the present invention provides the following technical solutions: An exciting agent special for UHPC based on phosphogypsum comprises the following raw materials in percentage by mass: 60-80 wt% of activated phosphogypsum, 5-15 wt% of alkaline excitation component, 5-15 wt% of aluminum sulfate active component, 2-10 wt% of early strength control component and 3-5 wt% of aluminum lignin sulfonate. The method has the beneficial effects that the chemical excitation system suitable for UHPC is formed by synergistically regulating and controlling phosphogypsum sulfate radical release, silicon-aluminum source dissolution dynamics and hydration product morphology, the release rate of sulfate radical in phosphogypsum and the dissolution rate of aluminum component can be effectively matched by reasonable raw material types and proportions, so that early hydratio