Effect of polycarboxylate superplasticizer and calcium nitrite on the fluidity and early strength of belite sulfoaluminate cement

IF 16.4 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Accounts of Chemical Research Pub Date : 2023-12-13 DOI:10.1680/jadcr.23.00023

Juan Fu, Baorui Hu, Wei Guo, Yueyang Hu, Cuifeng Jiang

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Abstract

Belite sulfoaluminate cement is attracting increasingly attention and considered as a prospective alternative to Ordinary Portland cement (OPC) owing to the lower preparation temperature and CO₂ emission. However, it still has disadvantages of poor workability and low early strength. Accordingly, this study investigated the effect of compound polycarboxylate superplasticizer (PCE) and early strength agent, calcium nitrite (Ca(NO₂)₂), on the flowability and early strength of BCSA cement. The variation patterns of setting time, fluidity, strength and PCE adsorption of the paste were measured. Furthermore, the hydration products and microscopic morphology were analyzed by the heat of hydration, X-ray diffraction analyzer and scanning electron microscope. The results showed that Ca(NO₂)₂ effectively enhanced the adsorption of PCE onto the surface of BCSA cement particles, leading to a notable improvement in the fluidity of the paste (reaching up to 275 mm). In the initial hydration stage, 0.7% PCE compounded with 1.2% Ca(NO₂)₂ inhibited the formation of ettringite (AFt), resulting in prolonged setting time. However, it deepened the hydration degree of BCSA for 3d and refined the hydration product, AFt crystals. Consequently, the compressive strength has been increased to 95.75 MPa and 107.13 MPa for BCSA cement at 3d and 28d, respectively.

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聚羧酸盐超塑化剂和亚硝酸钙对褐铁矿硫铝酸盐水泥流动性和早期强度的影响

由于制备温度较低和二氧化碳排放量较少，贝利特硫铝酸盐水泥正受到越来越多的关注，并被视为普通硅酸盐水泥（OPC）的替代品。然而，它仍然存在工作性差和早期强度低的缺点。因此，本研究探讨了复合聚羧酸盐超塑化剂（PCE）和早强剂亚硝酸钙（Ca(NO2)2）对 BCSA 水泥流动性和早强的影响。测量了水泥浆的凝结时间、流动性、强度和 PCE 吸附的变化规律。此外，还利用水化热、X 射线衍射分析仪和扫描电子显微镜分析了水化产物和微观形态。结果表明，Ca(NO2)2 能有效增强 BCSA 水泥颗粒表面对 PCE 的吸附，从而显著改善水泥浆的流动性（最大可达 275 毫米）。在初始水化阶段，0.7% 的 PCE 与 1.2% 的 Ca(NO2)2 复配可抑制乙丁睛石（AFt）的形成，从而延长凝结时间。然而，它却加深了 BCSA 的水化程度 3d，并完善了水化产物 AFt 晶体。因此，BCSA 水泥在 3d 和 28d 时的抗压强度分别提高到 95.75 MPa 和 107.13 MPa。

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来源期刊

Accounts of Chemical Research 化学-化学综合

CiteScore

31.40

自引率

1.10%

发文量

312

审稿时长

2 months

期刊介绍： Accounts of Chemical Research presents short, concise and critical articles offering easy-to-read overviews of basic research and applications in all areas of chemistry and biochemistry. These short reviews focus on research from the author’s own laboratory and are designed to teach the reader about a research project. In addition, Accounts of Chemical Research publishes commentaries that give an informed opinion on a current research problem. Special Issues online are devoted to a single topic of unusual activity and significance. Accounts of Chemical Research replaces the traditional article abstract with an article "Conspectus." These entries synopsize the research affording the reader a closer look at the content and significance of an article. Through this provision of a more detailed description of the article contents, the Conspectus enhances the article's discoverability by search engines and the exposure for the research.