硅酸盐学报

高钾硅酸盐水泥熟料中C₂S-α’_L的形成及其对水化性能的影响

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杨庆春 ¹ , 吴佳明 ² , 于丽波 ² , 高兆霖 ² , 蒋军 ³ , 叶正茂 ¹^,²

硅酸盐学报 | 低碳水泥与固废资源化利用专题—研究论文 2026,54(5): 1564-1575

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硅酸盐学报 |低碳水泥与固废资源化利用专题—研究论文 2026 , 54 (5) : 1564 -1575

高钾硅酸盐水泥熟料中C₂S-α’_L的形成及其对水化性能的影响

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杨庆春¹, 吴佳明², 于丽波², 高兆霖², 蒋军³, 叶正茂¹^,²

作者信息

^1．热带海洋工程材料及评价全国重点实验室，海南大学，海口 570228

^2．济南大学材料科学与工程学院，济南 250022

^3．盐城工学院材料科学与工程学院，江苏盐城 224051

通讯作者:

叶正茂（1975—），男，博士，教授。

作者简介:

杨庆春（1997—），男，博士。

Formation of C₂S-α'_L in High-Potassium Portland Cement Clinker and Its Influence on Hydration Performance

Qingchun YANG¹, Jiaming WU², Libo YU², Zhaolin Gao², Jun JIANG³, Zhengmao YE¹^,²

Affiliations

^1.State Key Laboratory of Tropic Ocean Engineering Materials and Materials Evaluation, Hainan University, Haikou 570228, China

^2.School of Materials Science and Engineering, University of Jinan, Jinan 250022, China

^3.College of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, Jiangsu, China

Corresponding Author:

YE Zhengmao (1975-), male, Ph.D., Professor. E-mail: mse_yezm@ujn.edu.cn

YANG Qingchun (1997-), male, Ph.D. E-mail: yangqigchun@163.com

出版时间: 2025-08-12 doi: 10.14062/j.issn.0454-5648.20250335

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摘要

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随着中国优质石灰石资源的逐年降低及水泥窑协同处置的发展，熟料中的钾含量逐渐升高，使得熟料的28 d抗压强度降低。从矿物角度出来，虽然硅酸三钙（C₃S）和K₂O稳定的硅酸二钙（C₂S）多晶型均能有效提高熟料的28 d抗压强度，但是它们的含量存在竞争关系。本工作制备了一系列不同C₃S与C₂S-α’_L相比例的高钾硅酸盐水泥熟料，并借助X射线衍射、扫描电子显微镜、水化热分析等技术，研究了不同C₃S/C₂S-α’_L比例的高钾硅酸盐熟料矿物组成及水化行为。结果表明：随着C₃S/C₂S-α’_L比例的升高，C₂S-α’_L/C₂S-β及铝酸三钙/铝铁酸四钙（C₃A/C₄AF）的比值均升高；C₃S的颗粒尺寸增大并且边缘逐渐失去棱角，同时表面腐蚀坑增多；C₂S逐渐展现出更明显的双晶纹，其固溶的K⁺和Al³⁺逐渐减少，而中间相中K⁺的固溶量则增加。3 d水化放热量增加，但C₃A的二次水化峰提前出现，同时生成更多Hc相。本工作为提高硅酸盐水泥的熟料28 d抗压强度提供了一种新方法，并为高钾石灰石地区水泥工业的绿色低碳发展提供了理论指导。

关键词

高钾硅酸盐水泥熟料 / C₃S/C₂S-α’_L比例 / 矿物组成 / 水化性能

Abstract

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Introduction

Conventional modification of high-potassium cement clinker relies on adding SO₃ to reduce K₂O solid solution and boost C₃S content. However, SO₃ causes operational issues and stabilizes low-reactive C₂S-β, compromising strength. In this study, SO₃ was used to stabilize highly reactive C₂S-α'_L as a strength-enhancing phase, while K⁺ could suppress C₃S formation. To harness this "contradictory duality", an optimal C₃S/C₂S-α'_L ratio that could maximize the strength contribution of C₂S-α'_L without significantly sacrificing C₃S was established. This strategy could overcome the limitations of SO₃-based methods and enable an efficient utilization of high-potassium limestone.

Methods

Raw meals were formulated from analytical-grade reagents (i.e., CaCO₃, SiO₂, Al₂O₃, Fe₂O₃, K₂CO₃, CaSO₄·2H₂O ≥ 99.0%) with fixed silica modulus (SM=2.2), alumina modulus (IM=1.5), and K₂O content (2%, in mass). The lime saturation factor (KH) was adjusted from 0.84 to 0.92 to modulate C₃S/C₂S ratios. Raw materials were wet ground in a ball mill at 600 r/min for 1.5 h, dried at 105 ℃, pelletized under 100 kN, and then step-calcined (i.e., 950 ℃/1 h → 1450 ℃/30 min). The materials were followed by rapid air-quenching to inhibit C₂S-γ formation. The resulting clinker was dry ground to a fine powder with the sizes of ≤200 mesh, blended with gypsum of 3%, and cast into paste specimens (20 mm×20 mm×20 mm, w/c=0.3) for standard curing at 20 ℃ and 95% RH for 3-d/28-d ages.

The chemical composition was analyzed on borate-pressed pellets with a starch binder of 10% by X-ray fluorescence spectrometry (XRF). The phase quantification was determined by X-ray diffraction (XRD)-Rietveld refinement (Bruker D8 Advance, 5°-80°, 40 kV/20 mA) via a software named TOPAS V4. 2 with March-Dollase texture correction for the key phases. The microstructural evolution was characterized by scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS) (gold-sputtered polished sections, 10-point EDS averaging) and optical microscopy (NH₄Cl-etched surfaces). The hydration kinetics were monitored by isothermal calorimetry (TAM Air, at 20 ℃ for 72 h), while the thermal decomposition behavior was assessed by thermogravimetric analysis (TGA) (RT→550 ℃ at 10 ℃/min under N₂). The amorphous content in hydration products was quantified using corundum internal standard (20%) after ethanol immersion and vacuum drying.

Results and discussion

The results demonstrate that elevating the C₃S/ C₂S-α'_L ratio fundamentally restructures phase equilibria and ion distribution. As the ratio increases from 0.78 to 1.80, K⁺ solid solubility in C₂S is decreased by ~42% (quantified via EDS point analysis), destabilizing the metastable α'_L phase and triggering its transformation to C₂S-β, which is evidenced by α'_L content reducti on from 39.27% to 25.08% and intensified twinning striation. Concurrently, K⁺ migration toward interstitial phases increases the conversion from C₃A-o to C₃A-c, correlating with increasing C₃A content (i.e., from 9.97% to 1.02%) and declining C₄AF (i.e., from 8.94% to 7.39%). Based on the microstructural analysis, enlarged C₃S crystals with prominent etch pits emerge at high ratios due to K⁺-enriched liquid phases suppressing nucleation, while promoting disordered growth. This is compounded by elevated C₃A/C₄AF ratios increasing melt viscosity, hindering ion diffusion. The elemental mapping confirms that K⁺ predominantly partitions into C₂S and interstitial phases, with minimal C₃S incorporation (i.e., <0.3%, in mole).

The mechanical performance exhibits dual-phase characteristics. The 3-d strength is increased by ~18 MPa across the ratio gradient, driven by three synergistic factors, i.e., increased C₃A hydration activity, accelerated reaction kinetics from free CaO, and enhanced C₃S surface defects. The 28-d strength is declined by ~12 MPa, mechanistically linking to hydration restructuring. The result of calorimetry reveals sulfate depletion peaks advancing for 1.7 hours at higher ratios due to a rapid gypsum consumption by abundant C₃A. This shifts hydration products from AFt to Hc phases, which is evidenced by the XRD quantification, where AFt content decreases from 5.44% to 1.19% at 3 d, while Hc increases from 3.94% to 6.14%. At 28 d, Hc dominates (i.e., 7.55% at the highest ratio), with AFt nearly depleted (i.e., 0.27%).

The C-S-H gel morphology transitions from needle-like aggregates (i.e., Ca/Si=1.99 at a low ratio) to flaky networks (i.e., Ca/Si=1.26 at a high ratio). This structural shift reduces K⁺ adsorption capacity. The data establishe a Ca/Si ratio as a critical variable governing gel-K⁺ interactions, resolving prior discrepancies.

Conclusions

As the C₃S / C₂S-α'_L ratio decreased, the solid solubility of K⁺ and Al³⁺ in C₂S declined, whereas K⁺ incorporation in interstitial phases increased. This ultimately reduced the C₂S-α'_L / C₂S-β ratio in clinker, while elevating the C₃A-o/C₃A-c ratio. Decreasing the ratio could significantly enlarge C₃S particle size in high-potassium clinker, resulting in less distinct edges and increased etch pits. Although the fundamental morphology of C₂S remained largely unchanged, its surface became rougher with pronounced twinning striations.

The 3-day compressive strength of high-potassium clinker diminished at a lower C₃S/ C₂S-α'_L ratio, whereas the 28-day strength exhibited an inverse trend. As C₂S-α'_L competitiveness weakened, the peak heat flow and cumulative heat release in hydration curves both intensified. However, the sulfate depletion peak could emerge earlier, accompanied by increased hydrocalumite (Hc) phase content, further amplified when C₃S dominated over C₂S-α'_L.

The C-S-H gel morphology transitioned from aggregated needle-like fibers at low C₃S/ C₂S-α'_L ratios to flake-assembled network structures at high C₃S/ C₂S-α'_L ratios.

Key words

high potassium silicate cement clinker / C₃S/C₂S-α'_L ratio / mineral composition / hydration behavior

引用本文

杨庆春, 吴佳明, 于丽波, 高兆霖, 蒋军, 叶正茂. 高钾硅酸盐水泥熟料中C₂S-α’_L的形成及其对水化性能的影响. 硅酸盐学报, 2026 , 54 (5) : 1564 -1575 . DOI: 10.14062/j.issn.0454-5648.20250335

Qingchun YANG, Jiaming WU, Libo YU, Zhaolin Gao, Jun JIANG, Zhengmao YE. Formation of C₂S-α'_L in High-Potassium Portland Cement Clinker and Its Influence on Hydration Performance[J]. Journal of the Chinese Ceramic Society, 2026 , 54 (5) : 1564 -1575 . DOI: 10.14062/j.issn.0454-5648.20250335

基金

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国家自然科学基金(52172018; 52302021)
山东省重点研发计划(2021CXGC010301)

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2026年第54卷第5期

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文章信息

doi: 10.14062/j.issn.0454-5648.20250335

接收时间：2025-04-28
首发时间：2026-09-20
出版时间：2025-08-12

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出版历史

收稿日期：2025-04-28
修回日期：2025-05-19

基金

国家自然科学基金(52172018; 52302021)

山东省重点研发计划(2021CXGC010301)

作者信息

^1．热带海洋工程材料及评价全国重点实验室，海南大学，海口 570228

^2．济南大学材料科学与工程学院，济南 250022

^3．盐城工学院材料科学与工程学院，江苏盐城 224051

通讯作者:

叶正茂（1975—），男，博士，教授。

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2种不同金属材料的力学参数

科 Family	属数 Number of genus	种数 Number of species	占总种数比例 Percentage of total species (%)	属 Genus	种数 Number of species	占总种数比例 Percentage of total species (%)
鹅膏菌科Amanitaceae	2	11	5.26	鹅膏菌属 Amanita	10	4.78
小菇科 Mycenaceae	2	12	5.74	丝盖伞属 Inocybe	5	2.39
多孔菌科 Polyporaceae	8	14	6.70	蜡蘑属 Laccaria	5	2.39
红菇科 Russulaceae	3	23	11.00	小皮伞属 Marasmius	6	2.87
				小菇属 Mycena	11	5.26
				光柄菇属 Pluteus	5	2.39
				红菇属 Russula	17	8.13
				栓菌属 Trametes	5	2.39

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