硅酸盐学报

活性炭及其碱改性对超硫酸盐水泥抗碳化性能的影响

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宋中旭 ¹ , 王洋 ² , 陈衡 ¹ , 葛勇 ²

硅酸盐学报 | 研究论文 2025,53(2): 406-415

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硅酸盐学报 |研究论文 2025 , 53 (2) : 406 -415

活性炭及其碱改性对超硫酸盐水泥抗碳化性能的影响

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宋中旭¹, 王洋², 陈衡¹, 葛勇²

作者信息

^1．济南大学山东省建筑材料制备与测试技术重点实验室，济南 250022

^2．哈尔滨工业大学交通科学与工程学院，哈尔滨 150090

通讯作者:

陈衡（1986—），男，博士，副教授。

作者简介:

宋中旭（1999—），男，硕士研究生。

Influence of Activated Carbon and Its Alkaline Treatment on Carbonation Resistance of Supersulfated Cement

Zhongxu SONG¹, Yang WANG², Heng CHEN¹, Yong GE²

Affiliations

^1.Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials, Jinan University, Jinan 250022, China

^2.School of Transportation Science and Engineering, Harbin Institute of Technology, Harbin 150090, China

Corresponding Author:

CHEN Heng (1986-), male, Ph.D., Associate Professor. E-mail: mse_chenh@ujn.edu.cn

SONG Zhongxu (1999-), male, Master candidate. E-mail: songzhxu@163.com

出版时间: 2025-02-20 doi: 10.14062/j.issn.0454-5648.20240030

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摘要

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超硫酸盐水泥（SSC）是一种由矿粉、石膏以及少量碱激发剂（5%以内，质量分数）组成的低碳胶凝材料，其抗碳化性能极差，已为其规模化应用重要瓶颈。将具有高CO₂吸附能力的活性炭和经氢氧化钙（CH）改性的活性炭掺入SSC（0.5%和1.0%，质量分数），探究它们对SSC碳化前后力学性能、碳化深度、物相组成、微观形貌的影响规律和机理。结果表明，活性炭可为SSC中C-（A）-S-H凝胶提供成核位点，增加C-（A）-S-H凝胶的生成量，提升C-（A）-S-H凝胶的Ca/Si比，密实孔隙结构，改善SSC的力学性能与抗碳化性能。然而，CH改性活性炭降低C-（A）-S-H凝胶的含量，增加浆体的碳化深度和孔隙率，显著降低SSC的力学性能与抗碳化性能。活性炭作为一种提升SSC抗碳化性能的有效组分，在其孔内负载其他功能组分，亦有望为SSC乃至其他水泥基材料的功能化提供重要手段。

关键词

超硫酸盐水泥 / 活性炭 / 抗碳化性能 / 微观结构

Abstract

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Introduction

Supersulfated cement (SSC) is a low-carbon material made from slag, gypsum, and a small amount of alkali activator. However, the poor carbonation resistance limits its large-scale application. In this study, activated carbon with high CO₂ adsorption capacity, as well as activated carbon modified by calcium hydroxide (CH), were doped into SSC (0.5% and 1.0%, in mass) to investigate the effects on the mechanical properties, carbonation depth, phase composition and microscopic morphology before and after the carbonation of SSC. This research aims at providing a effective methond to increase the carbonation resistance of SSC.

Methods

P·I 42.5 Portland cement (conforming to GB 175—2023), S95 powder, gypsum and coconut shell-based activated carbon particles (Jiangsu Hartel Carbon Materials Technology Co., Ltd.) were used. The activated carbon powder particles were ball-milled and passed through a 150 μm sieve. The activated carbon particles were immersed in saturated CH solution for 48 h and dried to obtain CH-modified activated carbon. The water-cement ratio of both paste and mortar specimens was 0.4. The dosage of activated carbon was 0, 0.5%, and 1.0% of the total mass, respectively. The compressive strength of mortar specimens (40 mm×40 mm×160 mm) were tested after curing for standard cured for 3, 28 d and after carbonation for 1, 3, 7, 14 d. The hydration degree of slag in SSC before carbonation was analyzed by EDTA method. The phase composition of hardened SSC before and after carbonation were measured by combination of a thermal gravimetric analyzer (TGA) and X-ray diffraction (XRD), The pore structure and micro-morphology hardened SSC before and after carbonation was tested by low-field nuclear magnetic resonance (LF-NMR, field emission scanning electron microscopy (ZEISS GeminiSEM 560), respectively.

Results and Discussion

Activated carbon significantly improved the carbonation resistance and mechanical properties of SSC. Similar to nanomaterials such as carbon nanotubes, the active functional groups on the surface of activated carbon can provide nucleation sites for the growth of C-(A)-S-H gels, a phenomenon that has been confirmed by SEM results. Combined with the analysis of TG and XRD, it can be seen that this nucleation effect increases the number of C-(A)-S-H gels in the SSC. Meanwhile, according to the LF-NMR, the activated carbon would decrease the porosity and critical pore size of the SSC, thus enhance the compressive strength before and after carbonation.

After carbonation, the activated carbon group generated more calcite than the control group. This indicates that activated carbon promotes the formation of C-(A)-S-H gel and possibly increases the proportion of Ca²⁺ in the gel. This is related to the strong adsorption capacity of activated carbon for Ca²⁺. Therefore, the mechanism by which activated carbon enhances the carbonation resistance of SSC is as follows: Activated carbon provides nucleation sites for C-(A)-S-H gel, promotes the formation of C-(A)-S-H gel, densifies the pore structure, thereby improving the mechanical properties and carbonation resistance of SSC. Furthermore, the clusters formed by activated carbon and C-(A)-S-H gel contribute to improve the distribution uniformity of the gel within SSC, further enhancing structural stability.

Furthermore, activated carbon has a high CO₂ adsorption capacity. After the carbonation decomposition of the C-(A)-S-H gel encapsulated on the surface of activated carbon, the exposed activated carbon can absorb the invading CO₂. Saturated activated carbon might act as a 'barrier' to CO₂, preventing CO₂ penetration and further enhancing carbonation resistance.

The carbonation resistance effect of CH-modified activated carbon is significantly lower than that of activated carbon. The CH distributed in the activated carbon could have dissolved into the liquid phase of the SSC and mainly act as an alkali activator. This leads to an excessive amount of alkali activator in the SSC system, thus reducing the C-(A)-S-H gel content, increasing the AFt content, and making the overall structure looser and more susceptible to carbonation. Therefore, activated carbon is effective in enhancing SSC's carbonation resistance and can also be used to load other functional components.

Conclusions

This study demonstrates that activated carbon could significantly enhance the performance of SSC, particularly the mechanical properties and carbonation resistance. The results show that activated carbon can provide more nucleation sites for the generation of C-(A)-S-H gels, enhance the Ca/Si of C-(A)-S-H gels, increase the amount of C-(A)-S-H gel, densify the pore structure, and improve the compressive strength by 10.6% at the dosage of 0.5%. However, the enhancement effect diminishes at higher activated carbon content.

In contrast, CH-modified activated carbon would lead to increase in the carbonation depth and porosity of SSC, significantly reducing its mechanical properties and carbonation resistance. This could be due to CH-modified activated carbon fails to effectively adsorb and immobilize CO₂, instead of raising the alkali activator content in SSC. The excess alkali activator results in a decrease in C-(A)-S-H gel content, an increase in AFt content, and a more porous and easily carbonated structure.

This paper demonstrates the significant practical value of activated carbon as a low-cost material. It not only greatly enhances the mechanical properties and carbonation resistance of SSC, but also offers greater functionalization potential due to its porous structure. By loading other components into the pores of activated carbon, activated carbon is expected to provide an effective means for the functionalization of SSCs and even other materials. The multifunctionality of activated carbon not only opens up new paths for optimizing the properties of materials, but also offers the possibility in a wider range of construction materials in the future.

Key words

supersulfated cement / activated carbon / carbonation resistance / micro-structure

引用本文

宋中旭, 王洋, 陈衡, 葛勇. 活性炭及其碱改性对超硫酸盐水泥抗碳化性能的影响. 硅酸盐学报, 2025 , 53 (2) : 406 -415 . DOI: 10.14062/j.issn.0454-5648.20240030

Zhongxu SONG, Yang WANG, Heng CHEN, Yong GE. Influence of Activated Carbon and Its Alkaline Treatment on Carbonation Resistance of Supersulfated Cement[J]. Journal of the Chinese Ceramic Society, 2025 , 53 (2) : 406 -415 . DOI: 10.14062/j.issn.0454-5648.20240030

基金

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国家自然科学基金(52102021)
山东省自然科学基金(ZR2021QE058)

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2025年第53卷第2期

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文章信息

doi: 10.14062/j.issn.0454-5648.20240030

接收时间：2024-01-11
首发时间：2026-10-22
出版时间：2025-02-20

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收稿日期：2024-01-11
修回日期：2024-03-04

基金

国家自然科学基金(52102021)

山东省自然科学基金(ZR2021QE058)

作者信息

^1．济南大学山东省建筑材料制备与测试技术重点实验室，济南 250022

^2．哈尔滨工业大学交通科学与工程学院，哈尔滨 150090

通讯作者:

陈衡（1986—），男，博士，副教授。

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https://castjournals.cast.org.cn/joweb/gsyxb/CN/10.14062/j.issn.0454-5648.20240030

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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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