An efficient approach for sustainable fly ash geopolymer by coupled activation of wet-milling mechanical force and calcium hydroxide

被引：33

作者：

Yang, Jin ^{[1
,2
]}

Tang, Yuanzhen ^{[1
]}

He, Xingyang ^{[1
,2
]}

Su, Ying ^{[1
,2
]}

Zeng, Jingyi ^{[1
]}

Ma, Mengyang ^{[3
]}

Zeng, Linghao ^{[1
]}

Zhang, Shaolin ^{[4
]}

Tan, Hongbo ^{[5
]}

Strnadel, Bohumir ^{[3
]}

机构：

[1] Hubei Univ Technol, Sch Civil Engn Architecture & Environm, Wuhan 430068, Peoples R China

[2] Hubei Univ Technol, Bldg Waterproof Engn & Technol Res Ctr Hubei Prov, Wuhan 430068, Peoples R China

[3] VSB Tech Univ Ostrava, Ctr Adv & Innovat Technol, Ostrava 70800, Czech Republic

[4] China Construct Third Bur First Engn Co LTD, Wuhan 430040, Peoples R China

[5] Wuhan Univ Technol, State Key Lab Silicate Mat Architecture, Wuhan 430070, Peoples R China

来源：

JOURNAL OF CLEANER PRODUCTION | 2022年 / 372卷

关键词：

Wet; -milling; Fly ash; Compressive strength; Calcium hydroxide; Geopolymer; COMPRESSIVE STRENGTH; NAOH CONCENTRATION; SODIUM-CARBONATE; SLAG; PERFORMANCE; MICROSTRUCTURE; EFFLORESCENCE; RHEOLOGY; BEHAVIOR;

D O I：

10.1016/j.jclepro.2022.133771

中图分类号：

X [环境科学、安全科学];

学科分类号：

08 ; 0830 ;

摘要：

Geopolymer is a potential substitute for high-emission cement production. Therefore, the use of fly ash with high emission as a geopolymer is an environmentally friendly and inexpensive direction. However, fly ash (FA) is a high amorphous precursor with low pozzolanic reactivity making it difficult to be activated by calcium hy-droxide. In this study, the coupling of wet-milling mechanical force and calcium hydroxide was used to prepare high-performance alkaline calcium activated geopolymers. Two kinds of FA slurries with different particle sizes of D-50 = 2.96 mu m and 14.2 mu m were prepared, activated by calcium hydroxide (CH) with the content of 4%, 11% and 19%. Results indicated that the increase of calcium hydroxide content was beneficial to developing strength, effectively improving the chloride resistance, compacting the microstructure, but increasing the autogenous shrinkage of the geopolymers. These improvements are especially apparent in the wet-milled fly ash geopolymers (WFA) due to the pre-depolymerization implemented by wet-milled mechanical forces, and coupled with the activation effect of CH to improve the depolymerization efficiency and condensation reaction. The compressive strength of WF-CH-19 was three times higher than that of FA-CH-19, reaching 29.3 MPa at 28 d, and the compressive strength growth of WF-CH-11 even reached 591.67% at 1 d. Meanwhile, the main chain length (MCL) and Al/Si of calcium silicate hydrates were clearly improved, and pore structure was significantly refined with capillary pore increased from 29.79% to 89.23%. In addition, FA and WFA geopolymers have significant advantages over Portland cement in the environmental impact indicators such as E-energy and E-CO2.

引用

页数：13