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Metal Mine ›› 2025, Vol. 54 ›› Issue (10): 295-300.

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Effect of Coal Gasification Slag Content on the Properties and Hydration of Composite Alkali-Activated Cementitious Materials#br#

LU Ding1　ZHANG Jin1　HU Zhihang1,2,3　WANG Qing1,2,3　GU Xiaowei1,2,3　XU Xiaochuan1,2,3   

  1. 1. School of Resources and Civil Engineering,Northeastern University,Shenyang 110819,China;
    2. Liaoning Institute of Technological Innovation in Solid Waste Utilization,Shenyang 110819,China;3. Northeastern University
    Smart Water Conservancy and Resource Environment Science and Technology Innovation Center,Shenyang 110819,China
  • Online:2025-10-15 Published:2025-11-10

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Abstract: Coal gasification slag (CGS),rich in amorphous aluminosilicate minerals,has the potential to serve as a precursor
for alkali-activated materials (AAMs). This study investigated the technical feasibility of utilizing CGS to partially replace
granulated blast furnace slag (GBFS) in preparing AAMs. Different dosages of CGS (0,20%,40%,60%) were used to
replace GBFS, activated by NaOH. The macroscopic properties were evaluated by setting time, fluidity, and compressive
strength tests,while the early hydration process and hydration products were analyzed using isothermal calorimetry,X-ray diffraction
(XRD),thermogravimetric analysis (TG-DTG),and Fourier transform infrared spectroscopy (FTIR). The results
showed that CGS within 40% effectively mitigated the rapid setting of NaOH-AAMs,retarded the early hydration rate,and did
not impair the development of compressive strength. The compressive strength initially increased and then decreased with increasing
CGS content,reaching an optimum at 40% replacement,where the 28-day compressive strength was 29. 4 MPa,representing
a 15. 3% increase over the pure slag system. The primary hydration product was calcium (alumino) silicate hydrate
(C-(A)-S-H) gel,which was the main source of strength. However,when the CGS content increased to 60%,the formation of
C-(A)-S-H gel was significantly reduced,leading to a decrease in strength. This study demonstrates that CGS can effectively
replace part of GBFS in AAMs production,with an optimal dosage of 40%,providing a pathway for the high-value resource utilization
of coal gasification slag.

Key words: alkali-activated cementitious materials,coal gasification slag,slag,compressive strength,hydration reaction

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