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摘要:
This study aimed to investigate the evolution of compressive strength and microstructure of hydrated magnesium silicate (MgO-SiO2-H2O) cement with Mg(OH)2 (MH) as a modifier under standard and carbonation curing conditions. Isothermal calorimetry, fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetry analysis (TGA) were used to analyze the hydration rate as well as the degree of hydration of the MgO-SiO2-H2O cements, and to determine the types of the physical phases and the mass fractions of the hydration products. The porosity structure and micro-morphology of MgO-SiO2-H2O cement were characterized by mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). The results indicated that MH could slightly enhance the fluidity of MgO-SiO2-H2O cement. As the dosage of MH increased, the compressive strength of MgO-SiO2-H2O cement showed an initial increase followed by a decrease, reaching optimal mechanical properties at a 1 % dosage. The addition of 1 % MH accelerated the hydration rate of MgO-SiO2-H2O cement and the formation of M-S-H gel. Carbonation curing could convert a portion of MH into hydrated magnesium carbonates (HMCs), improving the utilization of MgO, reducing the quantity of detrimental pores, and decreasing the porosity. Furthermore, considering the synergistic effects of MH and carbonation curing, the performance of MgO-SiO2-H2O cement could be further enhanced.
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来源 :
CONSTRUCTION AND BUILDING MATERIALS
ISSN: 0950-0618
年份: 2024
卷: 445
7 . 4 0 0
JCR@2022
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