TY - JOUR
T1 - Stability, hardening and porosity evolution during hydrothermal solidification of sepiolite clay
AU - Zhou, Lei
AU - Jing, Zhenzi
AU - Zhang, Yi
AU - Wu, Ke
AU - Ishida, Emile Hideki
N1 - Funding Information:
The work reported here was supported by the Shanghai Science and Technology Committee Program (China) (No. 09JC1413900 ) and the National Natural Science Foundation of China (Nos. 50872096 and 51072138 ).
PY - 2012/11
Y1 - 2012/11
N2 - Hydrothermal solidification of sepiolite clay was carried out at different curing temperatures (100 °C and 200 °C) with an introduction of calcium hydroxide. The addition of calcium hydroxide greatly affected the stability of sepiolite within sepiolite clay. When Ca/Si molar ratio (C/S) is lower than 0.4, sepiolite sustained well at both curing temperatures even for a long curing time (72 h), and above C/S = 0.4 sepiolite decomposed readily. During early-stage hydrothermal processing (before 12 h), fine-grained particles of calcium silicate hydrate (CSH) gel precipitated and provided an early strength enhancement for the specimens solidified at 100 °C and 200 °C respectively. After that, fibrous CSH(I) that formed after 12 h was responsible for the highest strength and platy tobermorite after 72 h led to a slight decrease in strength at 200 °C, while agglomerated sponge-like CSH gel formed after 72 h contributed to the highest strength at 100 °C. The intercrystalline pores of crystalline CSH, including CSH(I) and tobermorite, formed at 200 °C provided more porosity than the gel pores at 100 °C within solidified specimens.
AB - Hydrothermal solidification of sepiolite clay was carried out at different curing temperatures (100 °C and 200 °C) with an introduction of calcium hydroxide. The addition of calcium hydroxide greatly affected the stability of sepiolite within sepiolite clay. When Ca/Si molar ratio (C/S) is lower than 0.4, sepiolite sustained well at both curing temperatures even for a long curing time (72 h), and above C/S = 0.4 sepiolite decomposed readily. During early-stage hydrothermal processing (before 12 h), fine-grained particles of calcium silicate hydrate (CSH) gel precipitated and provided an early strength enhancement for the specimens solidified at 100 °C and 200 °C respectively. After that, fibrous CSH(I) that formed after 12 h was responsible for the highest strength and platy tobermorite after 72 h led to a slight decrease in strength at 200 °C, while agglomerated sponge-like CSH gel formed after 72 h contributed to the highest strength at 100 °C. The intercrystalline pores of crystalline CSH, including CSH(I) and tobermorite, formed at 200 °C provided more porosity than the gel pores at 100 °C within solidified specimens.
KW - Hardening
KW - Hydrothermal solidification
KW - Porosity
KW - Sepiolite clay
KW - Stability
KW - Tobermorite
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U2 - 10.1016/j.clay.2012.08.008
DO - 10.1016/j.clay.2012.08.008
M3 - Article
AN - SCOPUS:84867305614
VL - 69
SP - 30
EP - 36
JO - Applied Clay Science
JF - Applied Clay Science
SN - 0169-1317
ER -