TY - JOUR
T1 - Reaction mechanism of dolomite powder in Portland-dolomite cement
AU - Xu, Jiangtao
AU - Lu, Duyou
AU - Zhang, Shaohua
AU - Xu, Zhongzi
AU - Hooton, R. D.
N1 - Publisher Copyright:
© 2020 Elsevier Ltd
PY - 2021/2/8
Y1 - 2021/2/8
N2 - The purpose of this study is to provide a better understanding of the reaction mechanism of dolomite powder in Portland-dolomite cement (PDC). The hydration products and microstructure of PDC pastes were investigated by using XRD, TGA, MIP, and SEM, with Portland-limestone cement (PLC) as a comparison. Results show that dolomite exhibited a considerably higher chemical reactivity than limestone as the curing temperature increased. Different from the conventional dedolomitization reaction with brucite formation, the dolomite reaction in PDC at 40 and 60 °C produced hydrotalcite and calcite at the expense of portlandite. Moreover, the formed hydrotalcite was found to result in the decomposition of the Al-bearing products, such as monosulfate, monocarbonate and ettringite, due to its lower solubility. Overall, the reaction of dolomite increased the solid volume, densified the microstructure, and thus resulted in a refined pore structure and a higher long-term compressive strength of PDC compared to PLC.
AB - The purpose of this study is to provide a better understanding of the reaction mechanism of dolomite powder in Portland-dolomite cement (PDC). The hydration products and microstructure of PDC pastes were investigated by using XRD, TGA, MIP, and SEM, with Portland-limestone cement (PLC) as a comparison. Results show that dolomite exhibited a considerably higher chemical reactivity than limestone as the curing temperature increased. Different from the conventional dedolomitization reaction with brucite formation, the dolomite reaction in PDC at 40 and 60 °C produced hydrotalcite and calcite at the expense of portlandite. Moreover, the formed hydrotalcite was found to result in the decomposition of the Al-bearing products, such as monosulfate, monocarbonate and ettringite, due to its lower solubility. Overall, the reaction of dolomite increased the solid volume, densified the microstructure, and thus resulted in a refined pore structure and a higher long-term compressive strength of PDC compared to PLC.
KW - Dolomite powder
KW - Hydration products
KW - Reaction mechanism
UR - http://www.scopus.com/inward/record.url?scp=85096015577&partnerID=8YFLogxK
U2 - 10.1016/j.conbuildmat.2020.121375
DO - 10.1016/j.conbuildmat.2020.121375
M3 - 文章
AN - SCOPUS:85096015577
SN - 0950-0618
VL - 270
JO - Construction and Building Materials
JF - Construction and Building Materials
M1 - 121375
ER -