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Influence of metakaolin on the conversion and compressive strength of quaternary phase paste
Author(s) -
Ding Wenwen,
He Yongjia,
Lu Linnu,
Wang Fazhou,
Hu Shuguang
Publication year - 2020
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.17409
Subject(s) - metakaolin , dissolution , aluminate , phase (matter) , precipitation , materials science , solubility , hydrate , compressive strength , calcium silicate hydrate , chemical engineering , cement , mineralogy , chemistry , composite material , organic chemistry , physics , meteorology , engineering
Application of calcium aluminate cement in construction faces the challenges of high manufacturing cost and volumetric instability associated with hydrates conversion. This work introduces a newly developed high‐performance Ca 20 Al 26 Mg 3 Si 3 O 68 (Q phase)‐metakaolin (MK) composite binder. The influence of MK on the conversion and strength development of Q phase paste cured at 40°C was investigated. The mechanism of MK on the stability of synthetic hydrate was studied by solution chemistry, XRD, and NMR. The pure Q phase paste experiences a significant strength reduction due to hydrates conversion, whereas the Q phase paste containing 15% MK exhibits a continuous increase in strength. MK promotes the formation of CAH 10 , contributing to the refinement of pore structure and enhanced mechanical property. The Al V and Al IV dissolved from MK increase the Al(OH) 4 ‐ concentration in the pore solution, and then the solubility of CAH 10 decreases due to the common‐ion effect, thus inhibiting the subsequent precipitation of C 3 AH 6 . In addition, the release of dissolved alumina from MK considerably impedes silica dissolution, and consequently, the formation of C 2 ASH 8 is hindered at a higher content of MK.