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Effect of Temperature on C 3 S and C 3 S + Nanosilica Hydration and C – S – H Structure
Author(s) -
Sáez del Bosque Isabel F.,
MartínPastor Manuel,
MartínezRamírez Sagrario,
BlancoVarela María Teresa
Publication year - 2013
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.12093
Subject(s) - chemistry , portlandite , rheology , chemical engineering , materials science , composite material , cement , portland cement , engineering
This study aimed to monitor the effect of temperature and the addition of nanosilica on the nanostructure of the C – S – H gel forming during tricalcium silicate ( C 3 S ) hydration. Two types of paste were prepared from a synthesized T 1 C 3 S . The first consisted of a blend of deionized water and C 3 S at a water/solid ratio of 0.425. In the second, a 90 wt% C 3 S + 10 wt% of nanosilica blend was mixed with water at a water/solid ratio of 0.7. The pastes were stored in closed containers at 100% RH and 25°C, 40°C, or 65°C. The hydration reaction was detained after 1, 14, 28, or 62 d with acetone, and then pastes were studied by 29 Si magic angle spinning nuclear magnetic resonance ( 29 Si MAS NMR ).The main conclusion was that adding n SA expedites C 3 S hydration at any age or temperature and modifies the structure of the C – S – H gel formed, two types of C – S – H gel appear. At 25°C and 40°C, more orderly, longer chain gels are initially (1 d) obtained as a result of the pozzolanic reaction between nSA and portlandite (CH) ( C – S – H II gel formation). Subsequently, ongoing C 3 S hydration and the concomitant flow of dimers shorten the mean chain length in the gel.