Kinetics of Reaction in Cementitious Pastes Containing Silica Fume as Studied by 29Si MAS NMR

1998 ◽  
pp. 245-268 ◽  
Author(s):  
Harald Justnes
Keyword(s):  
Silica Fume ◽  
Mas Nmr ◽  
29Si Mas Nmr ◽  
Kinetics Of Reaction ◽  
Kinetics Of

Alkali activation of reactive silicas in cements: in situ 29Si MAS NMR studies of the kinetics of silicate polymerization

1996 ◽  
Vol 31 (13) ◽  
pp. 3365-3373 ◽  
Author(s):  
A. R. Brough ◽  
C. M. Dobson ◽  
I. G. Richardson ◽  
G. W. Groves
Keyword(s):  
Mas Nmr ◽  
Alkali Activation ◽  
29Si Mas Nmr ◽  
Nmr Studies ◽  
Kinetics Of

Hydration Activity of Silica Fume and its Effect on the Structure of C-S-H Gel

2013 ◽  
Vol 275-277 ◽  
pp. 2084-2087
Author(s):  
Lei Wang ◽  
Zhen He ◽  
Jianjun Yan
Keyword(s):  
Silica Fume ◽  
Chain Length ◽  
Cement Paste ◽  
Chemical Species ◽  
Pozzolanic Reaction ◽  
Mas Nmr ◽  
Experimental Results ◽  
Average Chain Length ◽  
29Si Mas Nmr ◽  
Alkaline Environment

Hydration activity of silica fume(SF) and its effect on the structure of C-S-H gel in silica fume-cement (SFC)pastes was studied by FTIR and 29Si MAS NMR combined with deconvoluton technique, respectively. The experimental results indicate that the cement of 48% and the SF of 41% can react in the paste with SF replacement for cement was 10% by weight and the average chain length (ACL) of SiO4 and/or AlO4 tetrahedra in C-S-H was 3.0 at 3d. At 120d, the cement of 65% and the SF of 96% could react, and the ACL of C-S-H was 3.7, which was higher than that in the plain cement paste (ACL was 3.1). In the highly alkaline environment of the cement paste, pozzolanic reaction of silica fume can potentially occur in two ways, the monosilicate formed after the structure of silica fume were broken can combine with Ca cations to form C-S-H directly. Moreover, these chemical species can also connect C-S-H dimers into highly polymerized C-S-H and increase the ACL of C-S-H.

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