Belite cements: modifications of calcium silicate hydrate (C-S-H) gel by alkaline hydrothermal activation

Journal Article · Sun Mar 15 04:00:00 EDT 2009 · ACI Materials Journal

OSTI ID:21176821

Guerrero, A; Goni, S; Dolado, J S ^[1]

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1. CSIC, Eduardo Torroja Inst. Construct. Sci., Madrid (Spain)

The C-S-H gel of two types of fly ash belite cements (FABC) are studied at a nanoscale (1 to 100 nm (39.4 to 3940 nin.)) by means of the specific surface area and pore-size distribution, which were measured by the sorption isotherms of nitrogen gas and the BET method. The two belite cements were fabricated by the hydro-thermal-calcination route of Class C fly ash in NaOH 1M solution (FABC-2-N) and demineralized water (FABC-2-W). Two differentiated zones in the pore-size distribution of the C-S-H gel at similar to 12 and similar to 3 nm (similar to 473 and similar to 118 nin.) with different influences in the mechanical strength were produced. The proportion of both zones depends on the age of hydration and type of belite cement. At early ages, the C-S-H gel of FABC-2-N develops both zones in a greater proportion than those of FABC-2-W. At later ages, the behavior is opposite: the C-S-H gel of FABC-2-W develops high proportion of pores of 3 nin (118 nm.) of diameter. Important quantitative correlations were found among these nanostructure characteristics of the C-S-H gel and macrostructural engineering property.

• OSTI ID: 21176821
• Journal Information: ACI Materials Journal, Journal Name: ACI Materials Journal Journal Issue: 2 Vol. 106; ISSN AMAJEF; ISSN 0889-325X
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
ADSORPTION ISOTHERMS
AGING
CALCIUM SILICATES
CEMENTS
FLY ASH
GELS
HYDRATION
MECHANICAL PROPERTIES
POROSITY
WASTE PRODUCT UTILIZATION