Role of aluminous component of fly ash on the durability of Portland cement-fly ash pastes in marine environment

Journal Article · Tue Jul 01 04:00:00 EDT 2003 · Waste Management

DOI:https://doi.org/10.1016/S0956-053X(03)00030-8· OSTI ID:20875616

Lorenzo, MaP; Goni, S; Guerrero, A

The durability, of mixtures of two kinds of Spanish fly ashes from coal combustion (ASTM class F) with 0, 15 and 35% replacement of Portland cement by fly ash, in a simulated marine environment (Na{sub 2}SO{sub 4}+NaCl solution of equivalent concentration to that of sea water: 0.03 and 0.45 M for sulphate and chloride, respectively), has been studied for a period of 90 days. The resistance of the different mixtures to the attack was evaluated by means of the Koch-Steinegger test. The results showed that all the mixtures were resistant, in spite of the great amount of Al{sub 2}O{sub 3} content of the fly ash. The diffusion of SO{sub 4}{sup 2-}, Na{sup +} and Cl{sup -} ions through the pore solution activated the pozzolanic reactivity of the fly ashes causing the corresponding microstructure changes, which were characterized by X-ray diffraction (XRD), mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). As a result, the flexural strength of the mixtures increased, principally for the fly ash of a lower particle size and 35% of addition.

• OSTI ID: 20875616
• Journal Information: Waste Management, Journal Name: Waste Management Journal Issue: 8 Vol. 23; ISSN WAMAE2; ISSN 0956-053X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ALUMINIUM OXIDES
CHLORINE IONS
COAL
ENVIRONMENT
FLEXURAL STRENGTH
FLY ASH
PORTLAND CEMENT
SCANNING ELECTRON MICROSCOPY
SEAWATER
SODIUM CHLORIDES
SODIUM IONS
SODIUM SULFATES
WATER POLLUTION
WATER POLLUTION CONTROL
X-RAY DIFFRACTION