International Concrete Abstracts Portal

Title: Utilization of jarosite/alunite residue for mortars restoration production

Author(s): O. Mauridou, A. Moropoulou, E. Aggelakopoulou

Publication: RILEM

Volume: 43

Issue: 1

Appears on pages(s): 167-177

Keywords: Restoration mortars, Lime, Jarosite/alunite residue, Mechcanical Strength, Characterization

DOI:

Date: 12/1/2009

Abstract:
he present study was carried out to produce artificial hydraulic lime mortars for repair and conservation of historic masonry using a jarosite/alunite precipitate, a waste product of a novel Greek hydrometallurgical process developed to treat economically low grade nickel oxides ores. Alternative mortars were prepared by mixing lime powder, quartz sand and the above residue, substituting lime up to 50%. The mortars were prepared and tested according to European Norm EN 1015. They were cured for periods of 28 and 90 days and the compressive and flexural strengths were determined. The best mechanical behavior was observed for the mortar with 50% lime replacement, which also presented a low ratio of compressive to flexural strength (f c/f f). X-Ray diffraction, TG-DTA and mercury porosimetry were used to characterize the hydration products at 28 and 90 days. The results showed that the jarosite/alunite residue was dissolved in the high alkaline environment of the mortar, producing CaSO4 · 2H2O and AlOOH. During hydration, gypsum and some of the Ca(OH)2 were consumed, together with aluminum hydroxide in order to produce ettringite, a fact that improved the mechanical behavior of the produced mortars.