Durability evaluation of cement exposed to combined action of chloride and sulphate ions at elevated temperature: The role of limestone filler

•Limestone filler role on cement durability exposed to SO4/Cl− ions, at elevated temperature.•Limestone presence led to less expansion and higher compressive strengths.•Non-expansive Friedel’s salt was formed in chloride baths reducing DEF.•Limestone filler reduced DEF and led to refinement of paste...

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Bibliographic Details
Published in:Construction & building materials 2016-10, Vol.124, p.558-565
Main Authors: Mavropoulou, N., Katsiotis, N., Giannakopoulos, J., Koutsodontis, K., Papageorgiou, D., Chaniotakis, E., Katsioti, M., Tsakiridis, P.E.
Format: Article
Language:English
Subjects:
Analysis
Blended cements
Cement
Chloride
Chlorides
Dichloropropane
Durability
Limestone filler
Mechanical properties
Sulphate attack
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Summary:•Limestone filler role on cement durability exposed to SO4/Cl− ions, at elevated temperature.•Limestone presence led to less expansion and higher compressive strengths.•Non-expansive Friedel’s salt was formed in chloride baths reducing DEF.•Limestone filler reduced DEF and led to refinement of paste pore structure. In the present investigation, the influence of sulphate and chloride ions combined action on cement durability and the role of limestone filler were investigated. Samples of a reference white CEM I42.5 (CRef) and the corresponding of a white CEM II42.5 (CL15) with a 15wt% limestone replacement were exposed for a period of 90days into three different curing baths (saturated Ca(OH)2 solution, 5wt% Na2SO4 solution and a composite solution of 5wt% Na2SO4 and 5wt% NaCl), at 50°C. Their compressive strengths were determined after 28, 56 and 90days of curing, whereas their expansion was estimated on a weekly basis by the length change measurement. The deterioration products characterization was carried out by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared spectrometry (FT-IR), Thermal Analysis (TG-DSC) and Mercury Intrusion Porosimetry (MIP). According to the results the addition of limestone filler led to the durability increment, as the corresponding mixtures presented lower expansion and higher compressive strengths, while in all cases the Cl ions presence mitigated the external sulphate attack, a fact that was mainly attributed to the Friedel’s salt formation.
ISSN:0950-0618
1879-0526
DOI:10.1016/j.conbuildmat.2016.07.134