Effects of limestone replacement ratio on the sulfate resistance of Portland limestone cement mortars exposed to extraordinary high sulfate concentrations

TOSUN FELEKOĞLU K., FELEKOĞLU B., Baradan B., Altun I. A.

CONSTRUCTION AND BUILDING MATERIALS, vol.23, no.7, pp.2534-2544, 2009 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 23 Issue: 7
  • Publication Date: 2009
  • Doi Number: 10.1016/j.conbuildmat.2009.02.039
  • Journal Name: CONSTRUCTION AND BUILDING MATERIALS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.2534-2544
  • Keywords: Portland limestone cement, Sulfate attack, Ettringite, Expansion, pH, THAUMASITE FORMATION, CONCRETE DETERIORATION, MINERAL ADMIXTURES, BLENDED CEMENTS, ATTACK TSA, TEMPERATURE, ETTRINGITE, FILLER, HYDRATION, FORM
  • Dokuz Eylül University Affiliated: Yes

Abstract

A comparative study has been performed on the sulfate resistance of Portland limestone cement (PLC) mortars exposed to extraordinary high sulfate concentrations (200 g/l). PLCs have been prepared by using two types of clinkers having different C3S/C2S ratios and interstitial phase morphologies. Blended cements have been prepared by replacing 5%, 10%. 20% and 40% of clinker with limestone. Cubic (50 x 50 x 50 mm) and prismatic (25 x 25 x 285 mm) cement mortars were prepared. After two months initial water curing, these samples were exposed to three different sulfate solutions (Na2SO4 at 20 degrees C and 5 degrees C, MgSO4 at 5 degrees C). Solutions were not refreshed and pH values of solutions were monitored during the testing stage. The compressive strength and length changes of samples have been monitored for a period of I year. Additional microstructural analyses have been conducted by XRD and SEM/EDS studies. Results indicated that in general, limestone replacement ratio and low temperature negatively affect the sulfate resistance of cement mortars. Additionally, clinkers of high C3S/C2S ratios with dendritic interstitial phase structure were found to be more prone to sulfate attack in the presence of high amounts of limestone.