THE PROBLEM OF THE SULPHATE RESISTANCE OF SLAG CEMENTS

THREE CLINKERS WITH CALCULATED TRICALCIUM ALUMINATE CONTENTS OF 10%, 8% AND 11% AND TWO GRANULATED BLAST-FURNACE SLAGS WITH ALUMINUM OXIDE CONTENTS OF 11.0% AND 17.7% WERE SEPARATELY GROUND TO SPECIFIC SURFACE VALUES OF 3000 SQUARE CENTIMETERS/G AND 5000 SQUARE CENTIMETERS/G (ACCORDING TO BLAINE). WITH THE ADDITION OF 5% GYPSUM, SLAG CEMENTS WITH BLASTFURNACE SLAG CONTENTS OF 5%, 15%, AND 85% WERE MANUFACTURED FROM THESE INGREDIENTS AND WERE TESTED FOR SULPHATE RESISTANCE BY MEANS OF THE SMALL PRISM METHOD. IN ADDITION, THE HYDRATE PHASES AND THE COMPOUNDS WHICH ARE FORMED IN THE REACTION WITH A 4.4% SODIUM SULPHATE SOLUTION WERE IDENTIFIED BY X-RAY ANALYSIS. THE TESTS FOR DETERMINING THE SULPHATE RESISTANCE SHOWED THAT PORTLAND BLASTFURNACE CEMENTS (HOCHOFEN CEMENTS) ARE RESISTANT TO SULPHATE ATTACK - IRRESPECTIVE OF THE COMPOSITION OF THEIR CLINKER AND BLAST-FURNACE SLAG COMPONENTS - IF THEY CONTAIN AT LEAST 65% GRANULATED BLASTFURNACE SLAG. SUCH CEMENTS CONTAINING LESS THAN 65% SLAG ARE SULPHATE-RESISTANT IF THE CLINKER COMPONENT HAS A LOW ALUMINA CONTENT. FINER GRINDING OF THE SLAG COMPONENT INCREASES THE SULPHATE RESISTANCE IF THE CEMENT CONTAINS MORE THAN 65% SLAG, AND LOWERS THE SULPHATE RESISTANCE IF THE SLAG CONTENT IS BELOW 65%. X-RAY INVESTIGATION SHOWED PORTLAND CEMENT FREE FROM TRICALCIUM ALUMINATE TO BE SULPHATE-RESISTANT BECAUSE ITS HYDRATION PRODUCTS CANNOT REACT WITH SULPHATE. IN THE HYDRATION OF SULPHATE-RESISTANT SLAG CEMENTS SULPHATE-SENSITIVE HYDRATION PRODUCTS ARE ALWAYS FORMED, BUT THESE CAN REACT WITH SULPHATE TO FORM TRISULPHATE (ETTRINGITE) ONLY IF THEY ARE SUSPENDED IN THE SULPHATE SOLUTION, BUT NOT IF THEY ARE CONTAINED IN A SAMPLE OF MORTAR. THIS CAN BE EXPLAINED EITHER ON THE ASSUMPTION THAT NO TRISULPHATE NUCLEI ARE ABLE TO FORM IN THE PORES OF THE HARDENED CEMENT PASTE CONSISTING OF SULPHATE-RESISTANT SLAG CEMENT, OR THAT THE DIFFUSION RESISTANCE OF THE HARDENED CEMENT PASTE IS SO GREAT THAT NO SULPHATE IONS CAN PENETRATE IT. /AUTHOR/

• Supplemental Notes:
  • Vol 19, No 9, PP 395-401
• Authors:
  • Locher, F W
• Publication Date: 1966-9

Media Info

• Serial:
  • Zement-Kalk-Gips

Subject/Index Terms

• TRT Terms: Aluminates; Aluminum oxide; Blast furnaces; Calcium compounds; Ettringite; Granular materials; Grinding; Hydration; Portland cement; Slag cement; Sulfate resisting cement; X ray analysis
• Subject Areas: Highways; Materials;

Filing Info

• Accession Number: 00212502
• Record Type: Publication
• Files: TRIS
• Created Date: Sep 1 1970 12:00AM