INFLUENCE OF OPEN POROSITY ON THE RESISTANCE OF MORTAR AND CONCRETE TO AGGRESSIVE SOLUTIONS. /IN GERMAN/
GRAPHS ARE USED TO SHOW THE INFLUENCE OF OPEN POROSITY, MEASURED BY MEANS OF GAS PERMEABILITY, ON THE SULPHATE RESISTANCE OF MORTAR. REDUCED PERMEABILITY TO GAS HAS A FAVORABLE EFFECT ON THIS RESISTANCE, WHILE THE FORMATION OF PHASES SIMILAR TO THAT OF ETTRINGITE, PLASTER, AND BRUCITE CAN BE REGARDED AS A CAUSE OF LOW RESISTANCE TO ATTACK. HIGH SULPHATE RESISTANCE IN PORTLAND CEMENT WITHOUT CALCIUM ALUMINATE (C3A) IS DUE TO THE REDUCED RATE OF HYDRATION OF CALCIUM ALUMINATE - FERRITE WHICH HAS A LOW NON OXIDE CONTENT; BLAST-FURNACE CEMENT WITH ITS HIGH CONTENT OF BLAST-FURNACE SAND IS SULPHATE RESISTANT BECAUSE OF ITS LOWER LIME CONTENT. IN THE CASE OF BOTH TYPES OF CEMENT, SULPHATE IONS DIFFUSE IN THE MORTAR AND CALCIUM AND HYDROXLY IONS DIFFUSE OUTSIDE THE HARDENED MORTAR. THIS RESULTS IN A LACK OF CALCIUM AND HYDROXYL ION CONCENTRATION NECESSARY FOR THE FORMATION OF ETTRINGITE, THE ACTION OF WHICH CAUSES SWELLING. /A/LCPC/RRL/
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Supplemental Notes:
- Vol 20, No 12, PP 555-561, 10 FIG, 4 TAB, 9 REF
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Authors:
- Ludwig, U
- Schwiete, H
- Publication Date: 1967-12
Media Info
- Serial:
Subject/Index Terms
- TRT Terms: Blast furnaces; Calcium compounds; Hydration; Hydroxides; Mortar; Permeability; Porosity; Portland cement; Sand; Solutions (Chemistry); Sulfate resisting cement; Sulfates
- Old TRIS Terms: Resistance; Solutions
- Subject Areas: Highways; Materials;
Filing Info
- Accession Number: 00212880
- Record Type: Publication
- Source Agency: Road Research Laboratory /UK
- Files: TRIS
- Created Date: Oct 13 1970 12:00AM