SEDL / STP / STP1061-EB / STP23452S

The Use of Large-Area Thin Sectioning in the Petrographic Examination of Concrete

St.John, DA
scientist, Inorganic Materials Section of Chemistry Division, Department of Scientific and Industrial Research, Petone,

Pages: 16    Published: Jan 1990

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Abstract

Large-area thin sectioning of a concrete core allows examination of micro-textural detail that is not observable by other petrographic techniques. Because the area of the section represents a large sampling of the core, this allows the relationship of faults and deterioration to both the outer surface and the internal texture to be determined and gives a good estimate of the degree of damage present in the concrete. The usefulness of the technique is illustrated by cases of alkali-aggregate reaction, soft water attack, high temperature corrosion and carbonation, and other textural faults in concrete. It is concluded that especially in the case of alkali-aggregate reaction the examination of large-area thin sections should be the preferred technique for microscopy as it appears to provide the range of textural information necessary for unequivocal diagnosis.