Photomicrographs of Aspdin Paste

Polished section photomicrographs were taken in reflected light unless otherwise indicated. 

Photograph 1-3 Unusually large belite in UPC in Aspdin paste. Note prominent lamellar extensions into ferrite matrix. Probably an effect of CaO resorption during slow cooling. (S A6608) 

Photograph 1-4 UPC in Aspdin paste. Water etch reveals dark-blue, coarsely crystalline aluminate, presumably C3A. (S A6609) 

Scrivener (1988) studied the Aspdin paste with backscattered electron imaging (BSE), showing clearly the development of hydration products pseudomor-phic after the original clinker crystals and drawing attention to the occurrence of layers of hydration product ( inner product ). 

In 1897 Tbrnebohm, a Swedish investigator, possibly realizing that because of compositional variation mineral names mightbe better suited for clinker phases than chemical formulas, clearly described the optical features of the principal clinker phases in thin sections and powder mounts and coined the terms alite, belite, celite, felite, and also glassy residue. Tbrnebohm stated that belite has two or three sets of cross striations and felite has one set of parallel striations formed at low temperature. Tbrnebohm related microscopical data to burning conditions, stating  

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