History of Clinker Microscopy

Microscopical descriptions of clinker phases had their origins in 1887 with the work of the French chemist LeChatelier. Following the methods of microscopical analysis of rocks developed by the English geologist 

founder of petrography and metallography, LeChatelier reported the presence of the following constituents in a portland cement clinker thin section  

colorless, angular crystals with a low birefringence, identified as tricalcium silicate 

Rounded, turbid, yellowish crystals with moderate birefringence, identified as dicalcium silicate 

A dark brown intermediate substance of irregular and ragged form with a lime-iron-aluminate composition (later shown to be calcium aluminoferrite) 

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Although it is not clear whether LeChatelier examined cement made by Joseph Aspdin, who patented Portland cement in England in 1824, a few comments on the nature of the Aspdin cement appear relevant to the history of clinker microscopy. 

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