Cement chemical nomenclature and other abbreviations

Chemical formulae in cement chemistry are often expressed as a sum of oxides thus tricalcium silicate, CajSiO, can be written as 3Ca0 Si02- This does not imply that the constituent oxides have any separate existence within the structure. It is usual to abbreviate the formulae of the commoner oxides to single letters, such as C for CaO or S for SiOj, CajSiOj thus becoming CjS. This system is often combined with orthodox chemical notation within a chemical equation, e.g. 

The formulae of the simple oxide phases (e g. CaO) are usually written in full. Other abbreviations and units used in this book are as follows  

C-S-H = poorly crystalline or amorphous calcium silicate hydrate of unspecified composition. Ggbfs = ground granulated blast furnace slag. Hep = hardened cement paste. Pfa = pulverised fuel ash (fly ash). 

AR = alumina ratio (alumina modulus). ASR = alkali silica reaction. LSF = lime saturation factor. SR = silica ratio (silica modulus). C, = analytical (total) concentration of x, irrespective of species, [x] = concentration of species x. x = activity of species x. RH = relative humidity. = 

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