Microindentation creep of monophasic calcium–silicate–hydrates

Microindentation creep results for monophasic synthetic C–S–H (C/S = 0.6–1.5), 1.4 nm tobermorite, jennite and calcium hydroxide at 11%RH are reported. Creep results for well hydrated cement paste and C3S ‘composite’ systems are also described. The significance of the co-linear behavior of creep modulus functions of indentation modulus and indentation hardness for C–S–H obtained by microindentation and nanoindentation methods is discussed. The porosity dependence of creep modulus and the general equivalence of density values determined by helium pycnometry and by calculations employing unit cell dimensions (obtained using X-ray crystallography techniques) are also discussed in terms of postulates for the existence of two types of C–S–H. Comment on the compatibility of the creep modulus data for 1.4 nm tobermorite and jennite with models of C–S–H present in cement paste is provided.