Microindentation creep of 45 year old hydrated Portland cement paste

Microindentation methods were used to study the creep behaviour of cement paste hydrated for 45 years. These old pastes were prepared having a wide range of water/cement ratios varying from 0·5 to 1·0. The porosity dependence of the indentation parameters (creep modulus, indentation modulus and indentation hardness) was determined and is discussed in the context of possible creep mechanisms. Microindentation creep was also determined for 3 year old cement paste and young paste hydrated for 3 and 7 days. Variation in creep behaviour of the cement pastes for the three age groups is discussed in terms of nanostructural differences.