Estimations of degree of hydration of portland cement pastes

Developments in concrete standards have identified the need to ensure that mix design and site practices will deliver durable concrete to the client. Satisfactory quality is not necessarily guaranteed by the adequate strength of standard samples since proper compaction, curing and finishing procedures on site need careful attention to ensure a concrete with a low permeability. Defects may only become apparent long after the contract is completed. In analysing site concrete, absolute precision is not necessary in seeking quantitative data. Reliable approximations will provide information as to how various practices can affect hydration and permeability. Work has been carried out on cement pastes, both with and without replacements, and laboratory and site concretes. This paper deals with procedures for assessing degrees of hydration and porosities in plain cement pastes with a view to applying some of the techniques to concrete.