A study of non-evaporable water content in cement-based mixtures with and without pozzolanic materials

Water is a critical component of all cement materials, contributing to mixing and placing, enabling hydration, and influencing material property development. Non-evaporable water is of particular interest because it is related to degree of hydration and provides insight to the behavior of pozzolanic materials.; The goals of this dissertation were to provide an in-depth review of past and current literature about water in cement materials coupled with a fully documented experimental program. Specific goals of the experimental program included the creation of a thermogravimetric (TGA) procedure and analysis to quantify different water classifications in the hydration products of cement-based materials, correlation of this TGA procedure with an oven drying/furnace ignition (OD/FI) procedure for measuring non-evaporable water content, and evaluation of pozzolanic material behavior through assessment of non-evaporable water contents and compressive strength over time.; The experimental program was conducted on both paste and mortar versions of four different mixtures: a control 0.33 water/cement mixture, and three 0.30 water/binder mixtures with 10% addition of either Class C fly ash, Class F fly ash, or silica fume. Non-evaporable water contents were measured from 6 hours to 227 days by the OD/FI and TGA procedures. Compressive strength was also measured simultaneously for comparative purposes.; The experimental work confirmed the reliability of the TGA procedure and demonstrated its compatibility with the OD/FI procedure. Moreover, the TGA results provided information about the CH and C-S-H/AFm bound water contents over time, and demonstrated that non-evaporable water content measurements overestimate chemically bound water content, particularly at later ages. Degree of hydration can be more reliably calculated from CH bound water content. The experiments also confirmed and extended previous results about pozzolanic material behavior, in particular the increase in compressive strength in all pozzolanic mixtures, the decrease of CH bound water content in silica fume mixtures, and the relationship between compressive strength and non-evaporable water content over time.