A Comparative Study Between the Early Stages Hydration of a High Strength and Sulphate Resistant Portland Cement and the Type II F Portland Cement Through Non Conventional Differential Thermal Analysis and Thermogravimetry

Alex Neves Junior,Romildo Dias Toledo Filho,Marcelo Mendes Viana,Jo Dweck

doi:10.1590/1516-1439.373714

Abstract

This work presents a study, which compares the early stages of hydration of a High Initial Strength and Sulphate Resistant Portland Cement (HIS SR PC) with those of Type II F Portland Cement (PC II), by Non-Conventional Differential Thermal Analysis (NCDTA) within the first 24 hours of hydration. Water/cement (w/c) ratios equal to 0.5, 0.6 and 0.66 were used to prepare the pastes. The hydration of these two types of cement was monitored on real time by NCDTA curves, through the thermal effects of the hydration reactions, from which cumulative evolved energy curves were obtained. These techniques allow one to analyse the influence of each type of cement on the main stages that occur during the hydration process. Thermogravimetric analysis were also performed at 4 and 24h of hydration for both cements, to analyse the influence of each kind of cement on the amount of the main formed hydrated products. The results showed that with 4h of hydration, the total combined water amount released from the hydrated products was higher for the PC II pastes than for the HIS SR PC pastes. Otherwise, with 24h of hydration, the amount of the total combined water released from the hydrated products was higher for the HIS SR PC pastes than for the PC II pastes.

Highlights

Thermogravimetric (TG) and derivative thermogravimetric (DTG) analyses have been used as a tool to study the hydration reactions in cementitious pastes[1,2,3]
The hydration behavior of two types of cement pastes during their first 24h of hydration was evaluated from Non-Conventional Differential Thermal Analysis (NCDTA) and TG/DTG analysis
Thermogravimetric and derivative thermogravimetric analysis allow one to quantify the hydrated products and to evaluate the influence of the HIS SR PC and PC II in the hydration reactions that occur in the first 24h

Summary

Introduction

Thermogravimetric (TG) and derivative thermogravimetric (DTG) analyses have been used as a tool to study the hydration reactions in cementitious pastes[1,2,3]. These techniques allows to determine the quantitative of the main formed hydration products, to study the effects of different mineral additives, as fly ash, silica fume, for example, by pozzolanic activity[4,5,6], to determine the carbonation degree of cementitious materials, by the consumption of Ca(OH)[2] and formation of CaCO3, as an indicative of durability or quantifying the CO2 captured in the own matrix[7,8].

Methods

Results

Conclusion