Hydration Kinetics and Microscopic Analysis of CaO-Type Expansive Clinker Treated with Carbonation

Abstract

Mineral composition, microstructure and hydration kinetics process of high-temperature carbonation treated CaO-type expansive clinker were studied by XRD, BSE-EDS, hydration and calcination methods. Deformation properties of cement mortars containing treated expansive clinker were tested by length measuring method. The results show that, high-temperature carbonation treatment makes the f-CaO in the surface layer of CaO-type expansive clinker transfer to CaCO3; cement mortar containing treated expansive clinker of low carbonate degree shows the same expansion curve shape but an increased final expansion ratio compared to that containing untreated expansive clinker, mortars containing treated expansive clinker of high carbonate degree shows the changed expansion curve shape with an increased final expansion ratio by more than 1 time. High-temperature carbonation treatment changes the hydration reaction controlling mechanism of CaO-type expansive clinker especially in early hydration process. This work is of great significance to the further research on preparation and properties of carbonation treated CaO-type expansive agent.