Influence of nucleation seeding on the performance of carbonated MgO formulations

The continuation of the hydration and carbonation reactions within reactive MgO cement formulations is inhibited by the formation of hydrate and carbonate phases around MgO particles, resulting in a low MgO utility and limited mechanical performance. This study introduces carbonate seeds into the po...

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Bibliographic Details
Published inCement & concrete composites Vol. 83; pp. 1 - 9
Main Authors Dung, N.T., Unluer, C.
Format Journal Article
LanguageEnglish
Published Elsevier Ltd 01.10.2017
Subjects
Carbonation
Compressive strength
Hydration
MgO
Microstructure
Carbonation
Compressive strength
MgO
Hydration
Microstructure
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Summary:The continuation of the hydration and carbonation reactions within reactive MgO cement formulations is inhibited by the formation of hydrate and carbonate phases around MgO particles, resulting in a low MgO utility and limited mechanical performance. This study introduces carbonate seeds into the pore space of MgO-based concrete mixes to enable the nucleation and growth of carbonates on the seed surfaces. The influence of seeds on the hydration and carbonation capability, mechanical performance and microstructural development was evaluated through isothermal calorimetry, water absorption and compressive strength measurements, along with TGA, XRD and SEM analyses. The introduction of ≤1% seed within the initial mix design increased the carbonate phase content and improved carbonation degree by up to 96% by increasing the availability of Mg(OH)2 for carbonation. The dense formation of carbonates in seeded samples enabled improved microstructures and 28-day strengths of 64 MPa, which were 33% higher than unseeded samples.
ISSN:0958-9465
1873-393X
DOI:10.1016/j.cemconcomp.2017.07.005