Tailoring high-magnesium cements for enhanced carbonation hardening and CO2 sequestration

Donglin Li, Pengjie Rong, Lei Yao, Songhui Liu, Saisai Zhang, Xuemao Guan, Jianping Zhu, Jian xin Lu, Chi Sun Poon

Research output: Journal article publicationJournal articleAcademic researchpeer-review

Abstract

The reduction of CO2 emissions from the cement industry remains a major challenge worldwide. This study investigates the feasibility of using high-magnesium limestone to prepare high-magnesium and low-calcium cementitious materials (HM-LCCs) with improved carbonation reactivity and CO2 sequestration capacity. The carbonation reactivity, hardening properties, phase assemblage, microstructure, and pore distribution of HM-LCCs synthesized with varying proportions of high-magnesium limestone were characterized by XRD, TGA, FT-IR, SEM, and LF NMR. It is found that with increasing substitution of high-magnesium limestone, the main mineral phases in clinker transformed from C2MS2 to C3MS2 and eventually to β-C2S and MgO, along with markedly enhanced grindability. The carbonation reactivity and degree increased progressively with increasing substitution of high-magnesium limestone. Properly tailored HM-LCCs exhibited excellent strength development up to 94.56 MPa after carbonation, dense microstructure, and significantly higher CO2 uptake. This study provides new insights into developing low-carbon cement by utilizing high-magnesian raw materials. The carbonation hardening and CO2 sequestration capacity of cement can be optimized by tailoring the Mg/Ca ratio and calcium silicate phase assemblage.

Original languageEnglish
Article number136849
JournalConstruction and Building Materials
Volume435
DOIs
Publication statusPublished - 12 Jul 2024

Keywords

  • Carbonation hardening
  • CO sequestration
  • High-magnesium cement
  • Microstructure
  • Mineral composition

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • General Materials Science

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