Influence of metakaolin content on the microstructure and strength in hardened LC3 paste

This study systematically investigates the impact of varying metakaolin contents on the compressive strength and microstructure of hardened limestone calcined clay cement (LC3) paste. The findings reveal that increasing metakaolin content intensifies the aluminum sulfate reaction peak and accelerate...

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Main Authors: Qi Luo, Xinyu Zhang, Junchao Yu, Guoqing Geng
Format: Article
Language:English
Published: Elsevier 2025-03-01
Series:Cement
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2666549225000118
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author Qi Luo
Xinyu Zhang
Junchao Yu
Guoqing Geng
author_facet Qi Luo
Xinyu Zhang
Junchao Yu
Guoqing Geng
author_sort Qi Luo
collection DOAJ
description This study systematically investigates the impact of varying metakaolin contents on the compressive strength and microstructure of hardened limestone calcined clay cement (LC3) paste. The findings reveal that increasing metakaolin content intensifies the aluminum sulfate reaction peak and accelerates its onset, while decreasing metakaolin leads to higher total calcium hydroxide (Ca(OH)₂) and calcium carbonate (CaCO₃) levels in the system. A specific threshold of 70 % metakaolin content is identified as optimal for pozzolanic activity; excess metakaolin remains unreacted. The addition of metakaolin refines the pore structure, reduces harmful large pores, and promotes the formation of ettringite and other hydration products, enhancing mechanical properties. Notably, a sample with 70 % metakaolin content exhibits higher compressive strength than one with 100 % metakaolin, indicating that metakaolin containing 30 % impurities (referred to as sand powder) demonstrates superior mechanical performance. These results support the development of LC3 as a commercially viable and eco-friendly alternative to Ordinary Portland Cement (OPC).
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publisher Elsevier
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series Cement
spelling doaj-art-3c2859c6c4be467ba810b6cd492470a72025-08-20T02:51:38ZengElsevierCement2666-54922025-03-011910013810.1016/j.cement.2025.100138Influence of metakaolin content on the microstructure and strength in hardened LC3 pasteQi Luo0Xinyu Zhang1Junchao Yu2Guoqing Geng3Department of Civil and Environmental Engineering, National University of Singapore, 117576, SingaporeSchool of Civil Engineering, Chongqing Jiaotong University, Chongqing 400074, PR ChinaChina Hebei Construction & Geotechnical Investigation Group Ltd, Shijiazhuang, Hebei Province 050227, PR China; Key Laboratory of Green Construction and Intelligent Maintenance for Civil Engineering of Hebei Province, Yanshan University, Qinhuangdao, Hebei Province 066004, PR ChinaDepartment of Civil and Environmental Engineering, National University of Singapore, 117576, Singapore; Corresponding author.This study systematically investigates the impact of varying metakaolin contents on the compressive strength and microstructure of hardened limestone calcined clay cement (LC3) paste. The findings reveal that increasing metakaolin content intensifies the aluminum sulfate reaction peak and accelerates its onset, while decreasing metakaolin leads to higher total calcium hydroxide (Ca(OH)₂) and calcium carbonate (CaCO₃) levels in the system. A specific threshold of 70 % metakaolin content is identified as optimal for pozzolanic activity; excess metakaolin remains unreacted. The addition of metakaolin refines the pore structure, reduces harmful large pores, and promotes the formation of ettringite and other hydration products, enhancing mechanical properties. Notably, a sample with 70 % metakaolin content exhibits higher compressive strength than one with 100 % metakaolin, indicating that metakaolin containing 30 % impurities (referred to as sand powder) demonstrates superior mechanical performance. These results support the development of LC3 as a commercially viable and eco-friendly alternative to Ordinary Portland Cement (OPC).http://www.sciencedirect.com/science/article/pii/S2666549225000118MetakaolinLC3HydrationPozzolanic reactionMechanical properties
spellingShingle Qi Luo
Xinyu Zhang
Junchao Yu
Guoqing Geng
Influence of metakaolin content on the microstructure and strength in hardened LC3 paste
Cement
Metakaolin
LC3
Hydration
Pozzolanic reaction
Mechanical properties
title Influence of metakaolin content on the microstructure and strength in hardened LC3 paste
title_full Influence of metakaolin content on the microstructure and strength in hardened LC3 paste
title_fullStr Influence of metakaolin content on the microstructure and strength in hardened LC3 paste
title_full_unstemmed Influence of metakaolin content on the microstructure and strength in hardened LC3 paste
title_short Influence of metakaolin content on the microstructure and strength in hardened LC3 paste
title_sort influence of metakaolin content on the microstructure and strength in hardened lc3 paste
topic Metakaolin
LC3
Hydration
Pozzolanic reaction
Mechanical properties
url http://www.sciencedirect.com/science/article/pii/S2666549225000118
work_keys_str_mv AT qiluo influenceofmetakaolincontentonthemicrostructureandstrengthinhardenedlc3paste
AT xinyuzhang influenceofmetakaolincontentonthemicrostructureandstrengthinhardenedlc3paste
AT junchaoyu influenceofmetakaolincontentonthemicrostructureandstrengthinhardenedlc3paste
AT guoqinggeng influenceofmetakaolincontentonthemicrostructureandstrengthinhardenedlc3paste