Effectiveness of PCE superplasticizers in calcined clay blended cements

Ran Li, Lei Lei, Tongbo Sui, Johann Plank

Research output: Contribution to journalArticlepeer-review

65 Scopus citations

Abstract

The impact of a calcined clay (CC) rich in meta kaolin (~50 wt%) present in composite cements at 0–40% substitution rate for the clinker was studied relative to the dispersing force of different PCE superplasticizers. It was found that CC increases the water demand of the blended cements considerably (+85% for the 60:40 blend vs. neat OPC). Furthermore, PCEs which fluidize OPC best also provide optimal performance in CC blended cements, but require much higher dosages (in OPC/CC 60:40, 4–6 times as compared to neat OPC). In all systems, HPEG-PCE produced superior dispersing performance over anionic MPEG-PCEs. A mechanistic study involving zeta potential measurements revealed that the initially negatively charged calcined clay surface adsorbs huge amounts of Ca2+ ions from the pore solution, thus facilitating adsorption of anionic PCE superplasticizers. The results signify that commercially available PCE products can effectively fluidize OPC/CC blended cements.

Original languageEnglish
Article number106334
JournalCement and Concrete Research
Volume141
DOIs
StatePublished - Mar 2021

Keywords

  • Blended cement (D)
  • Calcined clay
  • Natural clay minerals
  • Polycarboxylate (PCE) Superplasticizer
  • Workability (A)

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