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Title: Preferential adsorption of polycarboxylate superplasticizers on cement and silica fume in ultra-high performance concrete (UHPC)

Abstract

UHPC is fluidized particularly well when a blend of MPEG- and APEG-type PCEs is applied. Here, the mechanism for this behavior was investigated. Testing individual cement and micro silica pastes revealed that the MPEG-PCE disperses cement better than silica whereas the APEG-PCE fluidizes silica particularly well. This behavior is explained by preferential adsorption of APEG-PCE on silica while MPEG-PCEs exhibit a more balanced affinity to both cement and silica. Adsorption data obtained from individual cement and micro silica pastes were compared with those found for the fully formulated UHPC containing a cement/silica blend. In the UHPC formulation, both PCEs still exhibit preferential and selective adsorption similar as was observed for individual cement and silica pastes. Preferential adsorption of PCEs is explained by their different stereochemistry whereby the carboxylate groups have to match with the steric position of calcium ions/atoms situated at the surfaces of cement hydrates or silica.

Authors:
; ;
Publication Date:
OSTI Identifier:
22149352
Resource Type:
Journal Article
Journal Name:
Cement and Concrete Research
Additional Journal Information:
Journal Volume: 42; Journal Issue: 11; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0008-8846
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ADSORPTION; AFFINITY; CALCIUM IONS; CEMENTS; CONCRETES; FLUIDS; HYDRATES; PERFORMANCE; PLASTICIZERS; SILICA; STEREOCHEMISTRY; SURFACES; TESTING

Citation Formats

Schroefl, Ch., Gruber, M., and Plank, J., E-mail: sekretariat@bauchemie.ch.tum.de. Preferential adsorption of polycarboxylate superplasticizers on cement and silica fume in ultra-high performance concrete (UHPC). United States: N. p., 2012. Web. doi:10.1016/J.CEMCONRES.2012.08.013.
Schroefl, Ch., Gruber, M., & Plank, J., E-mail: sekretariat@bauchemie.ch.tum.de. Preferential adsorption of polycarboxylate superplasticizers on cement and silica fume in ultra-high performance concrete (UHPC). United States. doi:10.1016/J.CEMCONRES.2012.08.013.
Schroefl, Ch., Gruber, M., and Plank, J., E-mail: sekretariat@bauchemie.ch.tum.de. Thu . "Preferential adsorption of polycarboxylate superplasticizers on cement and silica fume in ultra-high performance concrete (UHPC)". United States. doi:10.1016/J.CEMCONRES.2012.08.013.
@article{osti_22149352,
title = {Preferential adsorption of polycarboxylate superplasticizers on cement and silica fume in ultra-high performance concrete (UHPC)},
author = {Schroefl, Ch. and Gruber, M. and Plank, J., E-mail: sekretariat@bauchemie.ch.tum.de},
abstractNote = {UHPC is fluidized particularly well when a blend of MPEG- and APEG-type PCEs is applied. Here, the mechanism for this behavior was investigated. Testing individual cement and micro silica pastes revealed that the MPEG-PCE disperses cement better than silica whereas the APEG-PCE fluidizes silica particularly well. This behavior is explained by preferential adsorption of APEG-PCE on silica while MPEG-PCEs exhibit a more balanced affinity to both cement and silica. Adsorption data obtained from individual cement and micro silica pastes were compared with those found for the fully formulated UHPC containing a cement/silica blend. In the UHPC formulation, both PCEs still exhibit preferential and selective adsorption similar as was observed for individual cement and silica pastes. Preferential adsorption of PCEs is explained by their different stereochemistry whereby the carboxylate groups have to match with the steric position of calcium ions/atoms situated at the surfaces of cement hydrates or silica.},
doi = {10.1016/J.CEMCONRES.2012.08.013},
journal = {Cement and Concrete Research},
issn = {0008-8846},
number = 11,
volume = 42,
place = {United States},
year = {2012},
month = {11}
}