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Title: The influence of silanized nano-SiO{sub 2} on the hydration of cement paste: NMR investigations

It is known that by adding a small amount of nanoparticles to the cement-based materials a strong influence on the workability, strength and durability is obtained. These characteristics of the material are fundamentally determined by the hydration process taking place after mixing the cement grains with water. In the present study the influence introduced by the addition of nano-silica with silanized surfaces on the hydration process was investigated using low-field nuclear magnetic resonance (NMR) relaxometry. The cement samples were prepared using gray cement at a water-to-cement ratio of 0.4 and a 5% addition of nanosilica. The surface of the nanoparticles was modified using a coating of Silane A174. The cement pastes were monitored during their standard curing time of 28 days. It was established that, by using unmodified nanosilica particles, an acceleration of the hydration process takes place as compared with the pure cement paste. On the other side, by adding silanized nanoparticles, the dormancy stage significantly extends and the hydration process is slower. This slowing down process could enhance the mechanical strength of cement based materials as a result of a better compaction of the hydrated samples.
Authors:
; ;  [1] ;  [2]
  1. Technical University of Cluj-Napoca, Department of Physics and Chemistry, 400114 Cluj-Napoca (Romania)
  2. “Babes-Bolyai” University, “Raluca Ripan” Chemistry Research Institute, Department of Polymer Composites, 400294 Cluj-Napoca (Romania)
Publication Date:
OSTI Identifier:
22494498
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1700; Journal Issue: 1; Conference: PIM 2015: 10. international conference on processes in isotopes and molecules, Cluj-Napoca (Romania), 23-25 Sep 2015; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CEMENTS; COMPARATIVE EVALUATIONS; HARDNESS; HYDRATION; MIXING; NANOPARTICLES; NUCLEAR MAGNETIC RESONANCE; SERVICE LIFE; SILANES; SILICA; SILICON OXIDES; SURFACES; WATER; WEAR RESISTANCE; YIELD STRENGTH