Detail publikace

Coagulated silica - a-SiO2 admixture in cement paste

Jaroslav Pokorný, Milena Pavlíková, Martina Záleská, Pavla Rovnaníková, Zbyšek Pavlík

Originální název

Coagulated silica - a-SiO2 admixture in cement paste

Typ

článek ve sborníku ve WoS nebo Scopus

Jazyk

angličtina

Originální abstrakt

Amorphous silica (a-SiO2) in fine-grained form possesses a high pozzolanic activity which makes it a valuable component of blended binders in concrete production. The origin of a-SiO2 applied in cement-based composites is very diverse. SiO2 in amorphous form is present in various amounts in quite a few supplementary cementing materials (SCMs) being used as partial replacement of Portland cement. In this work, the applicability of a commercially produced coagulated silica powder as a partial replacement of Portland cement in cement paste mix design is investigated. Portland cement CEM I 42.5R produced according to the EU standard EN 197-1 is used as a reference binder. Coagulated silica is applied in dosages of 5 and 10 % by mass of cement. The water/binder ratio is kept constant in all the studied pastes. For the applied silica, specific surface area, density, loss on ignition, pozzolanic activity, chemical composition, and SiO2 amorphous phase content are determined. For the developed pastes on the basis of cement-silica blended binder, basic physical properties as bulk density, matrix density, and total open porosity are accessed. Pore size distribution is determined using MIP analysis. Initial and final setting times of fresh mixtures are measured by automatic Vicat apparatus. Effect of silica admixture on mechanical resistivity is evaluated using compressive strength, bending strength, and dynamic Young’s modulus measurement. The obtained data gives evidence of a decreased workability of paste mixtures with silica, whereas the setting process is accelerated. On the other hand, reaction activity of silica with Portland cement minerals results in a slight decrease of porosity and improvement of mechanical resistivity of cement pastes containing a-SiO2.

Klíčová slova

coagulated silica, pozzolanic activity, bulk density, bending strength, compressive strength

Autoři

Jaroslav Pokorný, Milena Pavlíková, Martina Záleská, Pavla Rovnaníková, Zbyšek Pavlík

Vydáno

7. 7. 2016

Nakladatel

AIP Publishing

Místo

Terchova, Slovakia

ISBN

978-0-7354-1410-5

Kniha

THERMOPHYSICS 2016: 21ST INTERNATIONAL MEETING

Edice

Conference Proceedings

Číslo edice

1st

ISSN

0094-243X

Periodikum

AIP conference proceedings

Číslo

1752

Stát

Spojené státy americké

Strany od

040023-1

Strany do

040023-6

Strany počet

6

URL