Coagulated silica - a-SiO2 admixture in cement paste

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21110%2F16%3A00301103" target="_blank" >RIV/68407700:21110/16:00301103 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216305:26110/16:PU119659

Výsledek na webu

<a href="http://dx.doi.org/10.1063/1.4955254" target="_blank" >http://dx.doi.org/10.1063/1.4955254</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1063/1.4955254" target="_blank" >10.1063/1.4955254</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Coagulated silica - a-SiO2 admixture in cement paste

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

Coagulated silica - a-SiO2 admixture in cement paste

Popis výsledku anglicky

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.

Druh

D - Stať ve sborníku

CEP obor

JN - Stavebnictví

OECD FORD obor

—

Projekt

<a href="/cs/project/GA14-04522S" target="_blank" >GA14-04522S: Výzkum procesů při vytváření pevné struktury v soustavě oxid křemičitý-portlandský cement ve vztahu k vlastnostem pojiva</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

THERMOPHYSICS 2016: 21ST INTERNATIONAL MEETING

ISBN

978-0-7354-1410-5

ISSN

0094-243X

e-ISSN

—

Počet stran výsledku

6

Strana od-do

—

Název nakladatele

AIP Publishing, APL, the American Institute of Physics

Místo vydání

Melville, NY

Místo konání akce

Terchová

Datum konání akce

12. 10. 2016

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

000380816400026