Role of Nanosilica on the Early-Age Performance of Natural Pozzolan-Based Blended Cement

This investigation focused on the microstructura!., workability, mechanical, and hydration evolution of blended cements composed of natural pozzolan with nanosilica (NS). In Turkey, the most common supplementary cementitious materials are natural pozzolans of volcanic origin. Volcanic pumice is a na...

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Published inACI materials journal Vol. 115; no. 6; pp. 969 - 980
Main Authors Yıldırım, Gürkan, Dündar, Burak, Alam, Burhan, Yaman, İsmail Özgür, Şahmaran, Mustafa
Format Journal Article
LanguageEnglish
Published Farmington Hills American Concrete Institute 01.11.2018
Subjects
Age
Cement hydration
Chemistry
Concrete research
Fineness
Lava
Mechanical properties
Portland cements
Pozzolans
Pumice
Silica
Solidification
Studies
Weight
Workability
Turkey
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Summary:This investigation focused on the microstructura!., workability, mechanical, and hydration evolution of blended cements composed of natural pozzolan with nanosilica (NS). In Turkey, the most common supplementary cementitious materials are natural pozzolans of volcanic origin. Volcanic pumice is a naturalpozzolan produced by the release of gases during the cooling and solidification of lava. In this study, pumice powders with two different levels of fineness were used to replace ordinary portland cement (OPC) at 15%, 30%, and 45% by weight. Seven mixtures were proposed with different levels ofpumice fineness and OPC replacement rates, as well as an additional control mixture without pumice powder. Companion mixtures were also produced by adding 3% NS (by total weight of cementitious materials) into the proposed mixtures for a total of 14 different mixtures. Fresh properties measured by flow test and mechanical performance validated by microstructural analyses show that in the presence of NS, up to 30% pumice powder can be replaced with OPC without risking workability and 2-day strength measurements. In cases where the early-age strength is necessary after the first 7 days, the same level of replacement can be increased up to 45%. The successful outcomes of this study may compensate for the drawbacks of OPC use in concrete mixtures and popularize the use of natural pozzolans in locations where they are more commonly available.
ISSN:0889-325X
1944-737X
DOI:10.14359/51706848