Activation of fly ash through nanomodification

Shiho Kawashima, Pengkun Hou, Kejin Wang, David J Corr, Surendra P Shah

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Due to the high carbon emissions that result from cement production, it is desirable to limit the cement content of concrete to make it a more sustainable material. This is possible through substantial replacement of cement with supplementary materials, such as fly ash. The positive effects of this approach are twofold. First, reducing the cement content of concrete will reduce its carbon footprint. Second, fly ash is a coal combustion by-product, so essentially a waste material, which must be stored in landfills and enclosures if unused. Therefore, the productive use of fly ash by incorporating it into building materials at high volumes can help alleviate a waste storage issue. This paper is a summary of studies performed at the Center for Advanced Cement-Based Materials - Northwestern University, in collaboration with Iowa State University, relating to the activation of fly ash through nanomodification. Through seeding effects and increased reactivity, nanoparticles can accelerate cement hydration and subsequently the production of calcium hydroxide (CH), which can help activate the pozzolanic reaction of fly ash particles. Two types of nanoparticles are discussed in this summary paper: silica (SiO2) and calcium carbonate (CaCO3). The study on CaCO3 nanoparticles addresses the issue of dispersion, which is critical for nanomaterials, and the resultant effects on the hardening and early-age properties of fly ash-cement pastes. And the study on nano SiO 2 focuses on determining the mechanisms underlying the effect of the pozzolanic nanoparticle on the early-age and long-term compressive strength gain of fly ash-cement mortars.

Original languageEnglish (US)
Title of host publicationAdvances in Green Binder Systems 2012 - Held at the ACI Spring 2012 Convention
PublisherAmerican Concrete Institute
Pages1-11
Number of pages11
Edition294 SP
ISBN (Print)9781632663245
StatePublished - Jan 1 2012
EventAdvances in Green Binder Systems 2012 at the ACI Spring 2012 Convention - Dallas, TX, United States
Duration: Mar 18 2012Mar 22 2012

Other

OtherAdvances in Green Binder Systems 2012 at the ACI Spring 2012 Convention
CountryUnited States
CityDallas, TX
Period3/18/123/22/12

Keywords

  • Calcium carbonate
  • Dispersion
  • Fly ash
  • Nanoparticles
  • Nanosilica
  • Pozzolanic, microstructure

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Materials Science(all)

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