Pozzolanic activity of flint powder

Publikationstyp
Conference Paper
Date Issued
2019
Sprache
English
Author(s)
Osterhus, Lennart 
Ditz, Florian  
Schmidt-Döhl, Frank Michael  orcid-logo
Institut
Zentrum für Lehre und Lernen (ZLL)  
Baustoffe, Bauphysik und Bauchemie B-3  
TORE-URI
http://hdl.handle.net/11420/3292
Citation
Sustainable Construction Materials and Technologies (1): (2019)
Contribution to Conference
5th International Conference on Sustainable Construction Materials and Technologies, SCMT5 2019  
Publisher DOI
10.18552/2019/idscmt5060
Scopus ID
2-s2.0-85071119957
It was tested whether powdered flint is able to reach pozzolanic properties comparable to fly ash. The flint aggregates were crushed and milled to three different grain size fractions comparable to coal fly ash. The powdered flint was characterized and subsequently used as a substitute in mortar prisms. The compressive strength tests showed a potentially pozzolanic reactive behavior at 28 days of two different fine grained flint fractions. But comparable investigations after 92 days showed that the typical subsequent hardening of pozzolanic materials could not be obtained. The strength was much lower than the strength of comparable specimens with fly ash. Further, thermogravimetric analysis of the tested mortars after 28 days showed a much lower portlandite consumption compared with mortar with fly ash. The study concludes that at least the examined powdered flint with high density does not have the opportunity to replace coal fly ash as pozzolan.
Subjects
Activity index
Asr
Flint
Fly ash
Pozzolanic reaction