Development of an electro-chemical accelerated ageing method for leaching of calcium from cementitious materials
Artikel i vetenskaplig tidskrift, 2016

To facilitate the long term durability predictions of nuclear waste repositories, acceleration methods enhancing calcium leaching process from cementitious materials are needed, even though mechanisms not necessarily comparable to those predominant in a natural leaching process may be developed. In the previously published acceleration methods the samples are very small, which limits further physical or mechanical tests. In this paper, a new acceleration method based on electro-chemical migration is presented. The method although not driven with the same kinetics as in natural leaching, was designed in such a way that unnecessarily destructive by-effects could be minimized while promoting a higher leaching rate for a sample size suitable for further testing the mechanical and physical properties. It is shown that approximately 1x10^6 C of electrical charge per paste specimen of size Ø50 x 75 mm (approximately 230 g) is required to leach out the total amount of Portlandite. The chemical and mineralogical properties of leached samples are characterized by various techniques. It is concluded that aged samples are comparable to those leached in a natural leaching process as both are characterized by a layered system comprising an unaltered core delineated by total dissolution of Portlandite followed by a progressive decalcification of the calcium silicate hydrate gel.

Calcium leaching

Service life

Acceleration method

Nuclear waste management

Mineralogical properties

Författare

Arezou Babaahmadi

Chalmers, Bygg- och miljöteknik, Byggnadsteknologi

Luping Tang

Chalmers, Bygg- och miljöteknik, Byggnadsteknologi

Zareen Abbas

Göteborgs universitet

Thomas Zack

Göteborgs universitet

Per Mårtensson

Materials and Structures/Materiaux et Constructions

1359-5997 (ISSN)

Vol. 49 1-2 705-718

Ämneskategorier

Materialteknik

Samhällsbyggnadsteknik

Styrkeområden

Building Futures

Materialvetenskap

DOI

10.1617/s11527-015-0531-8

Mer information

Skapat

2017-10-07