==Abstract==

​

In iron-rich alkali-activated materials (AAMs), iron is present in both the ferrous and ferric

states. Fe3+ is considered to be present in a silicate network and the dissolution of Fe3+ under acid attack

can be taken as an indication of the deterioration of the AAMs framework. Conventional methods for

evaluating the acid resistance of AAMs are based on the durability standards for OPC concrete with

indicators such as mass change and dimensional change, or by measuring the corroded depth. All of

these methods are measured based on solid samples and many samples have to be prepared to obtain

different points in a time profile. Here we propose nuclear magnetic resonance (NMR) relaxometry

measurements as an in-situ method for the direct determination of dissolution kinetics of Fe3+ ions in

an acid solution with high temporal resolution. The leaching kinetics of iron-rich AAMs in (sulfuric)

acid can be described by the Real Physical Picture (RPP) kinetic model, which was originally used to

describe the gas-solid interaction. The fitting results show that the leaching process is controlled by

chemical reactions at the beginning and by diffusion over time.

​

== Full Paper ==

<pdf>Media:Draft_Sanchez Pinedo_72182712157.pdf</pdf>

​