Atomic force microscopy characterisation of alkali-silica reaction products to reveal their nanostructure and formation mechanism

Abstract

Microscopic studies on alkali-silica reaction (ASR) products revealed two distinct forms of solid ASR products. However, their chemical and morphological aspects have not been adequately understood. This study provides a new insight into the nanostructure of ASR products as examined by atomic force microscopy (AFM). Results reveals that the surface microscale morphology of the rosette-like ASR product is associated with the loss of surface water, and the granular ASR product is formed by the accumulation of nanoscale particles with a typical size of around thirty nanometers. Moreover, the application of AFM provides evidence for the fluid nature of the granular ASR product at high moisture content.