Lithium migration in a two-chamber set-up as treatment against expansion due to alkali–silica reaction

Alkali–silica reaction (ASR) affects numerous concrete structures worldwide. However, the intervention options for ASR in existing structures are limited. Lithium is proposed to suppress expansion. In this paper, an investigation on two-chamber lithium migration as treatment against ASR is presented. First, the influence of different levels of ASR development on lithium migration is studied. Results show that ASR development, if not followed by enough crack formation, hinders migration due to increase in resistivity. Second, the effects of different treatments, such as sodium and potassium removal, lithium migration (combined with the associated sodium and potassium removal) and lithium diffusion, on ASR expansion were evaluated. Lithium migration led to the lowest post-treatment expansion levels. © 2016 Elsevier Lt

Experimental techniques used to verify healing

There are many techniques to study materials. In this chapter the focus of experimental techniques to verify crack sealing (recovery against environmental actions) or crack healing (recovery against mechanical actions) has been limited to techniques that have been used and reported in self-sealing and self-healing research. To get a look and feel of the topic the chapter starts with a section on techniques which can be used to examine crack healing such as microscopy, X-ray diffraction and Raman spectroscopy. Next, the attention shifts from observing that something has been repaired to how well the repair has been. Following the definitions set out in chapter one, a differentiatiion has been made between techniques to verify recovery against environmental or mechanical actions. For recovery against environmental actions it turns out that permeability tests are often applied, while for recovery against mechanical actions the regain in strength by mechanical testing is the preferred choice

Experimental techniques used to verify healing

There are many techniques to study materials. In this chapter the focus o