Crack Initiation of Alkali-Activated Slag Based Composites with Graphite Filler

Abstract:

The alkali-activated slag is an alternative building material to ordinary Portland cement based materials. This type of material is effective in reducing CO₂ emissions and energy consumption. Addition of graphite powder increases its electric conductivity, hence, introducing new functionality to building materials such as self-sensing and self-heating properties. In this study, the effect of graphite filler on the crack initiation of alkali-activated slag composite is investigated. The graphite powder was added in the amount of 5, 10 and 15% with respect to the slag mass. Beam specimens with an initial stress concentrator were tested in three-point bending at the age of 28 days. The load versus crack mouth crack opening displacement (F–CMOD) diagrams were recorded during the fracture tests and subsequently evaluated using the Double-K fracture model. This model allows the quantification of two different levels of crack propagation: initiation, which corresponds to the beginning of stable crack growth, and the level of unstable crack propagation. The course of fracture tests was also monitored by acoustic emission (AE) method.

• Periodical: Key Engineering Materials (Volume 761)
• Pages: 57-60
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.761.57
• Online since: January 2018
• Authors: Hana Šimonová*, Libor Topolář, Pavel Rovnaník, Pavel Schmid, Zbyněk Keršner
• Keywords: Acoustic Emission, Alkali-Activation, Crack Initiation, Double-K Model, Fracture Test, Graphite, Slag

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