Investigation of the compressive self-sensing response of filler-free metakaolin geopolymer binders and coatings

Self-sensing cementitious materials are an effective method of monitoring existing infrastructure due to their high durability and high sensing performance. Geopolymers are ideal candidates for such applications due to their enhanced ionic mobility, high mechanical properties and compatibility with ordinary Portland cement structures. In this paper, self-sensing filler-free metakaolin geopolymer binders and coatings are explored under repeated compression. Polypropylene fibers were added to the mix design to tackle shrinkage issues making these materials more suitable for site and field applications. The sensing performance of metakaolin geopolymers is examined under various loading patterns and their strain sensing performance is characterized. The geopolymer sensors displayed high repeatability and stability under different loading regimes over multiple cycles. The gauge factor for non-fiber and fiber geopolymer binders ranged from 18.3 to 38.3. Similarly, the gauge factor for geopolymer coatings ranged from 20.7 to 43.2. Based on the findings of this study, these materials have dis-played the potential as a viable means of monitoring civil infrastructure under repeated compression.

Automated summary

This paper examines the self-sensing performance of filler-free metakaolin geopolymer binders and coatings under repeated compression. The addition of polypropylene fibers addresses shrinkage issues and improves the suitability for field applications. The sensing performance of metakaolin geopolymers is evaluated under various loading patterns, and their strain sensing performance is characterized. The geopolymer sensors demonstrate high repeatability and stability under different loading regimes, with gauge factors ranging from 18.3 to 38.3 for binders and 20.7 to 43.2 for coatings. Overall, these materials show potential as a viable means of monitoring civil infrastructure under repeated compression.