  Structural health monitoring (SHM) using self-sensing cement-based materials
has been reported before, where nano-fillers have been incorporated in
cementitious matrices as functional sensing elements. A percolation threshold
is always required in order for conductive nano-fillers modified concrete to be
useful for SHM. Nonetheless, the best pressure/strain sensitivity results
achieved for any self-sensing cementitious matrix are <0.01 MPa-1. In this
work, we introduce novel reduced graphene oxide (RGO) based electronic textile
(e-textile) embedded in plain and polymer-binder-modified cementitious matrix
for SHM applications. As a proof of concept, it was demonstrated that these
coated fabric-based sensors can be successfully embedded within the
cement-based structures, which are independent of any percolation threshold due
to the interconnected fabric inside the host matrix. The piezo-resistive
response was measured by applying direct and cyclic compressive loads (0.1 to
3.9 MPa). A pressure sensitivity of 1.5 MPa-1 and an ultra-high gauge factor of
2000 was obtained for the system of the self-sensing cementitious structure
with embedded e-textiles. The sensitivity of this new system with embedded
e-textile is many orders of magnitude higher than nanoparticle based
self-sensing of cementitious composites. The manufactured e-textile sensors
showed mechanical stability and functional durability over long-term cyclic
compression tests of 1000 cycles.
