Cross tension and compression loading and large-scale testing of strain and damage sensing smart concrete

Multifunctional self-sensing smart concrete can provide a structural health monitoring (SHM) solution that is robust, reliable, and low-cost. Smart concrete, which includes coarse aggregates with 15 mm size, brass fibers, silica fume, superplasticizer and water, has been developed as a promising multifunctional material. The normal and cross compression and split tensile tests were conducted on 75 mm cube samples; large scale compression test was conducted on 15 x 15 x 30 cm prism; large scale bending tests were applied to prisms with sizes 15 x 15 x 75 cm and 15 x 30 x 150 cm. The normal and cross compressive strain gage factors were 54 and 59 while linearities were 6.6% and 7%, respectively. Normal and cross tensile strain gage factors were 3.0 and 2.9 while corresponding linearities were 6.6% and 13%. As the sample size increased, the electrical resistivity increased and strain sensitivity decreased due to obstruction of electrons by aggregates that revealed a "size effect" for piezoresistivity of smart concrete. Large scale bending test results verified the piezoresistivity of smart concrete while crack formation and propagation increased the electrical resistance dramatically. Smart concrete can be utilized to monitor both strain and damage.