Compressive and Tensile Properties of Smart Piezoresistive Acrylamide Grouted Sand-Paper

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The study developed and evaluated piezoresistive acrylamide-grouted sand for real-time monitoring of grouted soils. Silica sand was permeated with water-soluble acrylamide grout containing conductive fibers, then tested in unconfined compression and splitting tension. Electrical impedance measurements showed that resistivity was the relevant sensing property; measurements at 300 kHz were used to reduce probe-related effects.<br /><br />Conductive-fiber content affected both strength and sensing performance. At 0.03% fiber by sand weight, compressive strength reached approximately 470 kPa and splitting tensile strength approximately 158 kPa. Increasing the fiber content to 0.06% reduced both strengths. Under compression, resistivity-based axial strain at peak load reached 7.3% for the 0.03% mixture, compared with 1.8% mechanical strain. Under splitting tension, its piezoresistive lateral strain reached 34.9%, compared with 4.5% lateral strain. These results demonstrate that electrical response can amplify deformation signals, particularly in tension.<br /><br />Vipulanandan p-q models closely reproduced the measured stress–strain and piezoresistive behavior. The Vipulanandan failure model also represented the failure data better than the Drucker–Prager model. Overall, the findings identify 0.03% conductive fiber as the most effective mixture tested and support the potential of smart grouted sand for monitoring during curing and throughout service.

Keywords

piezoresistive

acrylamide grout

grouted sand

conductive fibers

electrical impedance

resistivity sensing

unconfined compression

splitting tension

Vipulanandan model

Drucker-Prager model