New Technology for Repairing and Monitoring with Smart Cement Grout-Paper

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The study developed a highly sensing cement grout containing 0.075% carbon fibers at a water-to-cement ratio of 0.8. Electrical resistivity was monitored during curing using a two-probe method, and compressive tests assessed how the grout’s sensing response changed under stress. The researchers also used the grout to repair damaged smart-cement specimens.<br /><br />Resistivity initially fell slightly, from 1.08 to 1.04 Ω·m within 180 minutes, then increased to 2.16 Ω·m after one day and 9.37 Ω·m after 28 days. The grout’s compressive strength rose from 2.96 MPa after one day to 16.47 MPa after 28 days. Under compression, it showed a pronounced piezoresistive response, with changes in resistivity related to applied stress.<br /><br />Vipulanandan curing and p–q piezoresistive models closely matched the experimental results. Correlation models also described changes in strength and piezoresistive secant modulus with curing time.<br /><br />For repair testing, 28-day-old smart-cement specimens were loaded to failure, submerged in grout for three hours, and cured for one day. Repaired specimens reached 18.05 MPa—68% of the original 26.54 MPa strength—and recovered 39% of the original piezoresistive strain at failure.<br /><br />The findings indicate that smart cement grout can support both repair and electrical monitoring of cementitious materials. Its resistivity can track curing and respond to mechanical stress, while the models provide a way to predict these behaviors.

Keywords

smart cement grout

carbon fibers

electrical resistivity

piezoresistive response

compressive strength

curing time

two-probe method

Vipulanandan model

damage repair

cementitious materials