Smart Cement Performance Enhancement with NanoAl2O3 for Real Time Monitoring Applications Using Vipulanandan Models

Abstract Nano aluminum oxide (NanoAl2O3) up to 1% was added to the smart cement with a water-to-cement ratio of 0.38 to investigate the effects on the sensing properties and compressive strength. Series of physical, curing and compressive loading experiments evaluated the smart cement behavior with and without NanoAl2O3 up to 28 days of curing. The addition of 0.5% and 1% NanoAl2O3 increased the initial sensing property (electrical resistivity) of the smart cement by 10% and 30% respectively. In a one day of curing, the maximum change in the electrical resistivity (RI24hr) for the smart cement without NanoAl2O3 was 375%. The RI24hr for the smart cement with NanoAl2O3 increased with the amount of NanoAl2O3. Addition of 1% NanoAl2O3 increased the compressive strength of the smart cement by 14% and 42% after 1 day and 28 days of curing respectively. The nonlinear Vipulanandan p-q curing model was used to predict the changes in electrical resistivity with curing time. The piezoresistivity of smart cement with the addition of NanoAl2O3 was over 500 times (50,000%) higher than the regular cement depending on the curing time and NanoAl2O3 content. Also a gage factor correlation model was used to relate the strain to the resistivity changes under compressive loading. The Vipulanandan p-q stress-strain and the piezoresistivity models also predicted the experimental results very well. A linear correlation was obtained between the RI24hr and the compressive strength of the modified smart cement based on the curing time.