Smart Ultrafine Cement Grouts Development, Characterization, and Modeling Multiple Behaviors and Testing the Capturing of Carbon Dioxide (CO2) Using Recycled Additives.

Smart cement is a highly piezo, thermo, and chemoresistive sensor that has many applications in infrastructures such as bridges and oil wells. However, the limitation of using smart cement in grouting applications such as maintenance, repairing, and sealing joints of various infrastructures can lead to some difficulties in monitoring the structures during the maintenance. Therefore, in this study, a new smart ultrafine (UF) cement grout sensor was developed to be used for real time monitoring with high sensing performance which can be implemented in grouting applications as a repairing and maintenance material to minimize failures. Smart ultrafine cement grout was developed with higher water-to-cement and binder ratios by modifying it with different green materials. Also, the rheology, curing, shrinkage, setting times, and piezoresistive behaviors of the smart ultrafine cement grouts were tested and also modeled. In order to identify easily monitorable and dependable sensing properties, a series of experiments were conducted using electrical impedance, and resistivity was identified as the critical property to monitor. The piezoresistive behavior of the ultrafine cement grouts was substantially improved by adding 0.05% of carbon fiber. Also, the curing of the smart ultrafine cement grout was monitored with resistivity changes and also modeled. The piezoresistive strain at peak stress varied from 217% to 277% based on the curing times and water to cement ratios. Also, the stress-piezoresistive strain behavior was predicted using Vipulanandan p-q model and the artificial neural network (ANN) model. By incorporating the green materials in the smart ultrafine cement grouts significantly increased its piezoresistivity compared to unmodified smart UF cement grout. Also, the smart ultrafine cement grouts rheology was modeled using the ANN, Herschel Bulkley and Vipulanandan models. The findings indicated that the inclusion of green materials led to a decrease in shear stress, whereas an increase in temperature resulted in an elevation of shear stress. In this study also, methods for capturing CO2 using various recycled materials in water were investigated. The results showed that certain materials can capture the CO2 in the water very fast and several parameters were monitored including the resistivity which turned out to be very sensitive.