Abstract:
Polymer grouts are used in improving the physical and mechanical properties of sand used in various applications including soil stabilization, stabilizing slopes, controlling pipe leaks and also solidifying contaminated soils. Polymer grouts are broadly characterized as organic and inorganic grouts. With the wide spectrum of applications, there is a need to make the polymer grouted soils highly sensing so that it can be monitored from the time of injection to the entire service life and also make the repaired sections highly sensing for real-time monitoring. In this investigation highly sensing acrylamide polymer grouted sand was developed. A two probe monitoring method has been developed to characterize the grouted and also monitor the changes with the curing time. Based on the impedance– frequency response the grouted sand was characterized as a resistance/resistivity based material. During the hardening process the change in the resistivity with curing time was continuously monitored to better understand the process. The grouted sand was also tested under compression and splitting tension to evaluate the sensing properties. For the unconfined compression test the strength of the grouted sand was 350 Pa and the axial failure strain was 2% and the piezoresistive axial failure strain was over 6%, over 3 times (300%) magnification of the sensing parameter. Under splitting tension the failure strength was about 140 kPa with the lateral strain of less than 2% and piezoresistive lateral strain of 20%, 10 time (1000%) more magnification of the sensing parameter. Vipulanandan p-q stress-strain and piezoresistive models were used to predict the stress-strain behavior and also the piezoresisitive behavior of the sensing grouted sand and the models predicted the behavior very well. Also failure models, Drucker-Prager model and Vipulanandan failure model, were evaluated to represent the grouted sand behavior.