Graphite Ore Tailings as Partial Replacement of Sand in Concrete

In the present investigation, a feasibility study was made for the first time by using graphite ore tailings (GOTS) as a replacement material for river sand in making mortar and concrete. As-received GOTS and treated GOTS (T-GOTS) at 1000 degrees C (1832 degrees F) were replaced with river sand and various percentages of replacement ranging from 10 to 100%, and their strength evaluation, were done by conducting compression and split tensile tests in mortar and concrete. Bond strength was evaluated using a pullout test and the permeability characteristic was assessed by water absorption and effective porosity tests. The quality of the concrete was assessed by electrical resistivity and ultrasonic pulse velocity measurements. The corrosion resistance evaluation was done by half-cell potential measurement, alternating current impedance or electrochemical impedance spectra, and potentio-dynamic polarization studies. From the studies, it is observed that river sand may be replaced with 40% T-GOTS and be effectively used for structural repair applications.