Liu, J, Wu, R, Wu, A & Wang, S 2017, 'Bleeding characteristics and improved mechanism of self-flowing tailings filling paste with low concentration', in A Wu & R Jewell (eds), Paste 2017: Proceedings of the 20th International Seminar on Paste and Thickened Tailings, University of Science and Technology Beijing, Beijing, pp. 162-169, https://doi.org/10.36487/ACG_rep/1752_19_Liu (https://papers.acg.uwa.edu.au/p/1752_19_Liu/) Abstract: In order to solve the bleeding problem of self-flowing tailings filling paste with low concentrations, the influences of the dosage of special additives on the bleeding rate were investigated. The improving mechanism of special additives on the bleeding of tailings filling paste was studied by measuring the bleeding rate and compressive strength of the paste and analyzing the scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and infrared spectroscopy (IR) of the hardened paste. The results show that when the paste concentration is 60%, the binder-to-tailings ratio is 1:6, and the dosage of special additive is 10%, the filling paste is not bleeding and the compressive strength of the hardened paste can increase by 43.5% at 3 days. A large amount of needle-like ettringite is generated in the hardened paste after adding the special additives, and the structure becomes denser. The special additives can effectively improve the bleeding of the filling paste and increase the compressive strength of the filling material at early age.