Structural characteristics of cement-based tail fill with sodium dodecyl sulfate, azodicarbonamide, and dodecyl trimethyl ammonium bromide

Abstract

The safety of mine-filled stopes is seriously affected by settlement and uneven pore distribution of cement-based tail fill (CTF). To further improve the mined-out areas' stability, it is found that foaming agents (FAs) can improve CTF's settlement characteristics. To better formulate FA-covered mine backfills (FCTFs), three principal FAs, namely, sodium dodecyl sulfate (SDS), azodicarbonamide (AC), and dodecyl trimethylammonium bromide (DTAB), were embraced in the existing research. Macro/micro properties of FCTF specimens were thoroughly examined by UCS tests and microstructure interpretations. Lab findings illustrate that diverse types of FA enhance CTF effects: DTAB>AC > SDS; DTAB-0.4 %, AC-0.4 % and SDS-0.6 % are the best dosage rates, and equivalent peak intensities are 0.7 MPa, 0.43 MPa and 0.55 MPa, respectively. Compared to None, the strength progress of FCTF specimens increased by 22 %, −27 %, and −7 %, respectively. Besides, FCTF's failure style is observed to happen in the form of shear failure along the loading direction. CTF specimens showed obvious ductility on stress-strain curvature, indicating that FA could well inhibit the expansion of cracks. To sum up, the research results can deliver a new way for comprehensive utilization of tailings.