Effect of alkaline rice straw fibers content and curing ages on static mechanical properties of cemented lithium mica tailings backfill

Abstract

Alkaline rice straw fibers (ARSF), as a widely available and recyclable plant fiber source, can provide new insights for improving the mechanical properties of backfill and the treatment of agricultural waste resources research. Different amounts of ARSF were prepared to enhance the cemented lithium mica tailings backfill (CLMTB), and uniaxial compression strength (UCS) tests and Brazilian splitting tensile strength tests were conducted to study the influence of ARSF on the static mechanical properties of CLMTB samples. Firstly, the flowability of mortars with different ARSF content was tested, the results showed that the flowability decreased by a maximum of 5.4 %, which met the construction requirements of cement mortar in the construction process. The UCS showed an increasing trend and then reduced with the increased ARSF content, with 0.15 % being the optimal content, showing a maximum increase of 14.2 %. Under Brazilian splitting loading conditions, the tensile strength gradually increased with the increased ARSF content, with 0.60 % being the optimal content. The UCS of the CLMTB samples showed exponential growth with increased curing age. Additionally, there was a linear functional relationship between the curing age and the tensile strength of the CLMTB samples. The experimental results indicate that the ARSF improved the toughness and changed the failure mode of the CLMTB samples. In the meantime, it increased the residual bearing capacity and the peak tensile strain of the CLMTB samples.