Low‐carbon 3DCP based on alkali‐activated materials and gold mining wastes: rheology, buildability and mechanical and durability related properties

Abstract

Alkali‐activated materials (AAM) are potential candidates to reduce the carbon footprint of 3DCP, especially incorporating mining wastes either as binders or aggregates. This paper assesses the performance of alkali‐activated ground granulated blast furnace slag (GGBFS) as main binder for 3DCP. A fine inert gold mining flotation waste (GM_FW) was incorporated as partial binder to control the quick structural buildup of alkali‐activated GGBFS that may jeopardize pumping and printing. Another inert gold mining overburden material (GM_OM) partially replaced a quartz aggregate in the mixes. Rheological studies (static yield stress, plastic viscosity and structural buildup) were carried out to determine the optimum percentage of both wastes in in the mixes. Buildability studies (printing height support prior to collapse) helped determine the promising mixes to print, which were later subjected to mechanical testing, apparent porosity and susceptibility to cracking and efflorescence. Results show that gold mining wastes are effective not only to further reduce the carbon footprint of 3DCP mixes, but also to allow the employment of alkali‐activated GGBFS with the desired printing open time, buildability and mechanical and durability performance.