Thixotropic characterisation of slag modified 3D printable metakaolin based geopolymer composite

Alkali activated materials applied in 3D printing construction: A review

“…Metakaolin was used as a precursor in about 13% of the studies, as the sole main precursor [ [61] , [62] , [63] , [64] , [65] , [66] ], with slag [ 66 ] and with Callovo-Oxfordian argillites calcined at 650 °C [ 62 ]. The other precursors used were Construction and demolition waste (CDW) [ 67 , 68 ], CDW + Bark Ash [ 69 ], CDW + Metakaolin + Bark Ash [ 69 ], and Burlewash soil (montmorillonite-rich) [ 70 ] .…”

“…About 77% of the studies used some aggregate or filler. Sand, of various origins, was the most used (92% of the studies with incorporation of aggregates/filler and 71% of all the articles) [ 10 , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [32] , [33] , [34] , [35] , [36] , [37] , [38] , [39] , [40] , [41] , [42] , [43] , [44] , [46] , [47] , [48] , [49] , 51 , 52 , 58 , 62 , 66 , 69 , 75 ]; Studies with up to three different particle size distributions of sand were identified, with the largest particle size being 2 mm. Sand/binder ratios were observed in values up to 2.00, but most of the studies used a sand/binder ratio of 1.5 (41% of the studies that presented sand as an aggregate).…”

“…Regarding 3D printing technology, the most used type of printer is the gantry printer [ 10 , [22] , [23] , [24] , [25] , [26] , [36] , [37] , [38] , [39] , [40] , 42 , 43 , 46 , [48] , [49] , [50] , [52] , [53] , [54] , [55] , [56] , [57] , [58] , [59] , [60] , [66] , [67] , [68] ], followed by robotic arms [21,63,70]. In the methodologies implemented in the construction industry there is also this trend: out of 13 techniques employed by material extrusion, eight use the gantry system (Contour Crafting, 3D Concrete Printing, Winsun, Total Kustom, Vulcan II, BOD2, and HuaShang Tengda), three use robotic arms (Apis Cor, XtreeE, and CyBe RC 3Dp), and two use a group of small robots (Minibuilders and Multiple robot printers) [ 3 ].…”