Mechanical behavior of K‐geopolymers reinforced with silane‐coated basalt fibers

Abstract

Geopolymers are a well-known class of amorphous ceramic materials based on inorganic-polymers with high contents of alumina and silica (made from metakaolin and fumed silica). 1,2 They are manufactured under ambient temperatures through the combination of the aluminosilicate source with an alkali solution, based on Na or K, in a SiO 2 environment. 1,3 During curing in solution, they undergo distinct processes of formation via: (a) dissolution, (b) polycondensation; and (c) precipitation. 3,4 Several designs have been evaluated in the literature, 2,3,5,6 and their main formulation is based on M 2 O•Al 2 O 3 •xSiO 2 •yH 2 O 1,5 ; where M represents the alkali (Na or K); and x and y are determined according to the molar ratios desired. Their applications have been growing in recent years, encompassing different purposes and markets, such as: (a) fire-resistant structures; 3,7 (b) nuclear waste encapsulation 4,7 ; (c) alternatives to cement-based materials. 8,9

Amorphous self‐glazed, chopped basalt fiber reinforced, geopolymer‐based composites

“…This involved increasing the amount of fibers as well as amount of glass in the potassium‐based and geopolymer composite. The optimum addition of superplasticizer was already known to be 0.5 wt % with respect to the geopolymer matrix 18 …”

“…To further optimize the strength of the composite, we needed to maximize the amount of fibers that could be added. Hence, we arrived at an optimum combination of 20 wt % basalt fibers/7.5 wt % glass frit/0.5 wt % superplasticizer 18 . Figure 9 is the micrograph of the optimized composition.…”

“…Glass frit (Uroboros Glass F1‐424‐96‐8) was added and high sheared for 2 min at 2000 rpm. To aid the mixing of large amounts of reinforcements, Betolin Sapetin ® D20 (Woellner GmbH) superplasticizer (0.5 wt % with respect to matrix) was added using a dropper and high sheared for 1 minute at 2000 rpm before adding the fibers 18 . The Kameny Vek ® ¼ inch chopped basalt fibers were added and mixed with a stirrer, followed by planetary mixing using the Thinky ® for 3 min at 1600 rpm.…”

“…The optimum addition of superplasticizer was already known to be 0.5 wt % with respect to the geopolymer matrix. 18 3.1.1 | Composition I-15 wt % basalt fibers/15 wt % glass frit/0.5 wt % superplasticizer…”

“…Hence, we arrived at an optimum combination of 20 wt % basalt fibers/7.5 wt % glass frit/0.5 wt % superplasticizer. 18 Figure 9 is the micrograph of the optimized composition.…”