Potassium‐Based Geopolymer Composites Reinforced with Chopped Bamboo Fibers

Abstract

Bamboo is a fast-growing, readily available natural material with tensile specific strength equivalent to that of steel (250-625 MPa/g/cm 3 ). In the pursuit of sustainable construction materials, a composite was made with potassium polysialate siloxo geopolymer as the matrix and randomly oriented chopped bamboo fibers (Guadua angustifolia) from the Amazon region as the reinforcement. Four-point flexural strength testing of the geopolymer composite reinforced with bamboo fibers was carried out according to ASTM standard C78/C78M-10 e1. Potassiumbased metakaolin geopolymer reinforced with 5 wt% (8 vol%) untreated bamboo fibers yielded 7.5 MPa four-point flexural strength. Scanning electron microscopy and optical microscopy were used to investigate the microstructure. In addition, X-ray diffraction was used to confirm the formation of geopolymer. the relationships between composition, processing, microstructure, and the properties of metakaolin-based geopolymers (MKGPs) and found that the best compressive strength is obtained when the Si:Al molar ratio is 2:1 in geopolymers. When compared to ordinary portland cement (OPC), geopolymers have faster setting time and lower density. The mechanical properties of geopolymers are superior to portland cement in general, but are influenced by the contents of the liquid phase in the mixture, the curing temperature, and the final porosity of the body. 5 The energy required to produce geopolymer is considerably lower than that required for OPC. The extent of reduction in energy depends upon the raw materials used to make the geopolymer. 7 They are processed as a liquid enabling them to be cast into any shape and cured at ambient or slightly elevated temperatures. However, like ceramics, pure geopolymers are brittle and are weak in tension. Their failure is catastrophic with very little warning signal. On the other hand, they can

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

“…Geopolymers exhibit a fragile behavior with low deformation capacity as is typical of ceramics 10 . The use of reinforcements has been well explored in distinct forms to enhance their strength and ductility, such as additions of: sand 10 and chamotte 10‐12 as particulate reinforcements; as well as incorporations of synthetic (PVA, 13 PE, 14 carbon, 15 glass, 16 steel 9 ), mineral (basalt 11,17 ) and natural (bamboo, 18 jute, 8 sisal 19 ) fibers. Basalt fibers appear to be an interesting compatible material to be incorporated into geopolymer binders due to their high tensile strength, alkali resistance, 11 durability, and resistance to elevated temperatures 16 …”

Formation of α/β‐Si3N4nanoparticles by carbothermal reduction and nitridation of geopolymers

“…[] In particular, their brittle nature has been a focus for a number of studies and has been extensively improved by making GP‐composites by consolidating the GP matrix with various reinforcements. []…”

Natural Fiber-Stabilized Geopolymer Foams—A Review

“…The average reported flexural strength was around 7.5 MPa. However, the pulled-out bamboo fibers on the scanning electron microscopy (SEM) images indicate a weak fiber matrix bonding [ 52 ]. Sá Ribeiro et al also investigated geopolymer–bamboo composites.…”