Geopolymer reinforced with E-glass leno weaves

This study explores the viability of fiberglass-geopolymer composites as an intermediate temperature structural ceramic composite. E-glass fibers are cheap, readily available, resistant to heat, electricity and chemical attack. Geopolymers are refractory and can be processed at room temperature. However, pure geopolymers have low tensile strength and fracture toughness, as is typical of ceramics. In this work, tensile and flexure properties of metakaolin-based sodium and potassium geopolymers reinforced with E-glass leno weaves were measured and the data was analyzed by Weibull statistics. The average tensile and flexural strengths for sodium geopolymer reinforced with E-glass leno weaves were 39.3 +/- 7.2 MPa and 25.6 +/- 4.8 MPa, respectively. For potassium geopolymer reinforced with E-glass leno weaves, the average tensile and flexural strengths were 40.7 +/- 9.9 MPa and 15.9 +/- 4.0 MPa, respectively. The composites were heat treated for one hour at two temperatures, 300 degrees C and 550 degrees C and their flexure properties were studied at room temperatures. The average flexural strengths for sodium geopolymer reinforced with E-glass leno weaves were reduced to 6.6 +/- 1.0 MPa after heat treatment at 300 degrees C, and 1.2 +/- 0.3 MPa after heat treatment at 550 degrees C, respectively. For potassium geopolymer reinforced with E-glass leno weaves, the average flexural strengths were 6.1 +/- 1.5 MPa and 1.3 +/- 0.3 MPa after heat treatment at 300 degrees C and 550 degrees C, respectively. SEM and EDS were performed to observe the fiber-matrix interface. XRD was done to check if the geopolymer was amorphous as expected.