Studi Struktur Mikro dan Kuat Lentur Komposit Geopolimer Serat Bambu dengan Temperatur Curing Berbeda

Abstract

Telah dilakukan studi struktur mikro dan kuat lentur komposit geopolimer berbahan dasar metakaolin dan penguat (agregat) serat bambu. Penelitian ini bertujuan untuk mengetahui nilai kuat lentur komposit geopolimer sebagai fungsi massa serat bambu (0,4 g,0,6 g, dan 0,8 g) serta suhu curing (150, 450 dan 750 • C). Komposit geopolimer serat bambu disentesis dengan metode alkali aktivasi metakaolin dengan model sandwich berbentuk persegi panjang dengan massa serat yang berbeda lalu di curing pada suhu 60 • C selama 1 jam. Sampel selanjut-nya di recurring masing-masing pada suhu 150, 450, dah 750 • C. Karakterisasi morfologi serta struktur kristal bahan dasar dan produk komposit geopolimer dilakukan dengan SEM dan XRD. Sifat termal serat bambu diukur menggunakan DSC. Hasil karakterisasi SEM menunjukkan ikatan antara matriks dengan serat bamboo belum sempurna akibat kehadiran celah yang cukup besar.Hasil karakterisasi dengan XRD memperlihatkan bahwa matriks geopolimer bersifat amorf. Uji mekanik berupa three bending points flexural strength yang dilakukan terhadap 3 sampel untuk setiap komposisi dan suhu curing menunjukkan kuat lentur tertinggi diperoleh dengan penambahan serat bambu sebesar 0.6 g (1.5% dari volume sampel) untuk setiap variasi suhucuring dengan nilai berturut-turut sebesar 665,90 ± 98,40 KPa, 947,29 ± 287,13 KPa dan 1155,62 ± 98,30 KPa. ABSTRACT Microstructure and flexural strength of composite-geopolymers based on metakaolin with bamboo fibers aggre-gate have been studied.The main objective of this study was to determine the flexural strength of composite-geopolymers as a function of bamboo fibers mass (0.4 g, 0.6 g, and 0.8 g) as well as their curing tempera-tures (150, 450, dan 750 • C). Composite-geopolymers were synthesized by using alkali activation method of metakaolin and they were formed in rectangular sandwich shape by varying the mass of bamboo fibers and then cured at 60 • C for 1 hour. The sample was then recurring at temperature of 150, 450, dah 750 • C, respectively. The morphology of the precursors and samples were examined by using SEM and XRD. Thermal properties of bamboo fibers were studied by using differential Perkin Elemer 400 differential scanning calorimetry (DSC). SEM characterization shows that the bond between the matrix of geopolymer and the aggregate is still weak due to the presence of appreciable wide gap. The matrix of geopolymer was amorf in nature based on XRD result. Three bending points flexural strength measurements on three samples for each composition and curing temperature showed that the highest flexural strength was achieved on fiber addition of 0.6 g (1.5% of sample volume) for all curing temperatures with magnitude of 665.90 ± 98.40 KPa, 947.29 ± 287.13 KPa dan 1155.62 ± 98.30 KPa.