Yazid Bindar
Chemical Engineering Program, Bandung Institute of Technology, Jl. Ganesha No. 10, Bandung 40132, Indonesia

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The Effect of Alkaline Activator Types on Strength and Microstructural Properties of Geopolymer from Co-Combustion Residuals of Bamboo and Kaolin Aprilina Purbasari; Tjokorde Walmiki Samadhi; Yazid Bindar
Indonesian Journal of Chemistry Vol 18, No 3 (2018)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (324.179 KB) | DOI: 10.22146/ijc.26534

Abstract

Geopolymer as a Portland cement substitute had been synthesized from alkaline activation of co-combustion residuals of bamboo and kaolin. Types of used alkaline activators were NaOH solution, KOH solution, a mixture of NaOH solution-water glass, and a mixture of KOH solution-water glass. Geopolymer with NaOH solution as activator had a compressive strength which was higher compared to geopolymer with KOH solution as an activator. However, geopolymer with NaOH solution-water glass as activator had a compressive strength which was lower compared to geopolymer with KOH solution-water glass as activator either at room temperature curing or at a curing temperature of 60 °C. The use of water glass with NaOH or KOH solution as activator could increase the compressive strength of geopolymer and yielded geopolymer having more dense and more homogeneous microstructure seen from SEM images. XRD patterns revealed the presence of sodium aluminosilicate hydrate in geopolymer with NaOH solution and NaOH solution-water glass as activators, and potassium aluminosilicate hydrate in geopolymer with KOH solution and KOH solution-water glass as activators. Furthermore, FTIR spectra indicated asymmetrical vibration of Si(Al)-O at around 1008 cm-1 related to geopolymer product.
Sulfuric Acid Resistance of Geopolymer Mortars from Co-combustion Residuals of Bamboo and Kaolin Aprilina Purbasari; Tjokorde Walmiki Samadhi; Yazid Bindar
ASEAN Journal of Chemical Engineering Vol 18, No 2 (2018)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (679.861 KB) | DOI: 10.22146/ajche.49533

Abstract

This study presents an investigation of the durability and microstructure of geopolymer mortars from co-combustion residuals of bamboo and kaolin when exposed to 5% sulfuric acid solution for 2, 4, and 6 weeks, respectively. Geopolymer mortars sized 5 x 5 x 5 cm were prepared from co-combustion residuals of bamboo and kaolin with alkaline activators, i.e. mixture of 10 N potassium hydroxide solution and sodium silicate solution, and cured at 60 oC in oven for 8 hours and then at room temperature for 28 days. Mortars from ordinary Portland cement were also prepared as control mortars. The parameters studied were visual appearance changes, mass changes, compressive strength changes, and microstructure changes. Microstructure changes were examined using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results revealed that geopolymer mortars showed better sulfuric acid resistance compared to ordinary Portland cement mortars in terms of lower mass loss and lower compressive strength loss.