Investigation of volcanic ash based geopolymers as potential building materials (original) (raw)
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Proceedings of the 18th LACCEI International Multi-Conference for Engineering, Education, and Technology: Engineering, Integration, And Alliances for A Sustainable Development” “Hemispheric Cooperation for Competitiveness and Prosperity on A Knowledge-Based Economy”, 2020
This research focuses on the search for materials susceptible to being alkaline activated for the generation of new geopolymer materials (alternative to fly ash and blast furnace slag). The potential use of volcanic ash from the Ubinas volcano (located in Moquegua, Peru) for geopolymer synthesis has been studied. NaOH solution has been used in different concentrations for the activation of volcanic ashes. The effect of the concentration of the NaOH solution on the mechanical properties (compressive strength and porosity) of the hardened specimens has been analyzed. Systems activated with solutions of 6, 9 and 12M has shown a good mechanical performance due to the formation of the main reaction product (N-AS -H gel) and a good wear resistance. The efflorescence effect when using high alkali contents has affected the wear results. This research opens a new gate to the use of this type of materials of volcanic origin and their use as resistant materials to wear and abrasion.
IOP Conference Series: Materials Science and Engineering, 2019
Volcanic ash is a product from an explosive type of volcanic eruptions. Fresh particles of volcanic ash are gritty, abrasive, vexatious and corrosive with huge scale dispersion. Consequently, it is the need of the hour to dispose this waste systematically to have relief from dilemmas like land fillings; climatic changes, pollution of the environment, water, and health hazards although the soil is a mineral intake. This crucially reviewed manuscript includes not merely the comprehension of the incorporation of volcanic ash to develop novel green Geopolymer composites but also to study its impact on the geopolymerization reaction kinetics and reactivity at dissimilar temperatures along with a precise account of its chemistry, mineralogy and the morphology.
Revista Boliviana de Quimica, 2020
In this study, it has been proposed a geopolymerization method that uses a low liquid/solid (L/S) ratio and the piston as a compaction method which has favored the compression strength achieved considering that the synthesis of geopolymers is characterized by the use of an alkaline solution with a high L/S ratio (greater than 0.45). The volcanic ashes from the Ubinas volcano (Peru's most active volcano) that are rich in Al2O3, SiO2 and CaO were alkaline activated with sodium hydroxide (NaOH) and sodium hydroxide with addition of sodium silicate (NaOH+Na2SiO3), both solutions with 12 M concentration, with a low liquid/solid (L/S) ratio of 0.1 and solid:solid
This paper looks at the possibility of using low reactive volcanic ash for making geopolymer cement. The research is directed towards (a) alteration of the reactivity of volcanic ash by mechanical activation, and (b) use of mechanically activated volcanic ash for the synthesis of a geopolymer. The effect of mechanical activation was quite visible on particle size distribution and the degree of crystallinity. The disappearance of some anorthite peaks and appearance of quartz peaks in volcanic ashes milled for 120 min demonstrate the change in mineralogy. The appearance of an intense carbonate band with milling time could be related to sorption of atmospheric CO 2 on the grains surface during mechanical activation. The manifestation of mechanical activation of volcanic ash was prominent on (a) the reaction kinetics, (b) microstructural development, and (c) physico-mechanical properties of the geopolymer product. The rate constant and extent of geopolymerization increased with milling time but decreased with curing temperature. This decrease is in non-conformity with other alumina-silicate materials used for geopolymerization such as metakaolin and fly ash. FEG-SEM and EDAX results revealed that the geopolymer gel obtained is mixture of poly(ferro-sialate-siloxo) and poly(ferro-sialate-disiloxo)
The present paper investigated the reactivity of volcanic ash in alkaline medium and reported the effect of synthesis conditions on microstructural and mechanical properties of volcanic ash-based geopolymers. The reactivity of volcanic ash was carried out by leaching it under different NaOH concentrations (8, 10, and 12 M) and temperatures (27, 60, and 80°C), and chemical composition of the filtrate measured by ICP-OES. The influence of silica modulus (1.4, 1.5, and 1.66) and curing temperatures (27, 60, and 80°C) on microstructural characteristics of the resulting geopolymers was assessed by Calorimetry test, XRD, FTIR, 27 Al and 29 Si MAS-NMR, TGA, and FESEM-EDX. The dissolution behavior of Si is influenced by NaOH concentration, while Al is more sensitive to temperature. The low amount of dissolved species is correlated with the low amount of heat released. XRD, FTIR, 27 Al and 29 Si MAS-NMR, and TGA have shown the evidence of changes occurred during geopolymerization of volcanic ash and the extent of reaction with varying silica modulus and curing temperature. FESEM and EDX have shown that geopolymers obtained are poly(ferrosialate-siloxo), poly(ferro-sialate-disiloxo), and poly(ferro-sialate-multisiloxo) binder types with Ca 2? , Mg 2? , and Na ? as charge-balancing cations. These structures are irrespective of silica modulus and curing temperature. The curing temperature is the main factor affecting the early compressive strength.
Following the Yogyakarta earthquake on May 27th, 2006, the ubsequent eruption of a volcano mud has been closely observed and analyzed by the geological community. The volcano mud, known as LUSI (LUlumpur, SI-Sidoarjo), began erupting near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia. LUSI offers a unique opportunity to study the genesis and development of a volcano mud. This paper summarizes the current knowledge about the potential of volcano ash as a raw material in geopolymer and as artificial aggregate. Previous experimental study shows that the volcano ash has a good performance when 5% and 10% OPC was replaced by volcano ash mixture. Volcano ash mixed with fly ash in certain composition has a potential to become a binder in geopolymer concrete. An effort to convert the volcano ash to artificial aggregate also shows good potential due to their specific gravity and water absorptions, and characterization of this material. The characterization of this material have been done through X-ray Fluorescence (XRF), X-ray Diffraction (XRD), Scanning Electron Micrograph (SEM), and Fourier Transform Infrared Spectroscopy (FTIR), and then compared to other materials. Sintered volcano ash showed good performance in terms of strength as a cement replacement material with OPC and fly ash. Volcano ash also showed good performance for porosity. This material has a potential as a raw material due to high compounds of SiO2 and Al2O3 in producing geopolymer composites, and as new artificial aggregate to be used in concrete application.
Physical Properties of Volcanic Ash Based Geopolymer Concrete
This paper describes the result of investigating volcanic ash of Mount Kelud as fly ash substitute material to produce geopolymer concrete. The test was held on geopolymer concrete blended with 0%, 25%, 50% and 100% fly ash replacement with volcanic ash. Natrium Hidroxide (NaOH) with concentration of 12 molar and Natrium Silicate (Na2SiO3) were used as alkaline activator. While alkali-activator ratio of 2 was used in this research. The physical properties was tested by porosity and setting time test, while split tensile strength presented to measure brittle caracteristic of geopolymer concrete. The result shown that increasing volcanic ash content in the mixture will increase setting time of geopolymer paste. On the other hand increasing volcanic ash content will reduce split tensile strength and porosity of geopolymer concrete. After all replacing fly ash with volcanic ash was suitable from 25% to 50% due to its optimum physical and mechanical properties.