scholarly journals Compressive Strength of Geopolymer Based on the Fly Ash Variation

2016 ◽  
Vol 841 ◽  
pp. 98-103 ◽  
Author(s):  
Antoni ◽  
Stephen Wibiatma Wijaya ◽  
Djwantoro Hardjito
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Power Plants ◽  
Sodium Hydroxide Solution ◽  
Chemical Properties ◽  
External Factors ◽  
Internal Factors ◽  
Internal And External Factors ◽  
Physical And Chemical

. This study was conducted to determine the factors that may affect the compressive strength of fly ash-based geopolyme, manufactured using fly ash obtained from different power plants. Fly ash obtained from different sources may have very different characteristics that affect the properties of geopolymer product. The source of variations in the geopolymer properties from the view point of the source materials can be classified into internal and external factors. Internal factors include the physical and chemical properties of the fly ash, while external factors associated with mixture proportion of geopolymer and the manufacturing process. From the experimental results, it was found that the size of the fly ash granules, the CaO and MgO content, and the carbon content in fly ash are the internal factors that may affect the compressive strength of geopolymer. On the other hand, the ratio of sodium silicate to sodium hydroxide in the alkaline solution and the molarity of the sodium hydroxide solution are the external factors influencing the compressive strength of geopolymer.

Development of Geopolymer Mortar from Metakaolin Blended with Agricultural and Industrial Wastes

2018 ◽  
Vol 766 ◽  
pp. 305-310 ◽  
Author(s):  
Chayanee Tippayasam ◽  
Sarochapat Sutikulsombat ◽  
Jamjuree Paramee ◽  
Cristina Leonelli ◽  
Duangrudee Chaysuwan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Chemical Properties ◽  
Cement Industry ◽  
Industrial Wastes ◽  
Engineering Properties ◽  
Alkali Solutions ◽  
Physical And Chemical

Geopolymer is a greener alternative cement produced from the reaction of pozzolans and strong alkali solutions. Generally, the cement industry is one of largest producers of CO2that caused global warming. For geopolymer mortar usage, Portland cement is not utilized at all. In this research, geopolymer mortars were prepared by mixing metakaolin, various wastes (fly ash, bagasse ash and rice husk ash) varied as 80:20, 50:50 and 20:80, 15M NaOH, Na2SiO3and sand. The influence of various parameters such as metakaolin to ashes ratios and pozzolans to alkali ratios on engineering properties of metakaolin blended wastes geopolymer mortar were studied. Compressive strength tests were carried out on 25 x 25 x 25 mm3cube geopolymer mortar specimens at 7, 14, 21, 28 and 91 air curing days. Physical and chemical properties were also investigated at the same times. The test results revealed that the highest compressive strength was 20% metakaolin - 80% fly ash geopolymer mortar. When the curing times increases, the compressive strength of geopolymer mortar also increases. The mixing of metakaolin and bagasse ash/rice husk ash presented lower compressive strength but higher water absorption and porosity. For FTIR results, Si-O, Al-O and Si-O-Na+were found. Moreover, the geopolymer mortar could easily plastered on the wall.

Effect of Mechanical Activation of Fluidized Bed Fly Ash on Geopolymer Properties

2019 ◽  
Vol 288 ◽  
pp. 51-58
Author(s):  
Gendenjamts Oyun-Erdene ◽  
Jadambaa Temuujin
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Mechanical Activation ◽  
Sodium Hydroxide ◽  
Fluidized Bed ◽  
Sodium Silicate ◽  
Sodium Hydroxide Solution ◽  
Chemical Activation ◽  
Weight Ratio ◽  
Particle Size Reduction

This paper is focused on the elucidation of mechanical activation effect of circulating fluidized bed combustion fly ash (Amgalan Thermal Station, Mongolia) on mechanical properties of geopolymers. Fluidized bed fly ash was mechanically activated for 15-120 minutes with a vibratory mill. The effect of mechanical activation was quite visible on the particle size reduction and on the degree of amorphization.Geopolymer samples were prepared from the raw and milled fluidized bed fly ashes by alkaline activation. Chemical activation was performed with 10M sodium hydroxide solution, as well as solutions containing a mixture of sodium silicate and sodium hydroxide with a weight ratio of 2:1. The geopolymer cubic specimens were cured at 70°C for 24 hrs and their 7 days uniaxial compressive strength was measured. After curing and drying, the bulk density, water absorption and apparent porosity of geopolymer samples were evaluated.X-ray powder diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetry-differential thermal analysis (TGA-DTA) have been used for the structural characterization of the CFA and the resulting geopolymers. The highest compressive strength of 32.4 MPa was achieved for the fly ash milled for 30 minutes and activated with the solution containing the sodium silicate and 10M sodium hydroxide at a weight ratio of 2:1. Non-milled CFA based geopolymers showed the compressive strength of 16.2 MPa after activation with the same solution. Mechanical activation resulted in an increase in the reactivity of the fluidized bed fly ash and that enhances the geopolymerization reactions.

scholarly journals Effect of Concentration of Sodium Hydroxide and Degree of Heat Curing on Fly Ash-Based Geopolymer Mortar

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Subhash V. Patankar ◽  
Yuwaraj M. Ghugal ◽  
Sanjay S. Jamkar
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Hydroxide Solution ◽  
Large Change ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Test Period ◽  
Hydroxide Solution ◽  
Increase With Increase

Geopolymer concrete/mortar is the new development in the field of building constructions in which cement is totally replaced by pozzolanic material like fly ash and activated by alkaline solution. This paper presented the effect of concentration of sodium hydroxide, temperature, and duration of oven heating on compressive strength of fly ash-based geopolymer mortar. Sodium silicate solution containing Na2O of 16.45%, SiO2 of 34.35%, and H2O of 49.20% and sodium hydroxide solution of 2.91, 5.60, 8.10, 11.01, 13.11, and 15.08. Moles concentrations were used as alkaline activators. Geopolymer mortar mixes were prepared by considering solution-to-fly ash ratio of 0.35, 0.40, and 0.45. The temperature of oven curing was maintained at 40, 60, 90, and 120°C each for a heating period of 24 hours and tested for compressive strength at the age of 3 days as test period after specified degree of heating. Test results show that the workability and compressive strength both increase with increase in concentration of sodium hydroxide solution for all solution-to-fly ash ratios. Degree of heating also plays vital role in accelerating the strength; however there is no large change in compressive strength beyond test period of three days after specified period of oven heating.

scholarly journals Geopolymer Mortar Incorporating High Calcium Fly Ash and Silica Fume

2019 ◽  
Vol 65 (1) ◽  
pp. 3-16 ◽  
Author(s):  
V.C. Prabha ◽  
V. Revathi
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Silica Fume ◽  
Sodium Hydroxide Solution ◽  
Test Results ◽  
Dense Microstructure ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Binder Ratio

AbstractAn attempt was made in the present work to study the compressive strength and microstructure of geopolymer containing high calcium fly ash (HCFA) and silica fume. Concentration of sodium hydroxide solution 8M, 10M, 12M & 14M, liquid to binder ratio 0.5 and sodium hydroxide to sodium silicate ratio 2.5 were selected for the mixes. Geopolymer mortar test results indicated that the mix with 40% silica fume by the weight of HCFA yielded higher compressive strength under ambient curing. The XRD pattern typically shows the major portion of amorphous phase of geopolymer. The existence of C-A-S-H gel, N-A-S-H gel and hydroxysodalite gel products were observed through SEM which developed dense microstructure and thus enhanced strength of HCFA and silica fume geopolymer.

scholarly journals Compressive Strength of Fly ash-based Geopolymer Concrete with a Variable of Sodium Hydroxide (NaOH) Solution Molarity

2018 ◽  
Vol 147 ◽  
pp. 01004 ◽  
Author(s):  
Herwani ◽  
Ivindra Pane ◽  
Iswandi Imran ◽  
Bambang Budiono
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Raw Materials ◽  
Sodium Hydroxide Solution ◽  
Solution Concentration ◽  
Geopolymer Concrete ◽  
Hydroxide Solution ◽  
Naoh Solution ◽  
New Material

Geopolymer concrete is a new material made by activating the raw materials which contain many elements of silica and alumina. Compressive strength of geopolymer concrete produced was influenced by the concentration of the activator solution. This paper presents an experimental investigation into fly ash-based geopolymer concrete. Research objective was to investigate the effects of alkaline activator solution (AAS) molarity on compressive strength of geopolymer concrete. Variable of the test were a solution to sodium hydroxide was chosen as the activator solution. Concentration of sodium hydroxide solution used was 10 M, 12 M and 14 M with ambient curing. The specimen is made of concrete cylinder with diameter 10 cm and height 20 cm as many as 9 pieces each variable. Compressive strength tests is performed when the concrete is 7, 14, and 28 days old. Results of the test are indicated that the increasing of sodium hydroxide (NaOH) solution concentration leads to improve the compressive strength of geopolymer concrete. The optimal compressive strength of geopolymer concrete was achieved at a concentration of sodium hydroxide solution (NaOH) of 12 M. Geopolymer concretes compressive strength only achieves around 50-60% of the planned.

scholarly journals Development of Sustainable Eco-friendly Geopolymer Composites for Construction Applications

2020 ◽  
Author(s):  
Mohamed Rabie ◽  
Mohammad Irshidat ◽  
Nasser Al-Nuaimi
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Power Plants ◽  
Sodium Hydroxide Solution ◽  
Testing Machine ◽  
Heat Curing ◽  
Alkali Solutions ◽  
Binder Ratio ◽  
Class F Fly Ash ◽  
Class F

Geopolymerization is a process where silica and alumina rich source materials turns into excellent binding materials by the aid of alkali solutions. Materials such as fly ash are by-products in energy power plants. Fly ash is classified based on its constituent materials. Fly ash class F mainly consists of alumina and silica. Compressive strength of class F fly ash geopolymer mortar is influenced by many factors such as the molarity of sodium hydroxide solution, fluid to binder ratio, Na2SiO3/NaOH ratio, curing duration and curing temperatures. The present study investigates the effect of these factors on the compressive strength of geopolymer mortar. For each combination, three cubes with dimensions of 50 x 50 x 50 mm were casted. After heat curing in the laboratory oven, the samples were tested on a universal testing machine for the compressive strength. The results showed very high early compressive strength of 63.9 MPa for samples cured at 80 °C and for a duration of 24 hr.

Variability and Trends in Iowa Fly Ashes

1986 ◽  
Vol 86 ◽  
Author(s):  
Scott Schlorholtz ◽  
Ken Bergeson ◽  
Turgut Demirel
Keyword(s):  
Fly Ash ◽  
Chemical Composition ◽  
Power Plant ◽  
Coefficient Of Variation ◽  
Power Plants ◽  
Chemical Properties ◽  
Physical Analysis ◽  
Fly Ashes ◽  
High Calcium ◽  
Physical And Chemical

ABSTRACTAn investigation has been made of the variability of physical and chemical properties of high-calcium (Class C) fly ashes from four Iowa power plants. The investigation summarizes results obtained from three years (1983 through 1985) of monitoring of the various power plants. All four of the power plants burn low-sulfur, sub-bituminous coal from Wyoming. Fly ash samples were obtained from the power plants in accordance to the procedures described in ASTM C 311. Laboratory testing methods were similar to those specified by ASTM C 311. During the three year period, 102 samples were subjected to chemical and physical analysis while an additional 349 samples were subjected to physical analysis only. In general, the four power plants produce fly ashes of similar mineralogy and chemical composition. The observed time variation of the chemical composition of fly ash from a single power plant was quite small. The sulfur content consistently showed the largest coefficient of variation of the 10 elements studied. Physical characteristics of the fly ashes (as measured by ASTM tests) were also fairly uniform over long periods of time, when considered on an individual power plant basis. Fineness, when measured by wet washing using a 325 mesh sieve, consistently exhibited the largest coefficient of variation of any of the physical properties studied.

Effect of Calcium Carbonate on Compressive Strength and Physical Properties of Alkali-Activated Lightweight Concrete

2017 ◽  
Vol 751 ◽  
pp. 550-555 ◽  
Author(s):  
Watcharapong Wongkeo
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Calcium Carbonate ◽  
Physical Properties ◽  
Sodium Hydroxide ◽  
Bulk Density ◽  
Lightweight Concrete ◽  
Sodium Hydroxide Solution ◽  
Atomic Ratio ◽  
Alkali Activated

This study presents the compressive strength and physical properties of alkali-activated lightweight concrete. Alkali-activated lightweight concrete was synthesized with fly ash, calcium carbonate and sodium hydroxide solution. Calcium carbonate was designed to replace part of fly ash at 5 and 10 wt.%. Sodium hydroxide solution at 5, 7.5 and 10 M was used as a liquid solution. Liquid to ash ratio (L/A ratio) at 0.45 was designed and aluminium powder was used as a foaming agent. The results showed that, the compressive strength of alkali-activated lightweight concrete made with fly ash was increased with NaOH concentration increased. The maximum compressive strength at 6.0 MPa was obtained from 10M NaOH mixture. For fly ash-calcium carbonate system, the compressive strength of lightweight concrete was improved when containing calcium carbonated, especially at 5 and 7.5 M NaOH mixtures. The maximum of compressive strength at 8.1 MPa and bulk density were obtained from the 5 wt.% calcium carbonated with 10M NaOH mixture. Water absorption and voids of all mixtures trend to decrease with increased NaOH concentration. XRD showed the sodium aluminum silicate hydrated as an alkali-activated product and composed of Si/Al atomic ratio at 2.1 and Na/Al atomic ratio at 1.4, respectively. Bulk density and compressive strength of alkali-activated lightweight concrete made with both fly ash and fly ash-calcium carbonated were acceptable in accordance with the specified criteria of TIS 2601. The well pore structure distribution of alkali-activated lightweight concrete was acceptable.

The Effect of Dry Mix Sodium Hydroxide onto Workability and Compressive Strength of Geopolymer Paste

2020 ◽  
Vol 12 (9) ◽  
Author(s):  
A. Z. Mohd Ali ◽  
◽  
N. A. Jalaluddin ◽  
N. Zulkiflee ◽  
◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Alkaline Solution ◽  
High Emission ◽  
New Material ◽  
Curing Regime ◽  
Solid Form ◽  
Geopolymer Paste

The production of ordinary Portland cement (OPC) consumes considerable amount of natural resources, energy and at the same time contribute in high emission of CO2 to the atmosphere. A new material replacing cement as binder called geopolymer is alkali-activated concrete which are made from fly ash, sodium silicate and sodium hydroxide (NaOH). The alkaline solution mixed with fly ash producing alternative binder to OPC binder in concrete named geopolymer paste. In the process, NaOH was fully dissolved in water and cooled to room temperature. This study aims to eliminate this process by using NaOH in solid form together with fly ash before sodium silicate liquid and water poured into the mixture. The amount of NaOH solids were based on 10M concentration. The workability test is in accordance to ASTM C230. Fifty cubic mm of the geopolymer paste were prepared which consists of fly ash to alkaline solution ratio of 1: 0.5 and the curing regime of 80℃ for 24 hours with 100% humidity were implemented. From laboratory test, the workability of dry method geopolymer paste were decreased. The compressive strength of the dry mix of NaOH showed 55% and the workability has dropped to 58.4%, it showed strength reduction compared to the wet mix method.

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