Correlation between Na2SiO3/NaOH and NaOH Molarity to Flexural Strength of Geopolymer Ceramic

2015 ◽  
Vol 754-755 ◽  
pp. 152-156 ◽  
Author(s):  
Nur Ain Jaya ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Che Mohd Ruzaidi Ghazali ◽  
M. Binhussain ◽  
Kamarudin Hussin ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Flexural Strength ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Alkali Activation ◽  
M 12 ◽  
Alkaline Activator

Clay based geopolymer ceramic were produced through the geopolymerisation process by the alkali activation of kaolin with an activator solution which is mixture of sodium silicate and sodium hydroxide and undergoes heating at elevated temperature. The concentration of NaOH used in this study was in the range of 6 M-12 M. The ratio of kaolin to alkaline activator used is 1.0. Three different ratios of Na2SiO3/NaOH of 0.16, 0.24 and 0.32 were used to investigate the optimum flexural strength. The samples were cured at 80 °C for 24 hours and sintered at temperatures ranging from 900 °C-1200 °C. The optimum flexural strength of 86.833 MPa is obtained when the ratios of Na2SiO3/NaOH is 0.24 with the NaOH concentration of 12M at 1200 °C.

Thermal Resistance of Fly Ash Geopolymers with Alumina as Additive

2018 ◽  
Vol 281 ◽  
pp. 182-188
Author(s):  
Yong Sing Ng ◽  
Yun Ming Liew ◽  
Cheng Yong Heah ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Hussin
Keyword(s):  
Elevated Temperature ◽  
Fly Ash ◽  
Thermal Resistance ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Room Temperature ◽  
Strength Degradation ◽  
Alumina Addition ◽  
Higher Temperature ◽  
Temperature Exposure

The present work investigates the effect of alumina addition on the thermal resistance of fly ash geopolymers. Fly ash geopolymers were synthesised by mixing fly ash with activator solution (A mixture of 12M sodium hydroxide and sodium silicate) at fly ash/activator ratio of 2.5 and sodium silicate/sodium hydroxide ratio of 2.5. The alumina (0, 2 and 4 wt %) was added as an additive. The geopolymers were cured at room temperature for 24 hours and 60°C for another 24 hours. After 28 days, the geopolymers was heated to elevated temperature (200 - 1000°C). For unexposed geopolymers, the addition of 2 wt % of alumina increased the compressive strength of fly ash geopolymers while the strength decreased when the content increased to 4 wt.%. The temperature-exposed geopolymers showed enhancement of strength at 200°C regardless of the alumina content. The strength reduced at higher temperature exposure (> 200°C). Despite the strength degradation at elevated temperature, the strength attained was relatively high in the range of 13 - 45 MPa up to 1000°C which adequately for application as structural materials.

The Effect of Curing Time on the Properties of Fly Ash-Based Geopolymer Bricks

2012 ◽  
Vol 626 ◽  
pp. 937-941 ◽  
Author(s):  
W.I. Wan Mastura ◽  
H. Kamarudin ◽  
I. Khairul Nizar ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
H. Mohammed
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Absorption ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Experimental Work ◽  
Base Material ◽  
Curing Time ◽  
Curing Conditions ◽  
Alkaline Activator

This paper reports the results of an experimental work conducted to investigate the effect of curing conditions on the properties of fly ash-based geopolymer bricks prepared by using fly ash as base material and combination of sodium hydroxide and sodium silicate as alkaline activator. The experiments were conducted by varying the curing time in the range of 1-24 hours respectively. The specimens cured for a period of 24 hours have presented the highest compressive strength for all ratio of fly ash to sand. For increasing curing time improve compressive strength and decreasing water absorption.

Effect of Fly Ash/Alkaline Activator Ratio and Sodium Silicate/NaOH Ratio on Fly Ash Geopolymer Coating Strength

2013 ◽  
Vol 594-595 ◽  
pp. 146-150 ◽  
Author(s):  
J. Liyana ◽  
Abdullah Mohd Mustafa Al Bakri ◽  
Kamarudin Hussin ◽  
C.M. Ruzaidi ◽  
A. Rashid Azura
Keyword(s):  
Fly Ash ◽  
Flexural Strength ◽  
Sodium Silicate ◽  
Sintering Temperature ◽  
Coating Material ◽  
Liquid Ratio ◽  
Alkali Activator ◽  
Alkaline Activator ◽  
Solid Liquid ◽  
Exposure Conditions

Fly ash geopolymer coating material potential used to protect surface used in exposure conditions. Ratio of fly ash/alkaline activator and Na2SiO3/NaOH play important parameter on determining the best flexural strength of geopolymer coating material. Fly ash and alkali activator (Al2O3/Na2SiO3) were mixed with the solids-to-liquid ratios in range of 1.0-3.0 and different ratios of Na2SiO3/NaOH (1.0-3.0) to prepare geopolymer coating material at constant NaOH concentration of 10 M. Effect of fly ash/alkaline activator ratio and Na2SiO3/NaOH on geopolymer coating was determined with respect to the highest flexural strength of the 1200oC sintering temperature of geopolymer coating substrates. The results concluded that the highest strength for fly ash geopolymer coating material is achieved 42 MPa when the solid/liquid ratio is 2.0 and the Na2SiO3/NaOH ratio is 2.5.

scholarly journals A study on the strength development of geopolymer concrete using fly ash

2017 ◽  
Vol 6 (4) ◽  
pp. 163 ◽  
Author(s):  
Ramesh Babu Chokkalingam ◽  
Ganesan N
Keyword(s):  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Sodium Hydroxide Solution ◽  
Fine Sand ◽  
Strength Development ◽  
Alkali Activation ◽  
Geopolymer Concrete ◽  
Water Contaminants ◽  
Significant Difference

Cement consumption is increasing day by day due to the tremendous development in the infrastructure facilities. The production of one ton of cement emits approximately one ton of carbon dioxide to the atmosphere. In order to reduce the use of cement a new-generation concrete has been developed such as geopolymer concrete (GPC).Geopolymer Geopolymer is a new material which has the potential to replace ordinary Portland cement. It is an inorganic material synthesized by alkali activation of amorphous aluminosilicates at ambient or slightly increased temperatures having an amorphous to semi-crystalline polymeric structure. In this study, low calcium flyash from Tuticorin was used to produce geopolymer concrete. The geopolymer was synthesized with sodium silicate and sodium hydroxide solutions. The sodium hydroxide pellets was dissolved in the distilled water to make free from mixing water contaminants. The ratio of sodium silicate and sodium hydroxide ratio was kept as 2.5. The concentration of sodium hydroxide solution is 12 Molarity (12M). Other materials used are locally available coarse aggregate and fine sand in surface dry condition. A polycarboxlate HRWRA La Hypercrete S25was used. Cubes of size 100mm were cast for six mix proportions of 450kg/m3 flyash+0.35W/B, 500 kg/m3 flyash+0.35W/B, 550kg/m3 flyash+0.35W/B, 450kg/m3 flyash+.0.40 W/B, 500kg/m3 fly ash+0.40W/B and 550kg/m3 flyash+0.40W/B. The specimens after casting in moulds were kept in oven at 60°C for 6 hours and left to air dry at room temperature and tested at 7 and 28 days. The test results revealed the compressive strength of 30 Mpa was achieved. There was not much significant difference in strength development at 28 days between the mixes due to the increase of flyash content. The microstructural images at 28 days revealed that there was not much difference in the microstructure due to the variation in flyash content from 450 kg/m3 to 550 kg/m3.

Effect of Curing Conditions on the Mechanical Properties of Fly Ash-Based Geopolymer without Sodium Silicate Solution

2014 ◽  
Vol 699 ◽  
pp. 15-19 ◽  
Author(s):  
Rosniza Hanim Abdul Rahim ◽  
Khairun Azizi Azizli ◽  
Zakaria Man ◽  
Muhd Fadhil Nuruddin
Keyword(s):  
Compressive Strength ◽  
Elevated Temperature ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Room Temperature ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Curing Temperature ◽  
Curing Time

Geopolymer is associated with the alkali activation of materials rich in Si and Al, and alkali activator such as sodium hydroxide is used for the dissolution of raw material with the addition of sodium silicate solution to increase the dissolution process. However, the trend of strength development of geopolymer using sodium hydroxide alone is not well established. This paper presents an evaluation on compressive strength of fly ash–based geopolymer by varying curing time with respect to different curing temperature using sodium hydroxide as the only activator. The samples were cured at room temperature and at an elevated temperature (60°C). Further analysis on the microstructure of geopolymer products cured at 60°C was carried out using Field Emission Scanning Microscopy (FESEM). It can be observed that the compressive strength increased as the curing time increased when cured at room temperature; whereas at elevated temperature, the strength increased up to a maximum 65.28 MPa at 14 days but gradually decreased at longer curing time. Better compressive strength can be obtained when the geopolymer was cured at an elevated temperature compared to curing at room temperature.

The Effect of Solid-to-Liquid Ratio and Temperature on Mechanical Properties of Kaolin Geopolymer Ceramics

2015 ◽  
Vol 660 ◽  
pp. 23-27 ◽  
Author(s):  
Romisuhani Ahmad ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Hussin ◽  
Andrei Victor Sandu ◽  
Mohammed Binhussain ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Flexural Strength ◽  
Relative Density ◽  
Sodium Silicate ◽  
Sintered Sample ◽  
Liquid Ratio ◽  
Naoh Solution ◽  
Sample Range ◽  
Alkaline Activator

The effect of solid-to-liquid ratio and temperature on the mechanical properties of kaolin geopolymer ceramics are studied. Kaolin and alkaline activator were mixed with the solid-to-liquid ratio in the range of 0.8-1.2. Alkaline activator was formed by mixing the 12 M NaOH solution with sodium silicate at a ratio of 0.24. Kaolin geopolymer ceramic have been produced by using powder metallurgy (PM) technique. The samples were heated at different temperature started from 900 °C until 1200 °C and the strength were tested. The relative density and flexural strength of sintered sample range approximately 84%-95% and 20-90 MPa respectively. The result revealed that the optimum flexural strength was obtained at solid-to-liquid ratio of 1.0 and the samples heated at 1200 °C achieved the highest flexural strength (90 MPa).

scholarly journals Effect of sodium hydroxide concentration on the compressive strength of geopolymer mortar using fly ash PLTU Tanjungjati B Jepara

2022 ◽  
Vol 955 (1) ◽  
pp. 012010
Author(s):  
A Kustirini ◽  
Antonius ◽  
P Setiyawan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Coal Industry ◽  
Waste Materials ◽  
Geopolymer Concrete ◽  
Sodium Hydroxide Concentration ◽  
Alkaline Activator ◽  
Maximum Compressive Strength

Abstract Geopolymer concrete is concrete that uses environmentally friendly materials, using fly ash from waste materials from the coal industry as a substitute for cement. To produce geopolymer concrete, an alkaline activator is required, with a mixture of Sodium Hydroxide and Sodium Silicate. This research is an experimental study to determine the effect of variations in the concentration of sodium hydroxide (NaOH) 8 Mol, 10 Mol, 12 Mol, and 14 Mol on the compressive strength of geopolymer concrete. Mortar Geopolymer uses a mixture of 1: 3 for the ratio of fly ash and sand, 2.5: 0.45 for the ratio of sodium silicate and sodium hydroxide as an alkaline solution. The specimens used a cube mold having dimension 5 cm x 5 cm x 5 cm, then tested at 7 days and 28 days. The test resulted that concentration of NaOH 12 Mol obtained the maximum compressive strength of geopolymer concrete, that is 38.54 MPa. At concentrations of 12 Mol NaOH and exceeding 12M, the compressive strength of geopolymer concrete decreased.

The Effect of KOH Concentration on Setting Time and Compressive Strength of Fly Ash-Based Geopolymer

2014 ◽  
Vol 625 ◽  
pp. 94-97 ◽  
Author(s):  
Tia Rahmiati ◽  
Khairun Azizi Azizli ◽  
Zakaria Man ◽  
Lukman Ismail ◽  
Mohd Fadhil Nuruddin
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Setting Time ◽  
Alkali Activation ◽  
High Concentration ◽  
Low Concentration ◽  
Optimum Result ◽  
Alkaline Activator

Geopolymer is produced from the alkali activation of materials rich in Si and Al such as fly ash. Sodium hydroxide (NaOH) with high concentration is normally used in geopolymerization. Limited research has been done with low concentration of alkali activator. This study confirms that KOH with low concentration affect the setting time and compressive strength of geopolymer in order to have good mechanical properties. Optimum result was observed at 4.5 M KOH. This result can be further developed to produce geopolymer with low alkaline activator for coating applications.

Potential of Marine Clay as Raw Material in Geopolymer Composite

2012 ◽  
Vol 626 ◽  
pp. 963-966 ◽  
Author(s):  
S.M. Tamizi ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Hussin ◽  
Che Mohd Ruzaidi Ghazali ◽  
J. Liyana ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Composite Materials ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Early Time ◽  
Raw Material ◽  
Marine Clay ◽  
Alternative Materials ◽  
Alkaline Activator ◽  
Marine Clays

In this research, marine clays has been studied its potential as a matrix composite materials that tend to be used as alternative materials to concrete. The study shows that marine clays which mixed with appropriate proportion of alkaline activator could have strength requirements for masonry cement. The alkaline activator that been used for the geopolymerisation reaction is sodium silicate and sodium hydroxide. Its compressive strength in early time reached 9-15 MPa.

Mechanical strength variation of zeolite-fly ash geopolymer mortars with different activator concentrations

2021 ◽  
Vol 12 (3) ◽  
pp. 96
Author(s):  
Roble İbrahim Liban ◽  
Ülkü Sultan Keskin ◽  
Oğuzhan Öztürk
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Sodium Hydroxide ◽  
Sodium Hydroxide Concentration ◽  
Binding Material ◽  
Alkaline Activator ◽  
Compressive And Flexural Strengths ◽  
Mechanical Strengths ◽  
Natural Precursor

Zeolite is of a significance for geopolymers as it is a natural precursor and does not require additional heat treatment for activation. However, aluminosilicates sourced from natural sources require additional handling for the best use of exploitation. In this study, geopolymers were synthesized by binary use of zeolite and fly ash as main binding material and sodium silicate and sodium hydroxide as alkaline activator. The influence of alkaline activator ratios and sodium hydroxide concentrations on the compressive strength and flexural strength of the zeolite-fly ash based geopolymers were studied. In this research, zeolite-fly ash based geopolymer mortars were produced by using 50% of natural zeolite (clinoptilolite) and 50% of C-type fly ash. Four different activator ratios (Na2SiO3/NaOH: 1, 1.5, 2 and 2.5) and two sodium hydroxide molarities (10M and 12M) was utilized to activate zeolite and fly ash in order to determine the effect of these parameters on the mechanical strengths of the produced geopolymer mortars. The results indicated that as the alkaline activator ratio and NH molarity were increased the compressive strength of the zeolite-fly ash based geopolymers also increased. The maximum compressive and flexural strength values obtained after 28 days of curing were 20.1 MPa and 5.3 MPa respectively and corresponds when used activator ratio of 2.5 and sodium hydroxide concentration of 12 molarity. The obtained results indicated that both the alkaline activator ratio and sodium hydroxide concentration affected the compressive and flexural strengths of zeolite-fly ash based geopolymer mortar specimens.

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