Microstructure Studies on Different Types of Geopolymer Materials

2013 ◽  
Vol 421 ◽  
pp. 384-389 ◽  
Author(s):  
A.M. Mustafa Al Bakri ◽  
Md Tahir Muhammad Faheem ◽  
Andrei Victor Sandhu ◽  
A. Alida ◽  
Mohd Arif Anuar Mohd Salleh ◽  
...  
Keyword(s):  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Room Temperature ◽  
Ordinary Portland Cement ◽  
Raw Materials ◽  
Raw Material ◽  
Binding Material ◽  
Different Types ◽  
Alkaline Activator

Geopolymer is a new binding material produced to substitute the ordinary Portland cement (OPC) function as a binder in concrete. As we know, different types of geopolymer will have different properties. In this research, the different types of geopolymer raw materials had been studied in term of microstructure. Different type of materials which is fly ash (class F) and kaolin had been mixed with alkaline solution consist of sodium silicate and sodium hydroxide with suitable geopolymer raw material to alkaline activator and sodium silicate to sodium hydroxide ratios. The geopolymer samples with different types of raw material were then cured at a temperature 70°C for 24 hr and maintained at room temperature until the testing was conducted. After the geopolymers were aged for seven days, the testing was conducted.

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 Borax on Lightweight Material from Cullet and Fly Ash

2016 ◽  
Vol 690 ◽  
pp. 109-113 ◽  
Author(s):  
Sutthima Sriprasertsuk ◽  
Phatthiya Suwannason ◽  
Wanna T. Saengchantara
Keyword(s):  
Thermal Conductivity ◽  
Heat Treatment ◽  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Silicate ◽  
Raw Materials ◽  
Raw Material ◽  
Test Results ◽  
Heat Process ◽  
Lightweight Material

This work investigated the recycling of fly ash waste and cullet as the raw materials for lightweight bodies produced by heat treatment and using sodium silicate as the binder. Borax was mixed with fly ash and cullet, and put into the block in dimension 10x10x2 cm3. The lightweight materials thus produced were then sintered at temperature of 800 °C. Density, compressive strength and thermal conductivity were determined. Borax showed a positive sintering effect on the porosity of lightweight material during the heat process. The compressive strength of lightweight material diminished with the reduction of density and thermal conductivity. Lightweight material manufactured with borax showed the lower density and thermal conductivity accompanied by the higher compressive strength. The test results indicated that using fly ash and cullet as the raw material with borax could obtain the lightweight material, thus enhancing the possibility of its reuse in a sustainable way.

scholarly journals Effects of Composition Type and Activator on Fly Ash-Based Alkali Activated Materials

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 63
Author(s):  
Chan-Yi Lin ◽  
Tai-An Chen
Keyword(s):  
Fly Ash ◽  
Sodium Hydroxide ◽  
Blast Furnace Slag ◽  
Raw Material ◽  
Granulated Blast Furnace Slag ◽  
Different Types ◽  
Short And Long Term ◽  
Furnace Slag ◽  
Alkali Activated

The compressive strengths of fly ash-based alkali-activated materials (AAM), produced using various activators of only sodium hydroxide, were measured. Fly ash-based AAM specimens, produced by mixing different kinds of fly ash and ground granulated blast-furnace slag (GGBFs) with an activator containing only sodium hydroxide, were cured at ambient temperature, and then placed in air for different numbers of days. The short- and long-term compressive strengths and shrinkage of fly ash-based AAM were measured and compared to one another. The effects of type of fly ash, alkali-equivalent content, GGBFs replace percentage, and ages on the compressive strengths and shrinkage of fly ash-based AAM were investigated. Even when different fly ash was used as the raw material for AAM, a similar compressive strength can be achieved by alkali-equivalent content, GGBFs replaces percentage. However, the performance of shrinkage due to different types of fly ash differed significantly.

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.

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.

Study of Geopolymeric Binders of Fly Ash/Metakaolin Mixtures Cured at Room Temperature

2014 ◽  
Vol 600 ◽  
pp. 338-344 ◽  
Author(s):  
Alexandre Silva de Vargas ◽  
Ruby M. de Gutierrez ◽  
João Castro-Gomes
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Room Temperature ◽  
Alkaline Solutions ◽  
X Ray Diffraction ◽  
Precursor Material ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

Geopolymerization is a chemical process in which aluminosilicate materials are precursors to obtain binders that have a low environmental impact. Fly ash has been used as a precursor for the development of these binders. However, thermal curing is needed to accelerate the polycondensation of aluminosilicate, which limits the application of this new binder in the construction industry. Thus, the objective of this study was to evaluate the feasibility to obtain such binders with good mechanical properties when cured at room temperature. The precursor material consisted of different mixtures of fly ash and metakaolin that were activated using combined sodium hydroxide and sodium silicate alkaline solutions. The effect on the compressive strength of different proportions of the alkaline solutions was studied. Compressive strengths of about 40 MPa were achieved at 91 days for the samples containing 70% fly ash and 30% metakaolin, activated using an alkaline solution of 50% sodium hydroxide and 50% sodium silicate. X-ray diffraction analysis showed the formation of natrite in geopolymeric samples, as well as the presence of crystalline compounds, such as quartz, mullite and hematite, in fly ash and metakaoline. Scanning electron microscopy analysis showed that in geopolymeric mixtures with higher compressive strength dissolution of fly ash and metakaolin particles occurred almost completely and that aluminosilicate dense gel has been formed extensively.

Preparation of Geopolymer Using Electrolytic Manganese Residue

2013 ◽  
Vol 591 ◽  
pp. 130-133 ◽  
Author(s):  
Rong Zhao ◽  
Feng Lan Han
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Boric Acid ◽  
Sodium Silicate ◽  
Raw Materials ◽  
Raw Material ◽  
Electrolytic Manganese ◽  
Electrolytic Manganese Residue ◽  
Calcined Kaolin

In this study, reference the method of preparing cement sand to produce geopolymer, using Electrolytic Manganese Residue(EMR), fly ash, magnesium slag (with boric acid), sodium silicate, sand, calcined kaolin as the main raw materials, focus on the study of using electrolytic manganese residue to produce Geopolymeric cement. Finally, through a series of comparison, we find out the best recipe of Geopolymer preparation, and the best ratio of each raw material is 80% EMR, 10% magnesium slag, 10% fly ash. In this way, the Geopolymer has the best mechanical properties.

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.

The Effect of Si/Al Ratio and Sodium Silicate on the Mechanical Properties of Fly Ash Based Geopolymer for Coating

2014 ◽  
Vol 803 ◽  
pp. 355-361 ◽  
Author(s):  
Afshan Asif ◽  
Zakaria Man ◽  
Khairun Azizi Mohd Azizli ◽  
Muhd Fadhil Nuruddin ◽  
Lukman Ismail
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Room Temperature ◽  
Maximum Strength ◽  
Coating Application ◽  
Solid Water ◽  
Water Ratio

The present study has been performed to see the effect of varying Si/Al ratio (1.85 to 3) by using same concentration of NaOH and same solid/water ratio for the development of mechanical properties at 28 days of room temperature and also select the Si/Al ratio for coating application. The performance of the geopolymer was investigated on the basis of compressive strengthSEM along with EDS. Pure sodium hydroxide specimens displayed decreased strength. However the combination of sodium hydroxide and sodium silicate specimen with aSi/Al ratio of 2 showed maximum strength, whereas the specimen after Si/Al ratio 2 showed decrease in strength.

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