Roles of Calcium in Geopolymer Containing Paper Mill Sludge Ash

2018 ◽  
Vol 917 ◽  
pp. 311-315 ◽  
Author(s):  
Norbaizurah Rahman ◽  
Andri Kusbiantoro ◽  
Nabilah Mamat ◽  
Khairunisa Muthusamy ◽  
Mohd Mustafa Al Bakri Abdullah
Keyword(s):  
Fly Ash ◽  
Mechanical Strength ◽  
Sodium Hydroxide Solution ◽  
Setting Time ◽  
Sodium Silicate Solution ◽  
Paper Mill ◽  
Curing Temperature ◽  
Paper Mill Sludge ◽  
Degree Of Reaction ◽  
Sludge Ash

High amount of calcium oxide (CaO) in source material is known to positively influence the mechanical strength of fly ash based geopolymer. This study was conducted to investigate the suitability of paper mill sludge ash (PMSA) to partially replace fly ash in geopolymer mortar based on its degree of reaction. Fly ash was activated by a combination of sodium silicate solution and 6 M sodium hydroxide solution. The mixtures were designed to replace fly ash content with PMSA at 5%, 10% and 15% (by weight of fly ash). To observe its effect on the mechanical strength, the specimens were cured in three different temperatures, which are 30°C, 60°C and 90°C for 24 hours. After 24 hours, the hardened specimens were demoulded and placed at room temperature until the testing days. Measurement on fresh geopolymer properties was conducted with setting time and flowability tests, while degree of reaction tests was conducted on the hardened specimen. Based on the results, 5% PMSA demonstrated superior degree of reaction than other mixtures, particularly at higher curing temperature.

Degree of Reaction and Alkali-Leaching of Geopolymer Containing Ca-Rich Source Material and Dipotassium Hydrogen Phosphate

2018 ◽  
Vol 765 ◽  
pp. 275-279 ◽  
Author(s):  
Norbaizurah Rahman ◽  
Andri Kusbiantoro ◽  
Khairunisa Muthusamy ◽  
Mohd Mustafa Al Bakri Abdullah
Keyword(s):  
Fly Ash ◽  
Setting Time ◽  
Sodium Silicate Solution ◽  
Paper Mill ◽  
Silicate Solution ◽  
Experimental Result ◽  
Hydrogen Phosphate ◽  
Degree Of Reaction ◽  
External Agent ◽  
Dipotassium Hydrogen Phosphate

Disparity of anion and cation in geopolymer framework may result in the formation of efflorescence on the surface of hardened geopolymer specimen. The existence of efflorescence would be intensified with the use of dipotassium hydrogen phosphate (K2HPO4) as a chemical retarder for geopolymer mixture. In this study, paper mill sludge ash (PMSA) was used as a Ca-rich aluminosilicate source to reduce the development of efflorescence crystals. PMSA was utilized to partially replace fly ash at 5% and 10% (by weight of fly ash). Meanwhile, K2HPO4 was used as the external agent with various proportions, which were 0.1%, 0.3%, and 0.5% (by weight of fly ash). The external agent in this study was purposed to extend the setting time and enhance the mechanical properties of geopolymer. Fly ash and PMSA (if any) were activated by reacting them with 6M sodium hydroxide and sodium silicate solution. Freshly cast specimens were cured for 24 hours in electronic oven with the temperature setting of 30°C and 90°C. They were demoulded after 24 h and kept at room temperature (28±2 °C) until the testing day. Evaluation on the setting time characteristic of fresh geopolymer mortar was conducted with Vicat test while degree of reaction was performed on the hardened specimens to measure the reaction of fly ash during geopolymerization. Based on the experimental result, the inclusion of 5% PMSA shows the greatest effect in reducing the development of efflorescence crystal and increase the degree of reaction of geopolymer system. It is presumed that PMSA has altered the geopolymerization process by activating calcium oxide precursors to form three tetrahedral structures in the framework.

Effect of Partial Replacement of Fly Ash by Metakaolin on Strength Development of Fly Ash Based Geopolymer Mortar

2017 ◽  
Vol 744 ◽  
pp. 131-135 ◽  
Author(s):  
Muhammad Zahid ◽  
Nasir Shafiq ◽  
Mohd Fadhil Nuruddin ◽  
Ehsan Nikbakht ◽  
Asif Jalal
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide Solution ◽  
Base Material ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Partial Replacement ◽  
Strength Development ◽  
Class C ◽  
Class F

This article aims to investigate the compressive strength variation by the addition of metakaolin as a substitute of fly ash in the fly ash based geopolymer mortar. Five, ten and fifteen percent by weight of fly ash was replaced by highly reactive metakaolin. Two type of fly ashes namely, ASTM class F and ASTM class C were used as a base material for the synthesis of geopolymer mortar. Eight molar sodium hydroxide solution mixed with sodium silicate solution was used as alkaline activator. For optimum geopolymerization, mortar was cured at sixty degree Celsius for twenty four hours duration. Results show different behavior of metakaolin replacement on compressive strength for two different types of fly ash based geopolymer mortar. Improvement in compressive strength was seen by addition of metakaolin in ASTM class F fly ash based geopolymer. On the other hand compressive strength was decreased abruptly in fly ash class C based geopolymer up to certain replacement level.

Water-Resistant Modification of Desulphurization Gypsum Block

2012 ◽  
Vol 182-183 ◽  
pp. 278-282
Author(s):  
Yan Mu ◽  
Ying Li Fu ◽  
Feng Qing Zhao
Keyword(s):  
Fly Ash ◽  
Mechanical Strength ◽  
High Performance ◽  
Water Resistance ◽  
Curing Temperature ◽  
Curing Time ◽  
Operating Property ◽  
High Mechanical Strength ◽  
Calcined Gypsum ◽  
Hemi Hydrate

A high performance water resistance agent KD-3 prepared from OPC cement, fly ash, slag and additives was used for the modification of hemi-hydrate desulphurization gypsum. Various factors on gypsum block were investigated. The prepared gypsum block possesses excellent water-resistance, good operating property and high mechanical strength. The optimized results was obtained: calcined gypsum 74.9%, KD-3 25%, retarder 0.1%, curing temperature 60°C and curing time 16h.

scholarly journals Contributions to the study of porosity in fly ash-based geopolymers. Relationship between degree of reaction, porosity and compressive strength

2016 ◽  
Vol 66 (324) ◽  
pp. 098 ◽  
Author(s):  
Y. Luna-Galiano ◽  
C. Fernández-Pereira ◽  
M. Izquierdo
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
The Other ◽  
Curing Temperature ◽  
Inverse Relation ◽  
Degree Of Reaction ◽  
Lower Porosity ◽  
Influencing Parameters ◽  
Closed Structure ◽  
Activating Solution

The main contribution of this paper relates to the development of a systematic study involving a set of parameters which could potentially have an impact on geopolymer properties: curing temperature, type of activating solution, alkali metal in solution, incorporation of slag (Ca source) and type of slag used. The microstructures, degrees of reaction, porosities and compressive strengths of geopolymers have been evaluated. Geopolymers prepared with soluble silicate presented a more compacted and closed structure, a larger amount of gel, lower porosity and greater compressive strength than those prepared with hydroxides. On the other hand, Na-geopolymers were more porous but more resistant than K-geopolymers. Although there is an inverse relation between degree of reaction and porosity, between compressive strength and porosity it is not always inversely proportional and could, in some cases, be masked by changes produced in other influencing parameters.

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 Factors Affecting the Setting Time of Fly Ash-Based Geopolymer

2016 ◽  
Vol 841 ◽  
pp. 90-97 ◽  
Author(s):  
Antoni ◽  
Stephen Wibiatma Wijaya ◽  
Djwantoro Hardjito
Keyword(s):  
Fly Ash ◽  
Initial Temperature ◽  
Ph Value ◽  
Setting Time ◽  
Chemical Properties ◽  
Curing Temperature ◽  
Factors Affecting ◽  
Ph Values ◽  
Physical And Chemical ◽  
And Chemical Properties

Fly ash is a waste from coal burning, that are generated with fluctuation both in its physical and chemical characteristics. This characteristics of fly ash when used in the making of geopolymer concrete will greatly affect the final products obtained. The pH value measured in fly ash, according previous research, can influence the setting time of geopolymer and fly ash with high pH values can cause flash-setting in the concrete. Understanding more clearly about the factors that affect the setting time of fly ash based geopolymer is important for further progress and development of the material. It was found that factors that influence the setting time of geopolymer was not only from the physical and chemical properties of the fly ash itself. Other factors such as composition and mix design, manufacturing process and environmental conditions can also affect its setting time. The experimental results showed that fly ash particle size, CaO and MgO content, in addition to ratio of sodium silicate and sodium hydroxide in the alkali solution, molarity of NaOH, initial temperature of the mixture, curing temperature, and mix volume could potentially influence the setting time of the geopolymer mixture.

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.

Synthesis and characterization of ceramics from coal fly ash and incinerated paper mill sludge

2008 ◽  
Vol 34 (8) ◽  
pp. 2137-2142 ◽  
Author(s):  
Erika Furlani ◽  
Sergio Brückner ◽  
Dino Minichelli ◽  
Stefano Maschio
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Paper Mill ◽  
Synthesis And Characterization ◽  
Paper Mill Sludge

Interrelationship Analysis of Geopolymer Components Using Pearson Correlation Technique

2014 ◽  
Vol 567 ◽  
pp. 417-421 ◽  
Author(s):  
Andri Kusbiantoro ◽  
Norbaizurah Rahman ◽  
Noor Fifinatasha Shahedan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Elemental Composition ◽  
Setting Time ◽  
Source Material ◽  
Curing Temperature ◽  
Strength Development ◽  
Correlation Technique ◽  
High Calcium ◽  
Geopolymer Binder

Performance of geopolymer based specimens is significantly affected by internal and external aspects. Curing temperature and air humidity are among the prominent external factors that contribute to the alteration of geopolymer properties. Nevertheless, internal component of geopolymer binder also carries essential effect to the hardened geopolymer binder produced. In this research, the study was concentrated on the elemental composition of source material components and their interrelation to the performance of geopolymer binder produced. Different types of fly ash were used as the source material in this research. Low calcium (class-F) fly ash was combined with high calcium (class-C) fly ash to determine the elemental composition effect, particularly SiO2, Al2O3, and CaO to the geopolymer properties. Analysis using SYSTAT statistical software indicated the importance of oxide composition of source material to the geopolymer specimens produced. Initial setting time of geopolymer paste was also possibly important to the compressive strength of geopolymer specimens produced. Nevertheless, final setting time indicated less importance to the compressive strength development of geopolymer binder.

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