Microstructure Study on Optimization of High Strength Fly Ash Based Geopolymer

2012 ◽  
Vol 476-478 ◽  
pp. 2173-2180 ◽  
Author(s):  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Hussin ◽  
Mohammed Binhussain ◽  
Ismail Khairul Nizar ◽  
Rafiza Abd Razak ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
High Strength ◽  
Curing Temperature ◽  
Mix Design ◽  
Dense Matrix ◽  
Microstructural Characteristics ◽  
Naoh Solution ◽  
Alkaline Activator

The compressive strength and microstructural characteristics of fly ash based geopolymer with alkaline activator solution were investigated. The sodium hydroxide and sodium silicate were mixed together to form an alkaline activator. Three parameters including NaOH molarity, mix design (fly ash/alkaline activator ratio and Na2SiO3/NaOH ratio), and curing temperature were examined. The maximum strength of 71 MPa was obtained when the NaOH solution of 12M, fly ash/alkaline activator of 2.0, Na2SiO3/NaOH of 2.5 and curing temperature of 60°C were used at 7th days of testing. The results of SEM indicated that for geopolymer with highest strength, the structure was dense matrix and contains less unreacted fly ash with alkaline activator

The Relationship of NaOH Molarity, Na2SiO3/NaOH Ratio, Fly Ash/Alkaline Activator Ratio, and Curing Temperature to the Strength of Fly Ash-Based Geopolymer

2011 ◽  
Vol 328-330 ◽  
pp. 1475-1482 ◽  
Author(s):  
M. M. A. Abdullah ◽  
H. Kamarudin ◽  
M. Bnhussain ◽  
I. Khairul Nizar ◽  
A.R. Rafiza ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Construction Industry ◽  
Curing Temperature ◽  
Test Results ◽  
Compression Tests ◽  
Naoh Solution ◽  
Alkaline Activator ◽  
Relationship Of ◽  
The Relationship

Geopolymer, produced by the reaction of fly ash with an alkaline activator (mixture of Na2SiO3 and NaOH solutions), is an alternative to the use of ordinary Portland cement (OPC) in the construction industry. However, there are salient parameters that affecting the compressive strength of geopolymer. In this research, the effects of various NaOH molarities, Na2SiO3/NaOH ratios, fly ash/alkaline activator, and curing temperature to the strength of geopolymer paste fly ash were studied. Tests were carried out on 50 x 50 x 50 mm cube geopolymer specimens. Compression tests were conducted on the seventh day of testing for all samples. The test results revealed that a 12 M NaOH solution produced the highest compressive strength for the geopolymer. The combination mass ratios of fly ash/alkaline activator and Na2SiO3/NaOH of 2.0 and 2.5, respectively, produced the highest compressive strength after seven days. Geopolymer samples cured at 60 °C produced compressive strength as high as 70 MPa.

Optimization of Alkaline Activator/Fly ASH Ratio on the Compressive Strength of Manufacturing Fly ASH-BASED Geopolymer

2011 ◽  
Vol 110-116 ◽  
pp. 734-739 ◽  
Author(s):  
Mohd Mustafa Al Bakri Abdullah ◽  
H. Kamarudin ◽  
Omar A.K.A. Abdulkareem ◽  
Che Mohd Ruzaidi Ghazali ◽  
A.R. Rafiza ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Alkaline Solution ◽  
Room Temperature ◽  
High Strength ◽  
Constant Ratio ◽  
Optimum Amount ◽  
Molar Ratios ◽  
Naoh Solution ◽  
Alkaline Activator

Fly ash and a mixture of alkaline activators namely sodium silicate (Waterglass) and sodium hydroxide (NaOH) solution were used for preparing geopolymer. The aim of this research is to determine the optimum value of the alkaline activator/fly ash ratio. The effect of the oxide molar ratios of SiO2/Al2O3, water content of the alkaline activator and the Waterglass% content were studied for each Alkaline activator/fly ash ratio. The geopolymers were synthesized by the activation of fly ash with alkaline solution at three different alkaline activator/fly ash ratios which were 0.3, 0.35, and 0.4 at a specific constant ratio of waterglass/NaOH solution of 1.00. The geopolymers were cured at 70°C for 24 h and cured to room temperature. Results revealed that the alkaline activator/fly ash ratio of 0.4 has the optimum amount of alkaline liquid, which shows the highest rate of geopolymerization compared to other ratios. A high strength of 8.61 MPa was achieved with 0.4 of activator/fly ash ratio and 14% of waterglass content.

scholarly journals An experimental study on the mix design optimization of fly ash-based geopolymers

2019 ◽  
Vol 25 (3) ◽  
pp. 259-265
Author(s):  
Evren Arioz ◽  
Omer Arioz ◽  
Mete Kockar
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
High Strength ◽  
Raw Material ◽  
Mix Design ◽  
Synthesis Conditions ◽  
Alkali Activator ◽  
Design And Synthesis

Geopolymers are materials suitable for utilization in the construction industry due to their superior properties, such as high strength and good durability. The properties of geopolymers can be configured due to mix design and synthesis conditions. In this study, the mix designs providing the highest compressive strength were investigated. For this purpose the sodium hydroxide/sodium silicate ratios and alkali activator/fly ash ratios were differentiated in the geopolymer synthesis. Fly ash was used as raw material. Geopolymer samples were cured at 80?C for 16 h and aged for 7 and 28 days in laboratory. The highest compressive strength was obtained as 27.36 MPa with alkali activator/fly ash ratio of 0.4 and sodium hydroxide/sodium silicate ratio of 1.0. The degree of reaction values were determined for all the geopolymer samples. Fourier Transform infrared spectroscopy (FTIR) was used for determining the chemical bonds in the structure. The spectrum of the samples revealed that more aluminosilicate gel formed for the sample providing the highest compressive strength.

scholarly journals Effect of molarity of sodium hydroxide and molar ratio of alkaline activator solution on the strength development of geopolymer concrete

2021 ◽  
Vol 309 ◽  
pp. 01058
Author(s):  
V Srinivasa Reddy ◽  
Karnati Vamsi Krishna ◽  
M V Seshagiri Rao ◽  
S Shrihari
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Ash Content ◽  
Mix Design ◽  
Molar Ratio ◽  
Strength Development ◽  
Geopolymer Concrete ◽  
Synergic Effect ◽  
Alkaline Activator

In the current study, effect of SiO2/Na2O ratio in Sodium silicate (Na2SiO3) solution, Na2SiO3/NaOH ratio and molarity of NaOH on the compressive strength of geopolymer concrete. A geopolymer mix design is formulated with various mixes are casted with alkali activator solution (AAS) / fly ash (FA) =0.5 and constant fly ash content. The molar ratio of SiO2/Na2O in Na2SiO3 solution is altered from 1.50 to 3.00 for different ratios of Na2SiO3/NaOH (2.0, 2.5 and 3.0) and also for various molarities of NaOH (8M,10M,12M,14M,16M and 18M) are studied for their synergic effect on the compressive strength of geopolymer concrete. Results highlighted that the 16M NaOH yields high compressive strength when SiO2/Na2O in Na2SiO3 solution is around 2.00 to 2.40 and Na2SiO3/NaOH=2.5.

Effect of Curing Time and Sintering to the Properties of Geopolymer Mortars

2017 ◽  
Vol 888 ◽  
pp. 184-187
Author(s):  
Salwa Ismail ◽  
Mohammad Faizal Mohd Razali ◽  
Izwan Johari ◽  
Zainal Arifin Ahmad ◽  
Shah Rizal Kasim
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Distilled Water ◽  
Curing Time ◽  
Pore Former ◽  
X Ray ◽  
Before And After ◽  
Naoh Solution ◽  
Added Water ◽  
Alkaline Activator

In this study, the geopolymer mortars were synthesized with fly ash (FA) and silica powder as aluminosilicate sources and a combination of sodium hydroxide (NaOH) solution, sodium silicate (Na2SiO3) solution and distilled water as alkaline activator. Commercial sago was used as a pore former in the mortars. The percentage of sago used were 10, 20 and 30 wt% of FA. The amount of added water used in each mixture was 5% by weight of FA, NaOH solution and Na2SiO3 solution. The formed geopolymer mortars were cured for 1, 3 and 7 days and sintered at 1000 °C. X-ray fluoresence (XRF) shown that FA contains higher amount of silica (SiO2) and alumina (Al2O3) which is important as aluminosilicate sources. The properties of the geopolymer mortars before and after sintered at 1000 °C have been investigated. The results show that geopolymer mortars with 10% of sago content with curing time of 7 days and sintered at 1000 °C give the highest compressive strength of 13.5 MPa.

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.

scholarly journals Effect of NaOH concentration and curing regime on geopolymer

2017 ◽  
Vol 10 (6) ◽  
pp. 1174-1181 ◽  
Author(s):  
C. N. LIVI ◽  
W. L. REPETTE
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Curing Temperature ◽  
Lower Amount ◽  
Alkali Concentration ◽  
X Ray Diffraction ◽  
Highest Weight ◽  
Thermogravimetric Data ◽  
Naoh Solution ◽  
Curing Regime

Abstract The effect of alkali concentration and curing temperature regime on fly ash-based geopolymer pastes was investigated in this study by using NaOH solutions. Prismatic specimens were molded, cured at 65 °C and 85 °C and submitted to flexural and compressive strength tests. Unreacted fly ash and geopolymers were characterized by X-ray diffraction and thermogravimetric analysis. In general, the mechanical strength was enhanced by increasing the molar concentration and the curing temperature. This trend was confirmed by thermogravimetric data. However, for a lower amount of NaOH there were no significant differences between the strength results. The mixture with the highest strength was obtained with the 16 M NaOH solution and curing temperature of 85 °C, which resulted in flexural strength of 4.20 MPa, compressive strength of 21.35 MPa and also the highest weight loss of 9.89%.

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.

Development of New Green Cement for Oil Wells

2016 ◽  
Vol 841 ◽  
pp. 148-156 ◽  
Author(s):  
Alagu Karthik Valliappan ◽  
Raja Rajeswary Suppiah ◽  
Sonny Irawan ◽  
Ridho Bayuaji
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
New Technology ◽  
Fluid Loss ◽  
Oil Well ◽  
Cement Slurry ◽  
Treatment Methods ◽  
Naoh Solution ◽  
Sodium Hydroxide Treatment

For many years, Ordinary Portland Cement (OPC) is used in oil well cementing operation. But the OPC gets degraded in the acidic environment because of having poor mechanical characteristics. A new technology called geopolymeric cement system is developed from the secondary byproducts of the industry to replace the conventional cement slurry in oil well cementing operation. This study focus on the preparation of cement slurry with new formulation using fly ash and alkali binders at two sodium hydroxide treatment methods with various concentrations of NaOH solution and analyzing the prepared cement slurry for compressive strength, defiance to acid and fluid loss amount. Different cement slurry compositions made of 70:30 fly ash to alkaline activator ratios with 10, 12, 14 Molar NaOH solution with two sodium hydroxide treatment methods of direct addition and mixing after one day soaking of NaOH were prepared and cured for 24 hours at a temperature of 80°C and pressure 3000 psi. The obtained cement specimens were tested for compressive strength, resistance towards acid and density. Then based on the results, geopolymer can be considered as alternative for Class G cement in oil well cementing operation due to its high compressive strength and high acid resistance.

scholarly journals A Mix Design Procedure for Alkali-Activated High-Calcium Fly Ash Concrete Cured at Ambient Temperature

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Tanakorn Phoo-ngernkham ◽  
Chattarika Phiangphimai ◽  
Nattapong Damrongwiriyanupap ◽  
Sakonwan Hanjitsuwan ◽  
Jaksada Thumrongvut ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Design Methodology ◽  
Design Procedure ◽  
Mix Design ◽  
Fly Ash Concrete ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Alkaline Activator ◽  
Alkali Activated

This research focuses on developing a mix design methodology for alkali-activated high-calcium fly ash concrete (AAHFAC). High-calcium fly ash (FA) from the Mae Moh power plant in northern Thailand was used as a starting material. Sodium hydroxide and sodium silicate were used as alkaline activator solutions (AAS). Many parameters, namely, NaOH concentration, alkaline activator solution-to-fly ash (AAS/FA) ratio, and coarse aggregate size, were investigated. The 28-day compressive strength was tested to validate the mix design proposed. The mix design methodology of the proposed AAHFAC mixes was given step by step, and it was modified from ACI standards. Test results showed that the 28-day compressive strength of 15–35 MPa was obtained. After modifying mix design of the AAHFAC mixes by updating the AAS/FA ratio from laboratory experiments, it was found that they met the strength requirement.

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