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.

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 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 Use of waste paper ash or wood ash as substitution to fly ash in production of geopolymer concrete

2021 ◽  
Vol 30 (3) ◽  
pp. 464-476
Author(s):  
Haider Owaid ◽  
Haider Al-Baghdadi ◽  
Muna Al-Rubaye
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Sodium Hydroxide ◽  
Wood Ash ◽  
Splitting Tensile Strength ◽  
Waste Paper ◽  
Geopolymer Concrete

Large quantities of paper and wood waste are generated every day, the disposal of these waste products is a problem because it requires huge space for their disposal. The possibility of using these wastes can mitigate the environmental problems related to them. This study presents an investigation on the feasibility of inclusion of waste paper ash (WPA) or wood ash (WA) as replacement materials for fly ash (FA) class F in preparation geopolymer concrete (GC). The developed geopolymer concretes for this study were prepared at replacement ratios of FA by WPA or WA of 25, 50, 75 and 100% in addition to a control mix containing 100% of FA. Sodium hydroxide (NaOH) solutions and sodium silicate (Na2SiO3) are used as alkaline activators with 1M and 10M of sodium hydroxide solution.The geopolymer concretes have been evaluated with respect to the workability, the compressive strength, splitting tensile strength and flexural strength. The results indicated that there were no significant differences in the workability of the control GC mix and the developed GC mixes incorporating WPA or WA. Also, the results showed that, by incorporating of 25–50% PWA or 25% WA, the mechanical properties (compressive strength, splitting tensile strength and flexural strength) of GC mixes slightly decreased. While replacement with 75–100% WPA or with 50–100% WA has reduced these mechanical properties of GC mixes. As a result, there is a feasibility of partial replacement of FA by up to 50% WPA or 25% WA in preparation of the geopolymer concrete.

scholarly journals Life Cycle Assessment and Impact Correlation Analysis of Fly Ash Geopolymer Concrete

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7375
Author(s):  
Xiaoshuang Shi ◽  
Cong Zhang ◽  
Yongchen Liang ◽  
Jinqian Luo ◽  
Xiaoqi Wang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Life Cycle Assessment ◽  
Life Cycle ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Co2 Emissions ◽  
Co2 Emission ◽  
Gray Relational Analysis ◽  
Geopolymer Concrete ◽  
Sodium Hydroxide Concentration

Geopolymer concrete (GPC) has drawn widespread attention as a universally accepted ideal green material to improve environmental conditions in recent years. The present study systematically quantifies and compares the environmental impact of fly ash GPC and ordinary Portland cement (OPC) concrete under different strength grades by conducting life cycle assessment (LCA). The alkali activator solution to fly ash ratio (S/F), sodium hydroxide concentration (CNaOH), and sodium silicate to sodium hydroxide ratio (SS/SH) were further used as three key parameters to consider their sensitivity to strength and CO2 emissions. The correlation and influence rules were analyzed by Multivariate Analysis of Variance (MANOVA) and Gray Relational Analysis (GRA). The results indicated that the CO2 emission of GPC can be reduced by 62.73%, and the correlation between CO2 emission and compressive strength is not significant for GPC. The degree of influence of the three factors on the compressive strength is CNaOH (66.5%) > SS/SH (20.7%) > S/F (9%) and on CO2 emissions is S/F (87.2%) > SS/SH (10.3%) > CNaOH (2.4%). Fly ash GPC effectively controls the environmental deterioration without compromising its compressive strength; in fact, it even in favor.

Effect of white soil substitution on fly ash based mortar geopolymers with sodium hydroxide activator

2020 ◽  
Vol 26 (1) ◽  
pp. 9-16
Author(s):  
Yulita Arni Priastiwi ◽  
Arif Hidayat ◽  
Dwi Daryanto ◽  
Zidny Salamsyah Badru
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Moisture Content ◽  
Sodium Hydroxide ◽  
Modulus Of Elasticity ◽  
Physical And Mechanical Properties ◽  
Test Results ◽  
Alkaline Activator ◽  
Made In

The presence of white soil in a geopolymer mortar affects the physical and mechanical properties of the mortar itself, especially in compressive strength, density and modulus of elasticity produced. Geopolymer mortar composed of fly ash, sand, water, and NaOH which acts as an alkaline activator compared to mortar from the same material, but white soil from Kupang is added as a substitution of fly ash. Specimens are made in six variations. Geopolymer mortar composers using a ratio of 1 binder: 3 sand with w/b of 0.5. Binder composed of fly ash with white soil substitution of 0; 5; 10; 15; 20 and 30% by weight of fly ash. An activator NaOH 8M solution was added to the mixture. Both white soil and fly ash pass of sieve no. 200 with a moisture content of 0%. Mortar made measuring 5x5x5 cm. The mortar was treated by the oven of method at 60 oC for 24 hours until the mortar does not change in weight. The test results show geopolymer mortar with 15% substitution of white soil to fly ash has the highest compressive strength, density and modulus of elasticity among other variations. In all mortar variations, compressive strength at 14 days has reached 75% of strength at 28 days.

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 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.

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.

scholarly journals Microstructure, Compressive Strength and Sound Insulation Property of Fly Ash-Based Geopolymeric Foams with Silica Fume as Foaming Agent

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3215
Author(s):  
Xinhui Liu ◽  
Chunfeng Hu ◽  
Longsheng Chu
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Silica Fume ◽  
Water Glass ◽  
Sound Insulation ◽  
Insulation Property ◽  
Foaming Agent ◽  
Alkaline Activator ◽  
Insulation Performance

Geopolymer as an alternative to cement has gained increasing attention. The aim of this article is to study the influence of the silica fume content and activator type on the porous fly ash-based geopolymer with silica fume as foaming agent. Geopolymeric foams were fabricated using low-calcium fly ash, silica fume, and sodium-based alkaline activator as initial materials. The designed silica fume contents were 0, 15, 30, and 45 wt % and two kinds of activators of water glass and sodium hydroxide were used for comparison. Phase composition, microstructure, mechanical properties and sound insulation properties of as-prepared bulks were systematically investigated. It was found that, with increasing silica fume content, the density and compressive strength decreased simultaneously, whereas the porosity and sound insulation performance were effectively enhanced. At the silica fume content of 45% with sodium hydroxide as activator, the porosity was increased 3.02 times, and, at the silica fume content of 45% with water glass as activator, the mean sound insulation value of 43.74 dB was obtained.

Correlation between Na2SiO3/NaOH Ratio and Fly Ash/Alkaline Activator Ratio to the Strength of Geopolymer

2011 ◽  
Vol 341-342 ◽  
pp. 189-193 ◽  
Author(s):  
Mohd Mustafa Al Bakri Abdullah ◽  
H. Kamarudin ◽  
I. Khairul Nizar ◽  
M. Bnhussain ◽  
Y. Zarina ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Aluminosilicate Gel ◽  
Alkaline Activator ◽  
Maximum Compressive Strength

Geopolymer requires an alkaline activator to induce it pozzolanic property and to accelerate the geopolymerisation process. The geopolymerisation process occurs due to the mixing of fly ash, sodium silicate and sodium hydroxide as the alkaline activator, which produces aluminosilicate gel that acts as a binder. As such, the ratios of fly ash to alkaline activator and Na2SiO3/NaOH play an important role in obtaining desirable compressive strength; the concentration of NaOH used in this study was 12 M. Different ratios of fly ash to alkaline activator (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0) and Na2SiO3/NaOH (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0) were investigated in order to determine the maximum compressive strength. The alkaline activator was mixed with fly ash with different ratio as mentioned above and the samples were cured at 70°C for 24 hours and tested on the seventh day. The maximum compressive strength was obtained when the ratios of fly ash to alkaline activator and Na2SiO3/NaOH were 2.0 and 2.5 with compressive strength 73.86 MPa.

Sign in / Sign up

Export Citation Format

Share Document