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.

Study on Properties of Foam Concrete Based on Fractal Theory

2011 ◽  
Vol 194-196 ◽  
pp. 1916-1919 ◽  
Author(s):  
Wen Ling Tian ◽  
Jiang Bo Yang ◽  
Xiao Yan Zhao
Keyword(s):  
Fractal Dimension ◽  
Fly Ash ◽  
Thermal Insulation ◽  
Fractal Theory ◽  
High Strength ◽  
Sound Insulation ◽  
Foam Concrete ◽  
Insulation Property ◽  
Foaming Agent ◽  
Thermal Insulation Property

Foam concrete is provided with light weight, thermal insulation, sound insulation and fire resistance, good seismic performance and other characteristics. To improve properties of foam concrete microstructure is studied with the help of fractal theory, fractal dimension related to mechanical properties and thermal performance of foam concrete is calculated by MATLAB language program. The results indicate that the microstructure of foam concrete showed significant fractal character, the fractal dimension is between 1.3 and 2.0. Apparent density, 28d compressive strength, and thermal conductivity decreases with the increase of fly ash and foaming agent content, fractal dimension increased. Formulas of fractal dimension and the fly ash, foaming agent content were established. Foam concrete with low density, high strength, and good thermal insulation property will be prepared conducted by the formulas.

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.

Factors Influencing the Strength of Alkali-Activated Slag Cement

2011 ◽  
Vol 368-373 ◽  
pp. 3240-3245
Author(s):  
Zhi Jun Zhou ◽  
Hui Li ◽  
Qiang Song ◽  
Bao Jing Shen
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Water Glass ◽  
Slag Cement ◽  
Alkali Activated Slag ◽  
Factors Influencing ◽  
Activated Slag ◽  
Alkali Activated

In this paper, water glass was chosen as activator to prepare Alkali-activated slag(AAS) cement. Effects of modulus and dosage of water glass, and admixture (fly ash, slag and silica fume) on the strength of AAS cement was investigated. It was found that the modulus of water glass had great effect on the strength of AAS cement when the mixing amount of water glass was less than 12%. With the incorporation of fly ash or slag, the strength of AAS cement decreased, however the incorporation of silica fume could promote the flexural and compressive strength of AAS cement slightly.

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.

scholarly journals Geopolymer Mortar Incorporating High Calcium Fly Ash and Silica Fume

2019 ◽  
Vol 65 (1) ◽  
pp. 3-16 ◽  
Author(s):  
V.C. Prabha ◽  
V. Revathi
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Silica Fume ◽  
Sodium Hydroxide Solution ◽  
Test Results ◽  
Dense Microstructure ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Binder Ratio

AbstractAn attempt was made in the present work to study the compressive strength and microstructure of geopolymer containing high calcium fly ash (HCFA) and silica fume. Concentration of sodium hydroxide solution 8M, 10M, 12M & 14M, liquid to binder ratio 0.5 and sodium hydroxide to sodium silicate ratio 2.5 were selected for the mixes. Geopolymer mortar test results indicated that the mix with 40% silica fume by the weight of HCFA yielded higher compressive strength under ambient curing. The XRD pattern typically shows the major portion of amorphous phase of geopolymer. The existence of C-A-S-H gel, N-A-S-H gel and hydroxysodalite gel products were observed through SEM which developed dense microstructure and thus enhanced strength of HCFA and silica fume geopolymer.

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.

Sign in / Sign up

Export Citation Format

Share Document