Effect of Activator Concentration on the Properties of Metakaolin-Based Geopolymer

2019 ◽  
Vol 11 (11) ◽  
pp. 1566-1573
Author(s):  
Chao Cui ◽  
Zhen Liu ◽  
Jianren Zhang ◽  
Chunsheng Cai ◽  
Hui Peng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Energy Dispersive Spectrometer ◽  
Curing Temperature ◽  
Activator Concentration ◽  
Reaction Products ◽  
Sem Images ◽  
Homogeneous Matrix ◽  
Ft Ir ◽  
Alkaline Activator

In the present study, an alkaline solution, prepared by sodium silicate (Na2SiO3) and sodium hydroxide (NaOH), was used as an activator for the preparation of a metakaolin-based geopolymer with high compressive strength. The effects of the factors, including the modulus (SiO2/Na2O ratio) of the alkaline activator, activator concentration, curing temperature, and curing time on the mechanical properties of the geopolymer were examined using orthogonal tests. Test results showed that the concentration of the alkaline activator is the primary factor affecting the mechanical properties of the geopolymer, followed by the modulus of the alkaline activator. The compressive strength of the geopolymer increases with an increase in activator concentration and decrease in the modulus of the alkaline activator. Subsequently, the reaction degree of the geopolymer and the reaction products corresponding to various concentrations of the activator were investigated using microcalorimetric analysis, Fourier Transform Infrared (FT-IR) analysis, and Scanning electron microscopy-Energy Dispersive Spectrometer (SEM-EDS) analysis, and the mechanism of the activator concentration affecting the geopolymer properties was also studied. It was found that the hydrolysis reaction and the polymerization degree were improved with an increase in the activator concentration. When the activator concentration increased from 50% to 80%, the compressive strength of the geopolymer increased from 21.54 MPa to 99.89 MPa. In addition, the SEM images also showed that the reaction products with a higher activator concentration, had a denser and more homogeneous matrix than that of products with a lower activator concentration.

scholarly journals The Effect of Alkaline Activator Types on Strength and Microstructural Properties of Geopolymer from Co-Combustion Residuals of Bamboo and Kaolin

2018 ◽  
Vol 18 (3) ◽  
pp. 397 ◽  
Author(s):  
Aprilina Purbasari ◽  
Tjokorde Walmiki Samadhi ◽  
Yazid Bindar
Keyword(s):  
Compressive Strength ◽  
Water Glass ◽  
Curing Temperature ◽  
Sem Images ◽  
Homogeneous Microstructure ◽  
Sodium Aluminosilicate ◽  
Naoh Solution ◽  
Alkaline Activator ◽  
Xrd Patterns ◽  
Sodium Aluminosilicate Hydrate

Geopolymer as a Portland cement substitute had been synthesized from alkaline activation of co-combustion residuals of bamboo and kaolin. Types of used alkaline activators were NaOH solution, KOH solution, a mixture of NaOH solution-water glass, and a mixture of KOH solution-water glass. Geopolymer with NaOH solution as activator had a compressive strength which was higher compared to geopolymer with KOH solution as an activator. However, geopolymer with NaOH solution-water glass as activator had a compressive strength which was lower compared to geopolymer with KOH solution-water glass as activator either at room temperature curing or at a curing temperature of 60 °C. The use of water glass with NaOH or KOH solution as activator could increase the compressive strength of geopolymer and yielded geopolymer having more dense and more homogeneous microstructure seen from SEM images. XRD patterns revealed the presence of sodium aluminosilicate hydrate in geopolymer with NaOH solution and NaOH solution-water glass as activators, and potassium aluminosilicate hydrate in geopolymer with KOH solution and KOH solution-water glass as activators. Furthermore, FTIR spectra indicated asymmetrical vibration of Si(Al)-O at around 1008 cm-1 related to geopolymer product.

scholarly journals Assessment of the Rheological and Mechanical Properties of Geopolymer Concrete Comprising Fly Ash and Fluid Catalytic Cracking Residue as Aluminosilicate Precursor

2021 ◽  
Vol 11 (7) ◽  
pp. 3032
Author(s):  
Tuan Anh Le ◽  
Sinh Hoang Le ◽  
Thuy Ninh Nguyen ◽  
Khoa Tan Nguyen
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Flexural Strength ◽  
Catalytic Cracking ◽  
Fluid Catalytic Cracking ◽  
High Alumina ◽  
Geopolymer Concrete ◽  
Sem Images

The use of fluid catalytic cracking (FCC) by-products as aluminosilicate precursors in geopolymer binders has attracted significant interest from researchers in recent years owing to their high alumina and silica contents. Introduced in this study is the use of geopolymer concrete comprising FCC residue combined with fly ash as the requisite source of aluminosilicate. Fly ash was replaced with various FCC residue contents ranging from 0–100% by mass of binder. Results from standard testing methods showed that geopolymer concrete rheological properties such as yield stress and plastic viscosity as well as mechanical properties including compressive strength, flexural strength, and elastic modulus were affected significantly by the FCC residue content. With alkali liquid to geopolymer solid ratios (AL:GS) of 0.4 and 0.5, a reduction in compressive and flexural strength was observed in the case of geopolymer concrete with increasing FCC residue content. On the contrary, geopolymer concrete with increasing FCC residue content exhibited improved strength with an AL:GS ratio of 0.65. Relationships enabling estimation of geopolymer elastic modulus based on compressive strength were investigated. Scanning electron microscope (SEM) images and X-ray diffraction (XRD) patterns revealed that the final product from the geopolymerization process consisting of FCC residue was similar to fly ash-based geopolymer concrete. These observations highlight the potential of FCC residue as an aluminosilicate source for geopolymer products.

Microstructural Features and Mechanical Properties of Autoclaved Saline Soil Brick: Part II: Mechanical Properties

2012 ◽  
Vol 510 ◽  
pp. 655-659
Author(s):  
Lie Qu ◽  
Jiu Jun Yang ◽  
Shou Xi Chai ◽  
Lei Guo ◽  
Su Li
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Hydrothermal Reaction ◽  
Saline Soil ◽  
Reaction Products ◽  
Quartz Powder ◽  
Water Binding ◽  
Binding Ratio ◽  
Compressive And Flexural Strengths ◽  
Optimal Material

The effects of different components, autoclaving temperature and time on the mechanical properties of saline soil bricks were investigated. The autoclaved curing schedule is optimized at autoclaving time of 3h and autoclaving temperature of 175. The optimal material formula consists of water-binding ratio 0.2, CaO 15%, finely grinded quartz powder 20 % and sand 20%, under which the compressive and flexural strengths of saline soil bricks reaches 31.9 Mpa and 7.8Mpa, respectively. Reducing water-binding ratio will effectively promote density, while increasing the amount of CaO will enhance the hydrothermal reaction products, density and the mechanical strength. In addition, adding finely grinded quartz powder and sand will further increase the hydrothermal reaction products and restrict volume shrinkage. Furthermore, elevating autoclaving temperature and extending autoclaving time are favorable to increase density and to improve mechanical properties. But autoclaving time exceeds 3h, the compressive strength will be reduced.

scholarly journals Novolac/Phenol-Containing Phthalonitrile Blends: Curing Characteristics and Composite Mechanical Properties

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 126 ◽  
Author(s):  
Hanqi Zhang ◽  
Bing Wang ◽  
Yanna Wang ◽  
Heng Zhou
Keyword(s):  
Mechanical Properties ◽  
Fracture Strain ◽  
Mechanical Test ◽  
Gelation Time ◽  
Mechanical Analysis ◽  
Curing Temperature ◽  
Hydroxyl Group ◽  
Rheological Analysis ◽  
Curing Characteristics ◽  
Ft Ir

The phenol-containing phthalonitrile resin is a kind of self-curing phthalonitrile resin with high-temperature resistance and excellent properties. However, the onefold phthalonitrile resin is unattainable to cured completely, and the brittleness of the cured product is non-negligible. This paper focuses on solving the above problems by blending novolac resin into phenol-containing phthalonitrile. Under the action of abundant hydroxyl group, the initial curing temperature and gelation time at 170 °C decrease by 88 °C and 2820 s, respectively, monitored by DSC and rheological analysis. FT-IR spectra of copolymers showed that the addition of novolac increased the conversion rate of nitrile. When the novolac mass fraction is 10%, the peak of nitrile group disappears, which means the complete reaction. The mechanical test of blends composites shows that the maximum fracture strain of 10 wt% novolac addition is 122% higher than those of neat phthalonitrile composites on account of the introduction of flexible novolac chain segments. The mechanical properties are sensitive to elevated post-cured temperature; this is consistent with the result of morphological investigation using SEM. Finally, the dynamic mechanical analysis indicated that the glass transition temperature heightened with the increase of novolac content and post-curing temperature.

scholarly journals Microstructural and Mechanical Properties of Alkali Activated Materials from Two Types of Blast Furnace Slags

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2089 ◽  
Author(s):  
Jun Xing ◽  
Yingliang Zhao ◽  
Jingping Qiu ◽  
Xiaogang Sun
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Blast Furnace ◽  
Thermal Stabilization ◽  
Hydration Process ◽  
Reaction Products ◽  
Basic Oxide ◽  
X Ray ◽  
Physical And Chemical ◽  
Alkali Activated

This paper investigated the effect of blast furnace slags (BFS) characteristics on the properties achievement after being alkali activated. The physical and chemical characteristics of BFS were determined by X-ray fluorescence (XRF), X-ray Diffraction (XRD) and laser granulometry. Multi-technical characterizations using calorimetry, XRD, Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry (TG-DTG), scanning electron microscope (SEM), nitrogen sorption and uniaxial compressive strength (UCS) were applied to give an in-depth understanding of the relationship between the reaction products, microstructure and BFS characteristics. The test results show that the microstructure and mechanical properties of alkali activated blast furnace slags (BFS) highly depend on the characteristics of BFS. Although the higher content of basic oxide could accelerate the hydration process and result in higher mechanical properties, a poor thermal stabilization was observed. On the other hand, with a higher content of Fe, the hydration process in alkali activated BFS2 lasts for a longer time, contributing to a delayed compressive strength achievement.

Feasibility Study on Composition and Mechanical Properties of Marine Clay Based Geopolymer Brick

2013 ◽  
Vol 594-595 ◽  
pp. 401-405
Author(s):  
S.M. Tamizi ◽  
Abdullah Mohd Mustafa Al Bakri ◽  
Hussin Kamarudin ◽  
C.M. Ruzaidi ◽  
J. Liyana ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Compressive Strength ◽  
Feasibility Study ◽  
Inorganic Polymer ◽  
Synthesis Process ◽  
Local Production ◽  
Marine Clay ◽  
X Ray ◽  
Alkaline Activator

Geopolymer is an inorganic polymer performed in synthesis process of an aluminosilicate material which activated by alkaline activator solution. Marine clay, considered to be a waste substance which have an important aluminosilicate sources in developing geopolymer synthesis since it contains sufficient amounts of alumina and silica. In this experimental study, local marine clay composition was been identified to determine the amount of alumina and silica. The raw sample compositions were identified by using X-ray fluorescence (XRF). Incorporated with it composition, compressive strength of brick were been tested in aged of 1, 2 and 3 day and compared with local production of cement brick (CB). This research is aimed at determining the properties of Kuala Perlis marine clay in order to verify its suitability as a pozzolana materials as well as the sufficient amount of Al and Si to enhance the properties of geopolymer brick.

COMPRESSIVE STRENGTH OF GEOPOLYMER MORTAR USING GROUND FERRONICKEL SLAG AND FLY ASH

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Jhutan Chandra Kuri ◽  
Md Nabi Newaz Khan ◽  
Prabir Kumar Sarker
Keyword(s):  
Stainless Steel ◽  
Compressive Strength ◽  
Fly Ash ◽  
Nickel Alloy ◽  
Strength Increase ◽  
Reaction Products ◽  
Huge Amount ◽  
Alkaline Activator ◽  
Ferronickel Slag

A huge amount of ferronickel slag is produced as a by-product of manufacturing ferronickel, which is used in stainless steel and nickel alloy. This paper presents the effect of using different percentages of ground ferronickel slag (GFNS) with fly ash (FA) on the workability and compressive strength of geopolymer mortar. A mixture of NaOH and Na2SiO3 solutions was used as the alkaline activator. It was found that the flow of fresh mortar decreased with the increase of GFNS content. This is attributed to the higher fineness and angular shape of GFNS particles as compared to spherical fly ash particles. The mortar cube specimens were heat-cured at 60 °C for 24 hours. The compressive strength of geopolymer mortar using 100% FA was 54 MPa and it increased by 17%, 21% and 36% for using 25%, 50% and 75% GFNS as fly ash replacement, respectively. The strength increase is attributed to the increase of Si/Al ratio by GFNS that favoured the production of alkali aluminosilicate reaction products.

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.

scholarly journals Effect of Sodium Aluminate Dosage as a Solid Alkaline Activator on the Properties of Alkali-Activated Slag Paste

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Bin Chen ◽  
Jun Wang ◽  
Jinyou Zhao
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Setting Time ◽  
Sodium Aluminate ◽  
Hydration Reaction ◽  
Hydration Products ◽  
Alkali Activated Slag ◽  
Alkaline Activator ◽  
Activated Slag ◽  
Alkali Activated

Extensive research into alkali-activated slag as a green gel material to substitute for cement has been done because of the advantages of low-carbon dioxide emissions and recycling of industrial solid waste. Alkali-activated slag usually has good mechanical properties, but the too fast setting time restricted its application and promotion. Changing the composition of alkaline activator could optimize setting time, usually making it by adding sodium carbonate or sodium sulfate but this would cause insufficient hydration reaction power and hinder compressive strength growth. In this paper, the effect of sodium aluminate dosage as an alkaline activator on the setting time, fluidity, compressive strength, hydration products, and microstructures was studied through experiments. It is fair to say that an appropriate amount of sodium aluminate could obtain a suitable setting time and better compressive strength. Sodium aluminate provided enough hydroxyl ions for the paste to promote the hydration reaction process that ensured obtaining high compressive strength and soluble aluminium formed precipitate wrapped on the surface of slag to inhibit the hydration reaction process in the early phase that prolonged setting time. The hydration mechanism research found that sodium aluminate played a key role in the formation of higher cross-linked gel hydration products in the late phase of the process. Preparing an alkali-activated slag with excellent mechanical properties and suitable setting time will significantly contribute to its application and promotion.

scholarly journals Influence of Filler Loading on the Mechanical Properties of Flowable Resin Composites

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1477 ◽  
Author(s):  
Ioana-Codruţa Mirică ◽  
Gabriel Furtos ◽  
Bogdan Bâldea ◽  
Ondine Lucaciu ◽  
Aranka Ilea ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Flexural Modulus ◽  
Filler Loading ◽  
The Other ◽  
Inorganic Filler ◽  
Resin Composites ◽  
Homogeneous Type ◽  
Sem Images

The aim of this study was to evaluate the correlation between the percent of inorganic filler by weight (wt. %) and by volume (vol. %) of 11 flowable resin composites (FRCs) and their mechanical properties. To establish the correlation, the quantity of inorganic filler was determined by combustion and shape/size analyzed by SEM images. The compressive strength (CS), flexural strength (FS), and flexural modulus (FM) were determined. The CS values were between 182.87-310.38 MPa, the FS values ranged between 59.59 and 96.95 MPa, and the FM values were between 2.34 and 6.23 GPa. The percentage of inorganic filler registered values situated between 52.25 and 69.64 wt. % and 35.35 and 53.50 vol. %. There was a very good correlation between CS, FS, and FM vs. the inorganic filler by wt. % and vol. %. (R2 = 0.8899–0.9483). The highest regression was obtained for the FM values vs. vol. %. SEM images of the tested FRCs showed hybrid inorganic filler for Filtek Supreme XT (A3) and StarFlow (A2) and a homogeneous type of inorganic filler for the other investigated materials. All of the FS values were above 50 MPa, the ISO 4049/2019 limit for FRCs.

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