scholarly journals The Effect of Activators on the Mechanical Properties and Microstructure of Alkali-Activated Nickel Slag

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Liwei Xu ◽  
Xuefang Wang ◽  
Can Guan ◽  
Wenda Wu ◽  
Lingling Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Energy Dispersive Spectrometer ◽  
Engineering Application ◽  
X Ray ◽  
Different Types ◽  
Lower Porosity ◽  
Infrared Spectrometer ◽  
Mercury Analyzer ◽  
Alkali Activated

In order to mitigate problems associated with environmental pollution, alkali-activated nickel slags (AANSs) may be used as an alternative to cementitious material. However, the understanding of their mechanical properties and microstructure is currently very limited. This paper therefore explores the influence of different types and contents of three solid alkali activators, Na2SiO3, NaOH, and Na2SiO3/Na2CO3, on the compressive strength of one-part AANS. Their microstructure, hydration components, and pore structure are analyzed by means of a scanning electron microscope, an energy-dispersive spectrometer, an X-ray diffractometer, an infrared spectrometer, and a mercury analyzer. The results show that the AANS with an Na2SiO3/Na2CO3 activator has a denser microstructure, lower porosity, and a smaller pore size when compared with the AANS with the Na2SiO3 or NaOH activators. Consequently, the compressive strength of the Na2SiO3/Na2CO3 sample reached a higher compressive strength (96 MPa) than that activated by Na2SiO3 or NaOH. This strength is optimal as well as more economical as Na2O, which increased from 0.107 mol to 0.123 mol, contributes little to compressive strength. The final part of the article discusses an optimal design for the engineering application of one-part AANS.

scholarly journals The Effect of Different Types of Internal Curing Liquid on the Properties of Alkali-Activated Slag (AAS) Mortar

2021 ◽  
Vol 13 (4) ◽  
pp. 2407
Author(s):  
Guang-Zhu Zhang ◽  
Xiao-Yong Wang ◽  
Tae-Wan Kim ◽  
Jong-Yeon Lim ◽  
Yi Han
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Deionized Water ◽  
Internal Curing ◽  
Control Group ◽  
Alkali Activated Slag ◽  
Different Types ◽  
Naoh Solution ◽  
Activated Slag ◽  
Alkali Activated

This study shows the effect of different types of internal curing liquid on the properties of alkali-activated slag (AAS) mortar. NaOH solution and deionized water were used as the liquid internal curing agents and zeolite sand was the internal curing agent that replaced the standard sand at 15% and 30%, respectively. Experiments on the mechanical properties, hydration kinetics, autogenous shrinkage (AS), internal temperature, internal relative humidity, surface electrical resistivity, ultrasonic pulse velocity (UPV), and setting time were performed. The conclusions are as follows: (1) the setting times of AAS mortars with internal curing by water were longer than those of internal curing by NaOH solution. (2) NaOH solution more effectively reduces the AS of AAS mortars than water when used as an internal curing liquid. (3) The cumulative heat of the AAS mortar when using water for internal curing is substantially reduced compared to the control group. (4) For the AAS mortars with NaOH solution as an internal curing liquid, compared with the control specimen, the compressive strength results are increased. However, a decrease in compressive strength values occurs when water is used as an internal curing liquid in the AAS mortar. (5) The UPV decreases as the content of zeolite sand that replaces the standard sand increases. (6) When internal curing is carried out with water as the internal curing liquid, the surface resistivity values of the AAS mortar are higher than when the alkali solution is used as the internal curing liquid. To sum up, both NaOH and deionized water are effective as internal curing liquids, but the NaOH solution shows a better performance in terms of reducing shrinkage and improving mechanical properties than deionized water.

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.

Effect of Polymer Admixtures on Mechanical Properties of Alkali-Activated Slag Mortars

2015 ◽  
Vol 1124 ◽  
pp. 145-150 ◽  
Author(s):  
Olesia Mikhailova ◽  
Pavel Rovnaník
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Polyethylene Glycol ◽  
Acrylic Acid ◽  
Polypropylene Glycol ◽  
Alkali Activated Slag ◽  
Different Types ◽  
Methyl Metacrylate ◽  
Activated Slag ◽  
Alkali Activated

Alkali-activated slag (AAS) binders have lower environmental impact due to its production process, but also have disadvantages as an increased shrinkage followed by formation of microcracks. The effect of polymer admixtures based on vinyl acetate, ethylene and acrylic acid ester, methyl metacrylate and different types of polyethylene glycol (PEG) and polypropylene glycol (PPG) on properties of alkali-activated slag concrete was studied. Admixtures used for mortars were tested to improve shrinkage, workability and compressive strength, flexural strength. The analysis also showed the effect of the admixtures on microstructure of the alkali-activated slag pastes and mortars.

scholarly journals Enhancing Density-Based Mining Waste Alkali-Activated Foamed Materials Incorporating Expanded Cork

CivilEng ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 523-540
Author(s):  
Imed Beghoura ◽  
Joao Castro-Gomes
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Pore Size ◽  
Physical And Mechanical Properties ◽  
Critical Parameters ◽  
Porous Structures ◽  
Foaming Agent ◽  
Al Powder ◽  
Highly Porous ◽  
Alkali Activated

This study focuses on the development of an alkali-activated lightweight foamed material (AA-LFM) with enhanced density. Several mixes of tungsten waste mud (TWM), grounded waste glass (WG), and metakaolin (MK) were produced. Al powder as a foaming agent was added, varying from 0.009 w.% to 0.05 w.% of precursor weight. Expanded granulated cork (EGC) particles were incorporated (10% to 40% of the total volume of precursors). The physical and mechanical properties of the foamed materials obtained, the effects of the amount of the foaming agent and the percentage of cork particles added varying from 10 vol.% to 40% are presented and discussed. Highly porous structures were obtained, Pore size and cork particles distribution are critical parameters in determining the density and strength of the foams. The compressive strength results with different densities of AA-LFM obtained by modifying the foaming agent and cork particles are also presented and discussed. Mechanical properties of the cured structure are adequate for lightweight prefabricated building elements and components.

scholarly journals Process Design for a Production of Sustainable Materials from Post-Production Clay

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 953
Author(s):  
Michał Łach ◽  
Reda A. Gado ◽  
Joanna Marczyk ◽  
Celina Ziejewska ◽  
Neslihan Doğan-Sağlamtimur ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Waste Production ◽  
Sustainable Materials ◽  
Post Production ◽  
Rich Material ◽  
Jurassic Limestone ◽  
By Products ◽  
Alkali Activated

Alkali activated cement (AAC) can be manufactured from industrial by-products to achieve goals of “zero-waste” production. We discuss in detail the AAC production process from (waste) post-production clay, which serves as the calcium-rich material. The effect of different parameters on the changes in properties of the final product, including morphology, phase formation, compressive strength, resistance to the high temperature, and long-term curing is presented. The drying and grinding of clay are required, even if both processes are energy-intensive; the reduction of particle size and the increase of specific surface area is crucial. Furthermore, calcination at 750 °C ensure approximately 20% higher compressive strength of final AAC in comparison to calcination performed at 700 °C. It resulted from the different ratio of phases: Calcite, mullite, quartz, gehlenite, and wollastonite in the final AAC. The type of activators (NaOH, NaOH:KOH mixtures, KOH) affected AAC mechanical properties, significantly. Sodium activators enabled obtaining higher values of strength. However, if KOH is required, the supplementation of initial materials with fly ash or metakaolin could improve the mechanical properties and durability of AAC, even c.a. 28%. The presented results confirm the possibility of recycling post-production clay from the Raciszyn II Jurassic limestone deposit.

scholarly journals Effect of Locally Available Wheat Straw Ash in Developing High Strength Concrete

2021 ◽  
pp. 19-28
Author(s):  
Muhammad Armaghan Siffat ◽  
Muhammad Ishfaq ◽  
Afaq Ahmad ◽  
Khalil Ur Rehman ◽  
Fawad Ahmad
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Wheat Straw ◽  
High Strength Concrete ◽  
High Strength ◽  
Optimum Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Strength Concrete ◽  
Straw Ash

This study is supervised to assess the characteristics of the locally available wheat straw ash (WSA) to consume as a substitute to the cement and support in enhancing the mechanical properties of concrete. Initially, after incineration at optimum temperature of 800°C for 0.5, the ash of wheat straw was made up to the desirable level of fineness by passing through it to the several grinding cycles. Subsequently, the X-ray fluorescence (XRF) along with X-ray diffraction (XRD) testing conducted on ash of wheat straw for the evaluation its pozzolanic potential. Finally, the specimens of concrete were made by consuming 10% and 20% percentages of wheat straw ash as a replacement in concrete to conclude its impact on the compressive strength of high strength concrete. The cylinders of steel of dimensions 10cm diameter x 20cm depth were acquired to evaluate the compressive strength of high strength concrete. The relative outcomes of cylinders made of wheat straw ash substitution presented the slight increase in strength values of the concrete. Ultimately, the C-100 blends and WSA aided cement blends were inspected for the rheology of WSA through FTIR spectroscopy along with Thermogravimetric technique. The conclusions authenticate the WSA potential to replace cement in the manufacturing of the high strength concrete.

UTILIZATION OF FLY ASH AND CONCRETE RESIDUE IN THE PRODUCTION OF GEOPOLYMER BRICKS

2017 ◽  
Vol 12 (1) ◽  
pp. 63-77 ◽  
Author(s):  
Siriporn Sirikingkaew ◽  
Nuta Supakata
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Phase Composition ◽  
Fly Ash ◽  
Industrial Waste ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

This study presents the development of geopolymer bricks synthetized from industrial waste, including fly ash mixed with concrete residue containing aluminosilicate compound. The above two ingredients are mixed according to five ratios: 100:0, 95:5, 90:10, 85:15, and 80:20. The mixture's physico-mechanical properties, in terms of water absorption and the compressive strength of the geopolymer bricks, are investigated according to the TIS 168-2546 standard. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses are used to investigate the microstructure and the elemental and phase composition of the brick specimens. The results indicate that the combination of fly ash and concrete residue represents a suitable approach to brick production, as required by the TIS 168–2546 standard.

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF HYPEREUTECTIC Al-Si/AlNp COMPOSITE

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1377-1382 ◽  
Author(s):  
SEULKI PARK ◽  
JINMYUNG CHOI ◽  
BONGGYU PARK ◽  
IKMIN PARK ◽  
YONGHO PARK ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Energy Dispersive Spectrometer ◽  
Microstructural Characterization ◽  
Weight Fraction ◽  
Reinforcement Particle ◽  
Hot Press ◽  
X Ray Diffraction ◽  
X Ray ◽  
Superior Mechanical Properties ◽  
Phase Evaluation

Hypereutectic Al - Si alloys with fine and evenly distributed Si precipitates have superior mechanical properties In this study, hypereutectic Al - Si alloy powders which contained 15 and 20wt% Si were prepared by a gas atomization process. 1, 3 and 5wt% AlN particles were blended with the Al - Si alloy powders using turbular mixer. The mixture was consolidated by Hot Press at 550°C for 1h under 60MPa. Relative density of the sintered samples was about 98% of theoretical density. This study was investigated by two ways. One is the effect of reinforcement weight fraction and the other is the effect of Silicon contents on the mechanical properties of the composite. Microstructural characterization and phase evaluation were carried out using X-ray Diffraction, Scanning Electron Microscopy equipped with Energy Dispersive Spectrometer. The results showed that the smaller the reinforcement particle size was and the better its distribution was, the higher ultimate tensile strength and hardness were.

scholarly journals Expansion volume of alkali activated foamed cork composites from tungsten mining mud waste with aluminium

2019 ◽  
Vol 274 ◽  
pp. 03002
Author(s):  
Imed Beghoura ◽  
Joao Castro-Gomes ◽  
Haroon Ihsan ◽  
John Pickstone ◽  
Nuno Estrada
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Physical And Mechanical Properties ◽  
Mechanical And Thermal Properties ◽  
Porous Structures ◽  
Expansion Process ◽  
Foaming Agent ◽  
Al Powder ◽  
Highly Porous ◽  
Alkali Activated

Several mixes of alkali activated foams from tungsten mud waste (MW), grounded glass (GG) and metakaolin (MK) were developed incorporating expanded granulated cork (EGC). This study presents preliminary results of the expansion process obtained with the addition of aluminium (AL) powder as a foaming agent. 0.3 wt.%, 0.4 wt.% to 0.5wt.% of AL powder were added to the alkali activated matrix. The physical and mechanical properties of the obtained foams, the effects of the type and amount of the foaming agent added are presented and discussed. Highly porous structures were obtained, with overall expansion up to 68.2% when the AL powder was added. The size and distribution of pores are shown. The compressive strength of foams in the case of highly porous structures achieved of 1.2 MPa for the samples containing 0.5 wt.% of AL powder. Mechanical and thermal properties of the cured structure are good and can therefore be used for applications in acoustic panels and lightweight prefabricated components for thermal insulation purposes.

scholarly journals Alkali Activated Paste and Concrete Based on of Biomass Bottom Ash with Phosphogypsum

2020 ◽  
Vol 10 (15) ◽  
pp. 5190
Author(s):  
Danutė Vaičiukynienė ◽  
Dalia Nizevičienė ◽  
Aras Kantautas ◽  
Vytautas Bocullo ◽  
Andrius Kielė
Keyword(s):  
Compressive Strength ◽  
Sodium Hydroxide ◽  
Sodium Hydroxide Solution ◽  
Bottom Ash ◽  
Control Sample ◽  
Test Methods ◽  
X Ray ◽  
Hydroxide Solution ◽  
Fine Grained ◽  
Alkali Activated

There is a growing interest in the development of new cementitious binders for building construction activities. In this study, biomass bottom ash (BBA) was used as aluminosilicate precursor and phosphogypsum (PG) was used as a calcium source. The mixtures of BBA and PG were activated with the sodium hydroxide solution or the mixture of sodium hydroxide solution and sodium silicate hydrate solution. Alkali activated binders were investigated using X-ray powder diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy (SEM) test methods. The compressive strength of hardened paste and fine-grained concrete was also evaluated. After 28 days, the highest compressive strength reached 30.0 MPa—when the BBA was substituted with 15% PG and activated with NaOH solution—which is 14 MPa more than control sample. In addition, BBA fine-grained concrete samples based on BBA with 15% PG substitute activated with NaOH/Na2SiO3 solution showed higher compressive strength compered to when NaOH activator was used −15.4 MPa and 12.9 MPa respectfully. The NaOH/Na2SiO3 activator solution resulted reduced open porosity, so potentially the fine-grained concrete resistance to freeze and thaw increased.

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