Effect of organic resin in glass wool waste and curing temperature on the synthesis and properties of alkali-activated pastes

Earth-based materials have shown promise in the development of ecofriendly and sustainable construction materials. However, their unconventional usage in the construction field makes the estimation of their properties difficult and inaccurate. Often, the determination of their properties is conducted based on a conventional materials procedure. Hence, there is inaccuracy in understanding the properties of the unconventional materials. To obtain more accurate properties, a support vector machine (SVM), artificial neural network (ANN) and linear regression (LR) were used to predict the compressive strength of the alkali-activated termite soil. In this study, factors such as activator concentration, Si/Al, initial curing temperature, water absorption, weight and curing regime were used as input parameters due to their significant effect in the compressive strength. The experimental results depict that SVM outperforms ANN and LR in terms of R2 score and root mean square error (RMSE).

Download Full-text

Grinding Kinetics of Slag and Effect of Final Particle Size on the Compressive Strength of Alkali Activated Materials

Minerals ◽

10.3390/min9110714 ◽

2019 ◽

Vol 9 (11) ◽

pp. 714 ◽

Cited By ~ 6

Author(s):

Evangelos Petrakis ◽

Vasiliki Karmali ◽

Georgios Bartzas ◽

Konstantinos Komnitsas

Keyword(s):

Particle Size ◽

Compressive Strength ◽

Particle Size Distribution ◽

Size Distribution ◽

Ageing Time ◽

Reduction Rate ◽

Curing Temperature ◽

Alkali Activation ◽

Final Particle ◽

Alkali Activated

This study aims to model grinding of a Polish ferronickel slag and evaluate the particle size distributions (PSDs) of the products obtained after different grinding times. Then, selected products were alkali activated in order to investigate the effect of particle size on the compressive strength of the produced alkali activated materials (AAMs). Other parameters affecting alkali activation, i.e., temperature, curing, and ageing time were also examined. Among the different mathematical models used to simulate the particle size distribution, Rosin–Rammler (RR) was found to be the most suitable. When piecewise regression analysis was applied to experimental data it was found that the particle size distribution of the slag products exhibits multifractal character. In addition, grinding of slag exhibits non-first-order behavior and the reduction rate of each size is time dependent. The grinding rate and consequently the grinding efficiency increases when the particle size increases, but drops sharply near zero after prolonged grinding periods. Regarding alkali activation, it is deduced that among the parameters studied, particle size (and the respective specific surface area) of the raw slag product and curing temperature have the most noticeable impact on the compressive strength of the produced AAMs.

Download Full-text

Alkali-Activated Slag/ Fly Ash Concrete: Mechanism, Properties, Hydration Product and Curing Temperature

International Journal of Innovative Technology and Exploring Engineering - Special Issue ◽

10.35940/ijitee.i7005.079920 ◽

2020 ◽

Vol 9 (9) ◽

pp. 204-215

Keyword(s):

Fly Ash ◽

Hydration Product ◽

Test Methods ◽

Curing Temperature ◽

Environmental Friendliness ◽

Alkali Activated Slag ◽

Fly Ash Concrete ◽

Activated Slag ◽

Alkali Activated Concrete ◽

Alkali Activated

Alkali-activated concrete (AAC) is mounting as a feasible alternative to OPC assimilated to reduce greenhouse gas emanated during the production of OPC. Use of pozzolana results in gel over-strengthening and fabricate less quantity of Ca(OH)2 which provide confrontation to concrete against hostile environment. (AAC) is potential due to inheriting the property of disbursing CO2 instantly from the composition. Contrastingly an option to ordinary Portland cement (OPC), keeping this fact in mind the goal to evacuate CO2 emits and beneficiate industrial by-products into building material have been taken into consideration. Production of alkali-activated cement emanates CO2 nearly 50-80% less than OPC. This paper is the general assessment of current report on the fresh and hardened properties of alkali-activated fly ash (AAF), alkali-activated slag (AAS), and alkali activated slag and fly ash (AASF) concrete. In the recent epoch, there has been a progression to blend slag with fly ash to fabricate ambient cured alkali-activated concrete. Along with that the factors like environmental friendliness, advanced studies and investigation are also mandatorily required on the alkali activated slag and fly ash concrete. In this way, the slag to fly ash proportion impacts the essential properties and practical design of AAC. This discusses and reports the issue in an intensive manner in the following sections. This will entail providing a good considerate of the following virtues like workability, compressive strength, tensile strength, durability issues, ambient and elevated-temperature curing of AAC which will improve further investigation to elaborate the correct test methods and to commercialize it.

Download Full-text

Low-Temperature Fabrication of Three-Dimensional Ceramic Substrate by Molding Inorganic Aluminosilicate Paste

Journal of Electronic Packaging ◽

10.1115/1.4043645 ◽

2019 ◽

Vol 141 (4) ◽

Cited By ~ 1

Author(s):

Hao Cheng ◽

Yang Peng ◽

Yun Mou ◽

Qinglei Sun ◽

Mingxiang Chen

Keyword(s):

Low Temperature ◽

Thermal Cycle ◽

Three Dimensional ◽

Ceramic Substrate ◽

Curing Temperature ◽

Three Dimension ◽

Thermal Reliability ◽

Manufacturing Accuracy ◽

Alkali Activated ◽

Resistance Tests

In this work, an easy and low-temperature fabrication method of three-dimensional (3D) ceramic substrate was proposed. A 3DPC ceramic substrate was fabricated by molding alkali-activated aluminosilicate cement (AAAC) to form up a dam (cavity) on direct plated copper (DPC) ceramic substrate at low temperature. The effects of viscosity and curing temperature of cement paste on the properties of the 3DPC were investigated. The prepared 3DPC ceramic substrate achieved precise dimensions and structure, especially the manufacturing accuracy error was less than 2.5%. By optimizing process parameters, the shear strength between dam and DPC substrate reached up to 9.5 MPa. Moreover, thermal cycle and heat resistance tests confirmed that 3DPC exhibits excellent thermal reliability. All experimental results demonstrated that 3DPC ceramic substrate could satisfy with three dimension packaging and integration.

Download Full-text

Composite Geopolymeric Binders of Fly Ash, Effect of the Particle Size and Addition of Calcium Aluminate Cement

MRS Proceedings ◽

10.1557/opl.2013.1119 ◽

2013 ◽

Vol 1612 ◽

Author(s):

L.L Cardona-Hernández ◽

J.I. Escalante-García

Keyword(s):

Particle Size ◽

Fly Ash ◽

Calcium Aluminate ◽

Calcium Aluminate Cement ◽

Curing Temperature ◽

Chemical Characteristics ◽

Factorial Experimental Design ◽

Response Variable ◽

Aluminate Cement ◽

Alkali Activated

ABSTRACTAn investigation on composite geopolymeric binders, based on alkali activated fly ash (PFA) substituted with low-alumina calcium aluminate cement (CAC), was carried out using a Factorial experimental design in which the factors and levels were: %Na2O, 8-12%; modulus of the solution Ms=SiO2/Na2O =0 - 2, 10-30 wt% of CAC and fineness of PFA (D90) from 161.8 to 6.46 microns. The contribution of each factor was estimated with the 28-day compressive strength as the response variable. The curing temperature was 24h@60°C, and then at 20°C until mechanical testing. The specimens were also characterized by XRD and SEM. The results showed that the grinding modified the morphology of the PFA without changing the crystallographic or chemical characteristics as detected by XRD; and improved the mechanical properties of the geopolymers. The strength increased notably with the Ms up to 1, and reduced for Ms >1; the strength increased with the %Na2O and %CAC. Electron microscopy showed a higher densification at smaller PFA particle size, and the CAC addition promoted the formation of zeolite and Na2O-Al2O3-SiO2-H2O products.

Download Full-text

Low Temperature Fabrication of Three-Dimensional Ceramic Substrate by Using Inorganic Alkali Activated Aluminosilicate Cement Paste for UV-LED Packaging

ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems ◽

10.1115/ipack2018-8226 ◽

2018 ◽

Cited By ~ 1

Author(s):

Hao Cheng ◽

Zi Zhou Yang ◽

Yang Peng ◽

Yun Mou ◽

Ming Xiang Chen

Keyword(s):

Shear Strength ◽

Low Temperature ◽

Cement Paste ◽

Three Dimensional ◽

High Strength ◽

Ceramic Substrate ◽

Curing Temperature ◽

Thermal Reliability ◽

Uv Led ◽

Alkali Activated

In this work, a low temperature method is proposed for the economical fabrication of three-dimensional (3D) ceramic substrate for Ultraviolet Light-Emitting Diodes (UV-LED) packaging. The 3D ceramic substrate using the inorganic alkali activated aluminosilicate cement paste (IAAACP) is molded by sacrificing the patterned wax mold. By controlling the viscosity, milling time, and curing temperature the of the IAAACP, the high strength 3D ceramic substrate is achieved, the corresponding shear strength reaches to 12.5MPa. After thermal shock and heat resistant test, the shear strength changed slightly, indicating the 3D ceramic substrate has excellent thermal reliability. These experimental results indicate that the prepared 3D ceramic substrate has a potential application for UV-LED packaging.

Download Full-text

Incorporation of Alkali-Activated Municipal Solid Waste Incinerator Bottom Ash in Mortar and Concrete: A Critical Review

Materials ◽

10.3390/ma13153428 ◽

2020 ◽

Vol 13 (15) ◽

pp. 3428 ◽

Cited By ~ 1

Author(s):

Rawaz Kurda ◽

Rui Vasco Silva ◽

Jorge de Brito

Keyword(s):

Literature Review ◽

Municipal Solid Waste ◽

Solid Waste ◽

Bottom Ash ◽

Curing Temperature ◽

Partial Replacement ◽

Alkali Activation ◽

Waste Incinerator ◽

Alkaline Activator ◽

Alkali Activated

In the light of one of the most common waste management issues in urban areas, namely the elimination of municipal solid waste (MSW; about 486 kg of the waste per capita were generated in the EU in 2017), this study discusses one technique as an outlet in the construction industry for the by-product of the waste’s incineration in energy recovery facilities (i.e., MSW incinerator bottom ash—MIBA). There have been some investigations on the use of MIBA as partial replacement of cement to be used in cementitious composites, such as concrete and mortars. However, the waste’s incorporation ratio is limited since further products of hydration may not be produced after a given replacement level and can lead to an unsustainable decline in performance. In order to maximize the incorporation of MIBA, some research studies have been conducted on the alkali activation of the waste as precursor. Thus, this study presents an extensive literature review of the most relevant investigations on the matter to understand the material’s applicability in construction. It analyses the performance of the alkali-activated MIBA as paste, mortar, and concrete from different perspectives. This literature review was made using search engines of several databases. In each database, the same search options were repeated using combinations of various representative keywords. Furthermore, several boundaries were made to find the most relevant studies for further inspection. The main findings of this review have shown that the chemical composition and reactivity of MIBA vary considerably, which may compromise performance comparison, standardization and commercialization. There are several factors that affect the performance of the material that need to be considered, e.g., type and content of precursor, alkaline activator, curing temperature and time, liquid to solid ratio, among others. MIBA-based alkali-activated materials (AAM) can be produced with a very wide range of compressive strength (0.3–160 MPa). The main factor affecting the performance of this precursor is the existence of metallic aluminum (Al), which leads to damaging expansive reactions and an increase in porosity due to hydrogen gas generation stemming from the reaction with the alkaline activator. Several approaches have been proposed to eliminate this issue. The most effective solution was found to be the removal of Al by means of eddy current electromagnetic separation.

Download Full-text

The Solidification of Lead-Zinc Smelting Slag through Bentonite Supported Alkali-Activated Slag Cementitious Material

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16071121 ◽

2019 ◽

Vol 16 (7) ◽

pp. 1121 ◽

Cited By ~ 3

Author(s):

Yanhong Mao ◽

Faheem Muhammad ◽

Lin Yu ◽

Ming Xia ◽

Xiao Huang ◽

...

Keyword(s):

Compressive Strength ◽

Water Glass ◽

Cementitious Material ◽

Curing Temperature ◽

Solid Ratio ◽

Zinc Smelting ◽

Lead Zinc ◽

Smelting Slag ◽

Alkali Activated ◽

Zinc Smelting Slag

The proper disposal of Lead-Zinc Smelting Slag (LZSS) having toxic metals is a great challenge for a sustainable environment. In the present study, this challenge was overcome by its solidification/stabilization through alkali-activated cementitious material i.e., Blast Furnace Slag (BFS). The different parameters (water glass modulus, liquid-solid ratio and curing temperature) regarding strength development were optimized through single factor and orthogonal experiments. The LZSS was solidified in samples that had the highest compressive strength (after factor optimization) synthesized with (AASB) and without (AAS) bentonite as an adsorbent material. The results indicated that the highest compressive strength (AAS = 92.89MPa and AASB = 94.57MPa) was observed in samples which were prepared by using a water glass modulus of 1.4, liquid-solid ratio of 0.26 and a curing temperature of 25 °C. The leaching concentrations of Pb and Zn in both methods (sulfuric and nitric acid, and TCLP) had not exceeded the toxicity limits up to 70% addition of LZSS due to a higher compressive strength (>60 MPa) of AAS and AASB samples. While, leaching concentrations in AASB samples were lower than AAS. Conclusively, it was found that the solidification effect depends upon the composition of binder material, type of leaching extractant, nature and concentration of heavy metals in waste. The XRD, FTIR and SEM analyses confirmed that the solidification mechanism was carried out by both physical encapsulation and chemical fixation (dissolved into a crystal structure). Additionally, bentonite as an auxiliary additive significantly improved the solidification/stabilization of LZSS in AASB by enhancing the chemical adsorption capacity of heavy metals.

Download Full-text

Influence of Curing Temperature on the Mechanical Properties of Alkali-Activated Bottom Ash Geopolymer Mortar

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.488-489.198 ◽

2011 ◽

Vol 488-489 ◽

pp. 198-201 ◽

Cited By ~ 1

Author(s):

Gum Sung Ryu ◽

Si Hwan Kim ◽

Kyung Taek Koh ◽

Su Tae Kang ◽

Jang Hwa Lee

Keyword(s):

Mechanical Properties ◽

Fly Ash ◽

Power Plants ◽

Bottom Ash ◽

Basic Research ◽

Molar Concentration ◽

Curing Temperature ◽

Active Research ◽

Alkali Activated Concrete ◽

Alkali Activated

The fabrication of Portland cement causes numerous problems accompanying the large exhaustion of gas. Even if fly ash, an industrial by-product produced in thermoelectric power plants, is recycled in concrete by partial replacing of cement, more than 50% remains still discharged in marine and ashore landfills and, continue to provoke environmental problems. Recently, active research has been dedicated to alkali-activated concrete that does not use cement as binder. This alkali-activated concrete as a cement zero concrete activated by alkali solution using bottom ash rich in Si and Al instead of cement is effective in reducing gas exhaustion. This study is a basic research for the fabrication of concrete without cement and using 100% of bottom ash among the industrial by-products. Therefore, the purposes are to develop cement zero concrete by evaluating the mechanical properties by age according to the change of the molar concentration and ratio (SH/SS) of the alkali-activator and the curing temperature, and to investigate the reaction mechanism. From the test results, the compressive strength increased with larger molar concentration and the optimal curing temperature was 60°C. In addition, the measurement of the leaching according to the molar concentration of fly ash having similar chemical composition showed that the leaching of Si4+ and Al3+ increased. Compared to 6M, the leached quantities of Si4+ and Al3+ were twice larger for 9M and 12M. The formation of gel at the surface of fly ash indicated that fly ash was more activated in higher alkaline environment.

Download Full-text

Factors Affecting Alkali Activation of Laterite Acid Leaching Residues

Environments ◽

10.3390/environments8010004 ◽

2021 ◽

Vol 8 (1) ◽

pp. 4

Author(s):

Konstantinos Komnitsas ◽

Georgios Bartzas ◽

Vasiliki Karmali ◽

Evangelos Petrakis

Keyword(s):

Compressive Strength ◽

Environmental Sustainability ◽

Structural Integrity ◽

Acid Leaching ◽

Sodium Silicate Solution ◽

Curing Temperature ◽

Alkali Activation ◽

Curing Time ◽

Synthesis Conditions ◽

Alkali Activated

In this experimental study, the alkali activation of acid leaching residues using a mixture of sodium hydroxide (NaOH) and alkaline sodium silicate solution (Na2SiO3) as activators is investigated. The residues were also calcined at 800 and 1000 °C for 2 h or mixed with metakaolin (MK) in order to increase their reactivity. The effect of several parameters, namely the H2O/Na2O and SiO2/Na2O ratios present in the activating solution, the pre–curing time (4–24 h), the curing temperature (40–80 °C), the curing time (24 or 48 h), and the ageing period (7–28 days) on the properties of the produced alkali activated materials (AAMs), including compressive strength, porosity, water absorption, and density, was explored. Analytical techniques, namely X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and elemental mapping analysis were used for the identification of the morphology and structure of the final products. The experimental results show that the laterite acid leaching residues cannot be alkali activated in an unaltered state, and the compressive strength of the produced AAMs barely reaches 1.4 MPa, while the mixing of the residues with 10 wt% metakaolin results in noticeably higher compressive strength (41 MPa). Moreover, the calcination of residues at 800 and 1000 °C has practically no beneficial effect on alkali activation. Alkali activated materials produced under the optimum synthesis conditions were subjected to high temperature firing for 2 h and immersed in distilled water or acidic solution (1 mol L−1 HCl) for 7 and 30 days in order to assess their structural integrity under different environmental conditions. This study explores the potential of alkali activation of laterite leaching residues amended with the addition of metakaolin for the production of AAMS that can be used as binders or in several construction applications in order to enable their valorization and also improve the environmental sustainability of the metallurgical sector.

Download Full-text