scholarly journals Influence of Particle Size on Compressive Strength of Alkali Activated Refractory Materials

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2227 ◽  
Author(s):  
Barbara Horvat ◽  
Vilma Ducman
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Mechanical Strength ◽  
Time Dependence ◽  
Water Glass ◽  
Curing Temperature ◽  
Refractory Materials ◽  
Alkali Activated

Influence of particle size on the mechanical strength of alkali activated material from waste refractory monolithic was investigated in this study. Precursor was chemically and mineralogically analysed, separated on 4 fractions and alkali activated with Na-water glass. Alkali activated materials were thoroughly investigated under SEM and XRD to evaluate the not predicted differences in mechanical strength. Influence of curing temperature and time dependence at curing temperatures on mechanical strength were investigated in the sample prepared from a fraction that caused the highest compressive strength.

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

Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 714 ◽  
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.

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

2019 ◽  
Vol 16 (7) ◽  
pp. 1121 ◽  
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.

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

2019 ◽  
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 slag and evaluate the particle size distributions 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 multi fractal 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.

scholarly journals Machine Learning Approaches for Prediction of the Compressive Strength of Alkali Activated Termite Mound Soil

2021 ◽  
Vol 11 (11) ◽  
pp. 4754
Author(s):  
Assia Aboubakar Mahamat ◽  
Moussa Mahamat Boukar ◽  
Nurudeen Mahmud Ibrahim ◽  
Tido Tiwa Stanislas ◽  
Numfor Linda Bih ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Construction Materials ◽  
Curing Temperature ◽  
Sustainable Construction ◽  
Support Vector ◽  
Learning Approaches ◽  
Artificial Neural Network Ann ◽  
Curing Regime ◽  
Alkali Activated

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).

High Strength Alkali Activated Slag Cements with Controlled Setting Times and Early Strength Gain

2015 ◽  
Vol 1100 ◽  
pp. 44-49 ◽  
Author(s):  
Pavel Krivenko ◽  
Oleg Petropavlovsky ◽  
Vit Petranek ◽  
Vasiliy Pushkar ◽  
Grigorii Vozniuk
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Water Glass ◽  
High Strength ◽  
Strength Gain ◽  
Setting Times ◽  
Alkaline Activator ◽  
Early Strength ◽  
Activated Slag ◽  
Alkali Activated

The paper discusses approaches to compositional build-up of high strength alkali activated cements made using water glass as alkaline activator represented by commercial products in a form of powder and liquid. The purpose was to study the influence of fineness of ground granulated blast-furnace slags, admixtures and additives, compatible with alkali activated cements, water glass and mode of manufacturing technology in order to reach high compressive strength (≥ 80 MPa at standard age (28 days)) and early strength (≥ 20 MPa after 3 h of hardening in normal conditions).

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

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.

scholarly journals Alkali-Activated Fly Ashes: Influence of Curing Conditions on Mechanical Strength

2018 ◽  
Vol 3 (2) ◽  
pp. 57-67
Author(s):  
Filipe Almeida ◽  
Nuno Cristelo ◽  
Tiago Miranda ◽  
Castorina S. Vieira ◽  
Maria De Lurdes Lopes ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Relative Humidity ◽  
Mechanical Strength ◽  
Research Groups ◽  
Fly Ashes ◽  
Curing Conditions ◽  
Alkaline Activation ◽  
Strength Tests ◽  
Higher Temperature ◽  
Alkali Activated

Alkaline activation of fly ashes is a procedure that enables an alternative binder which has been receiving much interest by several research groups particularly on the manufacturing of mortars and concretes. The properties of the materials that are developed during the alkaline activation are influenced by the curing conditions (temperature and relative humidity). Another relevant facet related to the curing procedures is the possibility of carbonation occur, which may have an impact on the mechanical strength of the alkaline cements. In this research, several sets of curing conditions were tested to understand which one results in a higher strength and reveals carbonation. Uniaxial compressive strength tests were conducted to assess mechanical behavior. The outcome suggests that higher temperature and low relative humidity yields higher mechanical strength.

scholarly journals Effect of Ordinary Portland Cement and Water Glass on the Properties of Alkali Activated Fly Ash Concrete

Minerals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 40 ◽  
Author(s):  
Vytautas Bocullo ◽  
Danutė Vaičiukynienė ◽  
Ramūnas Gečys ◽  
Mindaugas Daukšys
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Water Glass ◽  
Ordinary Portland Cement ◽  
Reference Sample ◽  
Freeze And Thaw ◽  
Naoh Solution ◽  
Increased Strength ◽  
Alkali Activated

This research presents the influence of ordinary Portland cement (OPC) and/or water glass addition on fly ash alkali-activated mortar and concrete. The results show that fly ash (FA) concrete activated with a NaOH solution and water glass mixture had better resistance to freeze and thaw, carbonation, alkali-silica reaction (ASR) and developed higher compressive strength and static elastic modulus compared with the FA concrete activated only with an NaOH solution. The addition of OPC contributes to the development of a denser microstructure of alkali activated concrete (AAC) samples. In the presence of water glass and OPC, the compressive strength (52.60 MPa) of the samples increased more than two times as compared with the reference sample (21.36 MPa) without OPC and water glass. The combination of OPC and water glass showed the increased strength and enhanced durability of AAC. The samples were more resistant to freeze and thaw, ASR, and carbonation.

Cracking and Mechanical Strength of NaOH-Slag Geopolymers

2011 ◽  
Vol 275 ◽  
pp. 218-221
Author(s):  
Bo Zhang
Keyword(s):  
Compressive Strength ◽  
Quantitative Analysis ◽  
Mechanical Strength ◽  
Mas Nmr ◽  
Curing Temperature ◽  
Cracking Tendency

The effect of the curing temperature and NaOH content on cracking tendency and compressive strength for NaOH-slag geopolymers is reported in relation to 29Si and MAS NMR structural analyses and XRD phase quantitative analysis.

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