The effects of Na2O/SiO2molar ratio, curing temperature and age on compressive strength, morphology and microstructure of alkali-activated fly ash-based geopolymers

2011 ◽  
Vol 33 (6) ◽  
pp. 653-660 ◽  
Author(s):  
Alexandre Silva de Vargas ◽  
Denise C.C. Dal Molin ◽  
Antônio C.F. Vilela ◽  
Felipe José da Silva ◽  
Bruno Pavão ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Curing Temperature ◽  
Alkali Activated

Effect of the Combined Using of Fly Ash and Granulated Blast Furnace Slag on Properties of Cementless Alkali-Activated Mortar

2011 ◽  
Vol 287-290 ◽  
pp. 916-921
Author(s):  
Kyung Taek Koh ◽  
Gum Sung Ryu ◽  
Si Hwan Kim ◽  
Jang Hwa Lee
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Curing Temperature ◽  
Mixture Ratio ◽  
Granulated Blast Furnace Slag ◽  
Alkaline Activator ◽  
Furnace Slag ◽  
Alkali Activated

This paper examines the effects of the mixture ratio of fly ash/slag, the type of alkaline activators and curing conditions on the workability, compressive strength and microstructure of cementless alkali-activated mortar. The investigation showed that the mixture ratio of fly ash/slag and the type of alkaline activator have significant influence on the workability and strength, whereas the curing temperature has relatively poor effect. An alkali-activated mortar using a binder composed of 50% of fly ash and 50% of granulated blast furnace slag and alkaline activator made of 9M NaOH and sodium silicate in proportion of 1:1 is seen to be able to develop a compressive strength of 65 MPa at age of 28 days even when cured at ambient temperature of 20°C.

Relationship between Microscopic Structures and Compressive Strength of Alkali-Activated Fly Ash Mortar

2010 ◽  
Vol 452-453 ◽  
pp. 737-740
Author(s):  
Hyun Jin Kang ◽  
Gum Sung Ryu ◽  
Gyung Taek Koh ◽  
Su Tae Kang ◽  
Jung Jun Park
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Curing Temperature ◽  
Microscopic Structure ◽  
Curing Conditions ◽  
The Relationship ◽  
Alkali Activated

This paper evaluates the relationship between the compressive strength and microscopic structure of geopolymer mortar using 100% of fly ash instead of cement. The experimental variable is the curing temperature, which may influence the compressive strength of the geopolymer. The compressive strength, porosity, XRD, SEM and EDS are examined after 48 hours of curing at 30, 60 and 90°C. The resulting compressive strength at 60°C appeared to be the largest. In order to evaluate the voids produced during the polymerization, the porosity was measured and showed also the largest value after curing at 60°C during 48 hours. Furthermore, SEM and EDS analyses verified clear improvement of the microstructure after 48 hours of curing at 60°C. Such result can be explained by the variation of the Si-Al ratio according to the curing conditions, which revealed to be lower for curing at 30 and 90°C than at 60°C and demonstrated that the curing temperature has significantly effect on the compressive strength of the geopolymer.

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).

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

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.

Experimental Study on Alkali-Activated Slag-Lithium Slag-Fly Ash Environmental Concrete

2011 ◽  
Vol 287-290 ◽  
pp. 1237-1240
Author(s):  
Lan Fang Zhang ◽  
Rui Yan Wang
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Fly Ash ◽  
Setting Time ◽  
Alkali Activated Slag ◽  
Percent Increase ◽  
Compressive Strength Of Concrete ◽  
Activated Slag ◽  
Lithium Slag ◽  
Alkali Activated

The aim of this paper is to study the influence of lithium-slag and fly ash on the workability , setting time and compressive strength of alkali-activated slag concrete. The results indicate that lithium-slag and fly-ash can ameliorate the workability, setting time and improve the compressive strength of alkali-activated slag concrete，and when 40% or 60% slag was replaced by lithium-slag or fly-ash, above 10 percent increase in 28-day compressive strength of concrete were obtained.

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