Effect of coffee husk ash as alkaline activator in one-part alkali-activated binder

Lima, Felipe Silva; Gomes, Thiago C. F.; Moraes, J.C.B.

doi:10.1016/j.conbuildmat.2022.129799

Cited by 17 publications

(8 citation statements)

References 38 publications

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“…However, it was observed that in both the C-PC and CA cases, strength measurements tended to stabilise beyond a potassium carbonate level of 20%. Compressive strength did not significantly change after 28 days of cure [23].…”

Section: Bfs/ca Physicochemical Characterizationmentioning

confidence: 77%

“…There was a steady increase in relative compressive strength values above 75% for a range of potassium carbonate concentrations and curing durations. Significantly, with the exception of CA-5% after seven days of curing, CA with potassium carbonate contents between 5.0 and 10.0 weight percent consistently displayed similar values surpassing 100% throughout all curing times, reaching as high as 193%, suggesting a more beneficial impact of the waste in comparison with the commercial activator in these circumstances [23]. However, identical compressive strength values ranging between 76 and 87% in all curing durations were obtained using potassium carbonate content of 15 and 20 weight percent.…”

Section: Figure 3 Compressive Strength Of Camentioning

confidence: 90%

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Investigation on Feasibility of Utilizing Coffee-Husk Ash as an Alkaline Activator in Geopolymer Concrete

P V,

Kadarkarai,

Thomas

et al. 2024

E3S Web of Conf.

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Cement production is the major source of global warming which induces 7% of total greenhouse gas emissions. Reducing the use of cement in construction industry needs to be adopted by any of the alternates. One of the best alternates to reduce the impact caused by the cement production process is geopolymer concrete which can completely replace the usage of cement. Geopolymer is trending technology which possess numerous advantages than ordinary Portland cement concrete technology. Geopolymer is produced by the mixing of solid precursor and monomer. Most widely used solid precursors are waste industrial byproducts such as fly ash, GGBS, metakaolin etc., and monomers are alkaline activators like sodium hydroxide and Na2SiO3. Meanwhile, the properties of geopolymer concrete are decided by the various parameters such as quantity of aluminosilicate source in precursor, ratio of NaO/SiO2, SiO2/Al2O3, NaOH/NaSiO3, solution to binder ratio, concentration of NaOH etc., The alkaline activators mostly used are chemical activators which is harmful to humans. Hence, there is a need of finding an alternate for chemical activators in the geopolymer concrete. In this proposed methodology, the chemical alkaline activators have been completely replaced by the waste residue product named coffee husk. Coffee husk is a residue produced from the coffee powder production industry. A total of 18.29 MMT of coffee husk ash has been produced every year. Coffee husk has an inbuilt composition of potassium which is one of the alkaline activators. However, the coffee husk ash needs to be calcinated by the use of oven before to use. In this research, an attempt has been made to utilize the Coffee husk ash (CA), as an alkaline activator and efficient activation mechanism of CA will be examined.

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Section: Bfs/ca Physicochemical Characterizationmentioning

confidence: 77%

Section: Figure 3 Compressive Strength Of Camentioning

confidence: 90%

Investigation on Feasibility of Utilizing Coffee-Husk Ash as an Alkaline Activator in Geopolymer Concrete

P V,

Kadarkarai,

Thomas

et al. 2024

E3S Web of Conf.

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“…As demonstrated in Table 1, the most commonly used caustic alkali element activators are NaOH and KOH [12,13], and the alkaline earth elements are Ca(OH) 2 and Mg(OH) 2 , which might be obtained from the active CaO or MgO from the furnace slag [14,15], and other solid wastes, such as acetylene sludge (mainly composed of Ca(OH) 2 ) [16]. Apart from these base chemicals, a few weak acid salts, including Na 2 CO 3 [17], K 2 CO 3 [18], Na 3 PO 4 [19], K 3 PO 4 , Na-COOH, K-COOH, Na-COOH-CH 2 , and K-COOH-CH 2 , can also be used as activators due to their innate basic hydrolysis reaction. In addition, water glass (Na 2 O•xSiO 2 •yH 2 O) is another widely used activator for aluminosilicate solid waste binder materials [20].…”

Section: Chemistry Of Alkali-activated Materialsmentioning

confidence: 99%

“…Acetylene sludge, fly ash Ca(OH) 2 [16] Slag Na 2 CO 3 [17] Blast furnace slag K 2 CO 3 , coffee husk ash [18] Blast furnace Slag Na 3 PO 4 [19] Blast furnace slag Water glass; water glass was combined with Na 2 CO 3 and NaOH [20] Blast furnace slag NaOH and Na 2 CO 3 [21] The chemical reaction between the alkali and the aluminosilicate, which governs the microstructure evolution and the final properties of the products, significantly depends on several factors, including the chemical composition of the raw materials [22], the curing temperature [23], the curing humidity [24], the curing method [25], and chemical additives [26]. It was claimed that the chemical reaction between the alkaline activators and the aluminosilicates can be divided into two types, namely the high-calcium/magnesium systems and the low-calcium/magnesium systems (as shown in Figure 1).…”

Section: Type Of Aluminosilicate Solid Waste Activators Referencementioning

confidence: 99%

Recycling of Aluminosilicate-Based Solid Wastes through Alkali-Activation: Preparation, Characterization, and Challenges

Feng,

Yi,

Zhao

et al. 2024

Buildings

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Recycling aluminosilicate-based solid wastes is imperative to realize the sustainable development of constructions. By using alkali activation technology, aluminosilicate-based solid wastes, such as furnace slag, fly ash, red mud, and most of the bio-ashes, can be turned into alternative binder materials to Portland cement to reduce the carbon footprint of the construction and maintenance activities of concrete structures. In this paper, the chemistry involved in the formation of alkali-activated materials (AAMs) and the influential factors of their properties are briefly reviewed. The commonly used methods, including X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TG), nuclear magnetic resonance spectroscopy (NMR), and X-ray pair distribution function technology, to characterize the microstructure of AAMs are introduced. Typical characterization results of AAMs are shown and the limitations of each method are discussed. The main challenges, such as shrinkage, creep, efflorescence, carbonation, alkali–silica reaction, and chloride ingress, to conquer for a wider application of AAMs are reviewed. It is shown that several performances of AAMs under certain circumstances seem to be less satisfactory than traditional portland cement systems. Existing strategies to improve these performances are reviewed, and recommendations for future studies are given.

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“…Biomass ashes may be utilised to prepare alkaline solutions when fabricating geopolymers. Ashes rich in SiO 2 are used to prepare alternative sodium silicate [ 16 , 17 , 18 , 19 , 20 ] and ashes rich in K 2 O can act as a substitute of KOH [ 21 , 22 , 23 , 24 ].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Thermochemical Treatments for Rice Husk Ash Valorisation as a Source of Silica in Preparing Geopolymers

et al. 2023

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The use of geopolymers has revolutionized research in the field of construction. Although their carbon footprint is often lower than that of traditional mortars with Portland cement, activators such as sodium silicate have a high environmental impact in the manufacturing of materials. Employing alternative alkali sources to produce geopolymers is necessary to obtain materials with a lower carbon footprint. The present research explores the use of rice husk ash (RHA) as an alternative source of silica to produce alkaline activators by four methods: reflux; high pressure and temperature reaction; thermal bath at 65 °C; and shaking at room temperature. To evaluate the efficiency of these methods, two types of experiments were performed: (a) analysing silica dissolved by the filtering/gravimetric method; and (b) manufacturing mortars to compare the effectiveness of the treatment in mechanical strength terms. The percentages of dissolved silica measured by the gravimetric method gave silica dissolution values of 70–80%. The mortars with the best mechanical strength results were the mixtures prepared with the thermal bath treatment at 65 °C. Mortar cured for 1 day (at 65 °C), prepared with this activator, yielded 45 MPa versus the mortar with commercial reagents (40.1 MPa). It was generally concluded that utilising original or milled RHA in preparing activators has minimal influence on either the percentage of dissolved silica or the mechanical strength development of the mortars with this alternative activator.

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Effect of coffee husk ash as alkaline activator in one-part alkali-activated binder

Cited by 17 publications

References 38 publications

Investigation on Feasibility of Utilizing Coffee-Husk Ash as an Alkaline Activator in Geopolymer Concrete

Investigation on Feasibility of Utilizing Coffee-Husk Ash as an Alkaline Activator in Geopolymer Concrete

Recycling of Aluminosilicate-Based Solid Wastes through Alkali-Activation: Preparation, Characterization, and Challenges

Evaluation of Thermochemical Treatments for Rice Husk Ash Valorisation as a Source of Silica in Preparing Geopolymers

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