Reactivation of hydrated cement powder by thermal treatment for partial replacement of ordinary portland cement

Semugaza, Gustave; Mielke, Tommy; Castillo, Marianela Escobar; Gierth, Anne Zora; Tam, Joo Xian; Nawrath, Stefan

doi:10.1617/s11527-023-02133-9

Cited by 10 publications

(3 citation statements)

References 52 publications

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“…This becomes clear by analyzing the peaks that occur at 27 • and 33 • . In addition, the peaks related to hydrated calcium silicate, which is mainly responsible for cement strength [43], are less intense for the NaOH composition, as observed in the peak at 30 • . The identification of CSH is possible through Rietveld refinement, since CSH is a compound with low crystallinity, according to the methodology defined in other studies [44].…”

Section: Comparison Between Reference and Coffee Husk Mortars Treated...mentioning

confidence: 94%

“…These results explain the compressive strength values obtained at 28 days, where it was observed that the reference composition and the KOH composition present equivalent strengths, while the NaOH mortar composition presents statistically lower compressive strength. This happened due to the non-formation of phases such as C-S-H and portlandite, responsible for the strength of the cement [43], and due to the NaOH content having acted as a retardant in the hardening process of the material.…”

Section: Comparison Between the Reference Mortars And Those With Natu...mentioning

confidence: 99%

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Chemical Treatments for Coffee Husks: Application in Mortar for Coating and Laying Blocks

2023

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(1) The use of agro-industrial wastes, such as coffee husks, in cementitious materials is a viable way to achieve the sustainable development of new construction materials. Traditionally, these wastes are applied after calcination, spending energy and financial resources. Furthermore, the calcination of these wastes contributes to a more sustainable environment. This is interesting because calcination treatments are usually more expensive than those using chemical treatments. Thus, the objective of this research is to evaluate the possibility of using coffee husks with the use of chemical treatments with sodium and potassium hydroxide in mortars for coating and laying blocks. (2) The methodology of this article consists of producing test specimens of mortar for coating and laying blocks in the composition 1:1:6:1.55 (cement: hydrated lime: sand: water), using coffee husks that will be incorporated in quantities of 2.5% in relation to the mass of the cement in its natural state and after treatment with sodium and potassium hydroxide. Compositions containing calcined coffee husks are evaluated for comparison purposes. The evaluated parameters were the mass density in the hardened state, water absorption by immersion and compressive strength. To complement these analyses, XRD, SEM and calorimetry tests were executed to compare the proposed treatments. (3) The results indicate that the use of treatments with NaOH and KOH allows for the use of coffee husks in mortars, since the parameters obtained were compatible with this type of application. The use of natural coffee husks is not possible due to their low compressive strength and high water absorption, caused by porosity. The use of alkaline treatments, especially with KOH, does not affect the hydration of the cement, allowing for the obtention of values statistically equivalent to the reference composition. The results with calcined coffee husks are even more promising due to the high content of amorphous potassium, which promotes the conversion of ettringite into hydrous calcium aluminate monosulfate. (4) It is concluded that, for the application of coffee husks in mortars for coating and laying blocks, the chemical treatment with KOH meets the necessary parameters—for example, a compressive strength greater than 2 MPa, making sustainable building materials and promoting the use of agro-industrial waste in building materials.

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Section: Comparison Between Reference and Coffee Husk Mortars Treated...mentioning

confidence: 94%

Section: Comparison Between the Reference Mortars And Those With Natu...mentioning

confidence: 99%

Chemical Treatments for Coffee Husks: Application in Mortar for Coating and Laying Blocks

2023

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“…However, cementitious material production not only affects construction but also greenhouse gas emissions and natural resource depletion (Hossain et al, 2021). There is a signi cant surge in CO 2 emissions from cement production, which is becoming expensive due to its energy-intensive production process, and certain countries are already experiencing shortages of the essential components (Danish et al, 2021; Ritchie et al, 2020; Semugaza et al, 2023). Cement production is a major contributor to CO 2 emissions and environmental issues (C. Chen et al, 2022;Mahasenan et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of Biochar and Charcoal and Their Application in the Construction Industry

Yadav

Sharma

2023

Preprint

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The construction industry heavily relies on cement, which contributes significantly to greenhouse gas emissions during production and depletes natural resources. Moreover, the decomposition of organic waste is a significant source of emissions that contribute to environmental damage due to the lack of proper management. However, biochar and charcoal derived from organic waste can be utilized as admixtures in concrete to minimize these emissions. This study investigates the mechanical properties of concrete with partial cement replacement using biochar and charcoal separately. The aim is to determine the optimal percentages of cement replacement and the effectiveness of using these byproducts to manage organic waste and reduce emissions. The report compares the behavior and suitability of biochar and charcoal in concrete based on the mechanical strength of the resulting concrete. It suggests that both materials exert distinct effects on the properties of concrete, with the optimal replacement percentage variations. However, it is noteworthy that biochar outperforms charcoal in all mechanical aspects of concrete and significantly improves flexural strength. However, more research is needed to determine the effect of different biochar on flexural strength in concrete. Recent research has demonstrated that incorporating biochar and charcoal as cement admixtures holds significant promise in reducing greenhouse gas emissions and mitigating the negative environmental impact of organic waste in the construction industry.

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Modification of Reactivated Cement Fines with Addition of Ground Blast Furnace Slag

Noel,

Alkhatib,

Gierth

et al. 2024

RILEM Bookseries

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Reactivation of hydrated cement powder by thermal treatment for partial replacement of ordinary portland cement

Cited by 10 publications

References 52 publications

Chemical Treatments for Coffee Husks: Application in Mortar for Coating and Laying Blocks

Chemical Treatments for Coffee Husks: Application in Mortar for Coating and Laying Blocks

Comparative Study of Biochar and Charcoal and Their Application in the Construction Industry

Modification of Reactivated Cement Fines with Addition of Ground Blast Furnace Slag

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