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Regeneration of hydrated cement: comparison of reactivity of fresh and recycled cement

Guillermo Meza HernandezRegeneration of hydrated cement: comparison of reactivity of fresh and recycled cement,VUB2020 (June).

In this master thesis a laboratory scale process of cement recycling was developed. Cement
paste (CP) was used to simulate concrete demolition waste fines. The reduction of particle
size of CP to
125µm was performed prior dehydration. Cement pastes type I and III were
dehydrated at
550C for two hours. Chemical characterization of cements was performed
before hydration and after dehydration. X-Ray diffraction (XRD) allowed to compare microstructural changes between fresh (FC) and dehydrated cement (DC). Other techniques
such as density and specific surface area (Blaine) were also used for characterization. FC
and DC were blended in 70-30, 50-50 and 30-70 ratios respectively. Mechanical performance of FC and BC mortars was studied by Resonalyser instrument, 3-point bending and
compressive tests. In addition, enhancement of mechanical properties was tried through
admixtures incorporation.
The experimental results show that recycled cement could be added as replacement of fresh
cement. FC/BC ratio used has a direct impact on the Young’s modulus and compressive
strength of BC mortars, this could be improved by the addition of admixtures. Further
experiments are needed to confirm mechanical performance.
Being cement one of the most used materials in the world, its recycling becomes an important task to continue developing. Despite the experimental confirmations needed,the
panorama is promising. Dehydration at low temperature might allow to reduce CO
2 emissions, prevent raw materials depletion as well as economical benefits to companies using
this kind of technology.


BibTeX

@phdthesis{,
    author      = "Guillermo Meza Hernandez",
    title       = "Regeneration of hydrated cement: comparison of reactivity of fresh and recycled cement",
    institution = "VUB",
    year        = "2020",
    address     = "",
    month       = "June",
    doi         = "",
    note        = "",
}