A novel use of calcium aluminate cements for recycling waste foundry sand (WFS)

Navarro-Blasco, Í.; Fernández, José María Fernández; Durán, A.; Sirera, R.; Álvarez, J.I.

doi:10.1016/j.conbuildmat.2013.06.071

Cited by 28 publications

(9 citation statements)

References 24 publications

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“…5a and 5e), with cracked surfaces and with several well identified compounds, such as hexagonal plate-like crystals of C 2 AH 8 metastable calcium aluminates [30] (Fig. 5b), in good agreement with the XRD results.…”

Section: Effect Of the Tio 2 On The Properties Of Cac Mortarssupporting

confidence: 75%

Photocatalytic NOx abatement by calcium aluminate cements modified with TiO2: Improved NO2 conversion

Perez-Nicolas

Balbuena

Cruz-Yusta

et al. 2015

Cement and Concrete Research

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Photocatalytic activity of TiO 2 was studied in two types of Calcium Aluminate Cement (CAC) under two different curing regimes. The effect of the TiO 2 addition on the setting time, consistency and mechanical properties of the CACs was evaluated. The abatement of gaseous pollutants (NO x ) under UV irradiation was also assessed. These cementitious matrices were found to successfully retain NO 2 : more abundant presence of aluminates in white cement (w-CAC, iron-lean) helped to better adsorb NO 2 , thus improving the conversion performance of the catalyst resulting in a larger NO x removal under UV irradiation. As evidenced by XRD, SEM, EDAX and zeta potential analyses, the presence of ferrite in dark cement (d-CAC, iron-reach) induced a certain chemical interaction with TiO 2 . The experimental findings suggest the formation of new iron titanate phases, namely pseudobrookite. The reduced band-gap energy of these compounds compared with that of TiO 2 accounts for the photocatalytic activity of these samples.

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Section: Effect Of the Tio 2 On The Properties Of Cac Mortarssupporting

confidence: 75%

Photocatalytic NOx abatement by calcium aluminate cements modified with TiO2: Improved NO2 conversion

Perez-Nicolas

Balbuena

Cruz-Yusta

et al. 2015

Cement and Concrete Research

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“…It can be observed that the NS mixes developed the highest flowability for a same type of binder, which was followed by the GS and FS mixes, respectively. The lower flow of GS and FS mixes compared with NS mixes agrees with past research on cement‐based mortars 18,25,29,30 and concretes 9,10,31,32 . The lower flow of the GS mixes compared with that of the NS mixes is due to the somewhat smaller size and higher angularity of GS particles than those of NS particles, which leads to forming thicker water layers and lower interparticle friction in NS mixes, as pointed to in Section 3.4.1.…”

Section: Test Results and Observationssupporting

confidence: 87%

Development of a waste‐based eco‐friendly structural mortar without Portland cement and natural sand

Gholampour

Ozbakkaloglu

Ngo

2020

Structural Concrete

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The aim of this study is to develop a new eco‐friendly structural mortar for reducing the CO2 emissions inherent in the use of cement in concrete together with the extraction of the nonrenewable natural sand (NS). This clean production is achieved by fully replacing cement with glass powder (GP), ground granulated blast furnace slag (GGBS) and fly ash (FA) as industrial by‐products, and NS with glass sand (GS) and foundry sand (FS) as waste‐based sands. To this end, 26 mortar batches were prepared, and their compressive and direct tensile strength and flowability were studied. Scanning electron microscopy and energy dispersive x‐ray spectroscopy were employed to link the microstructure of the mortars with the obtained properties. The results show that waste‐based mortars (WBMs) with NS have a higher flowability compared with those with GS (up to 44%) and FS (up to 47%). The results also reveal that the strengths of WBMs with GS are identical to those with NS, whereas these properties of mortars containing FS are slightly lower (up to 6%). In addition, the results show that when 80% of cement is replaced with GGBS and 100% of NS is replaced with GS or FS, the strength marginally reduces (up to 7%) compared with the conventional mortar, which is attributed to their similar hydration products amounts at the interfacial transition zones of binder‐sand. At cement replacement levels of 90–100%, the strength of the WBMs degrades; however, the loss in strength is limited to ~20–30%. These promising results indicate the possibility of developing new eco‐friendly mortars for structural applications by completely replacing cement and NS with waste materials.

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“…A standard siliceous sand (from IETCC) was used as aggregate (particle size < 2 mm). The granulometric distribution of this sand has been published elsewhere (Navarro-Blasco et al 2013) and is also available on the website of the Eduardo Torroja Instituto de Ciencias de la Construcción (https://www.ietcc.csic.es/en/arena-normalizada/). Fresh mortars were moulded into cylindrical containers (diameter 3 cm) and, after hardening of 90 days at 20ºC and 60% RH, slices of 1 cm of thickness were obtained as substrates to apply the coatings.…”

Section: Methodsmentioning

confidence: 99%

Development of Multifunctional Coatings for Protecting Stones and Lime Mortars of the Architectural Heritage

Speziale

González-Sánchez

Taşcı

et al. 2020

International Journal of Architectural Heritage

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Unique multifunctional coatings, comprising a 3D superhydrophobic agent and two nanostructured photocatalysts (solar-light sensitive 50/50 and 10/90 TiO 2 -ZnO nanoheterostructures), compatible with the inorganic substrates of the Built Heritage, have been designed.The synthesized nanoparticles showed an enhanced photocatalytic activity (tested by NO degradation) as compared with the raw TiO 2 and ZnO materials.Dispersing agents were used to optimize the coatings, avoiding agglomeration of the photocatalytic nanoparticles and increasing the stability of the suspensions. Four distinct dispersions were optimized and applied as coatings onto stony materials used in the Built Heritage, such as sandstone, lime mortar, granite and limestone. Their effectiveness was assessed by assessing hydrophobicity of the surfaces (static water contact angle), photocatalytic activity and self-cleaning as well as water vapour permeability of the treated specimens. These transparent coatings demonstrated high compatibility with the construction materials of the Architectural Heritage and showed a synergistic effect rendering a minimized water absorption, self-cleaning ability evidenced by the reduced adsorption of soiling deposits and a reasonable degradation of any trace that might be adsorbed, as well as a protecting hydrophobic environment for the photocatalyst.

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A novel use of calcium aluminate cements for recycling waste foundry sand (WFS)

Cited by 28 publications

References 24 publications

Photocatalytic NOx abatement by calcium aluminate cements modified with TiO2: Improved NO2 conversion

Photocatalytic NOx abatement by calcium aluminate cements modified with TiO2: Improved NO2 conversion

Development of a waste‐based eco‐friendly structural mortar without Portland cement and natural sand

Development of Multifunctional Coatings for Protecting Stones and Lime Mortars of the Architectural Heritage

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