Mechanical, microstructural and acid resistance aspects of improved hardened Portland cement pastes incorporating marble dust and fine kaolinite sand

Selim, F.A.; Hashem, F. S.; Amin, M.S.

doi:10.1016/j.conbuildmat.2020.118992

Cited by 37 publications

(11 citation statements)

References 35 publications

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“…The solids investigated in this study via XRF represent a similar state as the XRD pattern after ‘161 h, ground’ in Figure 9 a, whereas XRD patterns in other studies [ 1 , 3 , 6 , 19 , 20 , 21 , 22 ] investigated bulk samples, which are more comparable to the example after ‘161 h, washed, ground’ in this figure.…”

Section: Resultssupporting

confidence: 73%

“…The main link between chemistry and transport is mostly (over) simplified by using an (apparent) diffusion coefficient that should consider the changes in porosity [ 11 ]. Typically, the acidic acid attack on cement-based materials is investigated by using large samples such as cylinders or cubes [ 1 , 3 , 6 , 19 , 20 , 21 , 22 ]. Therefore, the changes in chemical composition and structural and mechanical properties can be studied.…”

Section: Discussionmentioning

confidence: 99%

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Thermodynamic Modeling and Experimental Validation of Acetic Acid Attack on Hardened Cement Paste: Effect of Silica Fume

et al. 2022

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Concrete structures are increasingly becoming exposed to organic acid attack conditions, such as those found in agriculture and food-related industries. This paper aims to experimentally verify the thermodynamic modeling of cement pastes under acetic acid attack. For this, a modeling approach implemented in IPHREEQC via Matlab is described, and results are compared with measured pH and compositions of equilibrated solutions (MP-AES) as well as unreacted/precipitated solids (XRF, XRD and STA) for a wide range of acid concentrations. The 11% replacement of cement by silica fume (SF) led to a 60 or 70% reduction (measured or modeled, respectively) of Portlandite content in the hardened cement paste due to the pozzolanic reaction resulting in higher content of CSH phases, which has effects on the progression of dissolution processes and a resulting pH with increased acid concentrations. Considering that no fitting parameter was used, the model predictions showed good agreement with measured values of pH, dissolved ion concentrations and composition of the remaining (degraded) solids overall. The discrepancies here were more pronounced at very high acid concentrations (equilibrium pH < ~4), i.e., after the full dissolution of hydrate phases due to limitations in the model used to describe Al-, Si- and Fe-gel phases and/or identified experimental challenges in precipitation of calcium and aluminum acetate hydrates.

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Section: Resultssupporting

confidence: 73%

Section: Discussionmentioning

confidence: 99%

Thermodynamic Modeling and Experimental Validation of Acetic Acid Attack on Hardened Cement Paste: Effect of Silica Fume

et al. 2022

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“…[31] after 7 and 28 days of hydration, respectively. The endothermic peak located at 505 °C, is assigned to the thermal destruction of Ca(OH) 2 [32,33]. The % mass loss of the first peak is 6.9 and 7.2, while for the second peak 2.1 and 2.8 after 7 and 28 days of hardening, respectively.…”

Section: X-ray Diffraction (Xrd)mentioning

confidence: 99%

Utilization of alum sludge waste for production of eco-friendly blended cement

Mohamed

El-Gamal

Farghali

2022

J Mater Cycles Waste Manag

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This work was focused on evaluating the suitability of replacing Portland cement (PC) by 5, 10 and 15 mass % of activated alum sludge waste (AAS) as a pozzolanic material. Exploitation of low-cost nanocomposite for bolstering the physical, mechanical, and stability against firing of PC–AAS-hardened composites was inspected. CuFe2O4 spinel nanoparticle with average particle size (~ 50 nm) was prepared. Inclusion of CuFe2O4 spinel in different PC–AAS-hardened composites bolsters their physicomechanical features at almost normal curing ages as well as their stability against firing. The positive impact of synthesized CuFe2O4 spinel was affirmed via TGA/DTG and XRD techniques, which indicated the presence of diverse hydration yields such as CSHs, CASHs, CFSH, and CuSH that enhance the overall physicomechanical characteristics and thermal stability of various PC–AAS-hardened composites. The composite containing (90 PC–10 AAS waste–2 CuFe2O4) offers many benefits from the economic and environmental view. Graphical abstract

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“…Instead, the material must be transported to a specialized facility that is built for the express purpose of dealing with hazardous waste 1 – 3 . It is essential to dispose of solid wastes, particularly alum sludge (AS), as quickly as is practically practicable to reduce the number of potential threats that may be posed to the environment 4 . However, processed alum sludge, which is sometimes referred to as TAS, contains significant quantities of silica dioxide and aluminum oxide, which are the primary components of cement 5 .…”

Section: Introductionmentioning

confidence: 99%

Cost-effective and green additives of pozzolanic material derived from the waste of alum sludge for successful replacement of portland cement

Mohamed

Farghali

Eessaa

et al. 2022

Sci Rep

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The major objective of this study was to examine the viability of using 5, 10, or 15 mass% of Activated Alum Sludge waste (AAS) instead of Ordinary Portland Cement (OPC) as a pozzolanic ingredient in concrete. This fundamental inquiry framed the investigation and OPC-AAS-hardened composites were studied to see whether they may benefit from inexpensive nanocomposites in terms of improved physical properties, mechanical strength, and resistance to heat and flame. The investigation set out to see how inexpensive nanocomposite might be put to use and the nanoparticles of CuFe2O4 spinel with an average size of less than 50 nm were successfully manufactured. Many different OPC-AAS-hardened composites benefit from the addition of CuFe2O4 spinel, which increases the composites' resistance to fire and enhances their physicomechanical properties at roughly average curing ages. Synthesized CuFe2O4 spinel was shown to have desirable characteristics by TGA/DTG and XRD. By using these methods, we were able to identify a broad variety of hydration yields, including C–S–Hs, C–A–S–Hs, C–F–S–Hs, and Cu–S–Hs, that enhance the physicomechanical properties and thermal resistivity of OPC-AAS-hardened composites as a whole. The composite material comprising 90% OPC, 10% AAS waste, and 2% CuFe2O4 has several positive economic and environmental outcomes.

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Mechanical, microstructural and acid resistance aspects of improved hardened Portland cement pastes incorporating marble dust and fine kaolinite sand

Cited by 37 publications

References 35 publications

Thermodynamic Modeling and Experimental Validation of Acetic Acid Attack on Hardened Cement Paste: Effect of Silica Fume

Thermodynamic Modeling and Experimental Validation of Acetic Acid Attack on Hardened Cement Paste: Effect of Silica Fume

Utilization of alum sludge waste for production of eco-friendly blended cement

Cost-effective and green additives of pozzolanic material derived from the waste of alum sludge for successful replacement of portland cement

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