The Determination of the Influence of pH Value of Curing Conditions on Portland Cement Hydration

Šiler, Pavel; Kolářová, Iva; Sehnal, Tomáš; Másilko, Jiří; Opravil, Tomáš

doi:10.1016/j.proeng.2016.07.393

Cited by 24 publications

(1 citation statement)

References 5 publications

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“…The pH of leachate flowing through the samples compacted at 75% is 8.12 ± 0.3 (Table 3). The increase in pH to circa 8 due to the hydration of CSH [37] promoted heavy metal precipitation [35,38], which was consequently entrapped among the pores, and thereby the interlocking of CSH (chemical clogging) as shown in Figure 5a. This phenomenon contributes to the further reduction in porosity and low hydraulic conductivity and therefore reduces the heavy metal concentration in leachate.…”

Section: Leachate Qualitymentioning

confidence: 99%

Leaching Behaviour of Synthetic Leachate through a Sewage Sludge and Red Gypsum Composite as Intermediate Landfill Cover

et al. 2023

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This paper examines the environmental impact of the use of compacted sewage sludge:red gypsum (SS:RG) mixture as intermediate landfill cover in terms of yield and quality of leachate as characterised by hydraulic conductivity and leaching behaviour. A series of column tests using the constant head method is carried out by percolating the synthetic leachate through samples that have been compacted at various degrees (60, 70, 75, 80 and 85%). The leachate quality is monitored at pre-determined days for pH, COD, Cu, Fe and Zn. In general, hydraulic conductivity decreases in three stages, in which the first stage is mainly attributed to the particle rearrangement and hydration of calcium silicate hydrate (CSH). The hydration of CSH increases the pH, which causes the heavy metal to precipitate and be entrapped within the matrices of CSH gel, thereby further reducing the porosity and hydraulic conductivity. A minimum of 75% compaction has shown favourable final porosity, hydraulic conductivity, and leachate quality, although a minimum of 80% compaction is recommended in order to achieve a satisfactory compressive strength of greater than 345 kPa for a landfill operation.

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Section: Leachate Qualitymentioning

confidence: 99%

Leaching Behaviour of Synthetic Leachate through a Sewage Sludge and Red Gypsum Composite as Intermediate Landfill Cover

et al. 2023

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Sulfate effects on sulfate-resistant cement–treated expansive soil

Raja

Thyagaraj

2020

Bull Eng Geol Environ

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Assessment of chemical and mechanical behavior of bamboo pulp and nanofibrillated cellulose exposed to alkaline environments

2019

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This study was performed to study the effects of the cement paste composition (calcium aluminate cement-CAC-and a geopolymer in comparison to Portland cement-OPC-) on bamboo pulp and nanofibrillated cellulose (NFC). The changes in the composition and chemical structure of the fibers were analyzed by X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR). The changes in the mechanical strength were evaluated through tensile tests on the fibers after immersion on the cement pastes, in the form of sheets. The XPS results showed that the immersion of the pulp and NFC in the different pastes (CAC, geopolymer and OPC) modified the chemical surface of these fibers: it was found removal of lignin and extractives and some degradation of hemicellulose and cellulose. The FTIR analysis indicated modifications in the hydrogen bonds energy. The tensile strength of pulp sheets decreased in 70% and 34% after immersion in OPC and geopolymer, respectively. The tensile strength of the NFC sheets decreased 36%, 68% and 54% after immersion in OPC, CAC and geopolymer, respectively. Thus, the response of the bamboo pulp and NFC immersed in different cement pastes was different due the inherent characteristics of such fibers, and not only the Portland cement should be considered as harmful to lignocellulosic fibers. Although CAC and geopolymer are free of calcium hydroxide, the high alkalinity of these pastes also accelerated the degradation process of lignocellulosic fibers.

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The Determination of the Influence of pH Value of Curing Conditions on Portland Cement Hydration

Cited by 24 publications

References 5 publications

Leaching Behaviour of Synthetic Leachate through a Sewage Sludge and Red Gypsum Composite as Intermediate Landfill Cover

Leaching Behaviour of Synthetic Leachate through a Sewage Sludge and Red Gypsum Composite as Intermediate Landfill Cover

Sulfate effects on sulfate-resistant cement–treated expansive soil

Assessment of chemical and mechanical behavior of bamboo pulp and nanofibrillated cellulose exposed to alkaline environments

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