NMR Analysis of Polyphosphoric Acid-modified Bitumens

Miknis, Francis P.; Thomas, Kenneth P.

doi:10.1080/14680629.2008.9690107

Cited by 17 publications

(16 citation statements)

References 7 publications

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“…The absence of a phosphorous signal in the liquid-state NMR spectra after hydrated lime was added to the PPA modified bitumen supports a previous study that showed that PPA does not react to form organo-phosphorous compounds when added to bitumen (Miknis and Thomas, 2008). If, for example, an organo-phosphate ester was formed by reaction with the phenolic component in bitumen, one would expect this compound to be soluble in CDCl 3 , and therefore, it would appear in the liquid-state spectra.…”

Section: Nmr Of Ppa and Hydrated Lime In Bitumensupporting

confidence: 83%

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NMR Study of Hydrated Lime and Limestone in Polyphosphoric Acid Modified Bitumen

Miknis¹,

Schuster²

2009

Road Materials and Pavement Design

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Phosphorous-31 NMR spectroscopy has been used to study the effect of hydrated lime and limestone fines on polyphosphoric acid (PPA)-modified bitumens. NMR spectra were acquired on bitumen samples that were first modified with PPA and on bitumen samples when hydrated lime was added before the PPA. In both cases the NMR spectra showed that calcium phosphates, primarily dibasic calcium phosphate (monetite), and calcium dihydrogen phosphate were formed as a result of an acid-base reaction between the PPA and the hydrated lime. Fourier Transform Infrared (FTIR) Spectroscopy showed that hydrated lime was still present in the bitumen after the PPA was neutralized by the hydrated lime. In another set of experiments in which a calcitic or a dolomitic limestone was substituted for hydrated lime, no reactions were observed between the limestones and the PPA.

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Section: Nmr Of Ppa and Hydrated Lime In Bitumensupporting

confidence: 83%

“…However, when added to bitumen AAM-1, there is a significant reduction in the intensities of the middle and end groups because of the hydrolysis reaction of the PPA with residual water in the bitumen. The hydrolysis of PPA by residual water in bitumen has been reported (Miknis and Thomas, 2008).…”

Section: Nmr Of Ppa Modified Bitumen and Limestone Aggregate Finesmentioning

confidence: 99%

NMR Study of Hydrated Lime and Limestone in Polyphosphoric Acid Modified Bitumen

Miknis¹,

Schuster²

2009

Road Materials and Pavement Design

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“…Even though it is commonly recognized that PPA reacts with asphalt, the exact nature of the reaction is not completely understood. An NMR study indicated a tendency of PPA to revert to orthophosphoric acid after mixing with asphalt [155]; therefore, the main effect is not dissimilar to that of other acids. It has been suggested that PPA acts through the neutralization of polar interactions between the stacked asphaltenes molecules, either through the protonation of basic sites or through esterification.…”

Section: Asphalt Modification With Polyphosphoric Acid (Ppa)mentioning

confidence: 88%

A review of the fundamentals of polymer-modified asphalts: Asphalt/polymer interactions and principles of compatibility

Polacco

Filippi

Merusi

et al. 2015

Advances in Colloid and Interface Science

525

184

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During the last decades, the number of vehicles per citizen as well as the traffic speed and load has dramatically increased. This sudden and somehow unplanned overloading has strongly shortened the life of pavements and increased its cost of maintenance and risks to users. In order to limit the deterioration of road networks, it is necessary to improve the quality and performance of pavements, which was achieved through the addition of a polymer to the bituminous binder. Since their introduction, polymer-modified asphalts have gained in importance during the second half of the twentieth century, and they now play a fundamental role in the field of road paving. With high-temperature and high-shear mixing with asphalt, the polymer incorporates asphalt molecules, thereby forming a swallowed network that involves the entire binder and results in a significant improvement of the viscoelastic properties in comparison with those of the unmodified binder. Such a process encounters the well-known difficulties related to the poor solubility of polymers, which limits the number of macromolecules able to not only form such a structure but also maintain it during high-temperature storage in static conditions, which may be necessary before laying the binder. Therefore, polymer-modified asphalts have been the subject of numerous studies aimed to understand and optimize their structure and storage stability, which gradually attracted polymer scientists into this field that was initially explored by civil engineers. The analytical techniques of polymer science have been applied to polymer-modified asphalts, which resulted in a good understanding of their internal structure. Nevertheless, the complexity and variability of asphalt composition rendered it nearly impossible to generalize the results and univocally predict the properties of a given polymer/asphalt pair. The aim of this paper is to review these aspects of polymer-modified asphalts. Together with a brief description of the specification and techniques proposed to quantify the storage stability, state-of-the-art knowledge about the internal structure and morphology of polymer-modified asphalts is presented. Moreover, the chemical, physical, and processing solutions suggested in the scientific and patent literature to improve storage stability are extensively discussed, with particular attention to an emerging class of asphalt binders in which the technologies of polymer-modified asphalts and polymer nanocomposites are combined. These polymer-modified asphalt nanocomposites have been introduced less than ten years ago and still do not meet the requirements of industrial practice, but they may constitute a solution for both the performance and storage requirements.

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“…To date many chemical agents have been introduced for the target of bitumen modification, such as: organo-metallic compounds [113,114], sulfur (S) [66,[115][116][117][118][119][120][121], polyphosphoric acid (PPA) [122][123][124], sulfonic acid [125], carboxylic anhydrides [126][127][128], silanes [129,130], thiourea dioxide [131], nanocomposite-modified bitumen [132][133][134][135][136][137][138][139][140], and reactive polymers [141][142][143][144][145][146][147][148][149][150][151][152][153][154][155]. However, from the above-mentioned chemical compounds only a few of them have been used practically.…”

Section: Bitumen Chemical Modifiersmentioning

confidence: 99%

“…The difficult investigation of the reactions between the bitumen molecules and PPA is due to the large number of molecules with different chemical structures and their possible interactions. In this respect, an NMR investigation has shown that PPA tends to revert to orthophosphoric acid after mixing with bitumen [123]. Orange et al claim that PPA neutralizes polar interactions between the asphaltene molecules, by protonation of basic sites or through esterification [186].…”

Section: Ppa-based Techniquesmentioning

confidence: 99%

Bitumen and Bitumen Modification: A Review on Latest Advances

et al. 2019

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This synthesis explores the state-of-the-knowledge and state-of-the-practice regarding the latest updates on polymer-modified bitumens (PmBs). The information in this study was gathered from a thorough review of the latest papers in the literatures related to modified bituminous materials, technologies, and advances. For this purpose, the paper is presented in two principle sections. In the first part, the bitumen itself is investigated in terms of chemical structure and microstructural systems. In the second part, the paper focuses on bitumen modification from different aspects for assessing the effectiveness of the introduced additives and polymers for enhancing the engineering properties of bitumen in both paving and industrial applications. In conclusion, the knowledge obtained in this study has revealed the importance of the chemical composition of base bitumen for its modification. It can be declared that while some polymers/additives can improve one or some aspects of neat bitumen properties, they can lead to compatibility problems in storage and production. In this respect, several studies showed the effectiveness of waxes for improving the compatibility of polymers with bitumen in addition to some benefits regarding warm mix asphalt (WMA) production.

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NMR Analysis of Polyphosphoric Acid-modified Bitumens

Cited by 17 publications

References 7 publications

NMR Study of Hydrated Lime and Limestone in Polyphosphoric Acid Modified Bitumen

NMR Study of Hydrated Lime and Limestone in Polyphosphoric Acid Modified Bitumen

A review of the fundamentals of polymer-modified asphalts: Asphalt/polymer interactions and principles of compatibility

Bitumen and Bitumen Modification: A Review on Latest Advances

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