Effect of clay materials on phase separation in plastic bag waste-modified bitumen during high-temperature storage

Phase separation at high storage temperatures is a significant challenge in the practical application of polymer-modified bitumen (PmB), as it impacts negatively the uniformity and stability of modified binders. This study evaluates the effects of montmorillonite (MMT) and kaolinite clay (KC) additi...

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Main Authors: Mohammed Nouali, Zohra Derriche, Elhem Ghorbel
Format: Article
Language:English
Published: Elsevier 2025-03-01
Series:Transportation Engineering
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Online Access:http://www.sciencedirect.com/science/article/pii/S2666691X25000065
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author Mohammed Nouali
Zohra Derriche
Elhem Ghorbel
author_facet Mohammed Nouali
Zohra Derriche
Elhem Ghorbel
author_sort Mohammed Nouali
collection DOAJ
description Phase separation at high storage temperatures is a significant challenge in the practical application of polymer-modified bitumen (PmB), as it impacts negatively the uniformity and stability of modified binders. This study evaluates the effects of montmorillonite (MMT) and kaolinite clay (KC) additions on phase separation in a High-density polyethylene (HDPE) plastic waste-modified bitumen. Clay minerals are widely studied as compatibilizing agents, that prevent binder phase separation in bitumen/polymer/clay blends as often evaluated through softening point testing. In addition to conventional physical and rheological evaluations, the apparent molecular weight distribution (AMWD) and a new bitumen dissolution test are proposed in this study for the first time to analyze phase separation in bitumen/plastic/clay ternary blends. Results indicate that while clay addition reduces phase separation potential of PmB as indicated by both softening point measurements and rheological derived phase separation indices, AMWD and dissolution test reveal significant phase separation occurs equally in both WP and WP/clay binders. Phase separation phenomenon occurs probably because Van der Waals forces between clay particles are insufficient to counteract the effect of plastic particle coalescence driving forces. As a result of phase separation, plastic particles migrate upward (creaming) and coalesce, while clay particles settle down at the bottom of the binder specimen. These findings demonstrate the limitations of consistency difference and rheological indices when used for evaluating phase separation in ternary blends. The AMWD and dissolution results offer more reliable evaluation methods for assessing phase separation in PmB.
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spelling doaj-art-fad43922dc014c23a15b2729971420872025-02-03T04:16:59ZengElsevierTransportation Engineering2666-691X2025-03-0119100306Effect of clay materials on phase separation in plastic bag waste-modified bitumen during high-temperature storageMohammed Nouali0Zohra Derriche1Elhem Ghorbel2Institut de recherche, ESTP: Grande école d'ingénieurs de la construction, Cachan, Postal address 94230, France; Laboratoire Travaux Publics ingénierie des Transports & Environnement (LTPiTE), Ecole Nationale Supérieure des Travaux Publics, Rue Sidi Garidi Vieux Kouba, Alger, Postal address 16051, Algeria; Corresponding author.Laboratoire Travaux Publics ingénierie des Transports & Environnement (LTPiTE), Ecole Nationale Supérieure des Travaux Publics, Rue Sidi Garidi Vieux Kouba, Alger, Postal address 16051, AlgeriaLaboratoire de Mécanique et Matériaux de Génie Civil (L2MGC), Cergy-Pontoise University, Voie Mail Gay-Lussac, Ville Neuville-sur-Oise Cergy-Pontoise, Paris, Postal address 95031, FrancePhase separation at high storage temperatures is a significant challenge in the practical application of polymer-modified bitumen (PmB), as it impacts negatively the uniformity and stability of modified binders. This study evaluates the effects of montmorillonite (MMT) and kaolinite clay (KC) additions on phase separation in a High-density polyethylene (HDPE) plastic waste-modified bitumen. Clay minerals are widely studied as compatibilizing agents, that prevent binder phase separation in bitumen/polymer/clay blends as often evaluated through softening point testing. In addition to conventional physical and rheological evaluations, the apparent molecular weight distribution (AMWD) and a new bitumen dissolution test are proposed in this study for the first time to analyze phase separation in bitumen/plastic/clay ternary blends. Results indicate that while clay addition reduces phase separation potential of PmB as indicated by both softening point measurements and rheological derived phase separation indices, AMWD and dissolution test reveal significant phase separation occurs equally in both WP and WP/clay binders. Phase separation phenomenon occurs probably because Van der Waals forces between clay particles are insufficient to counteract the effect of plastic particle coalescence driving forces. As a result of phase separation, plastic particles migrate upward (creaming) and coalesce, while clay particles settle down at the bottom of the binder specimen. These findings demonstrate the limitations of consistency difference and rheological indices when used for evaluating phase separation in ternary blends. The AMWD and dissolution results offer more reliable evaluation methods for assessing phase separation in PmB.http://www.sciencedirect.com/science/article/pii/S2666691X25000065BitumenWaste plasticPhase separationMontmorilloniteKaoliniteClay
spellingShingle Mohammed Nouali
Zohra Derriche
Elhem Ghorbel
Effect of clay materials on phase separation in plastic bag waste-modified bitumen during high-temperature storage
Transportation Engineering
Bitumen
Waste plastic
Phase separation
Montmorillonite
Kaolinite
Clay
title Effect of clay materials on phase separation in plastic bag waste-modified bitumen during high-temperature storage
title_full Effect of clay materials on phase separation in plastic bag waste-modified bitumen during high-temperature storage
title_fullStr Effect of clay materials on phase separation in plastic bag waste-modified bitumen during high-temperature storage
title_full_unstemmed Effect of clay materials on phase separation in plastic bag waste-modified bitumen during high-temperature storage
title_short Effect of clay materials on phase separation in plastic bag waste-modified bitumen during high-temperature storage
title_sort effect of clay materials on phase separation in plastic bag waste modified bitumen during high temperature storage
topic Bitumen
Waste plastic
Phase separation
Montmorillonite
Kaolinite
Clay
url http://www.sciencedirect.com/science/article/pii/S2666691X25000065
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AT elhemghorbel effectofclaymaterialsonphaseseparationinplasticbagwastemodifiedbitumenduringhightemperaturestorage