Cold mix asphalt recycling is a rehabilitation technique which is increasing in value due to its technical application, economical benefit and environmental sustainability. This research firstly aimed to investigate the effects of different foaming additives on the bitumen. Finally, detailed study on asphalt cold foamed materials were carried out. In the first section the features of virgin bitumen Ravenna with a 70/100 standard pen were evaluated, in order to compare them with the characteristics which were obtained by modifying the mixtures with different foamed additives (named M15, M18, M19, M21, M22. Laboratory samples preparation included the using of the machine “Wirtgen WLB10 S”, at different temperature values: 160°C, 170°C and 180°C. For each of the above mentioned temperatures, three water percentages (2% - 3% - 4%) were analyzed. In the second section nine mixtures were compacted. They were composed of: adhesion activator, cold regenerator and cement Cemento Portland CEM II/B-LL 32,5 R . The compaction of asphalt slabs was performed by using the gyratory shear compactor, which determined the workability and the self-compaction of the mixtures. Mechanical behavior characterization involved the following tests: 1) Indirect Tensile Strength test (which was performed in dry conditions at 0°C, 25°C and 40°C, and in wet conditions at 25°C), and 2) stiffness assessment (which was carried out by using the ITSM methodology at 0°C, 25°C and 40°C, and each of the previous temperatures was analyzed with frequency loads equal to 0.5Hz, 1Hz, 2Hz and 4Hz). Permanent deformations of the slabs were evaluated through creep dynamic test at 50°C, analyzing the following pressures: 50kPa, 100KPa, 200kPa and 400kPa. Moreover, potential performance improvements were evaluated by varying the curing time of the mixtures.
Il riciclaggio a freddo in sito delle pavimentazioni stradali in conglomerato bituminoso schiumato è una tecnica riabilitativa che ha conseguito un crescente apprezzamento grazie ai suoi vantaggi tecnici, economici ed ambientali. L’obbiettivo di questa tesi è l’indagine degli effetti sul bitume con l’introduzioni di differenti additivi schiumanti e, successivamente, uno studio approfondito sui conglomerati bituminosi a freddo schiumati. Il progetto si è articolato in due fasi. Nella prima fase si sono testate le proprietà schiumogene del bitume vergine Ravenna 70/100, le quali sono state confrontate con quelle ottenute dal medesimo bitume con l’aggiunta di cinque diversi additivi schiumogeni M15, M18, M19, M21, M22, testati a due concentrazioni sul peso del bitume differenti 0,3% e 0,6%. Le prove sono state eseguite tramite l’apposito macchinario Wirtgen WLB10 S a differenti valori di temperatura: 160°,170° e 180°C e, per ognuna di queste, si è fatto variare il contenuto d’acqua dal 2% a 4% variandolo ogni volta di un punto percentuale. Nella seconda fase sono state confezionate nove miscele contenti diversi composti tra cui: attivante di adesione, rigenerante a freddo e cemento Portland CEM II/B-LL 32,5 R. La compattazione è stata eseguita con pressa a taglio giratorio la quale ha permesso di estrapolare tutti i dati necessari per determinare grado di lavorabilità ed auto-addensamento . La caratterizzazione meccanica ha previsto differenti tipologie di prove. I test di trazione indiretta sono stati eseguiti alle temperature di 0°,25° e 40° in condizioni Dry, mentre 25° in condizioni Wet. Le prove per la determinazione del modulo di rigidezza si sono eseguite con la metodologia ITSM alle temperature di 0°,25 e 40° e, per ognuna di queste, si sono analizzate le seguenti frequenze di carico : 0.5Hz, 1Hz, 2 Hz e 4Hz. Per valutare l’entità delle deformazioni permanenti sono state eseguite prove di Creep dinamico alla temperatura di 50 ° con pressioni di 50Kpa,100Kpa,200Kpa e 400Kpa. Inoltre, si sono valutati i possibili incrementi prestazionali nelle prove sopra citate, variando il tempo di Curing dei conglomerati.
Valutazione sperimentale dell'effetto delle additivazioni nei conglomerati bituminosi riciclati a freddo mediante schiumatura
ZAMMARCHI, SIMONE;POLI, ALESSANDRO
2014/2015
Abstract
Cold mix asphalt recycling is a rehabilitation technique which is increasing in value due to its technical application, economical benefit and environmental sustainability. This research firstly aimed to investigate the effects of different foaming additives on the bitumen. Finally, detailed study on asphalt cold foamed materials were carried out. In the first section the features of virgin bitumen Ravenna with a 70/100 standard pen were evaluated, in order to compare them with the characteristics which were obtained by modifying the mixtures with different foamed additives (named M15, M18, M19, M21, M22. Laboratory samples preparation included the using of the machine “Wirtgen WLB10 S”, at different temperature values: 160°C, 170°C and 180°C. For each of the above mentioned temperatures, three water percentages (2% - 3% - 4%) were analyzed. In the second section nine mixtures were compacted. They were composed of: adhesion activator, cold regenerator and cement Cemento Portland CEM II/B-LL 32,5 R . The compaction of asphalt slabs was performed by using the gyratory shear compactor, which determined the workability and the self-compaction of the mixtures. Mechanical behavior characterization involved the following tests: 1) Indirect Tensile Strength test (which was performed in dry conditions at 0°C, 25°C and 40°C, and in wet conditions at 25°C), and 2) stiffness assessment (which was carried out by using the ITSM methodology at 0°C, 25°C and 40°C, and each of the previous temperatures was analyzed with frequency loads equal to 0.5Hz, 1Hz, 2Hz and 4Hz). Permanent deformations of the slabs were evaluated through creep dynamic test at 50°C, analyzing the following pressures: 50kPa, 100KPa, 200kPa and 400kPa. Moreover, potential performance improvements were evaluated by varying the curing time of the mixtures.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/108962