Polysaccharides-Reinforced Bitumens: Specificities and Universality of Rheological Behavior

The rheological properties of bitumens can be modified by the addition of specific chemical additives. Taking into account the molecular complex aggregation pattern, we hypothesized that macromolecules characterized by long, flexible, and hydrophilic chains can establish soft bridges connecting the different polar aggregates of asphaltenes, strengthening their overall hierarchical supra-structures, and consequently increasing rheological performance at higher temperatures. Here, we propose the use of low cost and high availability polysaccharides as chemical additives to improve the rheological characteristics of a bitumen and to strengthen its thermal resistance. Fourteen different low-cost and high-availability polysaccharides, (flours, gums, and extracts from vegetable products) have been tested. While alghae euchemae have proved to be the most effective additive, corn and 00 flours are the least effective. Attempts to explain their differences have been made considering their chemical interactions with the polar molecules of asphaltenes within the complex framework of their supramolecular hierarchical structures. Through Arrhenius analysis, a correlation between activation energy and preexponential factor has been found, which can be useful for practical purposes, together with an unexpected consistency with the behavior of simple liquids, despite the striking differences in structure. Furthermore, a qualitative model has been suggested. The added value of this work is the focus on polysaccharides constituting low-cost, high availability materials which are sometimes even found as waste in industrial processes, all factors which, together with the environmental issues connected with their use, can be considered for large-scale applications

investigation of new additives to reduce the fume emission of bitumen during asphalt concrete processing

Pavement materials play an important role in overall pavement sustainability including material acquisition processing, and transportation. The main objective of the present study is to evaluate the effectiveness of new additives, to reduce bitumen's fume emission expelled into the atmosphere, during the processing of asphalt concrete. The new additives act by trapping bitumen's volatile substances avoiding their release at high temperatures. In this paper, we have been tested the performance of 2 types of mesoporous silica-based additives (AntiSmog 1 and AntiSmog 2). The idea of using these additives to reduce the emission of fumes in bitumen has been submitted as a patent. To quantify and characterize the emitted fumes, thermogravimetry (TGA) and gas chromatography-mass spectrometry (GC-MS) technique have been used. Dynamic Shear Rheology (DSR) has been used to check the rheological properties and the possible sedimentation issues that could occur after the addition of the additive

Mathematical Model to Predict the Affinity Between Aggregate/Bitumen

The stones used for the construction of road surfaces have a complex mineralogical and hence chemical composition. They are made up of several types of minerals put together. This generates a significant difference in adhesion with the bituminous binder. The aim of this study is to create a mathematical model able to predict the adhesion between bitumen and stone on the basis of contact angle measurements made on different pure minerals. The mathematical model used was developed keeping in mind the exponential bond that the minerals have with the corresponding bond angle. This model also confirmed the established fact that the lower the value of Δ, the better the adhesion between the bitumen and the aggregate

Differential Scanning Calorimetry as a New Method to Evaluate the Effectiveness of Rejuvenating Agents in Bitumens

To date, few methods allow distinguishing a fluxing effect of an additive for bitumen from a regenerating effect. This research aims at identifying a method to accurately establish whether an oxidized bitumen has been regenerated or has simply been fluxed by a softener. Oxidized bitumens, simulating the aging process that results in road pavement lifetime, were prepared by the Rolling thin film oven test (RTFOT) procedure for 225 min and the Pressure Aging Vessel (PAV) procedure. Their asphaltene parts were extracted and analyzed by calorimetry (Differential Scanning Calorimetry DSC), and the results were compared with the presence and absence of a fluxing agent and real rejuvenators. The self-consistent results showed that the thermal properties of the asphaltene fractions is a sound probe to monitor the effect of rejuvenation clearly distinguishable from the mere fluxing effect. This preliminary study might allow the creation of standard protocols capable of identifying a priori the rejuvenating effect of an additive in the future. Furthermore, given the widespread use of calorimetry for the characterization, it tends to become a widely accessible and useful tool for this purpose in material characterization laboratories

Reimagining Gender: Negotiating Codified Gender in Games

Game making offers a unique opportunity for creators to bring to life universes that do not exist. In this act of creation, the game maker is given the tools to restructure the limits of not only the physical world, but the limits of the social world as well. As an influential cultural product, games have the potency to help players restructure their own understanding about higher social structures. This philosophical reflection examines personal struggles with a restrictive gender code and discusses the ways in which feminine figures in game culture shaped my concept of a sexual self. The presentation concludes with a plea for the reimagination of gender through this unique creative process

Postmortem of Queer Play: Facilitating Explorations of Gender and Sexuality in Role Playing Games

“Queer Play: Facilitating Explorations of Gender and Sexuality in Role Playing Games” was a UREAP research project that I undertook between April and September 2016 in which I investigated the potential for digital and analog roleplaying games to be used as tools to encourage players to embody characters with alternative identities. As part of this process, I developed my own tabletop role playing game, Vestige, to test these strategies with groups of players. The strategies I developed were synthesized from and inspired by existing role playing games, particularly those that are well known among queer gamers, though many lesser known games were reviewed as well. The investigation culminated with the implementation of an Affinities and Aversions system in Vestige, which encourages the player to play with shifting relationships and identities. As a result, even the most trope-based characters will undergo some sort of identity fluctuation through the process of extended play. The players, in turn, are given game space and even encouraged to explore gender and sexuality vicariously through the characters they create

A Study of Rubber-REOB Extender to Produce Sustainable Modified Bitumens

Thanks to greater attention to the environment and the depletion of non-renewable resources, the sustainability and the circular economy have become crucial topics. The current trend of pavement engineering is to reduce the use of standard bitumen by replacing it with more sustainable materials such as industrial residues and by-products. In this regard, the present study aims to characterize innovative extended bitumen using recycled materials. Due to promising preliminary results as bitumen modifiers, the powdered rubber from end-of-life tires and the re-refined engine oil bottom (REOB) have been investigated as feasible components of bitumen extenders. Nevertheless, several variables strongly aect the performance of the resulting binder, which cannot be neglected. Hence, this research focuses on the rubber\u2013REOB interaction in order to evaluate their optimum ratio, which may maximize the use and advantages of both recycled materials as suitable partial replacements for bitumen. Various rubber\u2013REOB ratios were considered and investigated by means of low and high frequency nuclear magnetic resonance (NMR) spectrometers and scanning electron microscope (SEM)

Eco-friendly additives for sustainable road pavements

Dottorato di Ricerca in Scienze della Vita. Ciclo XXXIL'obiettivo del presente studio è quello di sviluppare e valutare l'efficacia di nuovi additivi non tossici ed eco-compatibili per il settore delle pavimentazioni stradali. Attualmente, in tale settore, c'è la tendenza ad adottare pratiche eco-sostenibili rivolte alla salvaguardia della salute dei lavoratori e dell’ambiente. Nella presente ricerca i nuovi additivi sono stati caratterizzati e sviluppati al fine di ridurre le emissioni dei fumi potenzialmente tossici rilasciati dal bitume nell'atmosfera durante la produzione e la lavorazione dell’asfalto. Inoltre sono stati formulati e studiati nuovi bioadditivi capaci di migliorare l’adesione tra bitume e aggregati, modificare le caratteristiche reologiche del legante e migliorarne la resistenza all’invecchiamento (funzione antiossidante).Università della Calabri

Biomaterials and Their Potentialities as Additives in Bitumen Technology: A Review

The carbon footprint reduction mandate and other eco-friendly policies currently in place are constantly driving the trend of the synthesis and application of sustainable functional materials. The bitumen industry is not an exception to this trend and, every day, new technologies that facilitate safer, cost effective and more sustainable industrial processes and road paving operations are being researched and brought to light. A lot of research is currently ongoing to improve bitumen’s properties due to its use as a binder in road paving processes. Over the years, the most common method to improve bitumen’s properties has been with the use of additives. The major drawback in the use of these additives is the fact that they are substances of strong chemical nature which are either too acidic, too basic or emit toxic fumes and volatile organic compounds into the environment. In the long run, these chemicals are also toxic to the road pavement personnel that carry out the day to day industrial and paving operations. This led researchers to the initiative of synthesizing and applying biomaterials to be used as additives for bitumen. In this light, several studies have investigated the use of substances such as bio-oils, natural waxes, gum, polysaccharides and natural rubber. This literature review is aimed at classifying the different bio-based materials used to improve bitumen’s properties and to provide a deeper knowledge of the application of these biomaterials in bitumen technology. In general, we highlight how the research efforts elaborated herein could potentially foster safer, sustainable, eco-friendly approaches to improving bitumen’s properties while also promoting a circular economy

Green Husk of Walnuts (Juglans regia L.) from Southern Italy as a Valuable Source for the Recovery of Glucans and Pectins

Walnut green husk is an agricultural waste produced during the walnut (Juglans regia L.) harvest, that could be valued as a source of high-value compounds. In this respect, walnut green husks from two areas of Southern Italy (Montalto Uffugo and Zumpano), with different soil conditions, were investigated. Glucans and pectins were isolated from dry walnut husks by carrying out alkaline and acidic extractions, respectively, and then they were characterized by FT-IR, scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The colorimetric method for the enzymatic measurement of α- and β-glucans was performed. The maximum total glucan yield was recovered from Montalto walnut husks (4.6 ± 0.2 g/100 g DM) with a β-glucan percentage (6.3 ± 0.4) higher than that calculated for Zumpano walnut husks (3.6 ± 0.5). Thermal analysis (DSC) confirmed the higher degree of crystallinity of glucans from Zumpano. The pectin content for Montalto husks was found to be 2.6 times that of Zumpano husks, and the esterification degree was more than 65%. The results suggested that J. regia L. green husks could be a source of glucans and pectins, whose content and morphological and thermal characteristics were influenced by different soil and climate conditions