Half-warm mix asphalt with emulsion. An experimental study on workability and mechanical performances

Abstract One of the major sustainability-related challenge facing materials for asphalt pavements is the energy consumption and the release of harmful and odorous fumes. Reductions in these emission levels have been progressively achieved by a number of cleaner and low-temperature technologies. Recently, a further step towards an improved road pavement sustainability is represented by the half-warm mix asphalt (HWMA) mixtures, which are produced between 70 °C and 100 °C without negatively affecting their final performances. Among these methodological approaches, a very interesting solution for urban or low volume traffic roads is represented by HWMA mixtures prepared with a conventional warm emulsion and heated aggregates. Although this technique is capable of combining the advantages of hot and cold mixes, limiting some drawbacks, it is still little known and remains confined only to some regional areas (in Spain with the term mezclas templadas). There are no standards or specifications, but only some construction practices resulting from the experience gained in the field. Thus, a laboratory-scale experimental study was set up to analyze in detail the behavior of dense-graded HWMA mixes prepared with emulsion intended for a surface course layer of a low or medium traffic road. The objective was to evaluate the influence of three mix-design variables, such as compaction temperature, binder content and aggregate gradation on the volumetric and mechanical, i.e. indirect tensile strength and moisture susceptibility, properties of these mixtures. The rank comparison between the selected mixtures represented the starting point for improving on the one hand the mix-design process and on the other the operational procedures of production, transportation and placement

electronic nose for smart identification of roofing and paving grade asphalt

Abstract Asphalt is a complex mixture of hydrocarbons, whose properties strongly depend on the source and type of crude oil and refining processes. From a technical standpoint, intensive investigations carried out by the construction sector, above all by road researchers, have attempted to understand relationships between asphalt binder chemical structure, morphology and physical characteristics. Nevertheless, one challenge that the advance research on asphalt products actually face is to transfer this extremely high level of knowledge to applied industrial technologies for finding easy-to-use, quick and cost-effective test methods for quality control and identification of asphalt binders at refinery, terminal and plant. Thus, this paper focused on the development of a protocol for fingerprinting, including identification and discrimination, of asphalt cements using two different electronic noses (e-noses), also known as artificial olfactory systems (AOS). E-nose is a biomimetic non-destructive intelligent sensing instrument, which is designed to mimic the human sense of smell to detect, compare and classify odor sample, producing a qualitative output (fingerprint). Results suggested that a complementary combination of electronic nose technique and well-established analytical methodologies could be successfully used for the identification and discrimination of roofing and paving grade asphalt cements. Specifically, both sensing instruments were able to perform a good discrimination between products characterized by a different chemical nature and to verify the refinery process stability during production and a batch-to-batch crude oil consistency

Expanded polystyrene (EPS) in road construction: Twenty years of Italian experiences

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Worldwide comparison of survival from childhood leukaemia for 1995–2009, by subtype, age, and sex (CONCORD-2): a population-based study of individual data for 89 828 children from 198 registries in 53 countries

Background Global inequalities in access to health care are reflected in differences in cancer survival. The CONCORD programme was designed to assess worldwide differences and trends in population-based cancer survival. In this population-based study, we aimed to estimate survival inequalities globally for several subtypes of childhood leukaemia. Methods Cancer registries participating in CONCORD were asked to submit tumour registrations for all children aged 0-14 years who were diagnosed with leukaemia between Jan 1, 1995, and Dec 31, 2009, and followed up until Dec 31, 2009. Haematological malignancies were defined by morphology codes in the International Classification of Diseases for Oncology, third revision. We excluded data from registries from which the data were judged to be less reliable, or included only lymphomas, and data from countries in which data for fewer than ten children were available for analysis. We also excluded records because of a missing date of birth, diagnosis, or last known vital status. We estimated 5-year net survival (ie, the probability of surviving at least 5 years after diagnosis, after controlling for deaths from other causes [background mortality]) for children by calendar period of diagnosis (1995-99, 2000-04, and 2005-09), sex, and age at diagnosis (< 1, 1-4, 5-9, and 10-14 years, inclusive) using appropriate life tables. We estimated age-standardised net survival for international comparison of survival trends for precursor-cell acute lymphoblastic leukaemia (ALL) and acute myeloid leukaemia (AML). Findings We analysed data from 89 828 children from 198 registries in 53 countries. During 1995-99, 5-year agestandardised net survival for all lymphoid leukaemias combined ranged from 10.6% (95% CI 3.1-18.2) in the Chinese registries to 86.8% (81.6-92.0) in Austria. International differences in 5-year survival for childhood leukaemia were still large as recently as 2005-09, when age-standardised survival for lymphoid leukaemias ranged from 52.4% (95% CI 42.8-61.9) in Cali, Colombia, to 91.6% (89.5-93.6) in the German registries, and for AML ranged from 33.3% (18.9-47.7) in Bulgaria to 78.2% (72.0-84.3) in German registries. Survival from precursor-cell ALL was very close to that of all lymphoid leukaemias combined, with similar variation. In most countries, survival from AML improved more than survival from ALL between 2000-04 and 2005-09. Survival for each type of leukaemia varied markedly with age: survival was highest for children aged 1-4 and 5-9 years, and lowest for infants (younger than 1 year). There was no systematic difference in survival between boys and girls. Interpretation Global inequalities in survival from childhood leukaemia have narrowed with time but remain very wide for both ALL and AML. These results provide useful information for health policy makers on the effectiveness of health-care systems and for cancer policy makers to reduce inequalities in childhood survival

Global surveillance of cancer survival 1995-2009: analysis of individual data for 25,676,887 patients from 279 population-based registries in 67 countries (CONCORD-2)

BACKGROUND: Worldwide data for cancer survival are scarce. We aimed to initiate worldwide surveillance of cancer survival by central analysis of population-based registry data, as a metric of the effectiveness of health systems, and to inform global policy on cancer control. METHODS: Individual tumour records were submitted by 279 population-based cancer registries in 67 countries for 25·7 million adults (age 15-99 years) and 75,000 children (age 0-14 years) diagnosed with cancer during 1995-2009 and followed up to Dec 31, 2009, or later. We looked at cancers of the stomach, colon, rectum, liver, lung, breast (women), cervix, ovary, and prostate in adults, and adult and childhood leukaemia. Standardised quality control procedures were applied; errors were corrected by the registry concerned. We estimated 5-year net survival, adjusted for background mortality in every country or region by age (single year), sex, and calendar year, and by race or ethnic origin in some countries. Estimates were age-standardised with the International Cancer Survival Standard weights. FINDINGS: 5-year survival from colon, rectal, and breast cancers has increased steadily in most developed countries. For patients diagnosed during 2005-09, survival for colon and rectal cancer reached 60% or more in 22 countries around the world; for breast cancer, 5-year survival rose to 85% or higher in 17 countries worldwide. Liver and lung cancer remain lethal in all nations: for both cancers, 5-year survival is below 20% everywhere in Europe, in the range 15-19% in North America, and as low as 7-9% in Mongolia and Thailand. Striking rises in 5-year survival from prostate cancer have occurred in many countries: survival rose by 10-20% between 1995-99 and 2005-09 in 22 countries in South America, Asia, and Europe, but survival still varies widely around the world, from less than 60% in Bulgaria and Thailand to 95% or more in Brazil, Puerto Rico, and the USA. For cervical cancer, national estimates of 5-year survival range from less than 50% to more than 70%; regional variations are much wider, and improvements between 1995-99 and 2005-09 have generally been slight. For women diagnosed with ovarian cancer in 2005-09, 5-year survival was 40% or higher only in Ecuador, the USA, and 17 countries in Asia and Europe. 5-year survival for stomach cancer in 2005-09 was high (54-58%) in Japan and South Korea, compared with less than 40% in other countries. By contrast, 5-year survival from adult leukaemia in Japan and South Korea (18-23%) is lower than in most other countries. 5-year survival from childhood acute lymphoblastic leukaemia is less than 60% in several countries, but as high as 90% in Canada and four European countries, which suggests major deficiencies in the management of a largely curable disease. INTERPRETATION: International comparison of survival trends reveals very wide differences that are likely to be attributable to differences in access to early diagnosis and optimum treatment. Continuous worldwide surveillance of cancer survival should become an indispensable source of information for cancer patients and researchers and a stimulus for politicians to improve health policy and health-care systems

The histology of ovarian cancer: worldwide distribution and implications for international survival comparisons (CONCORD-2)

Objective Ovarian cancers comprise several histologically distinct tumour groups with widely different prognosis. We aimed to describe the worldwide distribution of ovarian cancer histology and to understand what role this may play in international variation in survival. Methods The CONCORD programme is the largest population-based study of global trends in cancer survival. Data on 681,759 women diagnosed during 1995â\u80\u932009 with cancer of the ovary, fallopian tube, peritoneum and retroperitonum in 51 countries were included. We categorised ovarian tumours into six histological groups, and explored the worldwide distribution of histology. Results During 2005â\u80\u932009, type II epithelial tumours were the most common. The proportion was much higher in Oceania (73.1%), North America (73.0%) and Europe (72.6%) than in Central and South America (65.7%) and Asia (56.1%). By contrast, type I epithelial tumours were more common in Asia (32.5%), compared with only 19.4% in North America. From 1995 to 2009, the proportion of type II epithelial tumours increased from 68.6% to 71.1%, while the proportion of type I epithelial tumours fell from 23.8% to 21.2%. The proportions of germ cell tumours, sex cord-stromal tumours, other specific non-epithelial tumours and tumours of non-specific morphology all remained stable over time. Conclusions The distribution of ovarian cancer histology varies widely worldwide. Type I epithelial, germ cell and sex cord-stromal tumours are generally associated with higher survival than type II tumours, so the proportion of these tumours may influence survival estimates for all ovarian cancers combined. The distribution of histological groups should be considered when comparing survival between countries and regions

The odour fingerprint of bitumen

Gli odori generati durante le diverse fasi di produzione e stesa dei conglomerati bituminosi per uso stradale costituiscono uno dei più rilevanti aspetti negativi legati a questa tipologia di attività. Sebbene a tali emissioni odorigene sia solo raramente associato un reale rischio tossicologico-sanitario, sia per la natura generalmente non pericolosa degli odoranti che per le concentrazioni abitualmente molto basse, tali flussi osmogeni possono limitare fortemente la fruibilità del territorio, rappresentando una causa di indubbio e persistente fastidio per la popolazione residente nelle vicinanze degli impianti, oggi molto spesso inseriti nel tessuto urbano. Dopo un’approfondita valutazione delle tecniche di rilievo dell’odore nella letteratura scientifica e nel quadro normativo internazionale, anche in ambiti apparentemente lontani da quello delle costruzioni stradali, si è deciso di focalizzare l’attività di ricerca sulla caratterizzazione dell’odore dei leganti bituminosi e delle relative emissioni attraverso due differenti approcci metodologici complementari: quello analitico e quello basato sui sistemi olfattivi artificiali o nasi elettronici. Tali dispositivi, il cui impiego rappresenta una soluzione ben conosciuta in svariati settori industriali per il controllo qualità e il monitoraggio in continuo, si configurano come strumenti, composti da una matrice di sensori e da un sistema di elaborazione, capaci di riconoscere odori semplici e complessi, con meccanismi riconducibili a quelli del sistema olfattivo umano, identificando una caratteristica globale della miscela odorosa, la cosiddetta impronta digitale odorosa o odour fingerprint. Questi strumenti hanno richiesto una lunga fase di calibrazione iniziale (flusso di misura, temperatura, quantità di bitume, tempo di iniezione), per il riconoscimento delle diverse sorgenti odorigene e la taratura della risposta, con notevolissimo impegno di analisi per l’adattabilità dei sensori a rilevare emissioni di miscele complesse di molecole quali quelle costituenti in prevalenza i bitumi stradali. I risultati delle varie indagini sperimentali condotte hanno evidenziato come l’approccio basato sui sistemi olfattivi artificiali possa essere effettivamente utilizzato, in affiancamento alle tradizionali tecniche analitiche, per lo studio del bitume nelle fasi della filiera produttiva dei conglomerati bituminosi. Le varie analisi analitico-sensoriali condotte con i nasi elettronici (Ise Nose 2000 e Cyranose 320) hanno, infatti, evidenziato una compatibilità tra principio di funzionamento dei sensori e tipologia delle emissioni dei leganti bituminosi, che ha permesso l’individuazione di specifiche impronte odorose (odour fingerprint) sia della matrice solida del bitume a temperatura ambiente sia delle emissioni generate alle varie temperature di processo. Attraverso l’elaborazione di una specifica procedura statistica di trattamento e post-processazione dei dati, è stato possibile attribuire una valenza quantitativa alla risposta prettamente qualitativa del naso elettronico. La tecnica gascromatografica ha permesso l’identificazione di oltre 200 composti alifatici nella complessa miscela idrocarburica di aerosol, vapori e gas emessa durante il processo di riscaldamento del legante bituminoso nelle varie fasi di realizzazione delle pavimentazioni stradali, evidenziando al contempo una loro gerarchia di comparsa in funzione della temperatura. Le strumentazioni analitiche (GC-MS e PID), impiegate per l’analisi dello spazio di testa dei bitumi, hanno, infatti, confermato come sia la temperatura il fattore preponderante nella generazione di tali sostanze aerodisperse. La parallela analisi con il naso elettronico ha permesso di evidenziare una variazione del profilo odorigeno delle emissioni contestualmente all’aumento di sostanze volatili. Le diverse tipologie di additivi, utilizzati per il confezionamento di conglomerati bituminosi tiepidi (WMA), pur essendo caratterizzati da uno specifico odore che li contraddistingue, non sono però in grado di instaurare con il bitume effetti di sinergia, additività o antagonismo, ma risultano essere da un punto di vista odoroso come elementi neutri. L’analisi analitico-sensoriale ha infatti mostrato come i profili odorigeni delle emissioni generate dal solo bitume alle varie temperature tendono ad essere coincidenti con quelle delle miscele bitume/additivo, sottolineando come l’odore del legante bituminoso tenda ad essere coprente o mascherante rispetto a quello degli agenti modificatori. Nemmeno l’utilizzo dell’additivo neutralizzatore di odori ha mostrato l’insorgere di variazioni nel profilo odorigeno delle emissioni, denotando un’insufficiente capacità di tale agente nel contenimento degli odori generati dal riscaldamento del bitume. L’insieme delle evidenze ottenute nel presente lavoro si configura pertanto come un valido punto di partenza per lo sviluppo di procedure e metodologie standardizzate, basate sul principio del naso elettronico, mirate al riconoscimento dell’odore generato durante le diverse fasi di produzione e stesa dei conglomerati bituminosi cui associare limiti di fastidio o molestia olfattiva.The odours generated during the different stages of production and laying of hot mix asphalt for road applications are one of the most significant negative aspects linked to this type of activity. Although these odorous emissions are only rarely associated to a real toxicological risk, both for the generally non-hazardous nature of odorants and for their very low concentrations, such osmogene fluxes can severely limit the land-use, representing a cause of undeniable and persistent annoyance for the population living near the plants, which are very often located in the urban fabric. After a detailed evaluation of the odour analysis techniques in the scientific literature and in the international regulatory framework, even in fields apparently distant from the road construction, it was decided to focus the research on the odour characterization of bituminous binders and their emissions through two different complementary approaches: the analytic one and that based on artificial olfactory systems, also called electronic noses. Such devices, which represent a well-established solution used in several industries for quality assurance and quality control and real-time monitoring, are instruments consisting of an array of partially selective sensors coupled to a suitable pattern-recognition system capable of recognising simple or complex odours. The operating principle, which reproduces the mechanism of human olfactory system, is based on the conversion of the interaction between gaseous molecules and sensor-coating materials into a recordable signal, often defined as odour fingerprint. These instruments have required a long initial calibration phase (measuring flow, temperature, amount of bitumen, injection time), for the recognition of different odour sources and the sensor response adjustment, with remarkable efforts for finding the sensors adaptability to detect emissions characterized by complex mixtures of compounds, such as those predominating constituents the bitumens for paving applications. The results of the experimental investigations have shown that the approach based on artificial olfactory systems can be effectively used, alongside the traditional analytical techniques, for the study of bitumen in several stages of the production chain of hot mix asphalt. The various analytical and sensory analyses conducted with electronic noses (Ise Nose 2000 and Cyranose 320) have, in fact, demonstrated the compatibility between the sensors’ working principle and the bitumen emissions, which allowed the identification of specific odour fingerprint both of the bitumen solid matrix at room temperature and of the emissions generated at various process temperatures. Through the elaboration of a specific statistical procedure for the treatment and post-processing of data, it was possible to assign a quantitative value to the purely qualitative responses of the electronic noses. The gas chromatographic technique has allowed the identification of more than 200 aliphatic compounds in the complex hydrocarbon mixture of aerosols, vapors and gases emitted during the bituminous binder heating process in the various stages of road pavement construction, highlighting at the same time a hierarchy of their appearance in relation to the temperature. The analytical instruments (GC-MS and PID), used for the analysis of the head space of bitumen, have, in fact, confirmed as the temperature represents the preponderant factor in the generation of such airborne substances. The parallel analysis with the electronic nose allowed to show a change in the emission odorous profile contextually to the increase of volatile substances. The different kinds of additives, used for the warm mix asphalts (WMA), although characterized by a specific odour that distinguishes them, are not able to establish with the bitumen effects of synergy, additivity or antagonism, but appear to be as neutral elements by an odorous point of view. The analytical-sensory analyses have in fact shown that the emissions odorous profiles generated by the bitumen at various temperatures tend to be coincident with those of the bitumen/additive blends, emphasizing as the bituminous binder odour tends to be hiding or masking compared to that of modifying agents. Even the use of the odour neutraliser additive has not shown the development of variations in the emissions odorous profiles, which indicates an insufficient capacity of such product in the containment of the odour generated by the bitumen heating. All the results obtained in the present work are therefore configured as valid starting points for the development of standardized procedures and methodologies based on the principle of electronic nose, aimed at recognizing the smell generated during the various stages of the production and laying of bituminous mixtures, to which associate olfactory limits of nuisance

Photoluminescent road surface dressing: A first laboratory experimental investigation [Revêtements routiers photoluminescents: étude expérimentale préliminaire en laboratoire]

The main objective of this experimental research was to analyze the possible use of afterglow photoluminescent pigments for road wearing courses. Thanks to their natural color or their glowing color, depending on their emission spectra, photoluminescent pigments could allow a better identification of different pavement zones in the darkness. We studied two type of pigments (masterbatches and powders), based on zinc sulfide (ZnS:Cu) or on strontium aluminate phosphors (SrAl2O4:Eu2+,Dy3 +), in different experimental conditions. Firstly, experiments were performed to determine the crystals' luminescent properties. Next, we investigated possible application of these materials in asphalt concrete and slurry seal, prepared by using clear binder and synthetic bitumen emulsion. The representative samples of photoluminescent Strontium Aluminate surface dressing were able to re-emit energy in the form of visible light for significant period of time, after exposure to daylight or artificial light. Assuring good performances in different condition, they could be having interesting suitable applications in a wide variety of contexts: low-volume roads, footpaths and bicycle lanes. © EDP Sciences, 2014