Experimental investigation on the use of waste elastomeric polymers for bitumen modification

The study described in this paper focused on the possible use of waste products coming from the production of styrene-butadiene rubber (SBR) and polybutadiene rubber (PBR), as bitumen modifiers. Modified binders containing these products were prepared in the laboratory with different polymer dosages and were thereafter subjected to the evaluation of empirical and rheological properties. For comparative purposes, the study also considered SBR and PBR products of premium quality. Ageing effects were also taken into account by means of proper laboratory simulations. Obtained results indicated that the two types of polymer (SBR and PBR) have completely different effects on the rheology and expected performance of the resulting modified binders. In particular, while the two polymers showed similar effects in terms of resistance to permanent deformation, the SBR products proved to be superior from the viewpoint of fatigue resistance. However, only minor differences were found when comparing the effects produced by premium quality and waste polymers. As a result of the experimental findings, it was concluded that the use of waste SBR polymers can be an attractive solution for the production of affordable modified binders

CHARACTERIZATION OF CRUMB RUBBER FROM END-OF-LIFE TYRES FOR PAVING APPLICATIONS

Crumb rubber (CR) derived from grinding of end-of-life tyres (ELTs) may be successfully used as a bitumen modifier or as a supplementary component in the production of bituminous mixtures employed for the construction and maintenance of road pavements. However, CRs deriving from different sources and processes yield effects on performance under traffic loading and on gaseous emissions produced during laying on site which may change considerably depending upon their physical and chemical properties. In order to quantitatively assess the possible variability of CR characteristics, samples were taken from 9 Italian and 2 foreign ELT processing plants. Investigation activities included field surveys, during which plants were examined in detail, and laboratory tests, which focused on physical and chemical characterization of CR. Based on the analysis of available technical information and experimental data, it was possible to find relationships between the peculiar characteristics of treatment cycles and corresponding CR properties

Design and Construction of a Full-Scale Test Section with Asphalt Rubber Gap-Graded Wearing Course Mixture

A full-scale test section with asphalt rubber gap-graded wearing course mixture was designed and constructed on a major infrastructure as part of a regional research and implementation project. Standard and performance-related laboratory tests were carried out in order to select constituent materials, define the job-mix formula and monitor construction operations. Gaseous emissions of the bituminous mixture sampled during laying were analyzed to assess the potential risks to which labourers are exposed during paving. Environmental compatibility was also evaluated by performing laboratory leaching tests. Based on the results obtained in the investigation, technical guidelines were validated and enhanced

Characterization of crumb rubber from end-of-life tyres for paving applications

Crumb rubber (CR) derived from grinding of end-of-life tyres (ELTs) may be successfully used as a bitumen modifier or as a supplementary component in the production of bituminous mixtures employed for the construction and maintenance of road pavements. However, CRs deriving from different sources and processes yield effects on performance under traffic loading and on gaseous emissions produced during laying on site which may change considerably depending upon their physical and chemical properties. In order to quantitatively assess the possible variability of CR characteristics, a wide experimental program was set out in order to analyze samples taken from 14 Italian and 2 foreign ELT processing plants. Activities included field surveys, during which plants were examined in detail, and laboratory investigations, which focused on physical and chemical characterization of CR. Based on the analysis of available technical information and experimental data, it was possible to find relationships between the peculiar characteristics of treatment cycles and corresponding CR properties

Design and Construction of a Full-Scale Test Section with Asphalt Rubber Gap-Graded Wearing Course Mixture

A full-scale test section with asphalt rubber gap-graded wearing course mixture was designed and constructed on a major infrastructure as part of a regional research and implementation project. Standard and performance-related laboratory tests were carried out in order to select constituent materials, define the job-mix formula and monitor construction operations. Gaseous emissions of the bituminous mixture sampled during laying were analyzed to assess the potential risks to which labourers are exposed during paving. Environmental compatibility was also evaluated by performing laboratory leaching tests. Based on the results obtained in the investigation, technical guidelines were validated and enhanced

Determinants of frontline tyrosine kinase inhibitor choice for patients with chronic-phase chronic myeloid leukemia: A study from the Registro Italiano LMC and Campus CML

BackgroundImatinib, dasatinib, and nilotinib are tyrosine kinase inhibitors (TKIs) approved in Italy for frontline treatment of chronic-phase chronic myeloid leukemia (CP-CML). The choice of TKI is based on a combined evaluation of the patient's and the disease characteristics. The aim of this study was to analyze the use of frontline TKI therapy in an unselected cohort of Italian patients with CP-CML to correlate the choice with the patient's features. MethodsA total of 1967 patients with CP-CML diagnosed between 2012 and 2019 at 36 centers throughout Italy were retrospectively evaluated; 1089 patients (55.4%) received imatinib and 878 patients (44.6%) received a second-generation (2G) TKI. ResultsSecond-generation TKIs were chosen for most patients aged <45 years (69.2%), whereas imatinib was used in 76.7% of patients aged >65 years (p < .001). There was a predominant use of imatinib in intermediate/high European long-term survival risk patients (60.0%/66.0% vs. 49.7% in low-risk patients) and a limited use of 2G-TKIs in patients with comorbidities such as hypertension, diabetes, chronic obstructive pulmonary disease, previous neoplasms, ischemic heart disease, or stroke and in those with >3 concomitant drugs. We observed a greater use of imatinib (61.1%) in patients diagnosed in 2018-2019 compared to 2012-2017 (53.2%; p = .002). In multivariable analysis, factors correlated with imatinib use were age > 65 years, spleen size, the presence of comorbidities, and & GE;3 concomitant medications. ConclusionsThis observational study of almost 2000 cases of CML shows that imatinib is the frontline drug of choice in 55% of Italian patients with CP-CML, with 2G-TKIs prevalently used in younger patients and in those with no concomitant clinical conditions. Introduction of the generic formulation in 2018 seems to have fostered imatinib use