Laboratory comparison of aging characteristics of warm mix asphalts involving natural and synthetic water containing additives

When comparing the aging characteristics of hot and warm mix asphalts from a technical point of view, it can intuitively be expected that a warm mix asphalt would be less subjected to aging-induced failures due to lower application temperatures. Since the side effects of warm asphalt technology should be investigated distinctly. This study addresses the aging investigation of properties of bituminous mixtures containing two (i.e., natural and synthetic zeolite) water based additives available on the market. Within the scope of this study, short- and long-term aging conditions were simulated on mixtures containing various contents of additives as well as on control specimens. The aging indices were determined based on the hardness ratio employing indirect tensile strength values in order to investigate the aging induced failures betide by time. Aging indices showed that the specimens with water containing additives demonstrate relatively better resistance against hardening than conventional hot mix asphalt specimens

Mechanical behavior of asphalt mixtures containing silica gels as warm additives

This paper presents the results of a study of some compounds capable of absorbing water into their structure (silica gel), as potential foaming binders. Asphalt mixtures were manufactured at different manufacturing and compaction temperatures, using four different silica gels. Static and dynamic tests were carried out to determine their behavior in asphalt mixtures. The results were compared with those obtained using hot-mix asphalt and warm-mix asphalt manufactured with zeolite. The lab results showed a similar behavior of asphalt mixtures containing either silica gel or zeolite.The research presented herein was sponsored by the Research Office of Universidad de La Frontera (DIUFRO) under the project number DI15-0089

The epidemiology and survival of extrapulmonary small cell carcinoma in South East England, 1970–2004

<p>Abstract</p> <p>Background</p> <p>Extrapulmonary small cell carcinoma (EPSCC) is a rare cancer and few studies describe its epidemiology. Our objectives were to compare the incidence and survival of EPSCC in South East England with small cell carcinoma of the lung (SCLC), to determine the most common anatomical presenting sites for EPSCC and to compare survival in EPSCC by disease stage and site of diagnosis.</p> <p>Methods</p> <p>We used data from the Thames Cancer Registry database for South East England between 1970 and 2004 to determine the incidence, most common anatomical sites, and survival by site, and stage of EPSCC. 1618 patients registered with EPSCC were identified. We calculated the age-standardised incidence rate for EPSCC using the European standard population and compared this to that for SCLC. We calculated survival using the Kaplan-Meier method for EPSCC and SCLC, and reported 3-year survival for different EPSCC anatomical sites and disease stages.</p> <p>Results</p> <p>The incidence of EPSCC was much lower than for SCLC, similar in males and females, and stable throughout the study period, with incidence rates of 0.45 per 100,000 in males and 0.37 in females during 2000–2004. In general, patients with EPSCC had a better 3-year survival (19%) than SCLC (5%). The most common anatomical sites for EPSCC were oesophagus (18%), other gastrointestinal (15%), genitourinary (20%), head and neck (11%), and breast (10%). Breast EPSCC had the best 3-year survival (60%) and gastrointestinal EPSCC the worst (7%).</p> <p>Conclusion</p> <p>This study suggests that EPSCC has a stable incidence and confirms that it presents widely, but most commonly in the oesophagus and breast. Site and extent of disease influence survival, with breast EPSCC having the best prognosis. Further studies using standardised diagnosis, prospective case registers for uncommon diseases and European cancer registries are needed to understand this disease.</p

Concurrent chemoradiotherapy with low dose weekly gemcitabine in stage III non-small cell lung cancer

BACKGROUND: Combined chemoradiotherapy (CRT) is the treatment of choice for stage III NSCLC. Gemcitabine (G) is a novel deoxycitidine analogue that has been proven to be a potent radiosensitizer. Twenty-two consecutive patients were treated with concurrent CRT to demonstrate the tolerability and efficacy of low dose G given weekly as radiosensitizer in stage III NSCLC. METHODS: Patients with KPS ≥70, adequate bone marrow reserve, with no prior radiotherapy (RT) and surgery were included. Eighteen patients had received prior induction chemotherapy (CT). G (75 mg/m(2)/week) was infused over 1 hour for 6 weeks. Thoracic RT was given two hours later over 6 weeks at 1.8 Gy/day fractions (total dose of 61.2 Gy). Pulmonary toxicity was evaluated with computed tomography scans in 6 weeks. RESULTS: Median age was 60 years (range, 48–75), median follow-up was 15 months (range, 2–40). Sixty-eight percent of patients were male and median KPS score was 90. Conformal 3D-RT planning was used in 64% of patients. G was given for a median of 5 weeks (range 1–9). Twelve patients (54.6%) received all planned CT. G was stopped because of intolerance in 6 and death in 2 patients. Seven patients (31.8%) had radiation pneumonitis. Twenty patients were evaluated for overall response, 1 patient (4.5%) had clinical CR, 81.8% had PR while 9.5% had SD. Median overall survival (OS) was 14 ± 5 months (95% CI 3–25). One- and 2-year OS rates were 55% and 38%. Sixteen patients died of disease-related events (6 with progression of primary tumor, 8 due to metastatic disease), 2 patients died of other causes. One- and 2-year progression-free survival and local control rates were 56%, 27% and 79%, 51%, respectively. CONCLUSION: G might be used as radiosensitizer for patients with stage III NSCLC who could not receive full doses CT with concurrent RT

Effect of polymers on rheological properties of waxy bitumens [Efecto de los polímeros sobre las propiedades reológicas de los betunes céreos]

The definition of bitumen wax has been formulated to facilitate the distinction between harmful wax and less harmful or non-harmful. Since exact behaviour of waxes within bitumens is not completely determined and the absence of cooperative study related to modification of bitumens involving different amounts of waxes, the values found in the study are thought to be useful in determining which content of wax and type of polymer would be better for the needs of petroleum refineries in different countries. The scope of this study is to minimize the negative effects of waxes within bitumens obtained from different sources. For this purpose, modified bitumen samples were prepared by using different types of polymers such as elastomers, plastomers and polyethylene groups. Following the determination of the contents of wax by Differential Scanning Calorimetry and TS EN 12606-1, rheological properties of waxy bitumens and polymer modified bitumens (PMB) were evaluated using dynamic shear rheometer tests. The intermediate temperature performance levels of PMB were also determined by fatigue parameters. Besides, rutting performance of PMB was evaluated using Zero Shear Viscosity and Multiple Stress Creep Recovery tests. © 2018 Pontificia Universidad Catolica de Chile, Escuela de Construccion Civil.La definición de cera bituminosa se ha formulado para facilitar la distinción entre cera nociva y menos nociva o no. Dado que el comportamiento exacto de las ceras en betunes no está completamente determinado y la ausencia de un estudio cooperativo relacionado con la modificación de betunes que involucran diferentes cantidades de ceras, los valores encontrados en el estudio se consideran útiles para determinar qué contenido de cera y tipo de polímero ser mejor para las necesidades de las refinerías de petróleo en diferentes países. El objetivo de este estudio es minimizar los efectos negativos de las ceras en los betunes obtenidos de diferentes fuentes. Para este propósito, se prepararon muestras de betún modificado usando diferentes tipos de polímeros tales como elastómeros, plastómeros y grupos de polietileno. Tras la determinación del contenido de cera por calorimetría de barrido diferencial y TS EN 12606-1, se evaluaron las propiedades reológicas de los betunes céreos y los betunes modificados con polímeros (PMB) utilizando pruebas de reómetro de cizallamiento dinámico. Los niveles intermedios de rendimiento de temperatura de PMB también fueron determinados por los parámetros de fatiga. Además, el rendimiento de celo de PMB se evaluó usando pruebas de Cero Cizalladura de Esfuerzo y Recuperación de Estrés Múltiple. © 2018 Pontificia Universidad Catolica de Chile, Escuela de Construccion Civil

Investigation of rheological effects of waxes on different bitumen sources

Wax in bitumen has been referred to as petroleum wax and is obtained from refining of paraffinic crude oils. The effects of wax on bitumen properties depend on the following factors: the source, chemical composition and rheology of the bitumen as well as the content, type, composition and crystallisation of the wax. There is a lack of literature reviews related to the effect of waxes on the rheology and properties of bitumen. The scope of this study is to evaluate the rheological properties of waxy bitumens obtained from different sources. Following the determination of wax contents by differential scanning calorimetry (DSC) and EN 12606-1, waxy bitumen properties were evaluated using conventional methods, rotational viscosity, dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests. The intermediate and high-temperature performances levels of bitumen were also determined according to the Superpave system by a DSR test performed on aged and unaged samples. Rutting performance of bitumens has been evaluated using zero shear viscosity (ZSV) and multiple stress creep recovery (MSCR) tests. © 2016 Informa UK Limited, trading as Taylor & Francis Group

An experimental study on waxy bitumens

10th International Conference on the Bearing Capacity of Roads, Railways and Airfields, BCRRA 2017 -- 28 June 2017 through 30 June 2017 -- -- 220519Almost all bitumen obtains from crude oil by refining process but only certain crude oils contain good quality bitumen for asphalt pavement. Naphthenic-base crude oils often give a large amount of bitumen that may be good quality, while paraffinic crude oils may give bitumen of good quality or yield bitumen not suitable for asphalt pavement. Wax in bitumen has been referred to as petroleum wax and is obtained from refining of paraffinic crude oils. In spite of the fact that high wax contents have been considered as a negative effect on the quality of the bitumen, there is no common agreement among the scientists regarding the effect on bitumen rheology and asphalt performance. The scope of this study is to evaluate the rheological properties of waxy bitumens obtained from different sources. Following the determination of wax contents by two different methods, various conventional methods were performed. The high temperature performance levels of bitumen were also determined according to Superpave system by Dynamic Shear Rheometer (DSR) test on samples before and after aging processes. The intermediate temperatures performances levels of bitumen were also performed by DSR. Rutting performance of bitumens has been evaluated using Zero Shear Viscosity (ZSV) and Multiple Stress Creep Recovery (MSCR) tests. © 2017 Taylor & Francis Group, London

Investigation of the rheological properties of elastomeric polymer-modified bitumen using warm-mix asphalt additives

In recent years, warm-mix asphalt (WMA) is extensively used in the hot-mix asphalt industry for reducing energy requirements and emissions by lowering mixing and compaction temperatures of bitumen. In addition, the use of polymer-modified bitumen (PMB) has become a very important part of pavement construction due to its superior performance, including less ageing, enhanced rutting resistance and lower fatigue cracking properties. This paper presents an experimental evaluation of elastomeric PMB involving WMA additives. In scope of the study, base bitumen has been modified with three different concentrations of styrene–butadiene–styrene (SBS) copolymer. The prepared PMB samples have been mixed with organic and chemical types WMA additives. Following the determination of the conventional properties as well as the rheological properties of the samples using dynamic shear rheometer, rutting behaviour of bitumen samples has been evaluated by zero shear viscosity test. The results of conventional bitumen tests showed a decrease in temperature susceptibility in PMB involving WMA additives. Based on the rheological test results, it was observed that the utilisation of organic WMA additive into PMB improves rutting performance of the modified bitumen especially in the 4% concentration of SBS copolymer. © 2016 Informa UK Limited, trading as Taylor & Francis Group