Evaluation of the characteristics of joint sealants

Füllsysteme für Fugen in Betonfahrbahnen sind während ihrer Nutzungsdauer vielfältigen Beanspruchungen ausgesetzt. Daraus leiten sich erhöhte Anforderungen an die Dauerhaftigkeit des Gesamtsystems „Fuge“ ab. Neben jahreszeitlich schwankenden klimatischen Änderunge spielen insbesondere zyklische Beanspruchungen durch den überrollenden Verkehr sowie die Alterung der Fugenmassen eine maßgebliche Rolle. Ziel dieses Forschungsprojekts war es, ein praxisorientiertes Prüfverfahren zu entwickeln, das zum einen das Gesamtsystem „Fuge“ bestehend aus Betonfugenflanke, Voranstrichmittel sowie der Fugenmasse umfasst und andererseits die maßgebenden Szenarien der in-situ-Beanspruchungen realistisch abbildet. Dazu wurden Systemprüfkörper bestehend aus Beton und Fugenfüllstoff definiert, an denen über die herkömmlichen Prüfungen am Füllstoff hinaus, statische Zug-/Scherversuche und zyklische Druck-/Zug-/Scherversuche an neuen und künstlich gealterten Proben vorgenommen wurden. Diese Prüfungen wurden sowohl an Laborproben (Referenz) als auch an Systemprüfkörpern aus Bohrkernen von originären Bestandstrecken durchgeführt. Die Untersuchungen zeigten u.a., dass die heiß verarbeitbaren Fugenmassen, mit Ausnahme der modifizierten Fugenmasse vom Typ N2+, infolge künstlicher Alterung erheblich versprödeten, d.h. bei deutlich reduziertem Dehnvermögen höhere Maximalspannungen aufwiesen. Dieser Effekt zeichnete sich auch bei den im dynamischen Scherrheometer ermittelten Phasenwinkeln und komplexen Schermoduln ab. Unter der Annahme eines exponentiellen Verlaufs der Alterung von heiß verarbeitbaren Fugenmassen, konnte für die künstliche Laboralterung ein simulierter Nutzungszeitraum von etwa 6 Jahren ermittelt werden. Für die kalt verarbeitbaren Fugenmassen erwies sich die für heiß verarbeitbare Fugenmassen herangezogene künstliche Alterung unter Druck und Temperaturbeanspruchung als nicht zweckmäßiges Verfahren. Zur ersten Validierung der entwickelten Laborprüfverfahren wurde im BAB-Netz eine heiß und eine kalt verarbeitbare Fugenmasse über die ersten 21 Monate Nutzungsdauer intensiv beobachtet. Unter Einbeziehung der Systemprüfungen an Labor- und in-situ-Proben wurde ein erster Bewertungsansatz entwickelt, mit dem, anhand wissenschaftlich orientierter Kenn- und Grenzwerte, Fugenmassen im nicht gealterten ebenso wie im künstlich gealterten Zustand bewertet werden können.Filling systems for joints in concrete pavements are exposed to a variety of stresses during their service life. This implies increased requirements for the durability of the whole "joint" system. In addition to seasonal unsteady climatic changes, cyclical loads caused by rolling traffic and the ageing of joint sealants are particularly relevant. The aim of this research project was to develop a practise-oriented test procedure that on one hand comprises the entire "joint" system consisting of the concrete joint flank, primer and the joint sealant and on the other hand realistically depicts the decisive scenarios of in-situ stresses. For this purpose, system test specimens consisting of concrete and joint filler were defined so that in addition to the conventional tests on the filler, static tensile/shear tests and cyclic pressure/tensile/shear tests could be carried out on new and artificially aged specimens. These tests were performed on laboratory samples (reference) as well as on system samples of drill cores from original existing pavements. The investigations demonstrated that the hot applied joint sealants, with exception of the modified joint sealant type N2+, were significantly embrittled due to artificial ageing, i.e. exhibiting higher maximum stresses with significantly reduced ductility. This effect also occurred with the phase angles and complex shear modulus determined in the dynamic shear rheometer. Based on the assumption of an exponential aging process of hot applied joint sealants, a simulated service life of about 6 years could be determined for artificial laboratory ageing. For the cold applied joint sealants, artificial ageing under pressure and temperature stress, which was used for hot applied joint sealants, proved to be inappropriate. For a first validation of the developed laboratory test procedures within the BAB network a hot and a cold processed joint sealant was intensively observed over the first 21 months of use. With involvement of system tests on laboratory and in-situ samples, an initial evaluation procedure was developed with which joint sealants in both unaged and artificially aged conditions can be evaluated on the basis of scientifically oriented characteristic and limit parameters

Impact of haemoconcentration during acute heart failure therapy on mortality and its relationship with worsening renal function

Treatment goals in acute heart failure (AHF) are poorly defined. We aimed to characterize further the impact of in-hospital haemoconcentration and worsening renal function (WRF) on short- and long-term mortality.Haematocrit, haemoglobin, total protein, serum creatinine, and albumin levels were measured serially in 1019 prospectively enrolled AHF patients. Haemoconcentration was defined as an increase in at least three of four of the haemoconcentration-defining parameters above admission values at any time during the hospitalization. Patients were divided into early (Day 1-4) and late haemoconcentration (>Day 4). Ninety-day mortality was the primary endpoint. Haemoconcentration occurred in 392 (38.5%) patients, with a similar incidence of the early (44.6%) and late (55.4%) phenotype. Signs of decongestion (reduction in BNP blood concentrations, P = 0.003; weight loss, P = 0.002) were significantly more pronounced in haemoconcentration patients. WRF was more common in haemoconcentration patients (P = 0.04). After adjustment for established risk factors for AHF mortality, including WRF and HF therapy at discharge, haemoconcentration was significantly associated with a reduction in 90-day mortality [hazard ratio (HR) 0.59, 95% confidence interval (CI) 0.37-0.95, P = 0.01]. The beneficial effect of haemoconcentration seemed to be exclusive for late haemoconcentration (late vs. early: adjusted HR 0.41, 95% CI 0.19-0.90, P = 0.03) and persisted in patients with or without WRF.Haemoconcentration represents an inexpensive and easily assessable pathophysiological signal of adequate decongestion in AHF and is associated with lower mortality. WRF in the setting of haemoconcentration does not appear to offset the benefits of haemoconcentration

Diagnostic value of the cardiac electrical biomarker, a novel ECG marker indicating myocardial injury, in patients with symptoms suggestive of non-ST-elevation myocardial infarction

The cardiac electrical biomarker (CEB) is a novel electrocardiographic (ECG) marker quantifying the dipolar activity of the heart with higher levels indicating myocardial injury.We prospectively enrolled 1097 patients presenting with suspected non-ST-elevation myocardial infarction (NSTEMI) to the emergency department (ED). Digital 12-lead ECGs were recorded at presentation and the CEB values were calculated in a blinded fashion. The final diagnosis was adjudicated by two independent cardiologists. The prognostic endpoint was all-cause mortality during 2\ua0years of follow-up.NSTEMI was the final diagnosis in 14% of patients. CEB levels were higher in patients with NSTEMI compared to other causes of chest pain (median 44 (IQR 21-98) vs. 30 (IQR 16-61), p\ua

Effect of definition on incidence and prognosis of type 2 myocardial infarction

Uncertainties regarding the most appropriate definition and treatment of type 2 myocardial infarction (T2MI) due to supply-demand mismatch have contributed to inconsistent adoption in clinical practice.This study sought a better understanding of the effect of the definition of T2MI on its incidence, treatment, and event-related mortality, thereby addressing an important unmet clinical need.The final diagnosis was adjudicated in patients presenting with symptoms suggestive of myocardial infarction by 2 independent cardiologists by 2 methods: 1 method required the presence of coronary artery disease, a common interpretation of the 2007 universal definition (T2MI); and 1 method did not require coronary artery disease, the 2012 universal definition (T2MI).Overall, 4,015 consecutive patients were adjudicated. The incidence of T2MI based on the T2MI definition was 2.8% (n\ua0=\ua0112). The application of the more liberal T2MI definition resulted in an increase of T2MI incidence of\ua06% (n\ua0=\ua0240), a relative increase of 114% (128 reclassified patients, defined as T2MI). Among T2MI, 6.3% of patients received coronary revascularization, 22% dual-antiplatelet therapy, and 71% high-dose statin therapy\ua0versus 0.8%, 1.6%, and 31% among T2MI patients, respectively (all p\ua0< 0.01). Cardiovascular mortality at 90\ua0days was 0% among T2MI, which was similar to patients with noncardiac causes of chest discomfort (0.2%), and lower than T2MI (3.6%) and type 1 myocardial infarction (T1MI) (4.8%) (T2MI vs. T2MI and T1MI: p\ua0=\ua00.03 and 0.01, respectively).T2MI has a substantially lower event-related mortality rate compared with T2MI and\ua0T1MI. (Advantageous Predictors of Acute Coronary Syndromes Evaluation [APACE] Study; NCT00470587)