Rheological behaviour of modified binders for different loading conditions and temperatures: a case of using pig tallow and crumb rubber from end-of-life tyres

This study investigates alternatives to Styrene-Butadiene-Styrene (SBS) polymer in asphalt mixtures by evaluating End-Of-Life tire (ELT) crumb rubber (CR) and fatty acid amide wax (FAA) derived from pig tallow. The research focuses on triple modification of binders with SBS, ELT and FAA to improve performance and reuse waste and industrial by-products in an economical and environmentally responsible manner. The results show that the incorporation of ELT and FAA significantly reduces the SBS content, achieving a 73 % improvement in elastic performance according to Multiple Stress Creep Recovery (MSCR) tests. In addition, this combination improves peak stress and fatigue life in Linear Amplitude Sweep (LAS) tests, demonstrating potential benefits in asphalt mixtures. The study concludes that the combination of pig tallow and end-of-life tire materials doubles the yield energy (Yield Energy of Asphalt Binders, BYET) compared to samples with higher SBS content. In particular, a modification with 6 % CR, 3 % SBS and 2 % FAA doubles the toughness (Er) of a binder with 5 % SBS. This contributes to higher tensile strength in asphalt mixtures, promoting sustainability and efficiency in the road construction industry. This study provides a deeper understanding of how the combination of ELT, FAA and SBS can optimize the properties of asphalt mixtures, highlighting the potential of these additives to improve performance, reduce costs and minimize environmental impact.This work was supported by the National Research and Development Agency (ANID) of Chile [FONDECYT Regular Nº1201029]

Sustainability in construction works: Reuse of sludge from tunnel boring in lime mortars

[EN]This study is based on reuse of sludge from tunnel boring for the manufacture of mortars with calcium hydroxide and their possible application in construction. Three samples have been tested with different percentages of sludge from tunnel boring obtaining high consistency. This percentage was used to produce two types of mortars, one with limestone-type aggregates and the other with siliceous-type material, which were then subjected to compression and flexural tests. The analysis shows that the use of these sludge, with calcium hydroxide and siliceous-type aggregates, helps to improve the mortars’ properties and increase their flexural strength to values above 4 MPa, which could be reused as a coating for underground work and road construction as long as its complies with the standard.Proyecto BATUCA 070/PC08/3-03.

Estudio del comportamiento reológico de mezclas y ligantes bituminosos utilizando modelos de viscoelasticidad fraccionaria

[ES]Este estudio se centra en el comportamiento viscoelástico de mezclas bituminosas compuestas de diferentes partículas de agregado mineral unidas mediante un aglutinante bituminoso. Las mezclas bituminosas son el material compuestos más utilizado en la construcción de capas de pavimentos flexibles. El estudio mecánico de estos materiales se realiza actualmente utilizando modelos viscoelásticos como el modelo de Burgers. Sin embargo, este modelo solo se limita a explicar algunos de los fenómenos viscoelásticos de una mezcla bituminosa, principalmente, por que fue desarrollado para explicar el comportamiento reológico de un material único con naturaleza dual (elástico y viscoso) y no para un conjunto de materiales como la mezcla bituminosa. Este trabajo presenta un nuevo enfoque, que proporciona un marco mas apropiado para el desarrollo de mezclas y ligantes bituminosos. El modelo presentado asume una partícula de árido limitada por un aglomerante bituminoso, el cual, fue desarrollado mediante la utilización de ecuaciones diferenciales fraccionarias, para la simulación de los fenómenos de fluencia y recuperación. Los resultados obtenidos demuestran que a diferencia del modelo de Burgers, el nuevo modelo puede ajustar las deformaciones a fluencia y predecir el comportamiento de recuperación al final del cada ciclo. Los datos entregados por el modelo cuantifican las propiedades mecánicas del esqueleto mineral de la mezcla y del ligante bituminoso, permitiendo correlacionar los ensayos de fluencia y recuperación para mezclas, con las dispuestas en el reómetro de corte dinámico mediante el ensayo MSCR (The Multiple Stress Creep Recovery), generando mayor detalle de las propiedades reológicas y mejorando el diseño de mezclas bituminosas

Post-COVID-19 syndrome and diabetes mellitus: a propensity-matched analysis of the International HOPE-II COVID-19 Registry

SARS-CoV-2; Reinfection; Respiratory complicationsSARS-CoV-2; Reinfección; Complicaciones respiratoriasSARS-CoV-2; Reinfecció; Complicacions respiratòriesBackground: Diabetes mellitus (DM) is one of the most frequent comorbidities in patients suffering from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with a higher rate of severe course of coronavirus disease (COVID-19). However, data about post-COVID-19 syndrome (PCS) in patients with DM are limited. Methods: This multicenter, propensity score-matched study compared long-term follow-up data about cardiovascular, neuropsychiatric, respiratory, gastrointestinal, and other symptoms in 8,719 patients with DM to those without DM. The 1:1 propensity score matching (PSM) according to age and sex resulted in 1,548 matched pairs. Results: Diabetics and nondiabetics had a mean age of 72.6 ± 12.7 years old. At follow-up, cardiovascular symptoms such as dyspnea and increased resting heart rate occurred less in patients with DM (13.2% vs. 16.4%; p = 0.01) than those without DM (2.8% vs. 5.6%; p = 0.05), respectively. The incidence of newly diagnosed arterial hypertension was slightly lower in DM patients as compared to non-DM patients (0.5% vs. 1.6%; p = 0.18). Abnormal spirometry was observed more in patients with DM than those without DM (18.8% vs. 13; p = 0.24). Paranoia was diagnosed more frequently in patients with DM than in non-DM patients at follow-up time (4% vs. 1.2%; p = 0.009). The incidence of newly diagnosed renal insufficiency was higher in patients suffering from DM as compared to patients without DM (4.8% vs. 2.6%; p = 0.09). The rate of readmission was comparable in patients with and without DM (19.7% vs. 18.3%; p = 0.61). The reinfection rate with COVID-19 was comparable in both groups (2.9% in diabetics vs. 2.3% in nondiabetics; p = 0.55). Long-term mortality was higher in DM patients than in non-DM patients (33.9% vs. 29.1%; p = 0.005). Conclusions: The mortality rate was higher in patients with DM type II as compared to those without DM. Readmission and reinfection rates with COVID-19 were comparable in both groups. The incidence of cardiovascular symptoms was higher in patients without DM

Experimental study on styrene–butadiene–styrene-modified binders and fly ash micro-filler contributions for implementation in porous asphalt mixes

Styrene-butadiene-styrene copolymer (SBS) can be used to improve the mechanical and deformation properties of the binder used in its manufacture. However, the high cost of and variability in processing limit its performance. A secondary modifier to solve these problems is nano- and micromaterials that allow for the generation of unique properties in polymeric systems. Based on this, this study experimented with fly ash micro-filler (µFA) in low proportions as a binder modifier with SBS for use in PA mixes. The FA residue is considered in 3% and 5% dosages on a base binder with 5% SBS. Rheological results show that µFA improves classical, linear viscoelastic (LVE), and progressive damage properties compared with the modified binder. The PA blends with µFA reduce binder runout, resulting in a thicker film, thus showing better abrasion resistance in dry and wet conditions. Samples with µFA increase the post-cracking energy in indirect tension due to higher ductility. However, they decrease the fracture energy due to higher cracking before failure. In addition, µFA manages to decrease the difference between dry and wet ITS.Regular FONDECYT project 1201029 funded by the National Research and Development Agency of Chil

Post-COVID-19 Symptoms and Heart Disease: Incidence, Prognostic Factors, Outcomes and Vaccination: Results from a Multi-Center International Prospective Registry (HOPE 2)

COVID-19; Heart disease; PersistentCOVID 19; Malaltia cardíaca; PersistentCOVID-19; Enfermedad cardíaca; PersistenteBackground: Heart disease is linked to worse acute outcomes after coronavirus disease 2019 (COVID-19), although long-term outcomes and prognostic factor data are lacking. We aim to characterize the outcomes and the impact of underlying heart diseases after surviving COVID-19 hospitalization. Methods: We conducted an analysis of the prospective registry HOPE-2 (Health Outcome Predictive Evaluation for COVID-19-2, NCT04778020). We selected patients discharged alive and considered the primary end-point all-cause mortality during follow-up. As secondary main end-points, we included any readmission or any post-COVID-19 symptom. Clinical features and follow-up events are compared between those with and without cardiovascular disease. Factors with p < 0.05 in the univariate analysis were entered into the multivariate analysis to determine independent prognostic factors. Results: HOPE-2 closed on 31 December 2021, with 9299 patients hospitalized with COVID-19, and 1805 died during this acute phase. Finally, 7014 patients with heart disease data were included in the present analysis, from 56 centers in 8 countries. Heart disease (+) patients were older (73 vs. 58 years old), more frequently male (63 vs. 56%), had more comorbidities than their counterparts, and suffered more frequently from post-COVID-19 complications and higher mortality (OR heart disease: 2.63, 95% CI: 1.81–3.84). Vaccination was found to be an independent protector factor (HR all-cause death: 0.09; 95% CI: 0.04–0.19). Conclusions: After surviving the acute phase, patients with underlying heart disease continue to present a more complex clinical profile and worse outcomes including increased mortality. The COVID-19 vaccine could benefit survival in patients with heart disease during follow-up.Non-conditioned grant (Fundación Interhospitalaria para la Investigación cardiovascular, FIC. Madrid, Spain). This nonprofit institution had no role in the study design; collection, analysis, or interpretation of data; in the writing of the report; nor in the decision to submit the paper for publication

Clinical Profile and Determinants of Mortality in Patients with Interstitial Lung Disease Admitted for COVID-19

COVID-19; Interstitial lung diseases; MortalityCOVID-19; Malalties pulmonars intersticials; MortalitatCOVID-19; Enfermedades pulmonares intersticiales; MortalidadBackground: Concern has risen about the effects of COVID-19 in interstitial lung disease (ILD) patients. The aim of our study was to determine clinical characteristics and prognostic factors of ILD patients admitted for COVID-19. Methods: Ancillary analysis of an international, multicenter COVID-19 registry (HOPE: Health Outcome Predictive Evaluation) was performed. The subgroup of ILD patients was selected and compared with the rest of the cohort. Results: A total of 114 patients with ILDs were evaluated. Mean ± SD age was 72.4 ± 13.6 years, and 65.8% were men. ILD patients were older, had more comorbidities, received more home oxygen therapy and more frequently had respiratory failure upon admission than non-ILD patients (all p < 0.05). In laboratory findings, ILD patients more frequently had elevated LDH, C-reactive protein, and D-dimer levels (all p < 0.05). A multivariate analysis showed that chronic kidney disease and respiratory insufficiency on admission were predictors of ventilatory support, and that older age, kidney disease and elevated LDH were predictors of death. Conclusions: Our data show that ILD patients admitted for COVID-19 are older, have more comorbidities, more frequently require ventilatory support and have higher mortality than those without ILDs. Older age, kidney disease and LDH were independent predictors of mortality in this population

Short- and Long-Term Prognosis of Patients With Takotsubo Syndrome Based on Different Triggers: Importance of the Physical Nature

Background Takotsubo syndrome (TTS) is an acute reversible heart condition initially believed to represent a benign pathology attributable to its self-limiting clinical course; however, little is known about its prognosis based on different triggers. This study compared short- and long-term outcomes between TTS based on different triggers, focusing on various physical triggering events. Methods and Results We analyzed patients with a definitive TTS diagnosis recruited for the Spanish National Registry on TTS (RETAKO [Registry on Takotsubo Syndrome]). Short- and long-term outcomes were compared between different groups according to triggering factors. A total of 939 patients were included. An emotional trigger was detected in 340 patients (36.2%), a physical trigger in 293 patients (31.2%), and none could be identified in 306 patients (32.6%). The main physical triggers observed were infections (30.7%), followed by surgical procedures (22.5%), physical activities (18.4%), episodes of severe hypoxia (18.4%), and neurological events (9.9%). TTS triggered by physical factors showed higher mortality in the short and long term, and within this group, patients whose physical trigger was hypoxia were those who had a worse prognosis, in addition to being triggered by physical factors, including age >70 years, diabetes mellitus, left ventricular eyection fraction <30% and shock on admission, and increased long-term mortality risk. Conclusions TTS triggered by physical factors could present a worse prognosis in terms of mortality. Under the TTS label, there could be as yet undiscovered very different clinical profiles, whose differentiation could lead to individual better management, and therefore the perception of TTS as having a benign prognosis should be generally ruled out

ODS en las aulas de ingeniería y arquitectura: tomar conciencia y transmitir

Memoria ID-014. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2021-2022

Elevated Troponins after COVID-19 Hospitalization and Long-Term COVID-19 Symptoms: Incidence, Prognosis, and Clinical Outcomes—Results from a Multi-Center International Prospective Registry (HOPE-2)

Background: Acute cardiac injury (ACI) after COVID-19 has been linked with unfavorable clinical outcomes, but data on the clinical impact of elevated cardiac troponin on discharge during follow-up are scarce. Our objective is to elucidate the clinical outcome of patients with elevated troponin on discharge after surviving a COVID-19 hospitalization. Methods: We conducted an analysis in the prospective registry HOPE-2 (NCT04778020). Only patients discharged alive were selected for analysis, and all-cause death on follow-up was considered as the primary endpoint. As a secondary endpoint, we established any long-term COVID-19 symptoms. HOPE-2 stopped enrolling patients on 31 December 2021, with 9299 patients hospitalized with COVID-19, of which 1805 were deceased during the acute phase. Finally, 2382 patients alive on discharge underwent propensity score matching by relevant baseline variables in a 1:3 fashion, from 56 centers in 8 countries. Results: Patients with elevated troponin experienced significantly higher all-cause death during follow-up (log-rank = 27.23, p < 0.001), and had a higher chance of experiencing long-term COVID-19 cardiovascular symptoms. Specifically, fatigue and dyspnea (57.7% and 62.8%, with p-values of 0.009 and <0.001, respectively) are among the most common. Conclusions: After surviving the acute phase, patients with elevated troponin on discharge present increased mortality and long-term COVID-19 symptoms over time, which is clinically relevant in follow-up visits