Comparing circulating fluidised bed fly ash and limestone as additions for cement

[Abstract:] Circulating fluidized bed combustion (CFBC) power plants produce as by-product large ash particles with elevated calcium content. They are not commonly accepted as addition for cement although presenting pozzolanic potential. To enhance the activity of this material, the CFBC ash was ground to fineness equal to that of the cement, simulating a joint milling with the clinker. This ground fly ash (GFA) was included in blended cements in ratios of 10%, 20% and 40%. These new cements with GFA surpassed 52.5 MPa at 28 days for even 40% of substitution. Contrasted with limestone addition, the most used in Europe, the cements with GFA presented higher compressive strength, better durability with the only drawback of a slight reduction in workability. This CFBC fly ash could be used as clinker replacement once ground to similar fineness than cement allowing high reductions in clinker consumption and its consequent carbon footprint reduction

Deformation recovery of reinforced concrete beams made with recycled coarse aggregates

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract:] The purpose of this research is to analyse the long-term deformations of reinforced concrete beams made of recycled coarse aggregates (RCA), using four different replacement ratios, 0%, 20%, 50% and 100%. For said purpose, three different loading stages were carried out: firstly, loading and sustained load for 1300 days, secondly, unloading and recovery where the deformations were registered over a one year period, and lastly, testing the concrete beams up to failure in order to analyse the effect of recycled aggregates on pre-cracked concrete members. The results led to the analysis of deformations under sustained load, as well as those produced after removing the load and the performance of pre-cracked members, while identifying the effect of recycled coarse aggregates on concrete performance in terms of plastic deformation, recoverability and concrete stiffness, and also on structural design.Ministerio de Industria, Economía y Competitividad; BIA2017-85657-

Flexural performance of reinforced concrete beams made with recycled concrete coarse aggregate

Versión aceptada de https://doi.org/10.1016/j.engstruct.2017.11.015[Abstract:] This work deals with the flexural performance of recycled concrete subjected to increasing loads up to failure. For this purpose, eight reinforced concrete beams were made with recycled coarse aggregates using two different water to cement ratios (0.50 and 0.65) and four replacement percentages (0%, 20%, 50% and 100%). Firstly, the basic concrete properties were determined (mechanical strengths and modulus of elasticity) and then, beam specimens were loaded up to failure using a four-point bending test at 28 days. As a result, bending moments, deflections, strains and curvatures were obtained at different load levels (cracking, service, yielding and ultimate state conditions), and also, the crack pattern. On the basis of these results, it can be noted that service, yielding and ultimate state of recycled concrete exhibits, in general, a similar trend to that of conventional concrete. However, the cracking behaviour shows differences between recycled and conventional concrete. Finally, code-based expressions were used to calculate bending moments and deflections under flexural load, taking into account the different content of recycled coarse aggregate.The study is part of the projects entitled: CLEAM: Clean, efficient and nice construction along its life cycle” funded by the Centre for the Technology and Industrial Development (CDTI) and led by the Group of Economical Interest CLEAM-CENIT, AIE comprising by the country’s largest construction companies (Acciona, Dragados, Ferrovial, FCC, Isolux Corsán, OHL and Sacyr) and some PYME (Informática 68, Quilosa and Martínez Segovia y asociados). HORREO “Robust self-compacting recycled concretes: rheology in fresh state and mechanical properties (Ref: BIA2014-58063-R)” funded by MINECO

1 PREHEALING: Design of concrete precast elements incorporating sustainable strategies for self-healing to increase their service life. Material characterization

This project deals with the analysis of the performance of concrete with internal curing aggregates (IC), low clinker cementitious materials and steel fibres, to be used in real applications in the field of precast industry. The low clinker cementitious material will be composed of clinker (C), metakaolin (MK) and limestone filler (LF) as powder material. In order to promote the sustainability of these products, a sustainable powder (SP) obtained from wood ash will be included. In addition, aggregates from coal bottom ash (CBA) will be used as internal curing water reservoirs. This section includes the characterization of these materials providing their main properties as particle size distribution, density or absorption, among other

The Role of Fatty Acid-Binding Protein 4 in the Characterization of Atrial Fibrillation and the Prediction of Outcomes after Catheter Ablation

Aims: The utility of biomarkers in characterizing atrial cardiomyopathy is unclear. We aim to test the ability of biomarkers of fibrosis (galectin-3 (Gal-3)) and adiposity (fatty acid-binding protein 4 (FABP4) and leptin) to predict: (1) the presence of low-voltage areas (LVA) in the electroanatomic voltage mapping; and (2) the recurrence of atrial fibrillation (AF) after pulmonary vein isolation (PVI). Methods: Patients referred for PVI were enrolled. Areas of bipolar voltage 20 ng/mL) was developed. Results: 299 patients were included. AF was paroxysmal in 100 (33%), persistent in 130 (43%) and long-standing persistent in 69 (23%). Multivariable analysis revealed age, left atrium area, and the proposed score as independent predictors of LVA. During a mean follow-up period of 972 ± 451 days, freedom from AF recurrence was 63%. The score incorporating AF pattern and FABP4 levels accurately predicted freedom from AF recurrence, stratifying risk into ranges from 28% (score of 1) to 68% (score of 3). Cox regression models identified the score including AF pattern + FABP4 as the best model for AF recurrence (hazard ratio 2.32; 95% CI, 1.19 to 4.5; p = 0.014). Conclusions: Traditional clinical classification of atrial cardiomyopathy may be improved by markers of adiposity (FABP4). The combination allows better prediction of the presence of LVA and AF recurrence post-PVI. Gal-3 provided no added predictive value

Role of Soluble ST2 Biomarker in Predicting Recurrence of Atrial Fibrillation after Electrical Cardioversion or Pulmonary Vein Isolation

This study aims to determine the predictive value of the soluble suppression of tumorigenicity 2 (sST2) biomarker in atrial fibrillation (AF) recurrence. This prospective, observational study included patients with AF referred for electrical cardioversion (ECV) or pulmonary vein isolation (PVI) procedures. Baseline characteristics were collected, and sST2 was determined at baseline and at 3 and 6 months of follow-up. sST2 was determined at baseline in a matched control group. Left atrial voltage mapping was performed in patients undergoing PVI. The sST2 maximal predictive capacity of AF recurrence was at the 3-month FU in the cohort of patients undergoing ECV with respect to 6-month AF recurrence with an AUC of 0.669, a cut-off point of 15,511 pg/mL, a sensitivity of 60.97%, and a specificity of 69.81%. The ROC curve of the sST2 biomarker at baseline and 3 months in the cohort of patients undergoing PVI showed AUCs of 0.539 and 0.490, respectively. The logistic regression model identified the rhythm (AF) and the sST2 biomarker at 3 months as independent factors for recurrence at 6 months in the ECV cohort. In the logistic regression model, sST2 was not an independent factor for recurrence at 6 months of follow-up in the PVI cohort. In patients who underwent ECV, sST2 values at 3 months may provide utility to predict AF recurrence at 6 months of follow-up. In patients who underwent PVI, sST2 had no value in predicting AF recurrence at 6 months of follow-up

Atrial fibrillation ablation in patients with arrhythmia‐induced cardiomyopathy: a prospective multicentre study

Abstract Aims This study aims to investigate the clinical and biochemical characteristics of patients with atrial fibrillation (AF) referred for ablation who develop arrhythmia‐induced cardiomyopathy (AiCM) as well as their long‐term outcomes after catheter ablation (CA). Methods and results A prospective multicentre study was conducted on consecutive AF patients who underwent CA. AiCM was defined as the development of heart failure in the presence of AF and an improvement of left ventricular fraction by at least 10% at 6 months after ablation. A subgroup of patients underwent peripheral and left atrial blood samples [galectin‐3, fatty acid‐binding protein 4 (FABP4), and soluble receptor for advanced glycation end products (sRAGE)] at the time of the procedure. Of the 769 patients who underwent AF ablation, 135 (17.56%) met the criteria for AiCM. Independent predictors of AiCM included persistent AF, male gender, left atrial volume, QRS width, active smoking, and chronic kidney disease (CKD). Biomarker analysis revealed that sRAGE, FABP4, and galectin‐3 levels were not predictive of AiCM development nor did they differ between groups or predict recurrence. There were no differences in AF recurrence between patients with and without AiCM (30.83% vs. 27.77%; P = 0.392) during a median follow‐up of 23.83 months (inter‐quartile range 9–36). Conclusions In the subset of patients referred for AF ablation, the development of AiCM was associated with persistent AF and CKD. Biomarker analysis was not different between groups nor predicted recurrence. Patients with AiCM benefited from ablation, with a significant improvement in left ventricular ejection fraction and similar AF recurrence rates to those without AiCM