Self-healing capability of conventional, high-performance, and Ultra High-Performance Concrete with commercial bacteria characterized by means of water and chloride penetration

Doostkami, H.; -; Universitat Politecnica de Valencia; M. Roig-Flores (2023). Self-healing capability of conventional, high-performance, and Ultra High-Performance Concrete with commercial bacteria characterized by means of water and chloride penetration. Construction and Building Materials. 401. https://doi.org/10.1016/j.conbuildmat.2023.13290340

Interfacial Transition Zone in Mature Fiber-Reinforced Concretes

[EN] The interfacial transition zone (ITZ) in concrete is the region of the cement paste that is disturbed by the presence of an aggregate or fiber. This work focuses on the ITZ around silica and dolomite grains and steel fibers. The analysis performed is based on: the macroscale properties of the specimens; petrographic analyses with polarized microscopy; and qualitative and quantitative SEM analyses. The following types of concrete were tested: standard quality (SQ); high-quality with steel fibers (PFRC); and ultra-high-performance fiber-reinforced concrete (UHPFRC). The most important parameters affecting ITZ are the properties of the disturbing elements and the mixture composition of the concrete. In PFRC, a differentiated zone of thickness 20 ¿m (787.40 ¿in.) was observed around a dolomite grain, showing a preferential growth of Ca-based compounds. In UHPFRC, SEM-EDS analysis revealed C-S-H of lower Ca/Si ratios in the proximity of fibers and aggregates.Roig-Flores, M.; Simicevic, F.; Maricic, A.; Serna Ros, P.; Horvat, M. (2018). Interfacial Transition Zone in Mature Fiber-Reinforced Concretes. ACI Materials Journal. 115(4):623-631. https://doi.org/10.14359/51702419623631115

Evaluation of the Self-healing Capability of Ultra-High-Performance Fiber-Reinforced Concrete with Nano-Particles and Crystalline Admixtures by Means of Permeability

[EN] Self-healing is the capability of a material to repair its damage autonomously. Ultra-High-Performance Fiber Reinforced Concrete (UHPFRC) has potentially higher self-healing properties than conventional concrete because of its lower water/binder content and controlled microcracking due to the high fiber content. This work uses a novel methodology based on the permeability to evaluate autogenous self-healing of UHPFRC and enhanced self-healing, incorporating several additions. To this purpose, one UHPFRC was selected and modified to include alumina nanofibers in 0.25% by the cement weight, nanocellulose (nanocrystals and nanofibers), in a dosage of 0.15% by the cement weight, and 0.8-1.6% of a crystalline admixture. The results obtained show that the methodology proposed allows the evaluation of the self-healing capability of different families of concrete mixes that suffered a similar level of damage using permeability tests adapted to the specific properties of UHPFRC.The authors would like to acknowledge the European Union¿s Horizon 2020 ReSHEALience project (Grant Agreement No. 760824).Doostkami, H.; Roig-Flores, M.; Negrini, A.; Mezquida-Alcaraz, EJ.; Serna Ros, P. (2020). Evaluation of the Self-healing Capability of Ultra-High-Performance Fiber-Reinforced Concrete with Nano-Particles and Crystalline Admixtures by Means of Permeability. Springer. 489-499. https://doi.org/10.1007/978-3-030-58482-5_45489499Homma, D., Mihashi, H., Nishiwaki, T.: Self-healing capability of fibre reinforced cementitious composites. J. Adv. Concr. Technol. 7(2), 217–228 (2009)Maes, M., Snoeck, D., De Belie, N.: Chloride penetration in cracked mortar and the influence of autogenous crack healing. Constr. Build. Mater. 115, 114–124 (2016)Edvardsen, C.: Water Permeability and Autogenous Healing of Cracks in Concrete, vol. 96 (1999)De Belie, N., et al.: A review of self-healing concrete for damage management of structures. Adv. Mater. Interfaces 5(17) (2018)Wang, H.L., Dai, J.G., Sun, X.Y., Zhang, X.L.: Characteristics of concrete cracks and their influence on chloride penetration. Constr. Build. Mater. 107, 216–225 (2016)Wang, K., Jansen, D.C., Shah, S.P., Karr, A.F.: Permeability study of cracked concrete. Cem. Concr. Res. (1997)Šavija, B., Schlangen, E.: Autogeneous healing and chloride ingress in cracked concrete. Heron 61(1), 15–32 (2016)Ismail, M., Toumi, A., François, R., Gagné, R.: Effect of crack opening on the local diffusion of chloride in cracked mortar samples. Cem. Concr. Res. 38(8–9), 1106–1111 (2008)Habel, K., Gauvreau, P.: Response of ultra-high performance fiber reinforced concrete (UHPFRC) to impact and static loading. Cem. Concr. Compos. 30(10), 938–946 (2008)Denarié, E., Brühwiler, E.: Strain-hardening ultra-high performance fibre reinforced concrete: deformability versus strength optimization. Restor. Build. Monum. 17(6), 397–410 (2014)Granger, S., Pijaudier-Cabot, G., Loukili, A.: Mechanical behavior of self-healed ultra high performance concrete: from experimental evidence to modeling. In: Proceedings of the 6th International Conference on Fracture Mechanics of Concrete and Concrete Structures, vol. 3, pp. 1827–1834 (2007)Escoffres, P., Desmettre, C., Charron, J.P.: Effect of a crystalline admixture on the self-healing capability of high-performance fiber reinforced concretes in service conditions. Constr. Build. Mater. 173, 763–774 (2018)Sisomphon, K., Copuroglu, O., Koenders, E.A.B.: Self-healing of surface cracks in mortars with expansive additive and crystalline additive. Cem. Concr. Compos. 34(4), 566–574 (2012)Roig-Flores, M., Moscato, S., Serna, P., Ferrara, L.: Self-healing capability of concrete with crystalline admixtures in different environments. Constr. Build. Mater. 86, 1–11 (2015)Roig-Flores, M., Pirritano, F., Serna, P., Ferrara, L.: Effect of crystalline admixtures on the self-healing capability of early-age concrete studied by means of permeability and crack closing tests. Constr. Build. Mater. 114, 447–457 (2016)Ferrara, L., Krelani, V., Carsana, M.: A ‘fracture testing’ based approach to assess crack healing of concrete with and without crystalline admixtures. Constr. Build. Mater. 68, 535–551 (2014)Ferrara, L., Krelani, V., Moretti, F.: On the use of crystalline admixtures in cement based construction materials: from porosity reducers to promoters of self healing. Smart Mater. Struct. 25(8), 1–17 (2016)Cuenca, E., Cislaghi, G., Puricelli, M., Ferrara, L.: Influence of self-healing stimulated via crystalline admixtures on chloride penetration. In: America Concrete Institute, vol. 2018(SP 326), pp. 1–10. ACI Spec. Publ. (2018)Borg, R.P., Cuenca, E., Gastaldo Brac, E.M., Ferrara, L.: Crack sealing capacity in chloride-rich environments of mortars containing different cement substitutes and crystalline admixtures. J. Sustain. Cem. Mater. 7(3), 141–159 (2018)López, J.Á., Serna, P., Navarro-Gregori, J., Camacho, E.: An inverse analysis method based on deflection to curvature transformation to determine the tensile properties of UHPFRC. Mater. Struct. 48(11), 3703–3718 (2014). https://doi.org/10.1617/s11527-014-0434-0López, J.Á.: Characterisation of the Tensile Behaviour of UHPFRC By Means of Four-Point Bending Tests, March 2017Negrini, A., Roig-Flores, M., Mezquida-Alcaraz, E.J., Ferrara, L., Serna, P.: Effect of crack pattern on the self-healing capability in traditional, HPC and UHPFRC concretes measured by water and chloride permeability. In: MATEC Web Conference, vol. 289, p. 01006 (2019

Effects of autogenous healing on the recovery of mechanical performance of High Performance Fibre Reinforced Cementitious Composites (HPFRCCs): Part 1

[EN] This paper presents the results are shown of a thorough characterization of the self-healing capacity of High Performance Fibre Reinforced Cementitious Composites (HPFRCCs). The capacity of the material will be investigated to completely or partially re-seal the cracks, as a function of its composition, maximum crack width and exposure conditions. The analysis will also consider different flow-induced alignments of fibres, which can result into either strain-hardening or softening behaviour, whether the material is stressed parallel or perpendicularly to the fibres, respectively. Beam specimens, initially pre-cracked in 4-point bending up to different values of crack opening, were submitted to different exposure conditions, including water immersion, exposure to humid or dry air, and wet-and-dry cycles. After scheduled exposure times, ranging from one month to two years, specimens were tested up to failure according to the same test set-up employed for pre-cracking. Outcomes of the self-healing phenomenon, if any, were analyzed in terms of recovery of stiffness, strength and ductility. In a durability-based design framework, self-healing indices quantifying the recovery of mechanical properties were also defined and their significance cross-checked.The support of Politecnico di Milano - Young Researchers 2011 grant to the project Self-healing capacity of cementitious composites is gratefully acknowledged. The authors also thank Matteo Geminiani, Raffaele Gorlezza and Gregorio Sanchez Arevalo for their help in performing experimental tests along different time steps of the project, in partial fulfilment of the requirements to obtain their MScEng degrees.Ferrara, L.; Krelani, V.; Moretti, F.; Roig-Flores, M.; Serna Ros, P. (2017). Effects of autogenous healing on the recovery of mechanical performance of High Performance Fibre Reinforced Cementitious Composites (HPFRCCs): Part 1. Cement and Concrete Composites. 83:76-100. doi:10.1016/j.cemconcomp.2017.07.010S761008

Self-healing capability of concrete with crystalline admixtures in different environments

The aim of this study is analyzing the self-healing effect of a crystalline admixture in four types of environmental exposure comparing with a reference concrete. Healing was studied by means of permeability tests on cracked specimens and physical closing of the crack was observed by optic microscope and quantified through crack geometrical parameters. The studied crack openings were under 300 pm and the time set for healing was 42 days. The results show a different healing behavior depending on the exposure and the presence of the crystalline admixture, demonstrating that the presence of water is necessary for the healing reactions. (C) 2015 Elsevier Ltd. All rights reserved.Roig Flores, M.; Moscato, S.; Serna Ros, P.; Ferrara, L. (2015). Self-healing capability of concrete with crystalline admixtures in different environments. Construction and Building Materials. 86:1-11. doi:10.1016/j.conbuildmat.2015.03.091S1118

The effectiveness of e-& mHealth interventions to promote physical activity and healthy diets in developing countries: a systematic review

Background: Promoting physical activity and healthy eating is important to combat the unprecedented rise in NCDs in many developing countries. Using modern information-and communication technologies to deliver physical activity and diet interventions is particularly promising considering the increased proliferation of such technologies in many developing countries. The objective of this systematic review is to investigate the effectiveness of e-& mHealth interventions to promote physical activity and healthy diets in developing countries.Methods: Major databases and grey literature sources were searched to retrieve studies that quantitatively examined the effectiveness of e-& mHealth interventions on physical activity and diet outcomes in developing countries. Additional studies were retrieved through citation alerts and scientific social media allowing study inclusion until August 2016. The CONSORT checklist was used to assess the risk of bias of the included studies.Results: A total of 15 studies conducted in 13 developing countries in Europe, Africa, Latin-and South America and Asia were included in the review. The majority of studies enrolled adults who were healthy or at risk of diabetes or hypertension. The average intervention length was 6.4 months, and text messages and the Internet were the most frequently used intervention delivery channels. Risk of bias across the studies was moderate (55.7 % of the criteria fulfilled). Eleven studies reported significant positive effects of an e-& mHealth intervention on physical activity and/or diet behaviour. Respectively, 50 % and 70 % of the interventions were effective in promoting physical activity and healthy diets.Conclusions: The majority of studies demonstrated that e-& mHealth interventions were effective in promoting physical activity and healthy diets in developing countries. Future interventions should use more rigorous study designs, investigate the cost-effectiveness and reach of interventions, and focus on emerging technologies, such as smart phone apps and wearable activity trackers.Trial registration: The review protocol can be retrieved from the PROSPERO database (Registration ID: CRD42015029240)

The Obemat2.0 Study: A Clinical Trial of a Motivational Intervention for Childhood Obesity Treatment.

The primary aim of the Obemat2.0 trial was to evaluate the efficacy of a multicomponent motivational program for the treatment of childhood obesity, coordinated between primary care and hospital specialized services, compared to the usual intervention performed in primary care. This was a cluster randomized clinical trial conducted in Spain, with two intervention arms: motivational intervention group vs. usual care group (as control), including 167 participants in each. The motivational intervention consisted of motivational interviewing, educational materials, use of an eHealth physical activity monitor and three group-based sessions. The primary outcome was body mass index (BMI) z score increments before and after the 12 (+3) months of intervention. Secondary outcomes (pre-post intervention) were: adherence to treatment, waist circumference (cm), fat mass index (z score), fat free mass index (z score), total body water (kg), bone mineral density (z score), blood lipids profile, glucose metabolism, and psychosocial problems. Other assessments (pre and post-intervention) were: sociodemographic information, physical activity, sedentary activity, neuropsychological testing, perception of body image, quality of the diet, food frequency consumption and foods available at home. The results of this clinical trial could open a window of opportunity to support professionals at the primary care to treat childhood obesity. The clinicaltrials.gov identifier was NCT02889406

Baseline characteristics of patients in the reduction of events with darbepoetin alfa in heart failure trial (RED-HF)

<p>Aims: This report describes the baseline characteristics of patients in the Reduction of Events with Darbepoetin alfa in Heart Failure trial (RED-HF) which is testing the hypothesis that anaemia correction with darbepoetin alfa will reduce the composite endpoint of death from any cause or hospital admission for worsening heart failure, and improve other outcomes.</p> <p>Methods and results: Key demographic, clinical, and laboratory findings, along with baseline treatment, are reported and compared with those of patients in other recent clinical trials in heart failure. Compared with other recent trials, RED-HF enrolled more elderly [mean age 70 (SD 11.4) years], female (41%), and black (9%) patients. RED-HF patients more often had diabetes (46%) and renal impairment (72% had an estimated glomerular filtration rate <60 mL/min/1.73 m2). Patients in RED-HF had heart failure of longer duration [5.3 (5.4) years], worse NYHA class (35% II, 63% III, and 2% IV), and more signs of congestion. Mean EF was 30% (6.8%). RED-HF patients were well treated at randomization, and pharmacological therapy at baseline was broadly similar to that of other recent trials, taking account of study-specific inclusion/exclusion criteria. Median (interquartile range) haemoglobin at baseline was 112 (106–117) g/L.</p> <p>Conclusion: The anaemic patients enrolled in RED-HF were older, moderately to markedly symptomatic, and had extensive co-morbidity.</p&gt

Trends and outcome of neoadjuvant treatment for rectal cancer: A retrospective analysis and critical assessment of a 10-year prospective national registry on behalf of the Spanish Rectal Cancer Project

Introduction: Preoperative treatment and adequate surgery increase local control in rectal cancer. However, modalities and indications for neoadjuvant treatment may be controversial. Aim of this study was to assess the trends of preoperative treatment and outcomes in patients with rectal cancer included in the Rectal Cancer Registry of the Spanish Associations of Surgeons. Method: This is a STROBE-compliant retrospective analysis of a prospective database. All patients operated on with curative intention included in the Rectal Cancer Registry were included. Analyses were performed to compare the use of neoadjuvant/adjuvant treatment in three timeframes: I)2006–2009; II)2010–2013; III)2014–2017. Survival analyses were run for 3-year survival in timeframes I-II. Results: Out of 14, 391 patients, 8871 (61.6%) received neoadjuvant treatment. Long-course chemo/radiotherapy was the most used approach (79.9%), followed by short-course radiotherapy ± chemotherapy (7.6%). The use of neoadjuvant treatment for cancer of the upper third (15-11 cm) increased over time (31.5%vs 34.5%vs 38.6%, p = 0.0018). The complete regression rate slightly increased over time (15.6% vs 16% vs 18.5%; p = 0.0093); the proportion of patients with involved circumferential resection margins (CRM) went down from 8.2% to 7.3%and 5.5% (p = 0.0004). Neoadjuvant treatment significantly decreased positive CRM in lower third tumors (OR 0.71, 0.59–0.87, Cochrane-Mantel-Haenszel P = 0.0008). Most ypN0 patients also received adjuvant therapy. In MR-defined stage III patients, preoperative treatment was associated with significantly longer local-recurrence-free survival (p < 0.0001), and cancer-specific survival (p < 0.0001). The survival benefit was smaller in upper third cancers. Conclusion: There was an increasing trend and a potential overuse of neoadjuvant treatment in cancer of the upper rectum. Most ypN0 patients received postoperative treatment. Involvement of CRM in lower third tumors was reduced after neoadjuvant treatment. Stage III and MRcN + benefited the most