COrrosión del concreto reforzado y DEgradación de sus propiedades MECánicas (CODE_MEC1): Etapa 1 Estudio experimental y modelación computacional de la carbonatación del concreto

Proyecto de Investigación (Código: 1490017) Instituto Tecnológico de Costa Rica. Vicerrectoría de Investigación y Extensión (VIE). Escuela de Ciencia e Ingeniería de los Materiales, Escuela de Ingeniería en Construcción, 2018En el sector civil de la construcción, el concreto y el refuerzo metálico representan aun los materiales de mayor importancia, aunque sean muy vulnerables por los agentes atmosféricos, como en el caso de su degradación por corrosión. En Costa Rica debido a la falta de métodos de monitoreo de las estructuras existentes, sumado a una deficiente política preventiva en términos de mantenimiento, se hace urgente el desarrollo de modelos predictivos que permitan intervenir a tiempo cualquier tipología de estructura antes de que comprometa de alguna forma la integridad de los usuarios. En este informe se presentan los resultados de un proyecto de investigación que abarca el estudio de la carbonatación del concreto por causa del gas CO2. En el proyecto se considera solamente el estudio experimental y la modelación de la carbonatación sin la presencia del refuerzo metálico. Se usan métodos de carbonatación en cámara acelerada y ensayos de difracción de rayos X, químicos y no destructivos con el objeto de obtener datos experimentales que sirvan de base para el desarrollo de un modelo computacional del mecanismo reactivo-difusivo de carbonatación. El modelo computacional ha sido validado comparando los resultados numéricos con los valores experimentales obtenidos con la campaña experimental. De acuerdo a los resultados obtenidos se puede concluir que el modelo describe satisfactoriamente el proceso de carbonatación y simula correctamente el avance del frente de carbonatación en el tiempo

Association of Adverse Pregnancy Outcomes With Hypertension 2 to 7 Years Postpartum

Background Identifying pregnancy-associated risk factors before the development of major cardiovascular disease events could provide opportunities for prevention. The objective of this study was to determine the association between outcomes in first pregnancies and subsequent cardiovascular health. Methods and Results The Nulliparous Pregnancy Outcomes Study Monitoring Mothers-to-be Heart Health Study is a prospective observational cohort that followed 4484 women 2 to 7 years (mean 3.2 years) after their first pregnancy. Adverse pregnancy outcomes (defined as hypertensive disorders of pregnancy, small-for-gestational-age birth, preterm birth, and stillbirth) were identified prospectively in 1017 of the women (22.7%) during this pregnancy. The primary outcome was incident hypertension (HTN). Women without adverse pregnancy outcomes served as controls. Risk ratios (RR) and 95% CIs were adjusted for age, smoking, body mass index, insurance type, and race/ethnicity at enrollment during pregnancy. The overall incidence of HTN was 5.4% (95% CI 4.7% to 6.1%). Women with adverse pregnancy outcomes had higher adjusted risk of HTN at follow-up compared with controls (RR 2.4, 95% CI 1.8-3.1). The association held for individual adverse pregnancy outcomes: any hypertensive disorders of pregnancy (RR 2.7, 95% CI 2.0-3.6), preeclampsia (RR 2.8, 95% CI 2.0-4.0), and preterm birth (RR 2.7, 95% CI 1.9-3.8). Women who had an indicated preterm birth and hypertensive disorders of pregnancy had the highest risk of HTN (RR 4.3, 95% CI 2.7-6.7). Conclusions Several pregnancy complications in the first pregnancy are associated with development of HTN 2 to 7 years later. Preventive care for women should include a detailed pregnancy history to aid in counseling about HTN risk

Early Pregnancy Atherogenic Profile in a First Pregnancy and Hypertension Risk 2 to 7 Years After Delivery

Background: Cardiovascular risk in young adulthood is an important determinant of lifetime cardiovascular disease risk. Women with adverse pregnancy outcomes (APOs) have increased cardiovascular risk, but the relationship of other factors is unknown. Methods and Results: Among 4471 primiparous women, we related first-trimester atherogenic markers to risk of APO (hypertensive disorders of pregnancy, preterm birth, small for gestational age), gestational diabetes mellitus (GDM) and hypertension (130/80 mm Hg or antihypertensive use) 2 to 7 years after delivery. Women with an APO/GDM (n=1102) had more atherogenic characteristics (obesity [34.2 versus 19.5%], higher blood pressure [systolic blood pressure 112.2 versus 108.4, diastolic blood pressure 69.2 versus 66.6 mm Hg], glucose [5.0 versus 4.8 mmol/L], insulin [77.6 versus 60.1 pmol/L], triglycerides [1.4 versus 1.3 mmol/L], and high-sensitivity C-reactive protein [5.6 versus 4.0 nmol/L], and lower high-density lipoprotein cholesterol [1.8 versus 1.9 mmol/L]; P<0.05) than women without an APO/GDM. They were also more likely to develop hypertension after delivery (32.8% versus 18.1%, P<0.05). Accounting for confounders and factors routinely assessed antepartum, higher glucose (relative risk [RR] 1.03 [95% CI, 1.00-1.06] per 0.6 mmol/L), high-sensitivity C-reactive protein (RR, 1.06 [95% CI, 1.02-1.11] per 2-fold higher), and triglycerides (RR, 1.27 [95% CI, 1.14-1.41] per 2-fold higher) were associated with later hypertension. Higher physical activity was protective (RR, 0.93 [95% CI, 0.87-0.99] per 3 h/week). When evaluated as latent profiles, the nonobese group with higher lipids, high-sensitivity C-reactive protein, and insulin values (6.9% of the cohort) had increased risk of an APO/GDM and later hypertension. Among these factors, 7% to 15% of excess RR was related to APO/GDM. Conclusions: Individual and combined first-trimester atherogenic characteristics are associated with APO/GDM occurrence and hypertension 2 to 7 years later

A many-analysts approach to the relation between religiosity and well-being

The relation between religiosity and well-being is one of the most researched topics in the psychology of religion, yet the directionality and robustness of the effect remains debated. Here, we adopted a many-analysts approach to assess the robustness of this relation based on a new cross-cultural dataset (N=10,535 participants from 24 countries). We recruited 120 analysis teams to investigate (1) whether religious people self-report higher well-being, and (2) whether the relation between religiosity and self-reported well-being depends on perceived cultural norms of religion (i.e., whether it is considered normal and desirable to be religious in a given country). In a two-stage procedure, the teams first created an analysis plan and then executed their planned analysis on the data. For the first research question, all but 3 teams reported positive effect sizes with credible/confidence intervals excluding zero (median reported β=0.120). For the second research question, this was the case for 65% of the teams (median reported β=0.039). While most teams applied (multilevel) linear regression models, there was considerable variability in the choice of items used to construct the independent variables, the dependent variable, and the included covariates

A Many-analysts Approach to the Relation Between Religiosity and Well-being

The relation between religiosity and well-being is one of the most researched topics in the psychology of religion, yet the directionality and robustness of the effect remains debated. Here, we adopted a many-analysts approach to assess the robustness of this relation based on a new cross-cultural dataset (N = 10, 535 participants from 24 countries). We recruited 120 analysis teams to investigate (1) whether religious people self-report higher well-being, and (2) whether the relation between religiosity and self-reported well-being depends on perceived cultural norms of religion (i.e., whether it is considered normal and desirable to be religious in a given country). In a two-stage procedure, the teams first created an analysis plan and then executed their planned analysis on the data. For the first research question, all but 3 teams reported positive effect sizes with credible/confidence intervals excluding zero (median reported β = 0.120). For the second research question, this was the case for 65% of the teams (median reported β = 0.039). While most teams applied (multilevel) linear regression models, there was considerable variability in the choice of items used to construct the independent variables, the dependent variable, and the included covariates

Estudio experimental de la carbonatación del concreto

In the construction sector, the concrete and the steel bars represent still the key components, although they are very vulnerable by the atmospheric agents, as in the case of their degradation caused by corrosion. In Costa Rica, due to the absence of effective monitoring methods of civil structures and preventive maintenance actions, predictive model are required to avoid damages to the structure and protect the safety of the users. In this work, we present the results of a study for the carbonation due to the CO2 gas, considering the experimental study of the concrete carbonation without the reinforcing bar. We use an accelerated carbonation chamber under strictly controlled conditions, X ray diffraction and chemical analysis to verify the progress of the carbonation depth in time. The experimental results show the effectiveness of the accelerated carbonation process and give the compression strength of the concrete samples for the different carbonation depth measured in time.En el sector civil de la construcción, el concreto y el refuerzo metálico representan aun los materiales de mayor importancia, aunque sean muy vulnerables por los agentes atmosféricos, como en el caso de su degradación por corrosión. En Costa Rica, debido a la falta de métodos de monitoreo de las estructuras existentes y a una deficiente política preventiva en términos de mantenimiento, se hace urgente el desarrollo de modelos predictivos que permitan intervenir a tiempo las estructuras antes de que se comprometa de alguna forma la integridad de los usuarios. En este artículo se presentan los resultados de una investigación sobre la carbonatación por causa del gas CO2, considerando el estudio experimental de la carbonatación del concreto sin la presencia del refuerzo metálico. Se usan métodos de carbonatación en cámara acelerada bajo condiciones muy controladas, ensayos de difracción de rayos X y químicos con el propósito de verificar el avance de la profundidad de carbonatación en el tiempo. Los resultados experimentales demuestran la efectividad del proceso en la cámara de carbonatación acelerada y brindan la variación de la resistencia a compresión de los especímenes de concreto, con el avance del frente de carbonatación en el tiempo