Ibero-American Project Research Articles

Concrete Carbonation in Mexico and Spain: DURACON Project, Four Year Evaluation

This work is part of the DURACON Ibero-American project, which seeks to characterize concrete durability under environmental conditions, based on reinforced concrete sample exposure in at least two different atmospheres (marine and urban), for each of the 11 countries in the project. Specimens were exposed to the environmental conditions of 13 Mexican sites (8 urban and 5 marine atmospheres). Concrete specimens were 15 x 15 x 30 cm, with 6 rebars each, and three concrete covers (15, 20 and 30 cm). Two concrete mixtures were used with water/cement ratios of 0.45 and 0.65, respectively. Six reinforced and six plain concrete specimens were placed on each exposure site. Environmental data was collected on each exposure site, including rainfall, relative humidity, time of wetness, temperature, wind velocity, and carbon dioxide/chloride concentrations. Corrosion rates and potentials, as well as concrete resistivity were measured in the reinforced samples. Carbonation depths were measured on the plain ones. The present work focused on the measurements of environmental parameters during the first two years of exposure to analyze the potentiality and the probability of carbonation-induced corrosion, and the evaluation of the corrosion initiation period for the reinforcing steel on the 13 Mexican exposure sites.

Reinforced Concrete Durability in Marine Environments DURACON Project: Long-Term Exposure

This paper presents the results, after a long-term evaluation in marine environments, from an Ibero-American project called “Effect of the environment on reinforcement durability” (DURACON). This p...

Investigaciones cooperativas iberoamericanas sobre ciencia-tecnología-sociedad. Dos proyectos ejemplares sobre evaluación y enseñanza de temas concretos

El artículo presenta dos proyectos de investigación cooperativa desarrollados por diversas instituciones en un conjunto de países (europeos y americanos) de lenguas ibéricas entre 2005 y 2013, período que incluye los procesos de preparación para solicitarlos y la fecha de finalización del segundo de ellos, actualmente en desarrollo. Aunque ambos fueron planificados antes de la publicación del documento sobre las Metas Educativas 2021, los objetivos e indicadores aplicados a la investigación educativa y a la educación en ciencia y tecnología (cyt) de dichas Metas coinciden con los objetivos de las dos iniciativas ejemplares, que tienen como marco la orientación ciencia-tecnología-sociedad (cts), ahora también denominada naturaleza de ciencia y tecnología (ndcyt).En el primero «Proyecto iberoamericano de evaluación de actitudes relacionadas con la ciencia, la tecnología y la sociedad» (piearcts), se realizó una evaluación transnacional de las actitudes y creencias que, respecto de esas cuestiones, tienen los estudiantes y profesores de los países participantes. La muestra final evaluada superó las 16.000 personas, y los resultados señalan que ni los docentes ni los alumnos poseen una adecuada comprensión de muchos de los temas de cts-ndcyt y que esas creencias varían entre grupos (entre países, ciencias y humanidades, hombres y mujeres, estudiantes universitarios de primer y último año, profesores en formación y profesores con experiencia).En el segundo proyecto, «Enseñar y aprender acerca de la naturaleza de ciencia y tecnología (eancyt): una propuesta innovadora para la educación», se diseñan secuencias didácticas para enseñar contenidos específicos de cts-ndcyt a estudiantes en sus aulas a fin de evaluar empíricamente su eficacia y calidad educativas. Se han ideado y elaborado secuencias sobre cuatro decenas de temas que, en la actualidad, se aplican en los salones de clase de los países participantes. Para terminar, se comentan aspectos concretos e impacto de la puesta en práctica de ambas iniciativas de cooperación y se mencionan los beneficios que para la práctica educativa tienen los materiales creados y los resultados de eficacia obtenidos en su aplicación experimental, disponibles para los docentes

Influence of the coating on the corrosion rate in concrete beams exposed to environment - DURACON Project

This work is part of the DURACON iberoamerican project, which deals with the characterization of the concrete durability exposed to environmental conditions at Iberoamerica, through the exposure of reinforced concrete specimens in at least two different environments, one marine and one urban, in each participating country. In this paper, results of the first eight months of the specimen exposition to environmental conditions in the Xalapa city, Mexico, are evaluated. The specimens were built with two types of concretes at 0.45 and 0.65 water/cement ratios. In all cases, the same type of cement with three thicknesses (1.5, 2.0 and 3.0 cm) of covering were used. The tests to evaluate the susceptibility to corrosion of the reinforced steel were resistance to linear polarization and monitoring of the corrosion potentials according to the ASTM C-876 norm.

Durability of concrete structures: DURACON, an iberoamerican project. Preliminary results

This work presents preliminary results of the international project: “Effect of the environment on reinforced concrete durability: DURACON”, which shows the physical, mechanical and chemical characterization of two different concrete mixtures prepared in the participating countries, as well as the environment to which the specimens are exposed. These results show the potentiality and probability of future reinforcement corrosion, depending on the type of mixture and the environment to which the structure is exposed. To that effect, concrete specimens, with and without reinforcement, were prepared for electrochemical and physical/mechanical/chemical testing using the existing materials in each participating country, following premises that enabled the preparation of similar concrete specimens. Two water/cement ratios (0.45 and 0.65) were selected, where the concrete with w / c = 0.45 had to have a minimum cement content of 400 kg m −3, and the other with w / c = 0.65 , a minimum compressive strength of 21 MPa. Ordinary Portland Cement (OPC), crushed coarse aggregate, and silica sand were used for concrete preparation. The specimens were exposed to several microenvironments including urban and marine conditions (at least two testing sites in each country), resulting into a total of 46 test sites distributed among 11 countries (Argentina, Bolivia, Brazil, Chile, Colombia, Costa Rica, Mexico, Spain, Uruguay, Portugal, and Venezuela). The environment was evaluated using ISO Standard 9223 and the concrete was characterized by measuring compressive strength, modulus of elasticity, total and effective porosity, and rapid chloride permeability according to ASTM standards, as well as resistance to water absorption, using the Fagerlund method. After 1-year exposure, some results of the corrosion potentiality and probability analysis of the reinforcement in several test sites based on environmental meteorochemical parameters show that, for specific microclimates like those in marine atmospheres, the most aggressive environment is that at Cabo Raso test site in Portugal, inducing the greater steel-corrosion probability. The least aggressive is the one at Valparaíso in Chile. It was also determined that Maracaibo, Venezuela, is the one that has the greatest probability of early rebar corrosion initiation by carbonation, with the test site at Cali, Colombia being the one that would induce the least corrosion probability.

Atmospheric corrosion of zinc Part 2: Marine atmospheres

AbstractThis paper summarises the results obtained in the MICAT (Mapa Ibero-Americano de Corrosao Atmosferica (Latin American Map of Atmospheric Corrosion)) atmospheric corrosion project (an Iberoamerican project on atmospheric corrosion, involving 14 countries and 75 atmospheric test sites) for zinc specimens exposed in the Latin American region for 1–4 years at 23 pure marine and 19 mixed marine (i.e. SO2 polluted) sites. The atmospheres at these sites were characterised climatologically and in terms of their pollution levels so that their corrosivity could be expressed in accordance with ISO standards. Morphological and chemical characterisation of the zinc corrosion product layers (ZCPLs) was performed using scanning electron microscopy coupled with energy dispersive spectrometry (SEM–EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and soluble salt evaluation techniques. The results obtained show that the corrosion rate of zinc is a function of both the chloride pollutio...

Atmospheric corrosion of zinc Part 1: Rural and urban atmospheres

AbstractThis paper summarises the results obtianed in the MICAT (Mapa Ibero-Americano de Corrosao Atmosferica (Latin American Map of Atmospheric Corrosion)) atmospheric corrosion project (an Iberoamerican project on atmospheric corrosion, involving 14 countries and 75 atmospheric test sites) for zinc specimens exposed for 1–4 years in 21 rural and urban atmospheres of the Latin American region. During the study, all of these atmospheres were characterised according to international standards. Complementary morphological and chemical studies were carried out using scanning electron microscopy coupled with energy dispersive spectrometry (SEM–EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) techniques, in order to correlate atmospheric characteristics and the properties of zinc corrosion product layers (ZCPLs). Soluble salts retained in these ZCPLs were also determined. The study has provided clear evidence about the wide range of zinc corrosion rates occurring in rural atmos...

CYTED-D AHI: An Ibero American project on intermediate moisture foods and combined methods technology

The CYTED-D project on intermediate moisture foods and combined methods technology (CYTED-D AHI) involved during a 4-year period 60 research centers in Ibero America and over 300 scientific and technical personnel. Major advances were made in preservation of local foods such as meats and meat products, milk and dairy products, fruits and vegetables and marine products by reduction of the water activity and the use of combined factors (mild heating, low pH, preservatives, etc.). The rationale, objectives, organizational aspects, major technological accomplishments and shortfalls are discussed in this paper. This technological development deserves a closer look, particularly by food technologists from less developed countries, where refrigeration facilities are scarce.

RecombinantTrypanosoma cruziantigens and Chagas' disease diagnosis: analysis of a workshop

A workshop organized by the Ibero-American Project of Biotechnology evaluated the diagnostic potential of several cloned Trypanosoma cruzi recombinant antigens for Chagas' disease serodiagnosis. A set of recombinants, Antigen 2, Antigen 13, SAPA, H49, A13, JL5, JL7, JL8, JL9, and RA1 provided by three different South American laboratories were probed with a panel of 236 South American serum samples. Antigens JL7, H49, Antigen 2, and A13 scored as the best diagnostic recombinant reagents. The results suggested that the main advantage of using cloned peptides for chronic Chagas' disease diagnosis resided in their highly specific immunoreactive properties.