Elier Pavón

Criteria for Identification of Ceramic Detachments in Building Facades with Infrared Thermography

Infrared thermography is a nondestructive technique with great application potential to study the pathologies of buildings. The use of passive thermography to evaluate building facades subjected to sun incidence has allowed interesting advances in the identification of regions with initial detachments that are not visible on the facade surfaces. There are, however, several difficulties in the methodology, especially regarding the best moment to visualize the anomalies. These moments depend mainly on the heat flow in the facade, which is not constant. The objective of this study is to identify the best conditions to visualize the anomalies by performing field and laboratory studies to evaluate delta-T and contrast functions. To this end, a laboratory study was developed. It consisted of heating and cooling experimental base plates with manufactured internal defects, which were monitored by a sequence of thermograms obtained continuously. The field study consisted of evaluating an area of a building facade with detachment patches. The thermal evolution of the facade was monitored continuously by thermography for 10 h. The results indicate that delta-T cannot be used as the sole parameter to identify the anomalies. It is also highlighted that knowing the direction of heat flow is important since the contrast functions have shown that the anomalies are best visualized at the beginning of the heat flow, heating or cooling. It proved that the criteria obtained in the laboratory are applicable to field studies, especially if it is possible to analyze previously the heat flow on the facade.

Propiedades del hormigón de árido reciclado fabricado con adiciones, activa e inerte

El trabajo de investigacion presentado en este articulo describe las propiedades fisicas, mecanicas y de durabilidad de los hormigones fabricados con el 25% y 100% de arido grueso reciclado utilizando adiciones activa e inerte (microsilice y filler de escoria de arco electrico). La fase experimental realizada consta de dos etapas: En la etapa 1 se realizo un estudio fisico-mecanico (resistencia a compresion y velocidad de ultrasonido); En la etapa 2 se evaluo la durabilidad de los hormigones reciclados fabricados con adiciones mediante los ensayos de difusion de cloruros, resistividad, absorcion y porosidad, lo que permitio comparar los resultados con el hormigon convencional fabricado con similar dosificacion. Los resultados demuestran que los hormigones reci-clados obtienen propiedades fisicas y mecanicas inferiores al hormigon convencional. Sin embargo, la durabilidad del hormigon reciclado fabricado con adiciones activas mejora las propiedades del hormigon convencional.