The thermal transmittance of building envelopes determines to a large extent the energy demand of buildings. Thus, there is a keen interest in having methods which can precisely evaluate thermal transmittance. From a scientific point of view, this study analyses the viability of the application of the thermometric method (THM), one of the most used methods in Spain. For this purpose, the test method has been improved by determining the adequate test conditions, the selection and installation of equipment, data acquisition and post-processing, and the estimation of uncertainty. We analyse eight case studies in a Mediterranean climate (Csa) to determine the potentials and limitations of the method. The results show that the values obtained through THM are valid under winter environmental conditions with relative uncertainties between 6% and 13%, while difficulties to perform the test in optimal conditions, and therefore to obtain valid results in warmer seasons, are detected. In this regard, the case studies which obtained a greater number of observations by performing the filtrate conditions were able to obtain representative results. Furthermore, there are significant differences depending on the kind of equipment and probes used during the experimental campaign. Finally, in warm climate regions a data filtrate can be considered for observations of a temperature difference higher than 5 °C, obtaining valid results for the case studies, although the rise in the thermal gradient can guarantee a greater stability of data.

The performances of expanded clay aggregate and wood ash as internal curing water reservoirs were studied in the mortar phase of a hypothetical high performance concrete with a low water-to-binder ratio. The two materials substituted the 15 and 30% of the sand volume. Two different binders, Portland cement and high-volume fly ash blended cement, were used. The compressive strength and the volume stability of the mortars in sealed and air-drying conditions were studied. Furthermore, the desorption capacity of the internal curing water reservoirs and the internal humidity inside the mortars during the first days after casting were analysed. The results shown that the reduction in the self-desiccation shrinkage was higher when the expanded clay aggregate was used, even in air-drying curing conditions, due to its higher desorption capacity in low-relative-humidity environments in comparison to that of the wood ash. However, wood ash had a stronger beneficial effect on early age autogenous shrinkage without significantly increasing the drying shrinkage. The two alternative aggregates influenced the strength moderately. Considering the technical, economic, and environmental implications of using the two lightweight aggregates, wood ash is recommended.

En España, la mayor parte del parque inmobiliario presenta un comportamiento energético deficiente. Para paliar dicha situación, se debe analizar, entre otros aspectos, su envolvente. De las diferentes propiedades que caracterizan los cerramientos, la transmitancia térmica es una de las más significativas. Sin embargo, las metodologías de evaluación in situ están planteadas para climas fríos, y los métodos teóricos tienen asociados una incertidumbre elevada. Ante esta circunstancia, resulta necesario estudiar su aplicación en climas suaves como el mediterráneo. El presente estudio analizó tanto los métodos teóricos existentes como los experimentales. Para ello se realizó una monitorización sobre cuatro casos de estudio durante el invierno. Los resultados pusieron de manifiesto que, con unas condiciones metrológicas correctas y una estabilidad de las condiciones ambientales, se pueden obtener resultados representativos.