Historical mortars from sixteenth to seventeenth century military forts located at the mouth of the Tagus River in Lisbon have been characterized by polarized light microscopy (PLM), thermal analysis (TG/DTA), X-ray diffractometry (XRD) and scanning electron microscopy + energy dispersive spectroscopy (SEM + EDS). The results indicate that the mortars used were all hydraulic lime-based. The presence of well-rounded lime lumps indicates a limited use of water during the lime hydration process. The detection of hydrated calcium chloroaluminate and carboaluminate compounds mostly at binder-aggregate interfaces provides evidence for the onset of pozzolanic reactions during mortar production as further confirmed by the presence of ceramic fragments in the aggregate fractions intentionally added by the fort builders to increase the hydraulic properties of the mortars. The higher mechanical strength and greater resistance to degradation processes imparted by these pozzolanic compounds could explain why, despite the extreme proximity of the investigated sites to the sea, salt weathering processes do not appear to have significantly affected the studied mortars.

Alentejo's religious buildings reflect undoubtedly the history and character of this southern Portugal region. Conservation of these buildings requires a deep knowledge of their masonry and renders' lime mortars to evaluate correctly their state of conservation, to avoid progression of pathologic situations, and to plan efficient interventions, with repair and substitution materials with similar characteristics. This article presents a synthesis of the main results obtained in the mortar characterization of religious buildings from Alentejo, which include Evora and Elvas Cathedrals, Mertola Mosque, and the Church of Amieira do Tejo. For each monument, several samples were collected from different sites and a set of tests was carried out, including chemical, mineralogical, and micro-structural tests, as well as physical and mechanical tests. The tested mortars correspond to different phases of construction and interventions on the buildings, comprising mainly origin periods from the twelfth to the eighteenth centuries; hence exhibited significant differences in composition and in application techniques. The obtained results of composition have given important information about the provenance of the materials used, including binder and sand types, and also about decay products and their correlation with the mortar's conservation state, which gave important clues on the repair strategy to adopt.

Evora Cathedral (one of the most emblematic monuments of Evora - Portugal) has suffered several conservation and restoration interventions through the ages, without, however, any type of previous knowledge about mortars and materials used. This work was carried out in order to identify the mortar's composition in different locations, which were attributed to different construction or conservation periods.The characterisation methodology involved a multidisciplinary set of chemical, physical, microstructural and mechanical techniques, and gave special attention to the use of microstructural characterisation techniques, particularly petrographical analysis and scanning electron microscopy for the identification of the mortar's constituents as well as in the evaluation of the state of conservation.The test results showed that two types of aerial binders were used, dolomitic and calcitic limes, the former being predominant. The aggregates used have a siliceous nature and are similar in composition to the granodiorites of the region around Evora. The mortars differ in the aggregate contents and, in some cases, crushed bricks were used as an additive. (C) 2008 Elsevier Inc. All rights reserved.

Mortars are common and essential elements of masonry historical buildings and are composed by a binder, aggregates and eventually, some additives. The binder provides consistency to this composite material, and until the emergence of Portland cement in the 19th century, lime was the main binder used. The aggregates are normally sand or rock fragments with variable sizes. The whole set is morphologically very similar to a sedimentary clastic rock with carbonate cementing. Following an old tradition of microscope use in this kind of rocks, it is not surprising the application of optical microscopy to mortars as also happened with concrete.

The alkali-silica reaction (ASR) and internal sulfatic reaction (ISR), normally both referred as internal expansive reactions, are among the most common causes of concrete structures deterioration worldwide. These reactions, which could be present simultaneously, origin products those are responsible for expansive stresses in the cement-based building materials, leading to severe cracking and loss of strength. The reaction products are also often amorphous or badly crystallized, or even present in very low content that they are very difficult to identify by current analytical physico-chemical techniques. The main macroscopic evidence of these degradation phenomena in concrete structures are the superficial occurrence of map-cracking, pop-outs and exudates (figure 1). Nevertheless, these symptoms are not exclusive and enough to establish a correct diagnosis.

The study of old mortars composition, using physical-chemical, mineralogical and microstructural characterization has an important role in the preservation of architectural heritage, allowing a deep knowledge about the materials used, construction techniques, possible repairs and degradation processes.

The study of old mortars, based on integrated metho dologies that combine mineralogical, microstructura l, chemical, physical and mechanical characterization has an important role on the preservation of architectonical cultural heritage, allowing a deep knowledge about the materials used, construction techniques, possible repairs and behavior [1-3]. In this context and in the scope of a project betwe en the National Laboratory of Civil Engineering (LNEC), the University of Evora and the Portuguese Institut e of Architectural Heritage (IPPAR) related to the characterization and conservation of traditional an d historical mortars from Alentejo’s religious buil dings, (CATHEDRAL Project - POCI/HEC/57915/2004), different mortars from two important classified monuments, the Santa Maria Church in Evora (Evora’s Cathedral), constructed between 13 th and 16 th centuries, and the Nossa Senhora da Assuncao Church in Elvas (Old Elvas Cathedral), constructed in the 16 th century, were collected and studied. In this work, we present the results of the mineral ogical characterization of the mortars that was accomplished by combining different techniques, namely optical microscopy, scanning electron microscop y coupled with Energy dispersive X-ray spectrometry ( SEM-EDS) and X-ray diffraction (XRD). The combined use of these techniques with the geologica l information allowed a detailed insight on the nat ure of the aggregates and binders, the identification of n eo-formation and alteration products and, in the ca se of Evora Cathedral, even the determination of the prov enance of the aggregates used. Relating this inform ation with historical data of the building it is possible to extract several conclusions about the construct ion materials and techniques used.

Ancient mortars from two Mertola’s important Roman monuments, the River Tower and the Cryptoportic, were characterized by optical microscopy, scanning electron microscopy, X-ray diffraction, thermogravimetric and chemical analyses. The results show that all mortars are calcitic aerial lime mortars and that the aggregates are composed of quartzitic river sand and crushed schist. Samples from the River Tower and particularly sample taken from the outer layer of the Cryptoportic show the presence of crushed ceramics and neoformation pozzolanic reaction compounds.

The study of old mortars, based on integrated metho dologies that combine mineralogical, microstructura l, chemical, physical and mechanical characterization has an important role on the preservation of architectonical cultural heritage, allowing a deep knowledge about the materials used, construction techniques, possible repairs and behavior (1-3). In this context and in the scope of a project betwe en the National Laboratory of Civil Engineering (LNEC), the University of Évora and the Portuguese Institut e of Architectural Heritage (IPPAR) related to the characterization and conservation of traditional an d historical mortars from Alentejo's religious buil dings, (CATHEDRAL Project - POCI/HEC/57915/2004), different mortars from two important classified monuments, the Santa Maria Church in Évora (Evora's Cathedral), constructed between 13 th and 16 th centuries, and the Nossa Senhora da Assunção Church in Elvas (Old Elvas Cathedral), constructed in the 16 th century, were collected and studied. In this work, we present the results of the mineral ogical characterization of the mortars that was accomplished by combining different techniques, namely optical microscopy, scanning electron microscop y coupled with Energy dispersive X-ray spectrometry ( SEM-EDS) and X-ray diffraction (XRD). The combined use of these techniques with the geologica l information allowed a detailed insight on the nat ure of the aggregates and binders, the identification of n eo-formation and alteration products and, in the ca se of Évora Cathedral, even the determination of the prov enance of the aggregates used. Relating this inform ation with historical data of the building it is possible to extract several conclusions about the construct ion materials and techniques used.