The challenge on development of repair mortars for historical buildings in severe marine environment: Paimogo fort, a case study

Abstract

The Paimogo fort, listed as a public interest property in 1957, is one of the several Portuguese military fortifications built near the ocean, in the 17th century. Within the scope of the restoration project developed by the Municipality of Lourinhã and its partners, for the revitalization and safeguarding of the Paimogo's fort, an extensive characterization of the original mortars was made and new repair mortars are being developed by National Laboratory for Civil Engineering. In this paper the development of the durable and compatible repair mortars for this case study is described. Some compositions based on the original mortars’ composition and characteristics, are briefly described and their main physical and mechanical characteristics are analysed and compared in successive ages. Applications of the same mortars on porous composite substrates were subjected to real environmental conditions in the Fort external area to check their performance and durability. The experimental results showed the importance of the in situ applications, since distinct behaviour was found. Moreover, it reveals that all the studied mortars absorb high volume of water and have low strength and higher deformability, when compared to the original ones. Thus, the choice of the formulations for application as a substitution render of the Fort walls is still in process of evaluation. Their performance and durability are being studied at longer ages and the formulations will be finetuned for further evaluation.