Assessing and monitoring with ultrasonic pulse velocity testing the critical effects of hygrothermal actions on the infill masonry walls of the envelope of buildings with reinforced concrete structure

Abstract

The external envelope of buildings with reinforced concrete structures (RCS buildings) is usually subjected to various external environmental actions. Among these external environmental actions, hygrothermal actions are particularly relevant, mainly related to external temperature and humidity variations. These variations could negatively influence the hygrothermal behavior of that envelope and lead to problems related to an increased risk of material degradation of the external face of unreinforced masonry (URM) infill walls of the building envelope URM infill. In the survey of the degradation of these URM infill walls and of concrete elements, nondestructive evaluation (NDE), such as ultrasonic pulse velocity testing (UPV testing), had been used before. The main objective of the study is to assess the potential use of UPV testing in the evaluation of the influence of moisture content in the behavior of URM infill walls, and the methodology of the study consists, firstly, concerning the hygrothermal actions, which RCS buildings are subjected, which are here described summarily. An assessment is made of the most usual types of degradation of URM infill walls of the envelope of RCS buildings, mainly due to moisture and thermal effects in URM infill walls. UPV testing in the survey of the degradation of the external face of URM infill walls of the building envelope, essentially due to hygrothermal actions, is analyzed, based on an example of the use of UPV testing in a building façade. Subsequently, the potential use of UPV testing in evaluating the influence of moisture content in the behavior of URM infill wall is made, particularly with the use of UPV testing in a compression test of a masonry specimen with variable moisture content during the test. Their results are presented, followed by a discussion of these results, and finally by the conclusions of the study.