The development of a computational model for low bond strength brick masonry is described. Cracking and failure in such masonry occurs typically at the interface between the masonry units and the mortar joints. As a result software based on a 2- dimensional discrete element analysis (UDEC) was used. One feature of the research was the method used to identify the material parameters for the constitutive model. The conventional method of obtaining material parameters from the results of testing small samples of masonry was thought to be problematic. Instead, the material parameters were obtained from the results of tests carried out in the laboratory on single leaf wall panels, each containing a large opening. Each panel was subjected to a gradually increasing vertical in-plane static point load until it collapsed. The wall panel tests were also modelled using UDEC. An optimization procedure was then used to tune the parameters used initially in UDEC in order to better simulate the pre- and post-cracking behaviour and the behaviour close to collapse of the panels tested in the laboratory. Having obtained the material parameters for UDEC, the model was then validated by comparing the UDEC-predicted behaviour of wall panels different to those used to determine the material parameters, with those tested in the laboratory. Some of the panels used for the validation process were reinforced with bed joint reinforcement, others were unreinforced but were of deeper and longer span construction. Good correlation was obtained between the results from the computational model and those obtained from tests in the laboratory.

Le recyclage ou la réutilisation des déchets de démolition de maisons individuelles, de petits collectifs et de sites industriels édifiés en terre cuite, est actuellement limité par la présence de déchets composites, formés par l’assemblage de terre cuite, de mortier et / ou de plâtre principalement. Dans l’optique de valoriser la terre cuite dans la même filière ou dans d’autres secteurs industriels, la présence de plâtre, pouvant générer des ions sulfates au contact de l’eau, est un obstacle. La principal option de fin de vie des déchets de terre cuite en mélange est ainsi l’enfouissement en installation de stockage de classe 3. Le but de cette thèse a été de développer une méthode de séparation des déchets de démolition de terre cuite, plus intéressante d’un point de vue environnemental que l’enfouissement, et permettant de récupérer des matières premières secondaires de terre cuite valorisables dans des filières pertinentes. Une étude du gisement a été réalisée afin d’établir la nature des assemblages en présence dans les déchets de déconstruction et de fournir des échantillons représentatifs. Ces échantillons ont permis la détermination des mécanismes d’adhésion des interfaces. Une méthode de séparation a ainsi été développée et la compatibilité des matières premières secondaires de terre cuite a été comparée vis-à-vis de trois filières de valorisation. / Recycling or reuse of demolition waste from individual houses, small collectives and industrial sites built with fired clay bricks, is currently limited by the presence of mixed waste, which is mainly an assembly of fired clay bricks, mortar and gypsum. In the perspective to valorize fired clay waste from demolition, the presence of gypsum, which may contain sulfates, is a restriction. Currently, the main end-of-life option for non-dissociated fired clay waste is the landfilling in waste storage facilities of class 3. The aim of this PhD thesis is to develop a separation process of mixed fired clay waste, environmentally more friendly than landfilling, in order to recover and valorize secondary raw materials in relevant industrial sectors. A study of the deposit has been done to identify the nature of the mixed demolition waste and to supply representative waste samples. Those samples enable to define the adhesion mechanisms at the interfaces. Then, a separation method has been developed. Finally, three routes have been investigated in order to valorize the recovered clay bricks.