Moisture expansion of clay bricks and brickwork

Bricks made from clay and shale expand after firing due to the effects of moisture. The expansion continues for many years, although the rate decreases greatly with time. The amount of moisture expansion is not uniform, varying over a range from about 0.03% to about 20%, depending on the raw materials used in brick manufacture and on the temperature at which the bricks are fired. The moisture expansion of bricks results in the expansion of walls that may lead to their cracking if movement joints are not provided to accomodate the expansion.La brique d'argile solidifi\ue9e se dilate durant un incendie, en raison de l'humidit\ue9. L'expansion, qui se poursuit pendant plusieurs ann\ue9es, s'att\ue9nue toutefois de fa\ue7on importante au fil du temps. Le degr\ue9 d'expansion par l'humidit\ue9 est irr\ue9gulier et varie d'environ 0,03 % \ue0 20 %, selon les mati\ue8res brutes utilis\ue9es dans la fabrication de la brique et la temp\ue9rature \ue0 laquelle la brique est expos\ue9e. L'expansion de la brique par l'humidit\ue9 provoque l'expansion du mur, laquelle risque de causer des fissures si les joints ne sont pas con\ue7us pour permettre une expansion.Peer reviewed: NoNRC publication: Ye