Moisture Induced Movement in Masonry Walls

Abstract

Masonry walls constructed out of fired clay or calcium silicate bricks undergo expansion due to the presence of moisture in cement mortar, cement render and wall tiling fixatives. This movement is not permanent and after the initial period of expansion the movement is reversed due to the loss of moisture. Such masonry walls also exhibit permanent movements. Calcium silicate walls undergo long term shrinkage while clay brick walls develop long term expansion. This research has shown that the timing of render application on calcium silicate brick walls influences the rate of long term contraction. The test wall which was naturally cured over a shorter period prior to the application of cement render developed comparatively lower compressive strain than the wall naturally cured over a longer time period. However, no meaningful relationship between the length of natural curing and the application of render was found for clay brick walls. This was possibly due to a relatively short testing period (142 days), s...