08-16-2014, 11:35 AM
Design Consideration
The durability of masonry mortars depends upon the volume changes during the process of setting, hardening and later due to temperature variations, moisture movement in the surrounding, changes in its own moisture content and the extent to which mortar will internally accommodate the stresses induced by these volumetric changes before yielding.
The compressive and bond strength of mud mortar decreases with the increase in moisture content in it. The compressive strength decreases by 0.8 to 1 N/mm2 at 6-10 percent moisture content
![[Image: mudgraph.jpg]](http://www.frontdesk.co.in/big/cm/mudgraph.jpg)
The bond between the mortar and masonry units if ruptured by the volumetric changes and the structural movements results not only in reduction in strength of masonry but also in formation of channels of seepage of water and other solutions into the masonry. This would aggravate the process of deterioration and affect resistance to chemical attack in aggressive environment.
Moisture to the extent of 5 to 8 percent by weight is likely to penetrate in the mud mortar even after plastering or pointing the exposed surface of masonry.
Basic stress in masonry with bricks of 7 to 10 N/mm2 and 3.5 N/mm2 shall not exceed 0.2 N/mm2 and 0.1 N/mm2, respectively.
Thickness of mud mortar should not be more than 20 mm in case of brick masonry works and 30 mm in case of stone masonry works.
The durability of masonry mortars depends upon the volume changes during the process of setting, hardening and later due to temperature variations, moisture movement in the surrounding, changes in its own moisture content and the extent to which mortar will internally accommodate the stresses induced by these volumetric changes before yielding.
The compressive and bond strength of mud mortar decreases with the increase in moisture content in it. The compressive strength decreases by 0.8 to 1 N/mm2 at 6-10 percent moisture content
The bond between the mortar and masonry units if ruptured by the volumetric changes and the structural movements results not only in reduction in strength of masonry but also in formation of channels of seepage of water and other solutions into the masonry. This would aggravate the process of deterioration and affect resistance to chemical attack in aggressive environment.
Moisture to the extent of 5 to 8 percent by weight is likely to penetrate in the mud mortar even after plastering or pointing the exposed surface of masonry.
Basic stress in masonry with bricks of 7 to 10 N/mm2 and 3.5 N/mm2 shall not exceed 0.2 N/mm2 and 0.1 N/mm2, respectively.
Thickness of mud mortar should not be more than 20 mm in case of brick masonry works and 30 mm in case of stone masonry works.