What can be done to minimize the sizes of cracks on the bottoms of architectural concrete beams? These detract seriously from the appearance of the rustications.
In the regions of flexural tension in the bottom of an architectural beam the depth of the rustication should be kept to a minimum. The rustication will require additional concrete below the steel equivalent to the depth of the rustication. Thus any cracks that occur in the tension zone will be wider at the surface. If the surface is sandblasted the width will be further accentuated by rounding of the edges of cracks. For these reasons it should help to reduce the amount of excess cover on the steel by using a shallower rustication in the tension zone.