Cracking Behavior of Base Restrained High Strength Plain Concrete Walls Due to Shrinkage

The cracking caused by volume change in plain and reinforced concrete walls restrained at their bases is a widespread problem. Moreover, when High Strength Concrete (HSC) may be used in construction of such walls, cracking behavior of such walls due to shrinkage must be studied. In this work, six walls with Length/Height (L/H) ratio of 6, 8 and 12, were cast using high strength concrete and monitored for 90days after appropriate curing. All the walls were of 500mm height and 100mm thickness and without horizontal reinforcement but only 150mm length vertical dowels extended from the base to provide base restraining. In the present work four out of six walls had been cracked, this finding is in conflict with what was believed by many researchers that base restrained high strength concrete walls could not cracked under weathering conditions. ACI 207.2R stated that cracks under shrinkage effect cannot be eliminated, but it was shown in this work that cracking could be prohibited by limiting the L/H ratio to be 6 or less in base restrained high strength plain concrete walls. In the current work it was shown that there were a large difference between the observed values of maximum crack width, minimum and maximum crack spacing in high strength base restrained concrete walls and those values calculated utilizing the equations developed for normal strength base restrained concrete walls.