Hello Mr. Hussein. The acceptable workability range of a mortar in the flow table test often is defined by standards that specify a certain range of work. For example, in Brazil we have the NBR 13276. It is important to remember that the type of mortar to be tested can generate distorted results in flow table test. There are published studies that question the efficiency of the flow table test for evaluating the workability of mortars with too much incorporated air additives. For these mortars, tests such as squezze flow and rheometry would be more indicated.