Problem of crack in a reinforced concrete structure still became a major issue for researchers. Current research is not shown a satisfactory result, particularly on the effect of repeated load on the crack width. The experiment was conducted using a one way concrete slab. The analytical model and the experiment result were used to analyze the maximum crack width. The Carpinteri method was used to analyze the initial crack depth and the fatigue crack growth rate on the composite materials (reinforced concrete slab). The result showed that at 10 Hz load frequency, steel stress ratio, reinforcement ratio and repeated load do affect the maximum crack width until bond fatigue limit state by three linear model includes: (i) initial stage wo, (ii) increased stage w and (iii) bond fatigue stage wf, where wo is the initial crack width and wf is the bond losses crack width. Based on concrete cover c/h = 0,15, w ≤ 0,30 mm, wf/wo = 1,30, and fs/fy ≤ 0,50. Therefore, we are proposed the spacing of one way concrete slab under repeated load shall not exceed 110.000/fs - 6,34 c (mm).