Core test 1. Five concrete cores were extracted from the columns of a building, and the results were as shown in the following table. What is your estimate of the concrete strength of these columns? No 1 2 3 4 5 Diameter (mm) 100 100 100 100 100 Core Samples Sample 1 Sample 2 Sample 3 Height (mm) 121 117 123 126 120 Height L (mm) 108.5 124.3 116 2.Three concrete cores were extracted from the flat slab of a building, and the results were as shown in the following table. What is your estimate of the concrete strength of this slab? Diameter D (mm) 64.2 64.2 64.2 Load (kg) 11800 10500 13200 14000 11200 1.7 1.9 1.8 L/D ratio Load (KN) 19.75 39.35 46.04