Figure 4: Cement paste ( w / c = 0 . 4 0 , with silica fume to cement ratio of 20 wt%, and without CNF) in the molds 24 hrs after casting. The beams were exposed to drying condition during this period and formed multiple deep shrinkage cracks. All of the beams were fractured into multiple pieces before demolding and therefore none of them could be tested in bending. The beams have a cross-section with the side length of 15.9 mm (0.625 inch) and length of 240 mm (9.5 in).