PSI - Issue 6

Vimal Kumar et al. / Procedia Structural Integrity 6 (2017) 11–18 Author name / Structur l Integrity Procedia 00 (2017) 000 – 0 0

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Fig. 4. Energy absorption capacity of reinforced and prestressed concrete slab

4.4. Damage in concrete slabs under multiple impact Crack patterns in the reinforced and prestressed concrete slabs were captured with the help digital camera to study progress in the damage under multiple impacts. Under first impact on the fresh specimens, no spalling or scabbing phenomena were seen neither on the front nor on the rear surface of both slabs (PC and RC). However, fine cracks and small impression was seen at the impact location due to hard contact between target slab and impactor, see Figs. 5 and 6. The size of the indentation was further increased under repeated impacts of drop weight. It was seen that the number of cracks and crack-width on front and rear surfaces were increased in both RC and PC slabs under successive impacts. For a given repetition of impact, the number of cracks were found to be lesser in prestressed concrete slab compared with its reinforced concrete counterpart. The cracks in the reinforced concrete slab were comparatively wider than that seen on prestressed concrete slabs. Under third repeated impact, scabbing phenomena was also seen in the reinforced concrete slab, however, on the other hand prestressed concrete has shown no significant scabbing, see Figs. 5(b) and 6(b). The reduction in the damage in the prestressed concrete could be due to higher impact resistance capacity of slabs due to induced prestress.

Fig. 5. Damage in reinforced concrete (RC) slab subjected to multiple impact s.