Soil structure interaction with steel fibre reinforced concrete floor slabs on grade

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University of New Brunswick
Typical industrial floor designs use conventional welded wire fabric (WWF) for shrinkage and temperature control. In recent years, steel fibre reinforced concrete (SFRC) has been increasingly used in slab-on-grade applications. Steel fibre reinforced concrete has the ability to produce a concrete with minimal cracking, and enhanced ductility and toughness. The soil structure interaction of WWF and SFRC slabs on two extreme types of subgrade, loose and compacted is examined in the present study. The load capacity and deformation response is investigated for five 2.5 m x 2.5 m x 0.15 m concrete slabs loaded under a centrally applied monotonic load. One slab is tested under cyclic loading. The load deformation response of each specimen is determined from the test data and comparisons of member response are made for the different types of reinforcement and subgrade. Within the scope of the test programme, the use of SFRC leads to an increase in the values of first cracking and ultimate load capacity when compared to WWF reinforced slabs on grade (for the steel dosages used in this project). At these critical points , the SFRC behaved in a ductile manner while the WWF reinforced concrete slabs showed a brittle response. It was also found that the overall deformation of a slab-on-grade is dependent on the flexural characteristics of the slab and the amount of rigid body settlement allowed by the subgrade.