The first part of this paper presents an experimental investigation on explosive spalling of six full-scale normal strength reinforced concrete slabs subjected to conventional fire curve ISO834 and severe hydrocarbon fire curve, performed at the Fire Research Centre, University of Ulster, UK focusing on concrete thermal behaviour and the explosive spalling phenomenon. Each slab was loaded with 65% of its BS8110 design load and was heated from the bottom side only. Temperatures profile was recorded at three depths within the slabs and the moisture content was also measured before and after the tests. The deflection of the slabs was recorded at the middle of the 3 m span. The second part of the paper presents a numerical study on the normal concrete slabs using the finite element method. The concrete slabs were modelled including the embedded reinforcement to conduct a non-linear transient structural analysis taking into account cracks appearance and creep. A comparison between the experimental and the FEM results is presented in the paper.