Density and strength of foamed concrete: The influence on dynamic characteristics of lightweight profiled composite slabs

This paper presents the experimental study on dynamic characteristics of lightweight profiled composite slabs. The density and strength of foamed concrete as topping material become the subject of interest. This type of floor system offers sustainable and reliable structural component in term of lightness, efficient construction processes and precast element. Although lightweight profiled composite slab may not a new thing in the construction industry, the understanding on the dynamic characteristics in term of natural frequency, damping ratio and mode shape are still ambiguous. Slab specimens, made of foamed concrete and Peva45 steel corrugated deck, were fabricated with size of 840 mm width, 1800 mm length and 125 mm thickness. The density of foamed concrete varies from 1400 kg/m3 to 1800 kg/m3. Within this range, foamed concrete has the compressive strength around 15.43 MPa to 32.23 MPa and the tensile strength approximately 1.06 MPa to 1.97 MPa. The natural frequency was observed to decrease with the increment of density and strength of foamed concrete. The natural frequency of lightweight composite slab is around 30 Hz to 35 Hz. Meanwhile, the damping ratio is considered quite high at the range of 3% to 5% where low density of foamed concrete gave more advantage in dissipating vibration within short period. The mode shape was visually obtained using MEScope and represents the bending behaviour.