 Precast concrete popularity is linked with low-seismic zones and more economical constructions because of fast building assembly, lower self weight (less material), etc.Precast hollow-core elements is also known as the most sustainable floor/roof system and has far smaller CO2 footprint than even CLT slabs.The precast concrete slab has tubular voids extending the full length of the slab, typically with a diameter equal to the 2/3-3/4 the thickness of the slab.