Sustainability of Thermally-Activated Precast Concrete Hollowcore-Floor Systems

Concrete is the most versatile and widely used man-made construction material in the world. However its production accounts for 5% of the world's CO2 emissions mainly due to high CO2 emissions of the cement manufacturing. Therefore reduction of CO2 emissions is one of the key targets of the concrete industry. Floors in buildings contain a major of mass of total building structure, therefore have a high material and embodied-carbon optimization potential. Precast concrete hollowcore-floors have up to 50% less embodied-carbon comparing to solid cast-in-situ concrete floors because about 40% less concrete and about 50% less reinforcement is used. Embodied-carbon of the hollowcore- floors can be further reduced up to three quarters while applying secondary materials and alternative binders. Precast concrete including thermally-activated hollowcore-floor systems also named as thermally-activated building systems (TABS) used for heating and cooling energy distribution can help reducing not only embodied but also operational CO2 emissions and in addition can contribute highly to the overall building's sustainable performance commonly assessed by BREEAM (Building Research Establishment's Environmental Assessment Method) which is one of the most widely used environmental assessment systems world-wide. The paper will present several case studies of project examples and focus on BREEAM sections where precast concrete can facilitate the scoring of credits. It will also compare other sustainability models and discuss how they fit for evaluating sustainability performance of precast concrete.