Concrete vs. steel

Concrete is a conventionally used material for construction while steel is now gaining momentum for its flexibility and reduced construction time. Both concrete and steel framed structures have environmental issues associated with their use, including a high embodied energy in their manufacture.

Concrete has some advantages; waste materials can be included within the mix, such as GGBS (Ground Granulated Blast-Furnace Slag) and PFA (Pulverised Fuel Ash). In addition, moves are being made to assess the potential of using recycled concrete, however, issues such as moisture content and material variability dictate that it is economically unviable.

Steel, while having a high lead time, is known for its fast erection on site. However, steel needs fire protection whereas within concrete this is inherent. Prefabrication of steel can allow thin film intumescent coatings to be applied offsite.

Efficiency within concrete construction is being improved by the adoption of hybrid solutions and innovations in formwork such as self-climbing forms. The use of precast concrete construction can also help to significantly reduce build time particularly where vertical elements are considered to be the main limitation.

Sacrificial probes can be integrated within concrete to provide strength determination at an early age and this is likely to help further improve construction methodologies.

Steel, being fast to erect, can allow the building to be occupied sooner. In addition, reduced labour costs are possible through dryness of form in comparison with concrete.

The construction of a steel framework is comparatively lightweight, as much as sixty percent lighter than a comparable reinforced concrete frame solution which might allow for a less expensive foundation system. In addition, modification to the building can sometimes be facilitated by simple removal of a structural steel member.