What is a disadvantage of concrete as a structural material?

Concrete, while being a widely utilized structural material due to its many strengths, does come with certain drawbacks. One significant disadvantage is that it requires careful formwork assembly. This careful assembly is crucial because concrete is typically poured into molds or formwork to achieve the desired shape and dimensions. Any imperfections or mistakes in this formwork can lead to structural weaknesses or aesthetically unpleasing outcomes.

The need for precise formwork also adds to construction time and costs, as it requires skilled labor to ensure that everything is set up correctly before the concrete is poured. Additionally, the removal of formwork can also be a labor-intensive process, requiring appropriate timetables to allow for curing and the structural integrity of the concrete.

In contrast, other aspects listed, such as concrete's good compressive strength, strong performance in tension (although it is generally weak in tension compared to materials like steel), and sustainable properties, highlight the material's advantages, which makes careful formwork assembly a critical challenge.