The minimum density for lightweight insulating concrete is 50 pounds per cubic foot, which is option 2) in the choices provided. This type of concrete offers benefits such as reduced load and improved thermal insulation.
The minimum density for lightweight insulating concrete is typically around 30 to 50 pounds per cubic foot. However, since none of the options fall in this range except for option 2), the correct answer to the question of what the minimum density for lightweight insulating concrete in pounds per cubic foot is would be 50 as per option 2).
This type of concrete is made with lightweight coarse aggregate mixed with fine aggregates like shale, clay, or slate, offering benefits such as load reduction, faster construction, and thermal protection. It's notable that the specific minimum density can vary depending on the particular mix and application.