What is the allowable MINIMUM specified compressive strength for concrete in foundations not exposed to weather?

The minimum specified compressive strength for concrete used in foundations that are not exposed to weather is 2,500 psi. This strength is deemed adequate for structural requirements in environments where the concrete will not be subjected to the elements. Foundations are critical structural components and require a certain level of strength to ensure stability and support.

Using the specified 2,500 psi allows for optimal performance in these conditions while remaining cost-effective. The choice of this minimum strength takes into account factors such as the load-bearing capacity required, the type of soil, and the absence of weather exposure.

Higher strengths, like 3,000 psi or 4,000 psi, while commonly used for various applications, exceed what is needed for foundations in protected environments. It is important to understand the context of strength requirements based on environmental exposure, as this will inform decisions during construction and materials selection.