What factor is crucial to prevent when constructing stockpiles using multiple layers?

Contamination is a crucial factor to prevent when constructing stockpiles using multiple layers because it ensures that the integrity and quality of the materials remain intact for their intended use. Constructing stockpiles in layers can lead to various materials coming into contact with one another, potentially resulting in contamination. This can occur if different types of aggregates or materials are mixed unintentionally, which can affect the properties of the final concrete or asphalt mix.

Preventing contamination is essential for maintaining the uniform quality of the aggregates. When aggregates from different sources or of different grades mix, it can alter the expected performance of the mixture, impacting factors such as strength, durability, and workability.

While efficiency, quality control, and segregation are important considerations in the construction of stockpiles, contamination specifically addresses the risks related to the mixing of materials that can negatively impact the end product. Therefore, managing contamination is vital to ensure that the stockpiled materials are suitable for use in construction projects.