Item 310 specifies that the mass percent of air voids should be in what range?

The correct range for the mass percent of air voids, as specified in Item 310, is typically set between 3% to 5%. This range is crucial in materials engineering, particularly in the context of concrete and asphalt mixtures, as it influences the material's durability, strength, and overall performance.

Air voids are intentional and play a significant role in the material properties. They help to accommodate thermal expansion, reduce the density of the mixture, and improve workability while also affecting the resistance to freeze-thaw cycles. Maintaining air voids within the specified range ensures that the material will perform optimally under various environmental conditions.

If the percentage of air voids is too low, it can lead to issues like inadequate drainage and increased susceptibility to damage from freeze-thaw cycles. Conversely, if the air voids exceed this range, the material may become too porous, leading to weakened structural integrity and reduced strength.

Understanding these implications helps when selecting and designing materials for specific applications, making the specified range of 3% to 5% vital for achieving the desired performance characteristics.