Which is a primary factor affecting the compaction mix properties?

The primary factor affecting the compaction mix properties is the type of aggregate used in the mix. Aggregate type significantly influences several aspects of the mix, including its workability, strength, and how well it can be compacted. Different aggregates have varying shapes, sizes, densities, and moisture absorption characteristics, all of which can impact the final performance of the compaction process.

For example, angular aggregates typically interlock better and provide greater stability compared to rounded aggregates, which can lead to improved load-bearing capacity when compacted. Additionally, the specific gradation of the aggregate affects the void spaces in the mix, thereby influencing the amount of binder that can coat the aggregates and subsequent compaction efficiency.

Choices like mix color, humidity level, and time of day may have some influence on other aspects of the mixing or laying process, but they are not primary determinants of the compaction properties of the mix itself. Color does not impact physical performance, while humidity and time of day can affect other operational factors, but they do not alter the fundamental characteristics of the mix as determined by the aggregate type.