Impact spacing is determined by which factors?

Impact spacing in asphalt paving is primarily influenced by the frequency of vibration and the travel speed of the roller. When a roller vibrates, it creates impacts on the asphalt surface, which helps in achieving compaction by rearranging the aggregate particles within the mix. The frequency of these vibrations directly determines how often these impacts occur, while the travel speed dictates how much area is covered by the roller in a given period.

If the travel speed is too fast in relation to the vibration frequency, there may be inadequate compaction, leading to voids in the asphalt mat. Conversely, if the speed is too slow, it may lead to overlapping impacts that could cause damage to the pavement. Thus, achieving the correct balance between vibration frequency and travel speed is crucial for optimal compaction and ultimately the performance of the asphalt pavement.

The other factors mentioned, such as the number of rollers in use, the temperature of the asphalt, and the weight of the roller, do not directly determine impact spacing. While they are important elements in the overall process of asphalt paving and compaction, they do not specifically dictate the spacing of impacts created by the roller's vibrations.