Lab Corner: Voids, vinyl and VMAs

By Mike Anderson, P.E.

Vinyl record lovers know that one of the joys of listening to an album is hearing the entire set of songs, not just the ones that get radio play or make it to curated playlists on streaming music services. They also know one of the pains of listening to vinyl is the inevitable skip that can happen if there is a scratch.

Years ago, one of those skips appeared in my copy of “Who’s Next” in the last song on side one (a reference with lost meaning in the digital music world) named “Song is Over.” The skip happened in the middle of the song while I was recording the album to a cassette tape to play in my car and corrected itself after a couple of repeats of the same word.


Understanding pavement distress in asphalt

By Mark Blow, P.E.

The majority of pavement distresses fall into two major categories: rutting and cracking. Both of these distresses have been around since the dawn of asphalt pavement construction.

The Marshall mix design procedure was developed over 80 years ago and attempted to account for these distresses using a stability test to deter rutting, along with a flow parameter to reduce cracking. As any experienced mix designer can attest, it is very easy to design a mixture that will not rut. This can be accomplished through the use of a dry mixture with a very hard binder. Rutting will no longer occur, at the cost of increased cracking.