In its ongoing series of “Observations from the FHWA Mobile Concrete Technology Center (MCTC),” the technology overview covers some practical workability tests for concrete used in slip-form paving.  

The information-packed information sheet provides a description of workability, then details the Box test and the VKelly test, both of which provide an enhanced assessment of concrete workability.

The illustrated publication describes features of both tests and says a common feature of both tests is they measure concrete’s response to vibration and better assess the workability of concrete during field placement. Though both tests can be used in the field, the primary use is during mix design/approval for optimizing concrete mixtures, the MCTC says.

The publication continues with a description of slump and explains why, in spite of limitations, slump testing is also important in concrete mixture evaluation.  A brief summary provides the reader with highlights of one of the MCTC’s latest publications.