Mix design procedure for micro-surfacing

The mix design procedure for micro-surfacing according to ASTM D 6372 (2010) requires the execution of the following tests (a) cohesion test, (b) wet track abrasion test, (c) loaded wheel test and (d) classification test, all described in ASTM D 6372 (2010). 

A similar mix design procedure is also proposed by ISSA A143 (2010). 

The aim of the mix design is to select a quick-setting target mix so that the micro-surfacing is opened to traffic as quickly as possible (within 1 h after placement at 24°C temperature and 50% or less humidity) and, after curing and initial traffic consolidation, resists compaction and maintains its high friction properties throughout the service life of the mixture. 

The cohesion test is used to determine two set times of the micro-surfacing mixture, the set time and the early rolling traffic time . 

Set time is defined as the elapsed time after casting a specimen of the micro-surfacing mixture wherein it cannot be remixed and no lateral displacement is possible when it is 

---