Subbase is a layer of construction that continues the load from the base to the sub
grade in the form of compacted grained material. The government’s new roads
needs of a large amount of natural aggregate to fulfill the target. The use of natural
aggregate for construction which is done massively and continuously will make it
scarce. The replacement of fine aggregate with waste material such as ground
granulated blast furnace slag (GGBFS) will prevent the environmental imbalance.
Thus, the objective of this research is to know the correlation between DCP and
CBR value from the fine aggregate replacement with GGBFS on unsoaked
condition. The GGBFS was used to replace 0%, 15%, 30%, and 45% of the fine
aggregate weight. From the correlation between DCP and CBR value resulted a a
strong relationship between CBR and DCP value for each fine aggregate
replacement with GGBFS. From the four variants, it can be known that the best
results are from the 30% aggregate replacement variant. From the five tests
performed on each variant, at 30% aggregate replacement, four tests got the best
results.