Prediction of unconfined compressive strength of old asphalt concrete using multiple regression

The recycle of old asphaltic concrete material (OAC) with cement additive is a relatively new pavement improvement method in road geotechnical engineering in Thailand. This paper describes the test results of recycled old asphaltic concrete mixed with various amounts of cement additive (OACC) at different durations of curing time, compared to the OAC without any additive. The test results show that the strength of OACC increases with the increase in amount of cement additive. A multiple regression model was developed for predicting the unconfined compressive strength (UCS) of the recycled old asphaltic concrete with cement additive (OACC) using cement content and curing time as input. The performance evaluations showed that predictions by the multiple regression model are very satisfactory in estimating the UCS.