Evaluating the Strength of Full Depth Reclamation (FDR) Mixtures Using RAP and Virgin Aggregate

Abstract

One of the fastest techniques used to rehabilitate damaged pavement is full depth reclamation (FDR). FDR technique depends on reusing the asphalt pavement using additives to form a durable base. These additives are mechanical, chemical, or bituminous. The most common type of additive used in FDR mixes is Portland cement. At the same time, Cement production represents a serious threat to the environment because of its dust. Therefore, this paper investigates the ability to use virgin aggregate as a mechanical additive because in some projects using the existing base is restricted due to the underground utilities and the second aim is to reduce the required percentages of the used cement. The tests were carried out on two mixes, the first mix is traditional FDR which includes recycled asphalt pavement (RAP) and old aggregate. The second mix is traditional FDR and contains virgin aggregate (VA). The two mixes were treated with different percentages of cement (0,2,4, and 6%) by the dry weight of the mix. The conducted tests were compaction (Modified Proctor test) and unconfined compressive strength (UCS) test. The UCS test mixes were cured for 7 days. The results showed that the maximum dry density (MDD) and Optimum moisture Content (OMC) increased by an increasing in cement content for the two mixes. The UCS test result showed that by the increase in cement percentages, the UCS values increased for the two mixes and the optimum cement content (OCC) for mix2 was lower than mix1 at the same value of UCS.