Resilient modulus is an important property used in the mechanistic analysis of pavement response under moving loads as well as
an input parameter for design of flexible pavements. The effectiveness and efficiency of pavement structural thickness design is
contingent on the accuracy in measuring the resilient modulus (MR). This research study investigates the effect of four factors
namely bitumen content, specimen diameter, test temperature and load duration on resilient modulus of bituminous paving mixes.
The specimens of dense graded hot mix asphalt (HMA) were prepared by Marshall Compaction method using 4% and 5% bitumen
content and with 4 in and 6 in diameter. The resilient modulus tests were conducted on these specimens using repeated-load
indirect test setup in Universal Testing Machine (UTM-25) at 25 C and 40 C temperature. Haversine-shaped wave load pulse
was used to simulate the traffic wheel loading for 100 ms and 300 ms load duration. The analysis of two-level full-factorial
designed experiments revealed that all four factors have a negative effect on resilient modulus of bituminous paving mixes.
Temperature was the most significant factor affecting the resilient modulus followed by load duration and specimen diameter. In
2-way interaction, diameter–temperature, diameter-load duration, and load duration-temperature were significant. The most
significant 3-way interaction was bitumen content-temperature-load duration. The results from the study suggest that in measuring
the resilient modulus, an appropriate temperature and load duration should be selected to quantify the representative resilient
modulus for in-situ conditions.