# Comparison of Embankment Properties with Clay Core and Asphaltic Concrete Core
## 2 Materials and Methods
### Testing of Asghtlic Concrete in the Laboratory
#### 2.2.1 Analysis of Asphaltic Concrete Mixture Design Results  
Testing asphaltic concrete by using the Marshall method serves as a technique for designing an asphaltic concrete mixture. This method provides information about aggregate material proportions and sizes. Each test reveals crucial properties that are essential for mixture design, including density, stability, flow, air void content (AV), and asphalt cement content (AC). In the current study, the objective is to determine the aggregate material proportions for different AV values, particularly 1%, 2%, and 3%. This investigation aims to understand how varying AV values affect the aggregate proportions and overall properties of the asphaltic concrete mixture. Therefore, on the basis of the results of the Marshall method testing for asphaltic concrete, three different aggregate material proportions that correspond to AV values of 1%, 2%, and 3% are obtained. This study aims to compare the differences in aggregate material proportions among the three designs. The comparison is presented in three parts: (1) aggregate material proportions; (2) aggregate material sizes; and (3) density, stability,  
Figure 2: Testing of aggregate and asphaltic concrete. and flow characteristics. This comparison provides insights into the effects of varying AV values on an asphaltic concrete mixture. 1. Aggregate Material Proportions. The aggregate material proportions obtained from the asphaltic concrete mixture design through Marshall method testing, with AV values of 1%, 2%, and 3%, and an AC of 6%, are presented in Table 5.  
Table 5 clearly shows that the aggregate material proportions, with an AC of 6% and an AV of 1%, have the highest percentage of aggregate material in Hot Bin 1 (size: <4.75 mm). This aggregate size is the smallest in the mixture, and it decreases gradually with an AV of 2% and 3%. However, for an AV of 3%, the highest percentage of aggregate material is found in Hot Bin 4 (size: 19.05 mm), which is the largest aggregate size in the mixture, and it decreases with an AV of 2% and 1%. This finding demonstrates that when aiming for a lower AV in asphaltic concrete with 6% AC, the proportion of aggregate material in Hot Bin 1 (size: <4.75 mm) increases, efficiently filling the voids between aggregates. Furthermore, when comparing equal proportions of aggregate material with varying AC values, AV decreases as AC increases. However, selecting an appropriate AC is crucial, because excessive amounts may reduce strength. 2. Aggregate material size gradation. The aggregate material size gradation obtained from the design of asphaltic concrete mixtures in accordance with AV values of 1%, 2%, and 3%, with 6% AC, is plotted on a scatterplot to compare it with Fuller's curve. Fuller's curve is a scatterplot of aggregate size distribution that provides the appropriate density and strength characteristics of asphaltic concrete mixtures. It is illustrated in Figure 3.  
As shown in Figure 3, the scatterplot of aggregate sizes obtained from the designed asphaltic concrete mixtures at AV values of 1%, 2%, and 3%, with 6% AC, closely resembles Fuller's curve in all three cases. However, the scatterplot is closest to Fuller's curve at an AV of 1%. This finding indicates that asphaltic concrete exhibits the most appropriate density and strength characteristics when comparing AV values of 1%, 2%, and 3%. 3. The density, stability, and flow characteristics. The properties of the asphalt concrete designed mixtures based on AV values of 1%, 2%, and 3%, an AC of 6%, and a compaction of 98% include density, stability, and flow (Table 6 and Figure 4). A comparison of AC with density, stability, flow, and AV for the three mix designs is presented. Stability refers to the maximum resistance to deformation, while flow denotes the mobility or unit volume reduction.