## 4 Results
### Pavement Stiffness
#### 4.1.1 Erbsville  
Figure 6 presents the elastic modulus and the mean stiffness (average of the RWP and LWP) for each testing season, while Figure 7 presents the deflection results for all the testing periods at Erbsville. The error bars represent one standard deviation from the mean in the positive and negative directions. A \(t\)-test was performed to confirm whether the RWP and LWP had different stiffness. The findings suggested that, at a 95% confidence level, there was no significant difference in February and April of 2022 (\(p\)-value 0.92 and 0.97, respectively). On the contrary, a considerable difference was found between these wheel paths in June 2022 (\(p\)-value 0.02). Figure 6: Erbsville LWD measured elastic modulus. The initial measured pavement elastic modulus (indicative of the pavement stiffness) was observed to be the most in the LCC350 (2506 MPa), followed closely by the LCC250 section (2449 MPa) and then the control (1265 MPa). However, these values only represent near freezing or freezing conditions, producing stiffer pavement layer conditions. In addition, only two testing points were completed per section at this time, which could be the reason for the wide gap in stiffness between the LCC and control sections. As can be noted with the error bars (and within each section), some variability in stiffness was seen. A similar trend was seen over the analysis period, with the LCC350 section having the stiffest pavement structure and the control having the least. Additionally, lower deflection values produced higher stiffness, as expected. A study by [PERSON] and [PERSON], [PERSON] and [PERSON] (2018) also found spatial variability in pavement subbase and subgrade stiffness when LWD and two other testing equipment were used to assess the pavement stiffness. However, this assessed unbound layers and inferred that the variability could be attributed to soil suction or pore pressure development due to transient loading of the LWD on fine-grained soil. Stiffness growth occurred over time. Comparing June 2019 and June 2022, a stiffness increase of 25% was found for the control, 24% for LCC350, and 23% for LCC250. The slightly lower increase for the LCC sections compared to the control could be because of these sections' subjection to continuous bus and turning traffic over time. Typically, the bus stops within these two sections, and most of the traffic turning right at the intersection stop and start at the LCC250 section. This could also explain why between December 2018 and February 2022, a stiffness decrease (15%) was observed only in the LCC350 section. Other factors, such as moisture content and layer temperature, could influence pavement stiffness (H  
LCC sections in April and June 2022 were significantly different from that of the control. Again, since the LCC sections are the most subjected to vehicular traffic, it is expected that deterioration should occur more rapidly than the control; this could be why the stiffness values were closer to that of the control in later years. That being said, the LCC sections still exhibited higher stiffness than the control. In conclusion, because only the subbase of the pavement structure was altered, it may be argued that the LCC layer enhanced the pavement structure's stiffness compared to the unbound granular B. The stiffness improvement was proportional to the thickness of the LCC. LSD analysis was done on the measured stiffness values between each testing month to determine if there was a seasonal effect on pavement stiffness. Seasonal stiffness analysis showed that the period when the stiffness was performed was a significant factor in determining its magnitude. The 95% LSD criteria were obtained to be 589 MPa for the control, 504 MPa for LCC350, and 191 MPa for LCC250. No significant difference was recorded in all the sections (at a 95% confidence level) for stiffness measured between April, June, and October when compared with each other. The relationships between these months had mean differences over two times below the 95% LSD criteria.