# Construction of Geosynthetic-Reinforced Pavements and Evaluation of Their Impacts
## 3 Construction Impacts on the Geosynthetic-Reinforced Pavements  
### Pressure at the Interface of Subgrade and Base  
The readings of the pressure cells at the interface of the subgrade and base layer were taken during the construction of the asphalt binder course (SP 19), and asphalt surface layer (SP 12.5). The data were collected every 10 s during the construction of the binder course and every minute during the construction of the surface layer. Although the traffic volume and construction truck specifications were not available, the construction equipment was consistent for all sections during each stage of construction by designating equipment to a specific lane in the test sections. All other construction traffic was kept on the lane that was not instrumented during the data collection period. By taking the difference between an individual sensor reading at the time, \(t\), and the first reading before construction, the readings of the pressure cells during construction of the asphalt binder course were plotted in Figure 9. Figure 9 details the readings from approximately 8:30 a.m. until 3:30 p.m. corresponding to the start and finish of construction, respectively.  
The construction timeline can be observed more clearly from the pressure readings of control and geogrid composite sections. The pressure increase ending at approximately 1 p.m. corresponds to the paving and compaction of asphalt concrete. During this time, the contribution of the geogrid composites on the subgrade as well as the fibreglass geogrid in the binder course can be inferred. It can be observed that the geogrid composite section (Section 3) shows more noise but with a similar trend to the control section, and experiences a maximum pressure of approximately 0.10 MPa. However, the pressure cell on the subgrade in the fibreglass geogrid section (Section 2) experienced a much lower pressure (0.03 MPa). Due to the absence of the paver and compaction equipment, the pressure levelled out as shown in the control and geogrid composite sections. During the paving of the binder course, the geogrid section experienced approximately 70% lower pressure on the subgrade compared with the other two sections, which may be attributed to the fibreglass geogrid reducing the impact of heavy construction trucks on the base and subgrade. It is believed that these measurements demonstrate the ability of the fibreglass geogrid to distribute the load and provide reinforcement during construction.  
Figure 9: Pressure at the Interface of Subgrade and Base during Binder Course Construction.  
Figure 10 shows the readings of the pressure cells collected during the construction of the asphalt surface course. From these results, a similar level of noise was demonstrated in all three sections. This may be attributed to the different data collection frequency (i.e., one measurement per minute) from the previous two construction activities. As shown in Figure 10, the trends of all three pressure cells are similar; however, larger peak pressure values were observed in the control section and geogrid composite sections.