3D Digital Design
Based on an accurate millimeter Digital Terrain Model (DTM) of the existing road surface a 3D Digital Design model is created, which ensures the optimal drainage of the road, improves cross-fall, minimizes longitudinal unevenness (improves IRI) and lowers the amount of milled material. When the milling plan is pre-designed, the milling operation process is more efficient and less likely to produce grade mistakes.
Exact Street Design Software (SW), allows full automation of the design process based on DTM, supplied project documentation (2D drawings, construction situation, characteristic sample sections, etc.), diagnostics data and/or other materials.
The automated optimization is focused on:
- The lowest possible International Roughness Index (IRI)
- Correcting cross-fall and super elevation to standard
- Compliance with the thickness of asphalt layers according to the project documentation
- Road surface drainage
- Tying in to existing features that are fixed, such as subsurface utilities, foundations, bridge abutments, curbs and gutters, driveways, saw cut lines for widening, and existing roadways for rehabilitation or reconstruction
- Minimizing grade raise
- Minimized amount of milled material (Not removing too much asphalt, which may compromise the structural integrity of the pavement structure.)
Exact Street design SW automatically optimize milling depth to correct cross-fall and super elevation to standard and safe road traffic.
Figure 2: Cross-slope diagram of existing cross-slope vs. design (optimized) cross-slope per station.
One of the main parameters for the optimization process is to achieve the ultimate smooth drive. Advanced algorithms that are implemented in Exact Street design SW are able to optimize IRI deeply below value 0.5 m/km. Typical value of IRI parameter after optimizing is 0.1 m/km!
Figure 3: Smooth drive optimization (IRI minimizing)
Constructing a 3D Digital Design Model before milling gives the ability to optimize the milling profile dependent on the specific client needs. The projects in remote locations where recycled asphalt is in high demand could have its milling profile adjusted so that additional recycled asphalt is generated to increase nearby quarry stocks. Alternatively, projects in a busy, urban center where existing recycled asphalt stockpiles are significantly full, the model could be adjusted such that the resulting recycled asphalt production is limited, reducing the required trucking and associated costs, as well as mitigating greenhouse gas emissions and improving storage availability.
Exact Street design SW allows to adjust the forecasted recycled asphalt production, trucking, and storage for each job, depending on the area's requirements. This micro technology can influence macro planning.
Critical areas identification
Exact Street design SW are able to automatically identify areas of the road where the road distortion is so significant that it’s not possible to correct cross-slope and longitudinal drive and in the same time avoid to mill too deep and risk to break through the pavement into the granular below.
Figure 4: Red Areas show milling depth over the 30mm limit which is not possible avoid when strict 2% cross-slope applied