1. Always Advancing Pervious
Pervious challenges:
Build tougher pavement.
Build pavement that drains well.
We can identify the challenge of building pervious concrete pavement that is more durable and will drain well. Our design and construction methods can advance mixtures and finishing methods. Our systems can be designed to be maintenance friendly by observing the specific unique functions of pervious concrete pavement in the practice of storm water management.

2. intro David Mitchell Bunyan Industries Equipment manufacturer
Allied with NRMCA and promoters of cement and ready mixed concrete
System designs
Hydrology
Mixture variations
Hi, I’m David Mitchell from Bunyan Industries. We previously covered mixtures and surface finishes. This section will cover the system design, site conditions and the outfalls that serve our hydrologic function.

3. objectives Evaluate the potential site and the owner site terrain
geotechnical properties of site soils
site precipitation
flow in/out
mixture design
detention design
landscape
adjacent pavement
traffic
exposure to deicing salts
Every site is different. Each has potential advantages and certain limits. The system designer should evaluate the site and apply certain features of the system to best serve the expectations of the owner.

4. objectives Educate the owner to expect:
differences in storm water function
porous surface texture
award contracts based on experience
tasks of guarding against deicing salts
tasks of guarding from contamination
tasks of prompt and proactive response
tasks of monitoring infiltration rates
tasks of regularly scheduled cleaning
tasks of remedial extraction
tasks of applying denisifiers and sealers
Those responsible for system design should also align the owner’s expectation of unique performance and the unusual tasks of protecting and maintaining the entire system. The pervious concrete storm water system should be designed to make each of these tasks easier and more effective. The potential owner of this pavement should understand that the system will not continue to function unless it drains well and is guarded against certain types of contamination.

5. Site conditions Permeability of soils at basin
Permeability of soils at 15 ft depth
Slope
Elevation:
slab section
detention basin
detention water at maximum
Precipitation
Potential inflow of water / silt
Discharge limits & fees for outflow
Use software called Pervious Concrete Hydrological Design to apply the variables of perc rate, precipitation rate for the pavement areas and include the areas which flow into the system. This will calculate the required thickness for detention basin aggregate. If the soils and water table will allow, an injection column may be installed to vent additional infiltration through shallow, impermeable soils.

6. Perimeter curb .
The slab section is surrounded by curbs of various type, intended to protect the pavement from surrounding areas. The curb also blocks the migration of surrounding soils into the voids of the detention aggregate. The edges of the detention aggregate are also isolated with a vertical silt barrier which is folded to form an “L” shape. The horizontal silt barrier is best achieved by placing a layer of coarse sand at 4 to 6 inch depth at the bottom of the detention basin aggregate. An alternate design may use filter fabric as a horizontal silt barrier but has historically shown to clog with silt.

7. slope .
Choose a slab elevation that is slightly higher than the surrounding terrain. A simple system is level. If slope is required, excavate the bottom of the detention basin to a level surface, install the vertical silt barrier around the perimeter. Secure the top edge of the vertical barrier to the formwork to remain at slab elevation. Install a level horizontal silt barrier. Fill the basin with detention aggregate to the bottom of the slab section.

8. Adjoined to asphalt .

9. Check dam .

10. Multi-layered pavement can reach multiple objectives.
Alternate vents
Multi-layered pavement can reach multiple objectives.

11. Tree wells

12. Exposed edge

13. Filter Fabric
Examine a sample of detention aggregate that is infiltrated with water. Silt can develop clogging on the fabric surface.
This is the main reason to use a layer of sand to build a horizontal silt barrier, rather than filter fabric. We refer to this as “planar occlusion

14. Water of convenience Water of necessity
waters
Water of convenience
Water of necessity

15. Structure Bridge formation Absorption
Wet, metallic sheen
Structure
Bridge formation
Absorption

16. Structure Bridge formation Absorption
Wet, metallic sheen
Structure
Bridge formation
Absorption

17. Particle packing Particle sizes: cement slag coal ash silica fume
nano silica
Entrained air
Paste density

18. Surface Exposure Wind Relative humidity
Moist cure
Surface Exposure
Wind
Relative humidity

19. Fog Evaporation inhibitor Curing compound Poly sheeting
Moist cure
Fog
Evaporation inhibitor
Curing compound
Poly sheeting

20. Super Absorbent Polymer

21. Thanks.