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Abstract

Fig 1: Unsatisfactory path at Catherine Zane Middle School.

The purpose of the project was to replace a incorrectly installed permeable pathway at Catherine Zane Middle School in Eureka, CA with a functioning permeable pathway. The previously installed pathway was uneven, and not permeable and produced undesirable loose gravel. The Project was successfully implemented and the middle school now has a solid, level but permeable concrete pathway in the Peace Garden.

Background

The project is being design and installed by Team^2 whose members are Ailynn Andersen, Jesse Bobrow, Catherine Carbajal and Julian Sicaud. Team^2 is a team in HSU's Engineering 215: intro to Design course taken in Spring 2018 and taught by Lonny Grafman. The client of the project is Catherine Zane Middle School, a STEAM(Science Technology Engineering and Math) who has had a relationship with facilitation projects on their campus for ENGR 215 courses. Team^2 client representative is Trevor Hammons.

Team^2!

Problem statement and criteria

In the Peace Garden a previous engineering team had incorrectly installed a permeable concrete pathway. We hypothesized that there was too much water in their mix which caused the cement to sink to the bottom of their installation and harden into an impermeable layer leaving too little cement in the top layer to properly set the top layer. Aggregate erosion resulted in loose gravel, which pedestrians tracked across campus. Our client wished us to solve these issues by implementing a pathway that was strong and durable, seamless with the other pathways and level and also permeable.

Criteria Weight (1-10)
Durability 10
Permeability 10
Functionality 8
Maintenance 7
Cost 6
Educational Value 5

Description of final project

The final product should be a permeable concrete pathway that seamlessly merges with the surrounding pathways and curbs. The path should be level and smooth ensuring a effortless and thoughtless user experience. the pathway material should also be porous and allow water to permeate through the pathway into the surrounding garden beds.

Prototyping

Prototype Porous concrete block.

Permeable Concrete is made from a mix of, ideally, equal sized round aggregates and Portland cement. typical mixtures are usually a 3:1 ratio of 3 part 3/8" pea gravel aggregate to one part Portland cement. We decided to test both permeability and viability as product of this ratio by testing it against a 4:1 ratio of aggregate to cement and a 2:1 ratio of aggregate to cement. We poured samples of each ratio into a one foot square mold to the depth of three inches.

Prototype permeability testing set up.

We decided to make site measurements of the old path installed in the Peace Garden. We made measurements of each sections dimensions and also each sections corner to a single point. these measurements were then entered into AutoCAD and rendered into a viable blueprint plan for the pathway. We also rendered a 3D example of a typical path section block of porous concrete. The pathway in the garden is approximately 62 feet long and is composed of ten sections that are approximately six feet long by two and a half feet wide by three inches tall. We calculated the overall volume concrete needed to pour was a little under forty cubic feet or just over a cub yard.

3D render of path section.
Plan for path install.

Costs

Our project would never have come to fruition without generous donations. The project budget was $400 but our expected costs rose to over $1000! Because of our donations and community help we only spent less than $200. Many of our heavy materials were thankfully donated but not able to be delivered therefore we spent some time having to move heavy materials with our own vehicles.

Materials Source Quantity Unit Retail Price per unit ($) Total Retail ($) Expenses ($)
3/8" Washed Pea Gravel Mercer-Fraser 2 Cubic Yard 60.00 120.00 Donated
3/8" Washed Pea Gravel Hensell Materials 2 5 gallon bucket 4.00 4.50 Donated
Weed Cloth Zane Middle School 1.2 100 feet 68.99 68.99 Donated
Mixing Wheelbarrow Larry Nichols/Zane 2   150.00 300.00 Donated
5 Gal. Bucket Julian Sicaud 4 4.99 4.99 Donated
1 Foot Wooden Stakes Zane Middle School 1 100 Stakes 17.50 17.50 Donated
Bender Board Zane Middle School 6 20 Feet 19.99 120.00 Donated
Fill Dirt Zane Middle School 2 Cubic Yard 7.99 15.99 Donated
Portland Cement Piersons Hardware 5 97 lb bag 16.99 84.95 Donated
Tarp Julian Sicaud 2 15.99 31.98 Donated
Shovel Julian Sicaud 2 23.86 23.86 Donated
Portland Cement Hensell Materials 1 47 lb bag 6.07 6.77 6.77
Portland Cement Shafer's Hardware 1 47 lb bag 9.99 10.84 10.84
Line Level Piersons Hardware 1 3.69 4.00 4.00
Shovel Piersons Hardware 1  21.99 23.86 23.86
Garden Hoe Shafers Hardware 2 16.99 16.99 16.99
Hose Valve Key Shafers Hardware 1  1.79 1.79 1.79
#9 x 2-1/2"  Deck Screws Hensel's Hardware 1 50 screws 9.78 9.78 9.78
Wood Almquist 14 Feet 1.09 16.44 16.44
1" x 4" pine Piersons Hardware 30 Feet 0.69 20.42 20.42
Wheel barrow Tube Miller Farms 2 9.64 19.28 19.28
Caulking Gun Harbor Freight Tools 1  2.99 2.99 2.99
Silicone caulk Harbor Freight Tools 2 Tube 3.99 7.98 7.98
Balloons Dollar Tree 5 Bag of 25 1.00 5.43 5.43
Caution Tape Shafers Hardware 1 Roll 7.59 7.59 7.59
Gloves Harbor Freight Tools 5 pair 7.99 7.99 7.99
Push Broom Shafers Hardware 1 7.99 7.99 7.99
Plastic Sheeting Piersons Hardware 1 9 x 400 Feet 24.99 27.11 27.11
TOTAL 990.01 197.25

Permeablepath18 Designhours 1.png

Testing Results

We ran three tests on each prototype ratio we poured of permeable concrete in order to determine the rate of permeability or the speed at which water moved through the material. To test our prototype slabs we built a box of wood around each block and added silicone to seal the inside seams and corners. we leveled with boxes and filled them two water balloons filled with approximately 2 gallons of water. We then popped both of the balloons at the same time and measured the time it took for the volume of water to permeate through the path. The table below contains the results of our tests. We found that each ratio, that is , 2:1, 3:1 and 4:1 of aggregate to cement, produced a viable, strong and highly permeable product. This told us that the mixing a precise ratio of aggregate to cement was not as crucial as other concerns, such as adding the correct moisture level or properly curing the mix after installation.

Trials 2:1 ratio 3:1 ratio 4:1 ratio
Trial 1 7.08 sec. 5.14 sec. 3.59 sec.
Trial 2 6.72 sec. 5.13 sec. 3.42 sec.
Trial 3 7.03 sec. 5.13 sec. 3.49 sec.

PERMEABILITY CHART.JPG

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How to Install a Permeable Concrete Pathway

Maintenance

This type of permeable walkway only needs to be maintained about twice a year. The most effective way to maintain this path is to power wash it two times a year. This ensures that small objects will not clog the holes in the path way.

Instructions

This is how to maintain. The step by step how to template {{How to}} is most likely best for this part.

File:Bpack bike trailer - demo 1.jpg
How to Do Something

Troubleshooting

This is only how to troubleshoot basic operation. For complex issues, the solution might just say contact ________. It should be a table in this format:

Problem Suggestion
Example issue Example solution or suggestion
Does not turn on Make sure it is plugged in
Another issue Et cetera

Discussion and next steps

Suggestions for future changes

This is where to lay out suggestions for how to make the project function better in the future.


References

See Help:Footnotes for more. Template:Reflist

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