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Zane Middle School permeable concrete 2
The Eco Team designed and built a semi permeable walkway for our client at Zane Middle School. They needed a pathway that will drain well, keep students from walking through the parking lot, and will withstand high foot traffic. We started by evaluating different materials that could be used to build a walkway. The constraints for building materials we considered were safety, cost, environmental impact, drainage and aesthetics.
The Eco team consists of five engineering students from Humboldt State University. Our names are McKenna Rayburn, Natalie Rynne, Jack Lisin, Shane Dotterer, and Makyle Harman. We are all students in Engineering 215 at Humboldt State University. Engineering 215 is Introduction to Design for Environmental Resources Engineering majors. Each semester, this class works with a client to design something for them.
Our Client is Zane Middle School in Eureka, CA. Our class was presented with a list of ideas that staff at Zane wanted for their school. Each group got to pick their favorite idea, and our group is building a semipermeable path in the front of the school. The staff of Zane Middle School want a pathway built in hopes that students will walk on the path instead of cutting through the school parking lot.
Understanding the Project Purpose
In front of the school there is a native garden that was planted by previous engineering 215 students. Next to the existing pathway is the undeveloped area that student walk through and track mud around from. Students walk through this area and the parking lot because it is a more direct route to the entrance of the school. The staff would like us to build a pathway where the students keep walking so they will not walk in the parking lot and the sidewalks will stay cleaner. This pathway will be next to the native garden.
Our goals for our pathway are to create a safe, durable walkway so that less students will walk in the parking lot. We wanted to optimize the durability of our pathway without sacrificing permeability. Our goal is that the school will be happy with the new pathway and it will make the front entrance look nicer.
Description of Final Project
After lengthy research, we found that gravel with cement mix was our best option. Using 3/8" crushed gravel and specific ratios of cement mix and water, our pathway should withstand heavy foot traffic and drain water well. Other benefits of this pathway is that snow and ice will melt faster due to the air pockets between the crushed gravel that allow water to drain through easily. It is the cheapest and most environmentally friendly option that best fulfills our client's criteria.
In order to build our pathway, we need to clear the ground of mulch and debris, dig roughly four inches down and level the ground we're paving. Once the area is cleared, we will set the bender board lining with stakes and wooden planks spaced every six feet for roughly 60 feet.
We have been researching and designing this pathway since the beginning of the semester and spent a combined total of 80 hours building the pathway. With five team members and our own classes to work around, we were able to complete the pathway in three days. The first day McKenna and Natalie mapped out the pathway location and cleared the redwood mulch out of the area. On our second work day we dug out the pathway completely, planted the stakes and bender board to line the edges, and paved the first 20ft of our pathway. By the third and final work day, we knew what we were doing and finished the rest of the pathway in a few hours.
Once the pathway has dried for few days, the Zane community can enjoy their new walk way. The only maintenance needed may be weeding and repairing small damaged sections. Small batches of the gravel and cement mixture can easily be made for repairs. Small repairs should take less than an hour of time and less than $20 assuming you don't already have any materials. We finished with a large quantity of excess gravel which was left at Zane Middle School. If they need to repair the pathway or would like to add more permeable pathways to their campus, all they need is cement mix and a bit of hard work.
The recipe we used to mix our concrete materials maximizes durability without sacrificing all of the permeability. A thicker mixture of cement will favor durability over permeability which is an advantage because Eureka does not experience heavy enough rainfall to be concerned about the pathway flooding. Through trial and error and many sample blocks, we found that the best ratio of materials is one part water, three parts cement mix, and nine parts crushed gravel. Our test samples were mixed by hand in five gallon buckets but we were able to use a cement mixer from the Engineering department at Humboldt State University for the construction of our final project .
Materials and Costs
|Pea Gravel||2 cu yd||$13.00 per ton||$36.00|
|Delivery of Gravel||1||Donated||Donated|
|Cement||20 47lbs bags||$6.74||$134.80|
|Bender Board Lining||120ft||$20.49||$61.47|
|Stakes||2 bags of 10||$11.99||$23.98|
|5 Gallon Buckets||4||Donated||Donated|
|Pressure Treated Wood||10||$1.50||$15.00|
We over estimated the amount of materials we would need to fill the pathway. We were able to return a bag of stakes, a roll of bender board, four bags of cement mix, and we left plenty of extra gravel for Zane to use in future projects.
We were able to reduce our costs significantly thanks to many donations from friends and business owners in the Humboldt community. A special thank you to the Campus Center for Appropriate Technology, Eureka Ready Mix, Piercens, Jens Hansen, Lowen Hobbs, and Colin from the HSU Engineering shop.
Discussion and Conclusion
We met our goal of creating a semipermeable pathway will provide students a safe walkway. As engineering students it is encouraging to see from day one that the work we do has a positive impact on our community. Our product meets all of our clients criteria. Zane middle school is happy to have a new addition in front of their native garden that will help make their school zone safer.