Maybe something like this would make sense if you want to utilize a lot of plastic waste:
www.ijteee.org/final-print/apr2014/Utili...stic-soil-Bricks.pdf

With the right mould you could probably make nice curved interlocking bricks out of the above.

Hi Kris,

Thanks for sharing the study on manufacturing waste plastic to soil bricks. OMG it's so technical Kris! Maybe we will just continue with shredded plastic, cement, and sand. Yesterday we went to our city dump and talked with the scavengers of our intentions to experiment on making latrine rings out of concrete and plastic. They were so happy and started gathering the materials for the exchange of rice.
Hope to see some developments this 2019 Kris and be able to turn garbage into toilets.

Thank you once again Kris for sharing your time with us.
Thank you and more power.

Sincerely yours,

Nelson

Hello Esther,

I'm Nelson from the Philippines and work for our city government as a sanitation worker. We've been using used tires as a pit latrine rings for our Zero Open Defecation Program. Today, used tires are hard to come by, slowing our campaign. We hope to experiment on concrete latrine rings next year with added plastic shredded materials with is abundant in our local landfill.

Hope this will work and be able to meet our target by 2022.

Thank you.

Sincerely yours,

Nelson

P.s. Hope to document it this time.