The concrete pours for modules four and five were completed today. While that might seem a little underwhelming compared to what we've accomplished at other points during this trip, creating two full sinks is actually an all hands on deck task that requires at least seven hours of dedicated labor. Today, I'm going to break down each component of a sink pour to help give you a better idea of the preparation and effort that is going into this project. Batching: The type of concrete that we have been creating requires four materials - cement, course aggregates (gravel), fine aggregates (sand), and water. When these four are combined, a chemical reaction occurs that binds them together in a stone like molecular structure. Because of the specific nature of our environment and sink design, we add a high range water reducer, a retarder, and fibers to our mix, which makes the concrete act more like a liquid and retain that workable state longer. The exact proportions of each material were carefully calculated by Dr. Ferron and Aleesha over the course of approximately 15 trial batches last week. Before each pour, the materials are gathered and carefully weighed out according to the mix design. Formwork: To ensure that the concrete acquires the correct shape, the local contractor, Prasit, helped the team create a set of wooden forms that rest on top of and around our foundation to provide that structure. While running trial batches in Austin, we learned that the wood has a tendency to stick to the concrete, so Julie and Pooja coated the entire form with motor oil to assist with removal. Additionally, we had to cut, install, and seal the drainage holes, seal the edges of the formwork to prevent leakage, and brace weak joints. Only after all of that has been done can the actual mixing begin. Mixing & Pouring: Creating the concrete requires combining all of the ingredients in a specific order in the mixer. Since concrete is a very volatile mixture, each batch has to be customized based on the specific characteristics that appear. Trey and Dr. Ferron were on mixing duty all day and cranked out nine full batches over the course of four hours. Once mixed, the concrete passes to the rest of the team, who pours it into the forms. To insure that no air bubbles form, marring the final surface, we used pieces of rebar to 'rod' the mix before using trowels to smooth out the final surface. This is the busiest part of the entire process and we all had to maintain constant communication to keep everything running smoothly. Finishing: After the pour, the concrete has to set for six to eight hours to achieve its initial hardness. Most people napped or watched Netflix in the intervening time (or studied for the LSAT - go Julie). Once it sets, the formwork has to be unscrewed and pried off of the surface as gently as possible to avoid marring the surface. At this point, the concrete still hasn't achieved its full strength however, so to support the ongoing chemical reactions, we have to cover the surface a layer of wet burlap sacks to retain moisture. If all of the preceding steps are executed our final product comes out looking like the sink below. So that's the art of the concrete pour. It's grueling and grimy, but also incredibly rewarding. Today was especially satisfying because we've completed all of our structural work, leaving only pipe work and drainage trenching for the next three days. Throughout the year, the advisory board that supervised our work expressed concern with the size of our scope so with the end in sight, we're proud of what we've been able to deliver to the community. As always, none of this would be possible without Khem's constant support. He's pictured below on his Harley racing back from the pipe store with some emergency fittings.
-Trey
4 Comments
Patrick Le
6/9/2018 08:42:51 pm
Yall needa hitch a ride in the side car or on the back of the motorcycle. Great work so far!
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Lorie Mosman
6/10/2018 07:33:57 pm
Thanks for sharing.....Didn't realize all the work that went into it. Amazing Kids Doing Amazing Things ......Keep it up....Luv ya
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Hannah Smith
6/11/2018 03:41:21 am
Khem the speed racer!! The sinks look great!
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PAVANA K ANNALURU
6/11/2018 05:40:46 pm
This is fantastic work guys. Great achievement .. Keep up good work. Above all, you are taking time to update the Blog. We are able to visualize and follow you.
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