In the determination of our final panel design specs, many tests need to be performed so as to optimize in terms of our concrete mix with regards to the ratio of cement to water and deterimine the required reinforcement. Below is the list of concrete samples created and what tests will be/are being performedin order to aid in our optimization:
Three concrete cylinders were poured February 15, 2012. One was an attempt to recreate the 2003 Sr. Design team "Positive Reinforcement's" mix that they used. The second and third were poured one with and one without bagasse to compare it's benefits in compression. These cylinders were tested March 7, 2012. These tests concluded that "Positive Reinforcement's" concrete was stronger than necessary, and that bagasse does not add any benefits in compression.
A second round of 5 test cylinders were poured on March 6, 2012. The purpose of this round of cylinders is to compare mix ratios. They were tested March 13, 2012. The conclusion from this round is a mixture consisting of a water to cement ratio of 0.7 with a base mass of 350lb of water is optimal due to a combination of strength and workability, among other criteria. It has been noticed that because sand does not maintain a given water saturation level, using a w/c ratio of 0.7 and a base mass of 350lb of water is only good as a starting point, from which modifications are made to achieve a slump of ~3 inches.
With each full panel that is poured, additional concrete from each batch is made into a cylinder and then tested 1-week after being poured to determine the strength of concrete contained in each panel.