Process Part I - Selecting the concrete ratio

For the past two weeks Leo and I have been testing different combinations of wood-aggregate concrete. The first test were completed using a range of wood chips, saw dust, cement and water.

The wood chips made the aggregate too brittle to be used for a paver, the sawdust was more appropriate, but still relatively crumbly. The next round of tests integrated sand back into the sawdust mixes to attempt to add structural stability to the concrete.

During this round of tests we also began sampling regular concrete mixtures of send, cement and water to use as a control, through this process we decided that the paver would hold up to foot traffic better if it was stabilized with a thin surface layer of conventional concrete. From this process we decided on two mixes that were close to what we were looking for and continued further experiments with these two mixes. For the wood-aggregate we are using a ratio of 3 parts cement, 5 parts saw dust, 1 part sand, 4 parts water. For the conventional concrete we are using 2 parts cement, 4 parts sand (2 coarse, 2 fine) and 1 part water.