This was the first attempt to recreate Roman concrete using Mt. St. Helen's ash. Thisshould be considered a pilot experiment to become familiar with the materials andhow they should be mixed, etc. Slides 1 - 8The mortar was mixed in a plastic tray with very low water content so it is very stiff. The mortar was pounded into the cylindrical molds using pea gravel as the aggregate. Extra material was placed in ice cube trays so it could be used for other testing and examination. After the cubes had cured, one was placed in water to see how well its hydraulic properties held up. As can be seen, the cube did not stand up very well to being placed in water and it fell apart. Slides 12 - 13One cube was broken to examine its internal structure. This cube was scratched with afingernail to see how strong the surface is.