All you dirt jumpers and trail riders out there, give this a shot. If you have, you are ahead of me. If not, give it a shot. There are buildings made with the same procedure. This will make jumps last with little work. The elements can do what they please... your jumps will be standing strong.
Here is a quick definition:
Rammed earth, also known as pisé de terre or simply pisé, is a type of construction material. It is an age-old building method that has seen a revival in recent years as people seek more sustainable building materials and natural building methods. Traditionally, rammed earth buildings are common in arid regions where wood is in scarce supply. In the family of building materials, rammed earth is a first cousin to adobe. It was used to create parts of the Great Wall of China.
To create a jump, berm, roller, using rammed earth techniques, a builder pounds layers of moist, sifted soil - mixed with a small amount of Portland cement - into into a lip, landing, berm, or roller. This soil is tamped down until its volume has been compacted by approximately 25 percent. This is the same process that you would use if you where building a jump, it just has cement in it now.
The best mixture for rammed earth contains approximately 30 percent clay and 70 percent sand, with a small amount of cement added.
For all you that do not know, there is a big difference between cement and concrete. Cement is the glue in concrete. So when you go get bags of cement, make sure they are cement and NOT concrete, mortar mix, or anything else. Remember cement.
You may be thinking, "I'm not going to spend a ton of money on something when dirt is free." I agree. When you go to get cement you can ask the manager if they have any broken bags for cheaper. I bought about 10 broken bags of cement for $4 form home depot.
I have built 4 lips and landings now, using the rammed earth procedure and it is rad. Remember, anything that you put cement in will have a gray tint to it when it dries.
Spring is almost here. Happy Building!