Rammed Earth N51 is a sixty-foot-long freestanding rammed earth wall built by a team of students and staff at MIT during the summer of 2005. The project combines research on historical and contemporary rammed earth methods with material research undertaken in the geotechnical laboratory at MIT.

The prototype wall reclaims a neglected outdoor space for the MIT School of Architecture and Planning while providing evidence about the aesthetics and longevity of rammed earth in New England. The project was led by MIT Master of Architecture candidate Joe Dahmen, advised by professor John Ochsendorf.