While we’ve completed construction on the rammed earth spiral, the project has really only just begun. Moving forward, our team is looking to properly introduce rammed earth into the Princeton community and to further research efforts by installing a sensor system to study rammed earth erosion and by building a solar-paneled roof over the spiral wall.
Community Engagement: Redefining Structures, Sustainability, and Service
Rammed earth is a uniquely sustainable, beautiful building material – and completely foreign to most people. With this project, we saw the opportunity to do more than research and focus on the idea that structures are built to interact with people. We wanted to create something that could broaden our community’s views on structures, sustainability, and service.
Working with the PACE Center for Civic Engagement, we’ve been able to expose Princeton students to rammed earth through volunteer events and service discussions. A student volunteer described how “the project had made us work together and become a single unit,” unknowingly hitting the mark on an ancient quality of earthen construction. Especially in developing areas where heavy machinery cannot be employed, earthen construction is known as a community building event. At a lunch event hosted by the PACE Center, our project incited a discussion between students from various departments about research as a form of service. We hope to hold similar events during the school year, as well as transform the Forbes Garden into a more usable space for all, where students can have class, a movie night, or just a place to relax and study.
We’ve also enjoyed holding workshops with local schools and summer camps, hoping to inspire students in civil engineering and STEM. Visiting students learn all about rammed earth construction and get to make their own rammed earth samples. Joint workshops with the Forbes Garden managers, sponsored by the Office of Sustainability, expose students to two very different but basic means of sustainability in their every day lives – sustainable food and shelter. So far, we’ve had collaborations with the Princeton YMCA, the Laurel School, and Princeton Nursery, and look forward to hosting more workshops in the near future.
Ongoing Research: Erosion Protection and Environmental Sensing
One of the primary reasons rammed earth is not a prevalent construction technique in areas with varied, seasonal climates such as New Jersey is a lack of understanding of structural erosion in winter temperatures and driving rain. Several studies have predicted that the actual erosion of rammed earth walls due to wind and rain in seasonal climates is negligible in comparison to the lifetime of the structures. Our research aims to compare the erosion of four rammed earth test walls, both with and without alterations to prevent erosion.
To quantify erosion, we will use an image-based modelling software to create 3D models of the wall and compare changes throughout time. We are also installing an array of soil moisture, temperature, humidity and radiation sensors to see how these environmental factors correlate to erosion on the different walls. As for the walls themselves, the different protection measures include chemical solutions – lime and silicone, and a natural solution – a native ivy. Our results can eventually add to the formation of rammed earth building codes and lead to the wider presence of rammed earth construction in seasonal climates.
Author: Amber Lin ’19