CASE STUDY 3 – Castellón.
TITLE.- Rammed Earth Wall. Tradition and evolution.
- Problem to solve. If we study what is the best way to protect ourselves from the inclemency of nature, it is easy to conclude that a cave is the best option. The obvious discomforts of a cave can be solved, but we cannot solve the access to sunlight and also that this natural cave is in the best location.
- If we reproduce the technical characteristics of the walls of a cave, we can enjoy the same comfort in the construction system known as Rammed Earth Wall.
- Collaborative scheme. Of the people with whom I can bring this case study to a successful conclusion, I highlight Fermí Font, whom I consider an archaeologist as well as a technical architect with a very remarkable knowledge of Rammed Earth construction, and Xavier Salvador, an architect with proven experience in the design and construction with natural raw materials, both from the architecture studio www.arenes.es that Xavier himself runs.
- Concept. The construction with compressed earth is very stable over time under certain conditions, as I pointed out in “Case Study 1 – Girona”. Its use in humid latitudes depends on improving its behavior in contact with water.
- The clay is naturally mixed with the earth and acts as a binder for the earth. This clay is very reactive with water, and mitigating the reaction depends on additions of other materials or, as we have done, specializing the material that we consider most useful in the composition of the clay. This matter is from the group of silicates.
- So, we created a compound considered as a Geopolymer designed as an evolution of the compressed earth wall with which, in addition, we can build the same quality in block format thus increasing the range of uses.
- Method. One of the aspects to which we reduce its gravity is that the earth must be compressed, impacting a weight on its surface. You have to use a lot of energy to compress the earth because its quality depends on this process.
- We use the usual methods in the construction of Rammed Earth but without compressing the earth beyond the manual effort when depositing the compound. This improvement in the method has an impact on the improvement of the simplicity of the process and in more reduced execution times, with what this means in monetization.
- Components. 85% of the natural raw material are local resources within an area of 50 km2 with an epicenter in Castellón. The nature of the components cover the mineral and vegetable spectrum, without the participation of hydrocarbons, and served in dry powder and different grain sizes. The following selection of components corresponds to the one that offered a more balanced result.
- Red clay, kaolin, crystal water, brick dust and sand, marble dust and sand, rice husk, dry grain cork, dry powder ash.
- Critical factors. Although the promotion of the construction of Rammed Earth walls grows, it is still considered as a residual construction system almost relegated to restoration.
- It is necessary to adapt the technical characteristics of our geopolymer to current regulations to complete the technical memory of the projects.
- Not using mineral binders such as limes or cements creates uncertainty in the professionals dedicated to the application and faculty management, so teaching the system in a seminar-workshop format is an obligation in order to generate confidence in the solution.
- Conclusion. The Rammed Earth construction system, together with our evolution as a geopolymer, covers all the solutions required in housing and smaller format pieces such as latticework or furniture.
- Since most of the necessary natural raw material is of local origin and the formulation of the compounds is different from the usual one, teaching this system to local professionals guarantees the generation of local wealth when the result of their experience is realized in consumer goods.