Rammed Earth Construction Development in Lebanon

Abstract

As a construction method, rammed earth makes use of raw earth, with little to no additives as a building material. Buckets of soil are placed into a mold and compacted in layers to build load-bearing walls. Once construction is complete, the molds can be removed immediately and the structure becomes ready for further construction steps. Rammed earth structures come with little material costs due to the common and immediate availability of earth as a resource on construction sites. They produce less carbon dioxide emissions throughout their life cycle and are completely recyclable, thus reducing environmental harm to a minimum. The simplicity with which rammed earth structures are built, coupled with the finishes that can be provided, make earth an accessible building material to fit many project costs, quality, and aesthetic requirements. Earthen homes also provide healthy living environments with regards to indoor temperature and humidity. This research aims to optimize the construction methods and material mixes to best fit the East Mediterranean region’s climatic conditions and soils, while developing an efficient and reusable formwork system. Two sets of six test walls with varying soil, sand, and additive ratios were built, one located in the Advancing Research and Enabling Communities (AREC) facility of the American University of Beirut (AUB), in Lebanon’s arid Bekaa Valley. The second set, located on AUB’s main campus in Beirut’s humid climate. The walls are instrumented with soil moisture and temperature sensors and sample cylinders representing the different mixes were tested for compressive strength. It was found that the sampling method used to make the test cylinders directly impacts test results and using the tools used on site to make the cylinders produced the most reliable results. The decrement factor and heat flux time lag of the walls were calculated using the temperature data gathered, and were shown to be impacted by the ambient external conditions. Construction quali