A Report of Contemporary Rammed Earth Construction and Research in North America

Rammed Earth (RE) is enjoying a renewed interest in North America. Contemporary stabilized rammed earth (SRE) builds upon traditional RE and incorporates rigid insulation and reinforcing steel, enhancing the structural and energy performance of the walls while satisfying current building codes. RE structures are currently engineered by licensed Structural Engineers using the Concrete Building Code or the Masonry Building Code. The construction process of contemporary SRE utilizes modern equipment and portland cement as a stabilizer, which can create walls of very high strength and durability. These structural walls are suitable for a broad range of heating and cooling climates. The incorporation of rigid insulation, fully encapsulated in the core of a wall and protected from pests or degradation, creates a high mass interior wythe that is thermally separated from the exterior, resulting in high thermal performance. Modern formwork allows walls to be built without the use of through ties, common in concrete construction and in some RE construction. Appropriately designed formwork may be reused many times with little waste of materials. The North American Rammed Earth Builders Association (NAREBA) collaborated with Unisol Engineering Ltd. and the British Columbia Institute of Technology (BCIT) on a battery of tests to obtain preliminary data to be used in support of engineering design. The tests included compressive strength comparisons, pull out rebar testing of both horizontally and vertically placed steel, simple beam tests, and the deflection of two composite wall columns with an insulation core and two types of reinforcing steel connections between the RE wythes.