Performance of Rammed Earth Exposed to High Temperature and Direct Fire Using Destructive and Nondestructive Analysis

Abstract

The environmental friendliness, good thermal performance and sustainable development of rammed earth structures have attracted the attention of numerous researchers and engineers in recent years. Nevertheless, the fire safety of rammed structures has not been extensively studied. The primary objective of this study is to investigate the mechanical properties of stabilized and unstabilized rammed earth exposed to direct fire under short elapsed time and high temperatures using a kiln. Rammed earth specimens with various mix designs were prepared and then exposed to high temperatures. Afterward, destructive and nondestructive tests were performed. Additionally, microstructural analysis was preceded to evaluate the change in chemical composition and microstructural of rammed earth specimens. The majority of the stabilized specimens exhibited thermal instability at 700°C. These specimens lost up to 85% of their compressive strength and 15% of their weight and change in their chemical composition. Under direct fire exposure, the rammed earth’s mechanical properties were not greatly impacted due to the short elapsed time. Compressive strength was increased in unstabilized (clay) RE specimens. A correlation between destructive and nondestructive properties was proposed. This study can be considered in the mix design of RE that experiences high temperatures.