Experimental study on thermal and humidity properties of modified rammed earth buildings in winter

Abstract

Rammed earth materials have been used in traditional buildings for thousands of years. Currently, with the interest in environmentally friendly societies, rammed earth construction has regained attention owing to its characteristics of energy conservation, environmental protection, low cost, and local material extraction. In this study, cement, gravel, sand, and polypropylene fibers were used as the modifying materials of rammed earth. The thermal and humidity physical parameters are measured at different moisture contents after modification, and the isothermal hygroscopic curves are fitted. The experimental findings demonstrated positive correlations between the specific heat capacity and thermal conductivity and the moisture content. The temperature and humidity of a modified rammed earth test building were recorded for seven days during winter. The test findings revealed that, throughout the test, the moisture content in the middle of the wall was consistently higher than that in the inner surface. When the outdoor temperature fluctuation was 14.95 °C, the inner surface temperature and indoor temperature fluctuation were 2.73 °C and 3.08 °C, respectively. Moreover, the inner surface temperature of the wall became maximum 7–8 h after the maximum outer surface temperature is reached, on average. The above data show that a modified rammed earth wall has exceptional heat and moisture storage capacities as well as heat and moisture buffering characteristics, which can reduce fluctuations in indoor temperature and humidity and create a more comfortable indoor living environment.