Chemo-thermo-hydro-mechanical behavior of a cement-stabilized rammed earth wall in interaction with the environment and underground soil

Abstract

This work presents a numerical investigation into the structural behavior of a newly built cement-stabilized rammed earth (CSRE) wall and its interaction with the underground soil and environment. Finite element simulations were used to obtain the results, which show that the average degree of cement hydration of the wall increases annually, with the rate of increment decreasing over time. Even after five years of curing, the cement is not completely hydrated. In the first year after construction, the degree of cement hydration is higher near the indoor side of the wall compared to the parts near the outside and underneath the ground due to the higher indoor temperature. The upper and indoor sides of the wall are generally drier than the lower and outdoor sides. Rising damp water that does not evaporate in time stores as a water source in the wall, making the wet areas expand in the following days. The average wall temperature first increases due to the hydration heat and later varies seasonally with the environment. Water has a significant impact on the thermal insulation qualities of the wall. The thermal insulation of the wall decreases due to rising damp but increases owing to water evaporation. The compressive strength of the wall is mainly controlled by cement hydration at an early age but is also impacted in the later four years by the humidity of the environment and the underground soil. The higher portion of the wall loses its strength later than the lower part since it takes longer for water to reach the upper side from the ground soil. This delay is dissipated on the wall surface owing to sufficient contact with the air. The shortage of water on the upper side of the wall leads to the hydration process in this area being governed chiefly by temperature.