Influence of water on the mechanical characteristics of rammed-earth material

Abstract

Earthen materials in general and rammed-earth in particular are ancient materials used for construction since time immemorial. Some earthen structures built centuries ago are still performing satisfactorily. However, in a lot of cases, the problem of durability still raises questions, since earthen material is very sensitive to water and since the maintenance is not always well done. This paper presents a study on the influence of water on the mechanical characteristics (compressive strength, Young modulus and Poisson ratio) of rammed-earth material. Experiments on suction were also carried out to study the relationship between suction and mechanical characteristics of rammed-earth. The results show that for low water contents: which are from the dry state (in the atmospheric conditions) to 4wt.%, the mechanical properties are constant. Explanations of this result are presented in relation to the capillary force between particles at the microscopic level of the material.

Mechanical and Microstructural Characterization of Rammed Earth Stabilized with Five Biopolymers

“…To simplify the discussion, "MIX" will be used as an abbreviation to refer to the 1:3 soilto-sand ratio preparation. The grain size distribution of the MIX has been chosen to have a maximum diameter of 2 mm in order to reduce the time required to prepare and condition the samples with smaller dimensions to execute the UCS test [18,19]. It has been reasonably assumed that this choice does not affect the possibility to investigate the effects of biopolymers on soil stabilization.…”

“…Copyright 2021 Scientific.Net. maximum diameter of 2 mm in order to reduce the time required to prepare and condition the samples with smaller dimensions to execute the UCS test [18,19]. It has been reasonably assumed that this choice does not affect the possibility to investigate the effects of biopolymers on soil stabilization.…”

“…A slenderness ratio of 2 (3.8 cm in diameter and 7.6 cm in height) was chosen to respect the guidelines for rammed earth and soil mechanics for UCS [19,54,55]. The size of the samples respects the criteria for the international ASTM standard of geotechnics D2166 and the State-of-the-Art Report of the RILEM TC 274-TCE (2021) on Testing and Characterization of Earth-based Building Materials and Elements [18,55].…”

“…Approximately 2 months were necessary to dry the samples and achieve the equilibrium of conditioning, estimated from the relative weight changes from 3 consecutive days smaller than 0.05%. A minimum of three samples for each different mixture was tested and the good reproducibility of the samples was ensured by standard A slenderness ratio of 2 (3.8 cm in diameter and 7.6 cm in height) was chosen to respect the guidelines for rammed earth and soil mechanics for UCS [19,54,55]. The size of the samples respects the criteria for the international ASTM standard of geotechnics D2166 and the State-of-the-Art Report of the RILEM TC 274-TCE (2021) on Testing and Characterization of Earth-based Building Materials and Elements [18,55].…”