A unified failure criterion for unstabilized rammed earth materials upon varying relative humidity conditions

Gérard, Pierre; Mahdad, Mohamed; McCormack, Alexandre Robert; Baudin, François

doi:10.1016/j.conbuildmat.2015.07.100

Cited by 68 publications

(40 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results (available in details in [14]) exhibit the following trends: -The UCS increases with suction: dryer is the soil and higher is the strength. -However, in the same time, the brittleness also increases with suction: the material is less and less ductile when the amount of water in the soil decreases.…”

Section: Uniaxial Compressive Strengthmentioning

confidence: 86%

Influence of atmospheric conditions on the strength of unstabilized earthen constructions

et al. 2016

Self Cite

View full text Add to dashboard Cite

Abstract. Uniaxial compression tests and indirect tensile tests are performed on compacted clayey silt samples upon varying suctions in order to assess the influence of changes in the relative humidity conditions on the strength of unstabilized rammed earthen building materials. The results show that suction plays an important role on the strength of the material. Also the ability of the Belgian clayey silt to develop sufficient mechanical strength to be used as an unstabilized earthen construction material is demonstrated whatever the relative humidity conditions, excepted the fully water saturated state. The experimental data are interpreted in the context of unsaturated soil mechanics using the generalized effective stress concept. This constitutive framework allows defining a unified failure criterion predicting the strength of the earthen building material as a function of the environmental hygroscopic conditions.

show abstract

Section: Uniaxial Compressive Strengthmentioning

confidence: 86%

Influence of atmospheric conditions on the strength of unstabilized earthen constructions

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…The effect of suction was included assuming a linear increase in tensile strength similar to the Barcelona Basic Model. More recently Gerard et al [12] presented results from tests on an unsaturated Belgian clayey silt with similar properties to a typical RE mix (without a gravel fraction), results of which were then used to validate a constitutive model based on a generalized effective stress (Bishop stress) approach with values suggested for the effective stress parameter . The attempt to fit an EC material into one of the two established methods for dealing with effective stress in unsaturated soils is an interesting development, also seen in [13].…”

Section: Constitutive Modellingmentioning

confidence: 99%

“…Figure 9 shows that strength almost doubled between the high and low suction conditions for both soils. It is unlikely that a practitioner would have the time or the facilities to derive full water retention curves for a given soil, for example Figure 10, or determine a full yield surface for their material, for example as in [12]. However, a change in strength of the magnitude shown in Figure 9 would be critical to a project's feasibility.…”

Section: Figurementioning

confidence: 99%

Challenges in treating earthen construction materials as unsaturated soils

et al. 2016

View full text Add to dashboard Cite

Abstract. Earthen construction is a loosely defined term covering both the materials and methods for creating structural components from mixtures of subsoil, often with the addition of chemical or mechanical stabilisers. There is evidence of Man creating earthen structures for thousands of years, and there are many world heritage sites containing earthen structures, some of which present issues in terms of conservation. In some parts of the world there is a growing market for new-build earthen structures and a key issue here is the lack of design codes. Since these materials are composed mainly of particulates and water it is natural to regard them as geotechnical in nature, where friction and the presence of water have a key influence on material properties, however until very recently this was not the case, with earthen construction materials regarded as weak concrete or masonry. In this paper we examine these opposing views and discuss the issues associated with regarding these materials as unsaturated soils. The paper is illustrated with outcomes from research at Durham University carried out over the past ten years.

show abstract

“…The grainsize distribution is: 13 % of clay, 64 % of silt and 26 % of sand. The permeability of the saturated silt compacted first at the Optimum Proctor compaction conditions (initial water content w 0 = 14.8%; initial dry density ρ d0 = 18.40 kN/m³ -see [9] for more details) and then resaturated is equal to 10 -10 m/s. The determination of the retention curve of the silt is based on the use of 2 techniques: the pressure plate apparatus [10] and the vapour transfer technique [11].…”

Section: Materials and Sample Preparationmentioning

confidence: 99%

On the mechanisms and kinetics of evaporation of a compacted silt

et al. 2016

Self Cite

View full text Add to dashboard Cite

Abstract. In order to define a convective evaporation model able to reproduce the evaporation rates according to the atmospheric conditions, drying tests have been performed on cylindrical samples of a compacted silt in a closed chamber where the relative humidity of the air is controlled by means of saturated saline solutions. Calibrating such models using experimental results from small sample sizes can indeed be an interesting alternative to simplify the experimental procedures and to reduce the test duration in comparison with the standard in-situ tests (e.g. lysimeter). However the influence of the size of the samples on the kinetics of evaporation has to be investigated. Samples with different diameters and heights are therefore tested. The results show that the observed mechanisms of drying are similar to those at the scale of the geostructure if the dimensions of the sample are higher than a critical height and a critical diameter. We show then that the experimental critical height is consistent with the concept of critical length proposed by Lehman et al. (2008), who expresses analytically when the hydraulic connection between the sample surface and the drying front is upset. Finally the kinetics of evaporation recorded under different relative humidities highlight that the mass transfer coefficient defined in the convective evaporation model does not depend on the relative humidity.

show abstract

A unified failure criterion for unstabilized rammed earth materials upon varying relative humidity conditions

Cited by 68 publications

References 25 publications

Influence of atmospheric conditions on the strength of unstabilized earthen constructions

Influence of atmospheric conditions on the strength of unstabilized earthen constructions

Challenges in treating earthen construction materials as unsaturated soils

On the mechanisms and kinetics of evaporation of a compacted silt

Contact Info

Product

Resources

About