Behaviour of unsaturated tuff- calcareous sand mixture on drying-wetting and triaxial paths

Abstract

The aim of the paper is to study the hydro-mechanical behaviour of a tuff and calcareous sand mixture. A first experimental phase was carried out in order to find the optimal mixture. This showed that the material composed of 80% tuff and 20% calcareous sand provides the maximum mechanical strength. The second experimental phase concerns the study of the drying-wetting behaviour of the optimal mixture. Triaxial shear tests in saturated and unsaturated states at constant water content were carried out on samples initially compacted at the MPO. Experimental results let to deduce the parameters necessary for the prediction of the hydro-mechanical behaviour of pavement formulated from tuff and calcareous sand mixtures, related to moisture. This optimal mixture satisfies the regulation rules and hence constitutes a good local eco-material, abundantly available, for the conception of pavements.

Co-valorization of Tuff and Sandy Residues in Roads Construction

“…In the lack of standard materials (as for gravel and sandy materials with desirable grain size distribution), to cover the growing needs in road construction in Adrar region, local materials as tuffs of calcareous crusts are the most used materials in pavements in the region. These materials cover an area of 300000 km 2 of the overall surface area of Algeria [26]. In this study, the tuff used is extracted from a quarry located 10 km to the East of the city of Adrar.…”

Hydro-mechanical behavior from small strain to failure of tuffs amended with dune sand – Application to pavements design in Saharan areas

“…For suction larger than 2 MPa, the technique of the saturated salt solutions was used. It consists in putting the soil specimens into a desiccator, where the relative humidity of the atmosphere is related to the nature of the chemical salt at a given temperature [24,26,28,29]. A detailed description of the above two techniques is presented in [47,49].…”

“…In fact, pavements in Saharan regions undergo repeated drying-wetting cycles and are therefore susceptible to problems of swelling-shrinkage, which have a real impact on their stability and durability. In the literature, the effect of drying-wetting cycles on the volumetric behavior of different compacted soils has been extensively investigated [21][22][23][24][25][26][27][28]. Useful correlations relating swelling indices to the liquid limit were also proposed [29,30] for practical purposes.…”

Valorisation of dune sand-tuff for Saharan pavement design

“…Several research studies have been carried out on the techniques of amending local materials with missing granular fractions (fine or coarse) [1][2][3][4][5][6]. Cabalar et al [5] have studied the influence of sand addition on the behaviour of sand/clay mixtures.…”