Field-oriented tests to evaluate the workability of cob and adobe
Résumé
Due to its low environmental impact, earth construction has received lot of consideration in recent years. Furthermore, in order to improve the quality of earth construction, there is a need for a better description and control of the earth consistency or rheology. Just as for concrete with the Abrams cone, there is need for a simple and robust test that is able to provide, under field conditions, the consistency of the earth and that has results that can be used to estimate the yield stress of a fine soil used for cob or adobe. Two types of field-oriented tests are optimized for field conditions the first one is based on the cone penetration test as used for the determination of the Atterberg limits and the second one is the ball dropping test already used onsite to check the adequacy between the earth consistency and the construction process. Finally, an experimental validation carried out on two types of soil shows that the yield stresses computed from the field-oriented tests is in agreement with the yield stresses obtained in a conventional way using a vane rheometer. © 2018, RILEM.