Yield stress measurement for earth-based building materials: the weighted plunger test

Earth-based building material processing is a challenge for new constructions. Moreover, field measurements to obtain the rheological properties of fresh materials are required in building applications. However, existing field-oriented tests were designed for more flowable materials, and new protocols for stiff materials are rarely available. In this paper, a field-oriented test of yield stress is developed for earth-based building materials accurate enough to identify small variations for demanding applications. The squeeze test is used as the reference measurement of yield stress. For pure clays and two clay-based materials, yield stresses could not be easily linked to two existing tests: the Atterberg limits and the falling plunger. Finally, a weighted plunger test was used to measure the yield stress as accurately as the squeeze test. The development of yield stress measurements for fresh earthen materials will help implement new building techniques on the field.