From mini-cone test to Abrams cone test: measurement of cement-based materials yield stress using slump tests

Stoppage tests in civil engineering consists in measuring the shape of a fresh material deposit after flow occurred. This measured geometrical value (slump, spread) is linked to the plastic yield value of these yield stress materials. The most famous example is the Abrams cone for concrete. In this work, the flow induced by a smaller cone test for cement pastes and grouts is studied. In a first part, the spread is theoretically linked to the plastic yield value. Experimental results on several cement pastes validate the obtained relation but also shows the necessity to take in account the surface tension effects for low yield stress materials. The modified relation allows the prediction of the plastic yield value from the measured spread. The proposed method is then applied to the Abrams cone and fresh concrete. It is demonstrated that it is only suitable for high slumps (>20 cm).