Abstract: As fresh mortar can be seen as a typical Bingham fluid,the characterization of its rheological parameters plays an important role in the research of the working performance of mortar and concrete.In the investigation,a flow curve is drawn by measuring the falling rate of 100mL mortar from a funnel under the weight of upper mortar,and the plastic viscosity and yield stress of mortar can be obtained through linear fitting to characterize the rheologi- cal properties of mortar.Then,the effects of the diameter of spout calibers and the inner diameters of splice cylin- ders on the test results were revealed,and the results are compared with those obtained by using a rotational vis- cometer.Finally,the reliability and repeatability of the proposed method are analyzed.The results show that (1) the sand size produces no influence on the test data of the proposed method,and the repeatability is good; (2) the test condition of the proposed method is a low shear rate under its own weight,which is similar to the actual work condition of concrete; and (3) although the absolute values of both the plastic viscosity and the yield stress which are obtained through the proposed method are different from those obtained by using the rotational viscometer,the change rules of the rheological parameters of the two methods are consistent.

Key words: cone-based rheometer, mortar, rheological parameter, plastic viscosity, yield stress