A new method to determine initial setting time of cement and concrete using plate test

摘要

The present study developed a new method for determination of cement and concrete setting times. The disadvantage of current methods is that most only determine setting time of either cement or concrete and cannot determine the setting time of all types of concrete and cement, especially those containing mineral admixtures. In the proposed method, a plate with a rough surface is rigidly attached to the bottom of a precision balance in a PVC cylinder and immersed in fresh mixture poured into the side of the cylinder opposite the balance. The shear force exerted on the plate increases over time and the value recorded by the balance increases moment-by-moment. The difference between the sequential weights recorded at specific intervals was maximized at the setting time moment. Three types of cement paste and three types of self-compacting concrete were evaluated using the new method. The initial setting time obtained by this method was confirmed using the results of existing test methods. The results show the feasibility and accuracy of the proposed plate test method to determine initial setting times of cement and concrete.