METHOD FOR TESTING SETTING TIME OF CEMENT-BASED MATERIAL

摘要

Disclosed is a method for testing the setting time of a cement-based material: testing the capillary negative pressure of a non-bleeding cement-based material, with the time at which the capillary negative pressure reaches a threshold value A as the initial setting time, and/or the time at which the capillary negative pressure reaches a threshold value B as the final setting time, wherein threshold value A is 8-10kPa, and threshold value B is 54-56kPa. Alternatively, threshold value A and threshold value B are determined by the following method: formulating a cement-based material for the determination of threshold values with the same raw materials at the same formulation ratio; after vibration-compaction, placing a portion into a measuring mold; after vibration-compaction, testing the capillary negative pressure of the non-bleeding cement-based material placed in the measuring mold; under the same conditions, synchronously testing and determining the initial setting time and final setting time of the cement-based material for the determination of threshold values by a penetration resistance method; the capillary negative pressure corresponding to the initial setting time and final setting time of the cement-based material for the determination of threshold values are respectively threshold value A and threshold value B. The method can not only be used in standard tests for a laboratory cement setting time under standard temperature conditions, but can also be used to realize remote, automatic, and continuous in situ monitoring for the setting time of a cast-in-situ concrete structure.