AASHTO T 186-20 PDF Download

AASHTO T 186-20 is a standard method of testing the early stiffening of hydraulic cement paste. This method is in agreement with ASTM C 451-18, with the only difference being the use of SI units. The objective of this test is to determine the rate at which the hydraulic cement paste transitions from the plastic state to the stiffening state.

The test procedure involves preparing a hydraulic cement paste and measuring its initial setting time and final setting time. The initial setting time is the time it takes for the cement paste to acquire enough stiffness to resist penetration by a standard needle, while the final setting time is the time at which the paste becomes completely stiff and loses its plasticity.

The test is conducted by carefully controlling the temperature and humidity conditions during the testing process. The paste is placed in a Vicat apparatus, and the needle is allowed to penetrate the paste at regular intervals until it no longer does so. The time taken for the paste to reach the specified penetration resistance at each interval is recorded.

AASHTO T 186-20 provides detailed instructions on the equipment, preparation of the paste, and the testing procedure for accurate and consistent results. This standard is essential for quality control and assessing the early stiffening characteristics of hydraulic cement paste in construction materials.