Development of time and temperature testing limits for a field water-to-cement ratio test

摘要

The Phoenix is a new test method that can measure the water-to-cementitious ratio (w/cm) in fresh concrete in 15 min by evaporating the mixing water and scaling the binder content. This work will aim to investigate how the results of the test changes with time after mixing and also the length of time the sample spends in the furnace. The time after mixing is important as the water in the mixture begins reacting with the binder as soon as mixing starts. Also, as materials are stored in the furnace the high temperatures may cause the materials to decompose and this would again change the results of the test. These are important questions that limit the timing in the test method and also provide insight into the early reactions of Portland cement with water. This work uses isothermal calorimetry, w/cm testing over time, thermogravimetric analysis, and degree of hydration tests to establish reasonable limits for the test method.