EVALUATION OF THE EFFECT OF REACTION TEMPERATURE AND REACTION TIME IN RAPID DETERMINATION OF POZZOLANIC REACTIVITY OF FLY ASH (API METHOD)

Abstract

 Optimization of the reaction time and temperature was investigated so that the API method can be applied to fly ash, which exhibits various physical and chemical properties associated with variations in the quality of fuel coal. When a suspension of fly ash, cement, and water mixed at a mass ratio of 1:1:40 was reacted at 80°C for 18 to 48 hours, the pozzolanic reaction did not converge, but the API value obtained under the reaction conditions of 80°C-28 hours showed a good correlation with the activity index at 28 days and 91 days of age. Cross-check tests were conducted by five laboratories using three types of fly ash with different reactivity at three repetition rates. The repeatability of the API method at three repetitions and the reproducibility of the evaluation values among the five laboratories were good, indicating that the API method has a relatively small error factor.