| Title |
Prediction of Setting Time of Super Retarding Concrete Incorporating Blast Furnace Slag |
| Keywords |
Setting Time ; Maturity ; Apparent Activation Energy ; Super Retarding Agent ; Equivalent Age |
| Abstract |
This paper presents a method to estimate the setting time of concrete using super retarding agent(SRA) and blast furnace slag(BS) under various curing temperature conditions by applying maturity based on equivalent age. To estimate setting time, the equivalent age using apparent activation energy(Ea) was applied. Increasing SRA content and decreasing curing temperature leads to retard initial and final set markedly. Ea at the initial set and final set obtained by Arrhenius function showed differences in response to mixture type. It is estimated to be from 20～33KJ/mol in all mixtures, which is smaller than that of conventional mixture ranging from 30～50KJ/mol. Based on the application of Ea to Freisleben-Hansen and Pederson's equivalent age function, equivalent age is nearly constant, regardless of curing temperature and SRA contents. This implies that the concept of maturity is applicable in estimating the setting time of concrete containing SRA and BS. A high correlation between estimated setting time and measured setting time is observed. Multi-regression model to determine appropriate dosage of SRA reflecting BS contents and equivalent age was provided. Thus, the setting time estimation method studied herein can be applicable to the concrete containing SRA and BS in the construction fields. |