Browse > Article
http://dx.doi.org/10.4334/JKCI.2006.18.6.759

Prediction of Setting Time of Concrete Using Fly Ash and Super Retarding Agent  

Han, Min-Cheol (Div. of Architectural Engineering, Cheongju University)
Publication Information
Journal of the Korea Concrete Institute / v.18, no.6, 2006 , pp. 759-767 More about this Journal
Abstract
This paper presents a method to estimate the setting time of concrete using super retarding agent(SRA) and fly ash(FA) under various curing temperature conditions by applying maturity based on equivalent age. To estimate setting time, the equivalent age using apparent activation energy($E_a$) was applied. Increasing SRA content and decreasing curing temperature leads to retard initial and final set markedly. $E_a$ at the initial set and final set obtained by Arrhenius function showed differences in response to mixture type. It is estimated to be from $24{\sim}35KJ/mol$ in all mixtures, which is smaller than that of conventional mixture ranging from $30{\sim}50KJ/mol$. Based on the application of $E_a$ 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. A high correlation between estimated setting time and measured setting time is observed. Multi-regression model to determine appropriate dosage of SRA reflecting FA contents and equivalent age was provided. Thus, the setting time estimation method studied herein can be applicable to the concrete containing SRA and FA in construction fields.
Keywords
super retarding agent(SRA); fly ash; maturity; setting time; equivalent age;
Citations & Related Records
연도 인용수 순위
  • Reference
1 한천구, 윤치환, '보통 및 초지연 콘크리트의 부어넣기 방법 방법에 따른 매스 콘크리트의 수화열 특성,' 대한건축학회연합논문집, Vol.4, No.3, 2002. 8, pp.35-42
2 Carino, N. J, The Maturity Method, CRC Handbook on Nondestructive Testing of Concrete, CRC Press, 1991, pp.101-146
3 Roberto, C. A. P. and Kenneth, C. H., 'Application of Maturity Approach to Setting Times,' ACI Materials Journal, Vol.96, No.6 1999, pp.686-691
4 ASTM, Standard Practice for Estimating Concrete Strength by the Maturity Method, ASTM C 1074-93, USA, pp.1-10
5 Freislenben, H. and Pederson, J., Maturity Computer for Controlled Curing and Hardening of Concrete Strength, Nordisk Betong, 1977, pp.19-34
6 Schindler, A. K., Concrete Hydration, Temperature Development, and Setting at Early Ages, Ph.D. Dissertation, The university of Texas at Austin, 2002, 531pp
7 Maria, C., Garci, J., and Hamlin, M. J., 'New Insights into the Effects of Sugar on the Hydration and Microstructure of Cement Pastes' Cement and Concrete Research, Vol.32, No.3, 2002.3, pp. 393-399   DOI   ScienceOn
8 한민철, 한천구, '적산온도방식에 의한 초지연제 사용 콘크리트의 응결시간 예측,' 대한건축학회논문집 구조계, Vol.21, No.5, 2005. 5, pp.105-112