Impact of slag replacement with cement on durability and workability of self-compacting concrete

Document Type : Original Article

Authors

1 M.Sc, Civil Engineering Faculty, Iran University of Science and Technology, Tehran, Iran

2 M.Sc, Civil Engineering Faculty, K.N. Toosi University of Technology, Tehran, Iran

3 Professor, Civil Engineering Faculty, K.N. Toosi University of Technology, Tehran, Iran

10.22065/jsce.2024.431045.3300

Abstract

In recent decades, the use of mass concrete in various infrastructure projects has significantly increased. Due to the larger dimensions of these sections and the higher volume of Portland cement, a decrease in the strength and durability of the core is often observed in these concrete sections. Industrial by-products such as blast furnace slag have increasingly been used as additives to produce mass self-compacting concrete. This research aims to control and reduce the peak temperature of mass concrete by replacing blast furnace slag with cement. Considering the relevant regulations, the study investigates the reduction or prevention of delayed ettringite formation and the reduction of concrete heat. Additionally, the enhancement of the durability, strength, and performance of self-consolidating concrete for large sections is evaluated. In this manner, four concrete mix designs with replacement percentages of 35%, 45%, and 55% blast furnace slag with cement, and one control mix design (with zero percent blast furnace slag replacement) were employed. To achieve a more detailed analysis of the impact of adding this material to mass self-consolidating concrete, various tests were conducted on fresh and hardened concrete as well as cement. The results indicate that with an increase in blast furnace slag replacement up to 55%, the cement heat has decreased by 28.79%. The workability of self-consolidating concrete using this cement has increased by 7.9% and 5.5% in slump flow and L-box tests, respectively, and good improvements in other performance tests have been observed. In mechanical tests, the concrete strength decreased at early ages with an increase in blast furnace slag but increased at later ages. In durability tests, the concrete's durability increased with up to 55% blast furnace slag replacement, and the increase in electrical resistivity was 14%.

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Articles in Press, Accepted Manuscript
Available Online from 14 March 2024
  • Receive Date: 30 December 2023
  • Revise Date: 18 February 2024
  • Accept Date: 14 March 2024