Effect of Rapid Hardening Cement and Setting Accelerator on the Freeze-Thaw Durability of Fly Ash Concrete

• Published in: Key Engineering Materials 2016-09, Vol.711, p.343-350
• Main Authors: Badr, Atef, Al Maroof, Haidar, Ioannou, Socrates
• Format: Article
• Language: English
• Subjects: Accelerators; Age; Age hardening; Cement; Cold; Concrete mixing; Concretes; Fly ash; Freeze-thaw durability; Hydration; Portland cements; Setting (hardening)
• ISSN: 1013-9826; 1662-9795; 1662-9795
• DOI: 10.4028/www.scientific.net/KEM.711.343

This paper presents the results of the second phase of an experimental research, which was carried out to investigate the freeze-thaw durability of fly ash (FA) concrete subjected to slow freeze-thaw cycles. The results of the first phase showed that FA had a significant detrimental effect on the freeze-thaw durability concrete. The lower resistance to freezing condition was attributed to the low early strength of FA concrete, at early ages, compared to Portland cement concrete. Therefore, rapid hardening Portland cement (RHPC) and setting accelerator (SA) were introduced, in the second phase, in a bid to modify the early age properties of FA concrete and, hence, enhance its freeze-thaw durability. The weight loss and residual strength of the specimens were assessed after specific number of freeze-thaw cycles. The results showed that the use of rapid hardening Portland cement (RHPC) and/or setting accelerator (SA) enabled earlier demoulding to take place and enhanced the early age strength of FA concrete. However, this did not necessarily improve the freeze-thaw durability of FA concrete. The effect RHPC and SA on the deterioration and residual strength of concrete containing fly ash was indifferent. Therefore, it is suggested that further research is needed to confirm the effect of RHPC and SA on the freeze-thaw durability of fly ash concrete.