Title: Effect of Tidal Zone and Seawater Attack on Alkali- Activated Blended Slag Pastes

Author(s): Alaa M. Rashad and Youssef A. Mosleh

Publication: Materials Journal

Volume: 119

Issue: 2

Appears on pages(s): 91-103

Keywords: alkali-activated slag (AAS); fly ash; marine environment; quartz powder; silica fume; strength deterioration ratio; tidal zone

DOI: 10.14359/51734355

Date: 3/1/2022

Abstract:
The marine environment has a significant deterioration effect on building materials. Among the different zones of the marine environment, the tidal zone has the highest deterioration. The current paper is the first attempt to study the effect of different treatment conditions—water curing, air curing, seawater curing, and simulated tidal zone—on the compressive strength and microstructure properties of alkali-activated slag (AAS) pastes without or with different mineral admixtures over different periods. Slag was partially replaced with 5 and 10% of different mineral admixtures—fly ash (FA), silica fume (SF), and quartz powder (Q)—by weight. After initial curing, the specimens were subjected to altered treatment conditions for 3, 6, and 12 months (M). The crystalline phases, microstructure analysis, and energy-dispersive X-ray spectra (EDS) of the selected samples were analyzed. The results indicated that the tidal zone has the highest aggressive deterioration on the specimens, followed by those exposed to seawater attack (submerged in seawater). The specimens cured in water exhibited the highest compressive strength, followed by those cured in air. The specimens containing Q showed the best performance, followed by those containing SF and FA, respectively, while the plain AAS pastes came in last place.