Valorization of limestone powder as an additive for fly ash geopolymer cement under the effect of the simulated tidal zone and seawater attack

Generally, buildings and constructions subjected to the harsh marine environment, especially tidal zone, are usually more susceptible to deterioration than others. Therefore, choosing the type of cement is important to limit this degradation. Limestone powder is widely used as a cementitious material in traditional Portland cement systems due to its availability and low cost. Unlike in the geopolymers, using limestone powder is still in its growth stage, especially in fly ash geopolymer cement. The recent article is the first attempt to enhance fly ash geopolymer cement with limestone powder aiming to limit the deterioration caused by seawater attack and the simulated tidal zone. For this reason, the fly ash was partially replaced with limestone powder at levels oscil-lating from 10 % to 60, by weight, with a stride of 10 %. After initial curing, the specimens were exposed to seawater attack and the simulated tidal zone for 3, 6 and 12 months. Other specimens were exposed to the air and tap water for the same periods for comparison purposes. Compared to the specimens cured in the air, the results disclosed that the specimens subjected to the simulated tidal zone showed the highest impairment ratios followed by those submerged in seawater, whilst the specimens submerged in tap water came in last place. The incorporation of limestone powder up to 20 % into fly ash geopolymer cement showed a positive effect in enhancing the compressive strength and limiting the deterioration caused by the harsh environment, whilst higher ratios than 20 % showed a negative effect.

Automated summary

Choosing the right type of cement is crucial to limit deterioration in buildings exposed to marine environments. By partially replacing fly ash with limestone powder, the compressive strength of the cement can be enhanced and the degradation caused by seawater and tidal zones can be reduced.