Effect of NaOH Molarity on the Strength and Microstructure of Natural Pozzolan-Based AAC

Abstract

Alarming levels of greenhouse gas emissions has triggered change in the mode of direction of building material research. In this pursuit, alkali activated binders (AAB), synthesized by activation of industrial by products and natural materials in the presence of highly alkaline solutions, have offered viable alternative to OPC. However, there are quite a number of variables which controls the properties of these binders. Among these parameters, SS/SH ratio and molarity of sodium hydroxide solution plays a very important role in the development of these binders. Therefore, this research investigates the effect of SS/SH ratio, subsequently, molarity of SH solution on the properties of natural pozzolan based AAB. The NP was activated with sodium silicate to sodium hydroxide ratio (SS/SH) between 2.0 to 2.75. Subsequently, the molarity of SH solution was varied between 8 to 14. The development in strength was monitored on the specimens cured at 60 °C. SEM and EDS techniques were used to determine the nature of the binder formed during alkali activation. The results have shown that SS/SH ratio of 2.5 and 14 molar SH solution resulted in higher strength and finer microstructure as compared to others. Also, it was understood that there exists a suitable silica modulus of combined activator which results in higher polymerization.

Mechanical and Microstructural Properties of Copper Slag Based Blended Geopolymer Concrete

“…Copper slag addition indicates amorphous nature and results in the nonidentification of products that were formed in alkali activation [37]. Any change in the hump affects the efficiency of the amorphous gels [38]. Additional CSH gel formation at ambient curing was also found due to the pozzolanic reaction of UFGGBFS which leads to high strength.…”

Influence of Silica Modulus and Curing Temperature on the Strength of Alkali-Activated Volcanic Ash and Limestone Powder Mortar

“…To mitigate the proliferation of CO 2 into the environment, researchers are focusing on developing viable and sustainable alternative friendly novel studied [28]. Ibrahim et al investigated the effect of silica modulus on alkali-activated natural pozzolan concrete [29]. Curing temperature is another very important parameter that affects the strength development of alkali-activated binders.…”