In this present experimental study, geopolymer cement is developed using high calcium fly ash and used in the production of one-part alkali-activated binders. At 8-16 percent of the total precursor materials, the HCFA was activated with anhydrous sodium metasilicate powder and cured in ambient condition. Five mixtures of one-part geopolymer paste were intended at a steady w/b proportion. Density, flowability, setting time, compressive strength, splitting tensile strength and molar ratio impact were envisaged. It was observed that the setting time of the designed one-part geopolymer paste decreases with higher activator content. The experimental findings showed that the resistance of one-part geopolymer cement paste increases with comparatively greater activator content. However, raising the granular activator beyond 12 percent by fly ash weight decreases the strength and workability of the established one-part geopolymer cement. The optimum mix by weight of the fly ash was discovered to be 12 percent (i.e. 6 percent Na2O). At 28 days of curing, one-part alkali-activated paste recorded the greatest compressive strength of almost 50 MPa. The density of the one-part geopolymer paste is nearly the same regardless of the mixes. Microstructural assessment by FESEM, FTIR and XRD has shown that the established geopolymer paste includes quartz, pyrrhotite, aluminosilicate sodium and hydrate gels of calcium aluminosilicate. Based on the experimental information acquired, it can be deduced that the strength growth of one-part geopolymer cement is similar to that of Portland cement.

The existing form of self-compacting concrete (SCC) comprises of a large amount of powdered and fine materials. In this study, a part of the cementitious material was replaced with constant high-volume fly ash, and a portion of fine aggregates was substituted by crumb rubber (CR). Besides that, silica fume (SF) was added, with the hope that by implementing a new type of nanomaterial, the loss in mechanical strength due to previous modifications such as rubberization and replacement will be prevented. Two variables were found to influence the constituent/component in the mix design: SF and CR. The proportion of SF varies from 0% to 10%, while that of CR from 0% to 30% by volume of the total river sand, where 55% of cement was replaced by the fly ash. A total of 13 rubberized SCC samples with CR and SF as controlling variables were made, and their design mix was produced by a Design of Experiment (DOE) under the Response Surface Methodology (RSM). The results reveal a slight increase in the mechanical properties with the addition of SF. The theoretical mathematical models and equation for each different mechanical strength were also developed after incorporating the experimental results into the software.

This research aims to study the effect of the dosage of anhydrous sodium metasilicate activator on the long-term properties of fly ash-based one-part alkali-activated binders (OPAAB) cured at ambient conditions. Powdered sodium metasilicate activator was utilized in the range of 8–16% by weight of the fly ash in producing the OPAAB. The properties examined are hardened density, compressive strength, flexural strength, water absorption, efflorescence formation, and microstructural analysis. The experimental result revealed that the binders exhibited excellent long-term strength properties. The compressive strength of the OPAAP is well correlated with its hardened density. The pastes were found to exhibit good soundness characteristics over the long-term. The absorption of water decreases with an increase in the activator dosage from 8–12%, and beyond that, the water absorption relatively remains the same. Field emission scanning electron microscope (FESEM) micrograph revealed uniformly formed solid matrices with the micro-crack present were observed in the samples. The larger pore size promotes the crystallization of the resulting hydrate substances (N, C)-A-S-H gel. The initial dissolution of the OPAAP occurred within the first 30 min. At longer age of curing, mixtures with a higher dosage of powdered activator tend to absorb less water. Strength properties beyond 28 days are considered as the long-term strength.