Evaluation of the Effect of Silica Fume on Amorphous Fly Ash Geopolymers Exposed to Elevated Temperature

Abstract

The properties of amorphous geopolymer with silica fume addition after heat treatment was rarely reported in the geopolymer field. Geopolymer was prepared by mixing fly ash and alkali activator. The silica fume was added in 2% and 4% by weight. The geopolymer samples were cured at room temperature for 28 days before exposed to an elevated temperature up to 1000 °C. The incorporation of 2% silica fume did not cause significant improvement in the compressive strength of unexposed geopolymer. Higher silica fume content of 4% reduced the compressive strength of the unexposed geopolymer. When subjected to elevated temperature, geopolymer with 2% silica fume retained higher compressive strength at 1000 °C. The addition of silica fume in fly ash geopolymer caused a lower degree of shrinkage and expansion, as compared to geopolymer without the addition of silica fume. Crystalline phases of albite and magnetite were formed in the geopolymer at 1000 °C.

Assessment of the Suitability of Ceramic Waste in Geopolymer Composites: An Appraisal

“…Hydrated gels turn out to be dehydrated on account of the evaporation of free water, and air voids take the place of water. The thermal conductivity of AAPs having noteworthy free water and hydrated gels will be higher than that of AAPs with minimum free water and dehydrated gels because the thermal conductivity of water is 25-fold greater than the thermal conductivity of air [115][116][117][118]. Generally, the WBP incorporating geopolymer paste mixtures displayed higher results for thermal conductivity during the investigation than the WCP-blended geopolymer paste mixtures.…”

Optimal Design of Ferronickel Slag Alkali-Activated Material for High Thermal Load Applications Developed by Design of Experiment

“…All prisms programmed for heating were exposed to a thermal load comprising a ramp of 5 • C/min up to 900 • C, followed by a constant temperature step spanning 2 h; then, the oven was turned off and the specimens were left to cool down in the oven (with the door shut) until the next day. For heating, an electrical 500 mm 3 oven was used, with a maximum heating capacity of 1100 • C. This heating regime was adopted to allow for comparison with previous studies that followed the same protocol [32,33] and others varying only the ceiling temperature, which was kept constant for 1 h [34][35][36]. The specimens' dimensions were measured with a vernier caliper, and the shrinkage/expansion was evaluated as the difference between pre-and post-high temperature exposure measurements.…”

Effect of Steel Fibers on the Interfacial Shear Strength of Flyash and GGBS based Geopolymer concrete activated with water glass

“…Researchers have investigated the process by which y ash rich in aluminosilicate reacts with alkali to generate geopolymer, an inorganic polymer binder. Numerous research projects have investigated the characteristics of concrete with geopolymer as the binder [5,6]. When materials containing alumina and silica are mixed with an alkaline solution, silicon (Si) and aluminum (Al) dissolve quickly, forming a three-dimensional polymeric chain [20].…”