Fire resistance of geopolymer concrete produced from Elazığ ferrochrome slag

Abstract

SUMMARYThis paper presents the effect of elevated temperatures up to 700°C on compressive strength and water absorption of two alkali-activated aluminosilicate composites (one of them is river sand aggregate geopolymer concrete; the other one is crushed sand aggregate geopolymer concrete) and ordinary Portland cement based concretes. To obtain binding geopolymer material, Elazığ ferrochrome slag was ground as fine as cement, and then it was alkali activated with chemical (NaOH and Na 2 SiO 3 ). Geopolymer concrete samples were produced by mixing this binding geopolymer material with aggregates. At each target temperature, concrete samples were exposed to fire for the duration of 1 h. Fire resistance and water absorption of geopolymer and ordinary Portland cement concrete samples were determined experimentally. Experimental results indicated that compressive strength of geopolymer concrete samples increased at 100°C and 300°C temperatures when compared with unexposed samples. In geopolymer concrete samples, the highest compressive strength was obtained from river aggregates ones at 300°C with 37.06 MPa. Water absorption of geopolymer concrete samples increased at 700°C temperature when compared with unexposed samples. However, a slight decrease in water absorption of concrete samples was observed up to 300°C when compared with unexposed samples. SEM and X-ray diffraction tests were also carried out to investigate microstructure and mineralogical changes during thermal exposure.

Formation of one-part-mixing geopolymers and geopolymer ceramics from geopolymer powder

“…The colour of the samples turned slightly lighter. The lightening of sample colours has been observed by Turkmen et al [56] and Zhang et al [57] for geopolymers based on slag and metakaolin-fly ash, respectively. It was supposed that the changing in colour is due to the dehydration of moisture and phase transformation at elevated temperature.…”

The Effect of Ordinary Portland Cement Substitution on the Thermal Stability of Geopolymer Concrete

“…Therefore, the results could provide a strong experimental support for the above hypothesis. Türkmen et al [35] also believed that the beneficial effect of thermal drying was helpful for the increase of compressive strength until 200 °C. Up to 200 °C, the enhancement in compressive strength of FAGCs containing cement also resulted from the following two primary reasons.…”

Freeze-Thaw and Fire Resistance of Geopolymer Mortar Based on Natural and Waste Pozzolans

“…The residual compressive strength of NZ-based mortars after their heat treatment is relatively higher than that of the materials on the basis of FA and GGBS. Turkmen et al [38] indicated that a significant decrease in the compressive strength was observed in all of the specimens after heating to 700°C. It was reported that this strength loss is largely attributed to decomposition of calcium hydroxide, which is known to occur between 450 and 500°C [39].…”