Effect of heat treatment temperature on ground pumice activation in geopolymer composites

Abstract

In emerging countries, the driving elements for sustainable development are greenhouse and global warming concerns and the need for the development of low-CO 2 cements as replacement for Portland cement. Pumice is an aluminosilicate-type material that can be condensed with NaOH and Na 2 SiO 3 solution and can be used for green building with reduction in CO 2 footprint. The present paper highlights the effect of curing temperature on Hasankale pumice activation. Four curing temperatures have been investigated in this paper, 25°C, 45°C, 65°C, and 85°C, and 65°C has been confirmed as the best temperature for ground pumice activation. Furthermore, the aging effect has been studied at different curing temperatures. The aging of the samples before 28 days has a remarkable effect on compressive strength gain, but after 28 days this effect is inconsiderable for all heat treatment temperatures.

Relationship between compressive strength and UPV of GGBFS based geopolymer mortars exposed to elevated temperatures

“…It is believed that this is due to heat curing at 60°C for 24 h, where by the geopolymer concrete experienced relatively fast polymerization, hence fast strength gain which resulted in no significant addition in compressive strength at the seventh day for higher ratio of sodium silicate to sodium hydroxide. In fact, the 28-day compressive strengths were reported to have slightly changed compared to the early strength of the specimens, though different materials [7,21]. Similar findings were achieved by Hardjito and Rangan [22] on fly ash based geopolymer concrete, which gained 1 day compressive strength of 17 MPa with 0.4 Na 2 SiO 3 to NaOH ratio and 57 MPa with 2.5 Na 2 SiO 3 to NaOH ratio.…”

“…The mechanical properties of geopolymers under elevated temperatures have been the subject of several studies [16][17][18][19][20][21]. Although, research shows the advantages of geopolymers under elevated temperatures and high residual strength even at temperatures of 800°C, research into the correlation between compressive strength and UPV on geopolymer concretes exposed to elevated temperatures are limited.…”

The effects of silica modulus and aging on compressive strength of pumice-based geopolymer composites

“…As it has been illustrated in Fig. 1 broad X-ray peaks are located 20-30°( 2h) showed very amorphous phase in sample textures [18].…”

“…Four curing temperatures have been investigated in authors previous work as 25, 45, 65, and 85°C, and according the results, 65°C has been confirmed as the best temperature for ground pumice activation. So 65°C have been selected as curing temperature in this work [18,21]. Then specimens were left standing for 48 h at 65°C in curing chamber.…”

Investigation of sulfates effects in perlite‐based geopolymer

“…Regarding the fact that geopolymer production is carried out unlike ordinary cement, that is, without calcination process, perhaps it is true that geopolymers pull the cement industry toward an eco‐friendly condition and maybe lead to the production of a green material as a substitute for OPC . The dominant method for producing geopolymers is curing in a temperature between 20 and 90°C and the produced geopolymers at these temperatures usually have an amorphous texture but under the influence of elevated temperatures, the probability of crystalline phase production increases. The previous work of the author refers to this subject .…”