INVESTIGATION OF KAOLIN BASED ONE PART GEOPOLYMERS

Sezer Çeti̇n,Mehmet Uğur Toprak,Seher Güz

doi:10.31796/ogummf.902041

Abstract

Kaolin based one-part geopolymers (produced by adding water to preground aluminosilicate+alkali mixture) were produced in this study. Effect of and silica fume addition and prewaiting time on microstructure, mechanical and mineralogical properties of geopolymers evaluated with X–ray Fluorescence (XRF), X–ray diffractometer (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectrometer (FT–IR). Kaolin based one-part geopolymers gained 7-day compressive strength of 66.73 MPa while silica fume addition enhanced the strength up to 88.57 MPa.

Highlights

Victor Glukhovsky, in the 1960s and 1970s made major contribution in identifying both calcium silicate hydrates, and calcium and sodium alumino-silicate hydrates as solidification products in geopolymerization (Davidovits, 2020)
Davidovits stated that these requirements can only be provided by inorganic polymermaterials and reported that a mineral such as kaolin may form a binder by alkali activation at a temperature as low as 100-150 °C, instead of heat treatment at 10001300°C.He introduced the term of geopolymer in 1978 (Davidovits, 1988)
The interatomic bonds examined in the Fourier Transform Infrared Spectrometer (FT–IR) analysis revealsgeopolymer formation

Summary

Introduction

Victor Glukhovsky, in the 1960s and 1970s made major contribution in identifying both calcium silicate hydrates, and calcium and sodium alumino-silicate hydrates as solidification products in geopolymerization (Davidovits, 2020). Davidovits began to work on new heat-resistant “plastic materials” after the catastrophic fires in France in 1970/73. Davidovits stated that these requirements can only be provided by inorganic polymermaterials and reported that a mineral such as kaolin may form a binder by alkali activation at a temperature as low as 100-150 °C, instead of heat treatment at 10001300°C.He introduced the term of geopolymer in 1978 (Davidovits, 1988). Davidovits has defined Si–O–Al bond as sialate bond and Si-O-Si bond as siloxo bond for aluminosilicate structures and this aluminosilicate structures known as “inorganic polymers”, “mineral polymers”(Davidovits, 1982). If Si/Al molar ratiosare 1, 2 and 3, this structures respectively defined as poly (sialate), poly(sialate-siloxo) and poly (sialate-disiloxo) (Davidovits, 1976). Molecular sequences of geopolymer systems with different Si/Al ratios and share of all oxygen atoms of SiO4 and AlO4 tetrahedrals shown in Figure 1 (Palomo, Grutzeck and Blanco-Varela, 1999; Provis, Lukey and van Deventer, 2005)

Methods

Results

Conclusion