Influence of diatomite addition in the properties of geopolymeric pastes: fluid loss control volume, thickening time and compressive strength

Abstract

Today, the diversity of available materials for use in engineering is very large, resulting in an increasing of specific materials for each type of application. The geopolymers have been studied for various decades. They are inorganic polymers that can provide cementing characteristics that emerge as a new class of high performance materials, capable of totally or partially replace the Portland cement in various applications. In this work, we studied the influence of the addition of diatomite on geopolymeric pastes based on metakaolin. The use of a new raw material abundant in nature and low value like the diatomite is another alternative as silica source to produce geopolymers. The diatomite is an amorphous silica and in this work it was used as an additive to improve some important properties in cement pastes based in geopolymers. The effect of adding of the diatomite the geopolymeric properties of the slurries was evaluated by comparing them with the properties of the geo-polymer based on metakaolin. To analyze the effects of diatomite concentrations in geopolymeric pastes, filtrate tests were performed, thickening time and compressive strength. Also presents the results of X-ray diffraction (XRD) and scanning electron microscopy (SEM) in order to gather information for a better understanding of the geopolymers cement microstructure. The results showed that the addition of diatomite changed drastically the microstructure and mechanical properties of geopolymer pastes. With the increasing in the concentration of diatomite, the filtrate volume decreases, independent on the temperature.

Keywords:
geopolymeric pastes; metakaolin; diatomite