ABSTRACT
Geopolymers are synthesized using anthropogenic raw materials and waste from the energy industry. Their preparation necessitates an alkaline activator, which facilitates the dissolution of raw materials and their subsequent binding. At present, geopolymers are considered a promising material with the potential to replace conventional cement-based products. This research investigates foamed geopolymer materials based on fly ash, natural fibers, and phase-change materials. The study utilized three distinct types of fibers and two phase-change materials manufactured by Rubitherm Technologies GmbH of Germany. This paper presents the results of the thermal conductivity coefficient and specific heat tests on the finished foams. Additionally, compressive strength tests were conducted on the samples after 28 days. Natural fibers decreased the insulation parameter by 12%, while PCM enhanced it by up to 6%. The addition of fibers increased the compressive strength by nearly 30%, whereas PCM reduced this by as little as 14%. Natural fibers and phase-change materials had an increased heat capacity by up to 35%. The results demonstrated the material's potential in various industrial sectors, with the primary areas of application being building materials and insulations. The findings illustrate the significant potential of these composites as energetically and environmentally sustainable materials.
ABSTRACT
Diatomites are well-known mineral materials formed thousands of years ago from the skeletons of diatoms. They are found in many places around the world and have a wide range of applications. This article presents innovative research related to the possibility of using diatomite as a filler in composites to improve their sound absorption properties. The results of the study of the effect of diatomite processing (calcination) and its degree of fineness on the sound absorption coefficient of thermoplastic composites are presented. Three fractions of diatomite (0 ÷ 0.063 mm; 0.5 ÷ 3 mm; 2 ÷ 5 mm) and its variable mass proportion (0, 25, and 50 wt.%) were used. The composites were made with flax fibers as a reinforcement, polylactide as a matrix, and diatomite as an additional filler. This paper also presents the results of oxide chemical composition, diatomite mineral phase composition, morphology, and thermal conductivity coefficient of all diatomite fractions studied. In addition, the average particle size for diatomite powder was also determined. The most important of the studies was the determination of the acoustic properties of the aforementioned composites. As a result of the tests, it was found that the smallest fraction of diatomite particles and a variant without thermal treatment give the best effect in terms of sound absorption.