Influence of Various Types of Waste on the Main Properties of Gypsum Based Composites for Thermal Insulations

Abstract

In the last decade numerous research studies were performed in the attempt to recycle several types of industrial waste. This study has as main objective the obtaining and characterization of gypsum based composite materials with various amounts of industrial wastes (flue gas desulfurization gypsum and recycled rubber). The main properties assessed for these materials were setting time, compressive strength, apparent density and thermal conductivity. The gypsum binder was partially replaced with thermally treated flue gas desulfurization gypsum (FGDgp_t) without an important negative impact on the compressive strength; if the replacement amount is up to 40 wt.% the resulted binder still meets the requirements imposed for this property by specific norm for gypsum plaster - EN 13279-1. The substitution of gypsum plaster with FGDgp_t shortens the setting time, therefore it was compulsory to use also sodium citrate as retarder addition. The addition of 5 wt.% rubber waste has a positive effect on the thermal conductivity of composite materials based on gypsum binder with/without FGDgp_t. Consequently, these materials could be used for the manufacture of low cost, eco-friendly thermal insulation materials.

Lightweight Gypsum Materials with Potential Use for Thermal Insulations

“…Due to the relatively low thermal treatment temperatures and the possibility to recycle it in close loops, the gypsum binder is considered environmentally friendly as compared with other types of inorganic cements [12]. Nowadays, one of the main utilizations of gypsum binder is the production of gypsum plasterboards (dry-walls) [11,12]; another utilization of gypsum binder is to produce thermal and sound insulation materials [4,11,[13][14][15][16][17][18]. According to Dolezelova et al [10], gypsum-based light materials can be used in construction to replace autoclaved aerated concrete (AAC) and the energy consumption for the manufacture of gypsum materials is lower as compared with the one used for the manufacture of AAC.…”

“…The thermal insulation materials based on gypsum can be obtained either by its mixing with lightweight aggregates, including various waste such as expanded polystyrene [18], rubber, polyurethane foam and chopped electric cables waste [15,16], or direct foaming using various types of gas generators (aluminum sulphate with citric acid, calcium carbonate or sodium bicarbonate [4,13,14]). The thermal conductivity of this type of materials can vary from 0.085 up to 0.416 W/(m.K) depending on the nature and dosage of the additions and the assessment method [4,10,14,15].…”

“…The presence of CaSO 4 •2H 2 O (CsD) as a main component in FGD gypsum justifies its use as a setting accelerator in gypsum binders. The CsD particles from FGD gypsum can act as nucleation sites for newly formed CsD crystals (by CaSO 4 •0.5H 2 O hydration), therefore accelerating the setting process [14,16].…”

Glass Fertilizers Obtained Using Sewage Sludge ASH Wastes

“…In 2010, more than 10 million tons of dried sewage sludge were generated from 27 European Union countries. Moreover, it is expected 13 million tons of sewage sludge to be generated from the 27 European Union countries due to the industrialization and urbanization [2][3][4][5]. In all European Union countries directives regarding sewage sludge management are introduced.…”

Glass Fertilizers Obtained Using Sewage Sludge ASH Wastes

“…In 2010, more than 10 million tons of dried sewage sludge were generated from 27 European Union countries. Moreover, it is expected 13 million tons of sewage sludge to be generated from the 27 European Union countries due to the industrialization and urbanization [2][3][4][5]. In all European Union countries directives regarding sewage sludge management are introduced.…”