TG and DSC studies on plaster residues as recycled material (original) (raw)
Related papers
Construction Materials
Plaster is primarily used as a building material obtained by the calcination of gypsum. Its rapid setting time (time for the mixture to solidify) and the low quality of labor generate a large amount of nonused material. Due to its solubility in water, wasted gypsum cannot be disposed of in the environment, and its recycling process is encouraged. In this work, quantitative phase analyses (QPA) using X-ray powder diffraction (XRPD) data and the Rietveld method were carried out to determine the amounts of each compound present in commercial, hydrated, and laboratory-recycled plasters, and the results compared with those obtained by thermogravimetric analysis (TGA). It was inferred that the Rietveld method associated with XRPD data is quite efficient since it identifies compounds not seen in the TGA. Furthermore, the amount of water used in the preparation of hydrated samples influences the proper hydration of the material and, consequently, the recycled composition of the samples.
Microstructure of Recycled Gypsum Plaster by SEM
Advanced Materials Research, 2014
Gypsum waste from building constructions is a material which can contaminate the soil and groundwater if is disposed directly in the soil or landfill without any control. In Brazil, these wastes are considered a recycle and/or recovery material, but the research of gypsum plaster recycling are very few at this moment. In this way, this work presents the microstructural characterization of two types of recycled plaster. The recycled plaster was produced by a grinding and calcination the building construction waste. Microstructural characteristics were evaluated by SEM observations. The results show similarities between crystals of recycled and commercial plasters.
Gypsum plaster waste recycling: A potential environmental and industrial solution
Journal of Cleaner Production, 2017
Gypsum plaster waste (GPW) represents a large fraction of the total construction and demolition wastes generated by society, which may contaminate the soil and water resources. Although previous studies have indicated the possibility of recycling GPW, it is not known so far, if the recycling process affects the rehydrated products and how many times the GPW can be recycled without changing its characteristics. The present paper evaluated the properties of recycled gypsum plasters produced from a GPW after 1, 3, and 5 recycling cycles, RGP-1, RGP-2, and RGP-3, respectively. The unhydrated and hydrated recycled products were characterized by EDX, XRD, DTA, TG, DTG, as well as by measuring the recycled plaster setting times and the mechanical properties of respective rehydrated products. The recycling process does not change the gypsum plaster chemical composition which is similar to the commercial gypsum plaster. Physical properties are changed: bulk density diminished, setting times were shorter due to the change in the grain size with the recycling process. The mechanical performance was good with similar results at longer ages. GPW recyclability has a great potential to be a successful industrial solution and it allows the production of new reusable products, with less negative environmental impacts.
African Journal of Disability
Background: Plaster of Paris (POP) is being used in different ways in the field of medicine, dentistry and rehabilitation. One of its uses is in the manufacture of models of body segments in prosthetics and orthotics. It is used as a one-off procedure in which the used material is dismantled and discarded. The disposal of discarded materials does not allow easy decomposition which then pollutes the environment. It is not known whether this material could be reused if recycled.Objectives: The main objective of the study was to recycle POP models and determine its reuse in producing models with identical qualities, and thus reduce environmental pollution.Method: The procedure adopted was to break discarded models into small pieces, remove impurities and dirt; then the sample models were milled, washed, dried and pulverised. The POP models were heated to evaporate crystalline water in order to determine for how many times it could be recycled while retaining the desired strength, setti...
Investigations on Recycling Methods of Gypsum Plaster Waste
Journal of University of Babylon for Engineering Sciences (JUBES), 2023
Humans need to keep on the clean environment in order to refine suitable life for the next generators. Where, the different industries formed by human, cause the environmental pollution by landfill with wastes produced from it and cause the consumption of fresh raw materials. One of these industries, is gypsum plaster industry. Where, a large amount of gypsum plaster waste is produced from different fields that use the gypsum plaster. Therefore, it is necessary to work on reduction of these wastes by reusing or recycling them with the least costs and procedures. This study aims to review the ways used to reduce gypsum waste amount and to figure ant the best among them. It can be concluded that the best ways to reduce the gypsum waste amount are by recycling it with the least costs or reusing it without any additional procedures.
Journal of Cleaner Production, 2019
Gypsum is widely used in the construction sector in internal coatings. The fact that the chemical composition of gypsum does not change makes the material fully and eternally recyclable, potentially solving the important problem of the large amounts of gypsum waste that each year go to landfills. Up to now, most of the works that use gypsum wastes subjected the material to a previous heating process. This implies a significant energy consumption, reducing the environmental benefits of the recycling process. This paper shows the second part of a research on which two different types of gypsum waste were used as a substitute of commercial gypsum: gypsum waste from industrial plasterboard production and flue gas desulphurization gypsum from a thermal central plant. In this research, the influence of the heating process on the development of new gypsum plaster composites containing different types and contents of waste was studied. Their mechanical properties and thermal conductivity were determined and a brief environmental analysis, using the Life Cycle Assessment method, was carried out. Based on the findings of this paper, it is confirmed that it is possible to substitute 100% of commercial gypsum with gypsum waste from industrial plasterboard production without any heating treatment, but maintaining a good performance. With this action, apart from the benefits in terms of environmental impacts, a slight improvement in the density, mechanical properties and thermal conductivity of the plaster was obtained.
Recycled Plaster and Red Ceramic Waste Based Mortars
International Journal of Engineering and Technology, 2015
Construction is the activity that generates more waste in the world. Even with international actions being done to seek sustainable solutions in human activities, few changes in the construction have been observed. In Brazil, measures are being taken to adapt the waste-generating activities to new environmental commitments. In 2002, a specific law on construction and demolition waste (CDW) (Res. 307 Law 12,305) was established to reduce its production or use its material and ensure its proper destination. In 2011 the plaster recycling was established by resolution 431 amending Res. 307. Thus, this work had the objective of using waste gypsum and red ceramic as building material. Different proportions were mixed and tests were made to evaluate their physical and mechanical performance and also optical microscopy. The results indicated that the mortar produced with recycled plaster and ceramic waste meets Brazilian technical standards as components of brick wall.
Journal of Building Engineering, 2020
The construction sector consumes 95% of the total production of gypsum due to its multiple applications. Gypsum plaster is one of the most common indoor coating material (pastes and mortars), but it can also be used in prefabricated products like plasterboards, blocks and decorative elements. Gypsum waste recycling provides a solution to an important environmental problem from the use of gypsum plaster, which is the generation of large amounts of wastes at different phases (production, construction, rehabilitation and demolition). This paper studies two different replacement alternatives of natural gypsum: Flue Gas Desulphurization (FGD) gypsum and gypsum waste obtained from industrial plasterboard production. The influence of the previous types, amounts of waste (25, 50, 75 and 100 wt%) and different heating temperatures (100 � C, 150 � C and 180 � C) and processes on the workability of gypsum plasters is evaluated and discussed, based on a microstructure analysis using XRD and SEM techniques. This research highlights the feasibility, in terms of workability, of using Gypsum Plasterboard Waste (GPW), without any heating process, as a replacement gypsum in plasters. Despite the fact that a higher amount of water was necessary in the production of the mixes, a good workability was achieved. On the other hand, the unfeasibility of using unheated FGD as a constituent of plasters was demonstrated. However, a good performance, in terms of workability, of the FGD was obtained when the powder was subjected to a heating process at 180 � C during 6 h.
Eco-efficiency of plasters for rehabilitation and new buildings
2nd International Conference on Sustainable, Environmentally Friendly Construction Materials, 2021
A review of the current state of art for air-lime, gypsum and earth based plasters for rehabilitation and new buildings, in terms of eco-efficiency, is presented. These mortars belong to Portuguese traditional architecture, responding to compatibility criteria most of the time. This factor, combined with a possible positive response to eco-efficiency evaluation, would bring interest for their application in rehabilitation as well as in new construction. To assess eco-efficiency of plasters, the considered factors are linked to the environmental impact of these products and to their contribution for occupants well-being. Some qualitative results concerning embodied energy for these mortars in a "cradle to gate" approach analysis are shown. The lack of a common, standardized and shared procedure for this evaluation seems an evidence, above all when the attempt of comparing results from different studies is made. Furthermore, common and specific characteristics mostly related to contribution for indoor comfort conditions are presented, as indicators of technical efficiency of those plasters. The potential for behaving as moisture regulators and passive removal materials not only affect users, but can also have an important role in energy savings. Lastly, durability is considered a key factor of eco-efficiency mainly to meet the purpose of minimising exploitation of raw materials. For this reason it is important to consider protective treatments or finishing system, for improving durability, always keeping in mind all the elements of the equation.
Construction and Building Materials, 2011
Plaster materials made of waste gypsum or flue-gas-desulferized (FGD) gypsum with chemicals, organic and inorganic additives were studied. Glucose, citric acid and sodium bicarbonate were incorporated to retard the hydration of plaster. Saw dust (SD), coconut fibers (CCF) and tobacco waste fiber (TWF) were incorporated to improve the thermal property. Diatomaceous earth (DE), fly ash (FA) and bottom ash (BA) were incorporated to improve the mechanical and thermal properties. Citric acid, TWF, sodium bicarbonate and glucose could be used to retard the setting time of fresh FGD-plaster to approximately 25 min comparable to that of commercial plaster while the other additives did not retard the hydration. In presences of these retarding additives, needle shaped gypsum changed into lower aspect ratio particles. SD, CCF, DE, FA and BA modified gypsum crystal growth and reduced the crystal length. These changes in morphology consequently gave significant alterations of mechanical and thermal properties of the materials. The additions of organic and inorganic additives resulted in a reduction of bulk density and increases in water absorption, and similar strength compared to commercial gypsum. A good thermal insulating property was obtained from the samples with the incorporation of coconut fiber, BA and DE. In addition, these samples had a good performance in fire proof.