Gypsum Plaster Research Articles

Effect of protective coating on axial resistance and residual capacity of self-compacting concrete columns exposed to standard fire

Self-Compacting Concrete (SCC) is a green construction material widely used in the construction industry. While normal weight concrete has notable performance under fire conditions, the open literature continues to lack works examining the structural fire performance of SCC elements. Intending to bridge this knowledge gap, the present study aims to understand the efficiency of different protective coatings on fire response and the residual capacity of SCC short columns. In this experimental investigation, SCC columns were primarily cast from Supplementary Cementitious Materials (SCM) such as Fly Ash (FA) and Ground Granulated Blast Furnace Slag (GGBFS) with partial replacement of fine aggregate by utilising the optimum content of Expanded Perlite Aggregate (EPA). Then, a thermal protective coating comprising of Cement Perlite Plaster (CPP) was developed using Ordinary Portland Cement (OPC) and the EPA. The fire performance of SCC elements was examined when protected with the newly developed coating as well as Gypsum Plaster (GP), Basalt Wrapping (BW), and Carbon Wrapping (CW) when exposed to ISO 834 standard fire curve for 60, 90, 120, and 180 min. The experimental results revealed that SCC specimens developed using GGBFS had better resistance to all exposure durations than the FA-SCC specimens. Also, it was noted that the CPP-protected SCC specimens exhibited higher residual strength capacity, followed by GP-protected SCC specimens, compared to the BW and CW-SCC specimens under axial load.

Effect of different strengthening materials on tensile behaviour of plasters and renders

The purpose of strengthened plasters (interior applications) and renders (exterior applications) in this paper is to control cracks at the interface between the main structure and the infill wall rather than strengthen masonry and reinforced concrete structures. Cracks in plasters and renders have caused severe issues that need to be resolved urgently. Cracks affect not only the aesthetics but also the normal use of a building. The presence of cracks changes the perceptions of the owners of a structure, forcing them to question its safety and even take legal action against its developer. Consequently, the present paper discusses the effects of different strengthening materials on the tensile behaviour of plasters and renders, particularly on the first cracking. One test group without strengthening materials and six test groups with strengthening materials were tested under uniaxial tensile loads. Each experimental group included the same six specimens. A glass fibre-reinforced polymer (GFRP) grid, two types of basalt fibre-reinforced polymer (BFRP) grids, and three types of welded wire meshes (WWMs) were selected as the strengthening materials in the tests. Four types of plasters and renders were used: cement mortar, anti-crack mortar, gypsum plaster, and thermal insulation mortar. The crack pattern, stain–stress relationship, first cracking strain, energy dissipation capacity in the uncracked stage, and microstructure were investigated to gain better insight into the tensile behaviour of the plasters and renders. It was found that a strengthening material with a small mesh size resulted in numerous cracks and a narrow crack spacing. The stress–strain curves of the strengthened specimens could be divided into uncracked and cracked stages. The higher slopes in both stages of the strengthened specimens could be attributed to the higher longitudinal strain coefficient, smaller opening size, and larger cross-sectional area of each strand of the strengthening materials. The first cracking strain of the unreinforced specimen was smaller than that of a strengthened specimen. Stronger bond strength between plaster/render and strengthening material, smaller mesh size and greater cross-sectional area of each strand of strengthening material led to the larger first cracking strain. The energy dissipation capacity in the uncracked stage of the strengthened thermal insulation mortar was the least. The energy dissipation capabilities in the uncracked stage of the plasters/renders reinforced with BFRP grid-2 and WWM-3 were the second-highest and highest, respectively. The bond strengths of the GFRP and BFRP grids to the plasters/renders were stronger than those of the WWMs. The bond strengths between the gypsum plaster and the reinforcing materials were the highest, whereas those between the thermal insulation mortar and the strengthening materials were the lowest. Additionally, stress–strain relationships were proposed for the strengthened plasters and renders; the results were found to be in good agreement with the test results.

Waste management of grits as filler in gypsum plasters: a new approach

The reuse of industrial waste plays a crucial role in avoiding environmental impacts caused by incorrect disposal. Industrial production commonly generates huge volumes of wastes, and also increased costs associated with waste management and landfills maintenance. This study investigates the reuse of grit waste, from the cellulose kraft industry, as filler in gypsum plaster. Samples were prepared in proportions of 100/0, 85/15, 75/25 and 50/50 gypsum/grits and tested at 7, 14, 21 and 28 days. The mechanical resistance with incorporation of up to 25 wt% grit as filler is greater than that recommended in the regulatory standards. Flexural and compression strength tests for 15 wt% of gypsum replaced achieved values of 4.5 and 8.3 MPa, respectively. The manufacture of gypsum/grit is a viable solution for waste management and has great potential for enabling fabrication of gypsum plaster board, a low-cost and more sustainable new material.

Fabrication and Performance of Microencapsulated Phase-Change Material/Gypsum Plaster Tile for Thermal Energy–Storage Building Material

In this work, microencapsulated phase change material (MEPCM) with the eutectic mixture of stearic acid (SA) and coconut oil (CO) as the core and melamine formaldehyde (MF) as the shell was developed by emulsion-polymerization method to be applied in the gypsum plaster tile as a passive way for thermal energy storage (TES) applications. Thermal and chemical characterization, particle size distribution (PSD), and thermal resistance of the developed MEPCM were investigated. The effects of adding MEPCM on thermal conductivity, density, and mechanical strength of gypsum plaster tile were reported. The results indicated an optimum eutectic combination ratio of 20%–80% by weight of SA-CO, MF concentrations of 75% by weight with 73.5% encapsulation efficiency for the synthesized MEPCM, phase change temperature of 21°C to 28.6°C and TES of 35.04 J/g. The reliability and thermal stability of the produced MEPCM was proved and implied no degradation in the chemical structure of MEPCM after repeated melting and solidification processes due to protection of core materials by MF shell. The gypsum/MEPCM composite resulted acceptable mechanical strength with thermal conductivity of 0.33 W/(m · K) and density of 919 kg/m3. The calculated extent of thermal energy storage for the simulated room that covered with G/M33 with 10% by weight of MEPCM in the interior walls and roof showed about 12% reduction in energy consumption.

Microstructure and Mechanical Properties of Gypsum Board Produced from Water Hyacinth Fiber

The objective of this article was to study the morphological characteristic and mechanical properties of gypsum boards. The gypsum plaster (GP) type 1 was replaced by water hyacinth fiber (WHF) at the dosages of 0, 50, 75, 100, and 150 by mass. The scanning electron microscopy (SEM) was used to observe their morphological characteristics, whereas mechanical properties of gypsum board were based on the TIS 219-2552. The thermal conductivity (k) was tested by according to ASTM E 1225 standard. Test results found that the morphological characteristics of the WFH showed rather roughness; thus, the voids of WHF increased. The thermal conductivity of gypsum boards incorporated with WHF tended to decrease as the void increased. Finally, it was determined that the water absorption (AW) and two bending forces (FL and FW) of the gypsum board including WHF were insufficient for compliance with the TIS 219-2552 standard.

The Green Patina and Chromatic Alterations on Surfaces of Gypsum Plaster Casts by Lucio Fontana: Multidisciplinary Investigations in a Case Study of Contemporary Art

Literature reports on Lucio Fontana’s work have focused on the study of the pictorial surface of his paintings. Consequently, to the best of our knowledge, this paper presents the first scientific investigation of gypsum objects made by this artist. These are the gypsum plaster casts made for the construction of the fifth door of the Milan Cathedral, Italy, which were discovered after 60 years, and which showed a green patina and chromatic discolorations. With the aim of understanding the microbiological or chemical nature of the stains, the surfaces of the tiles were investigated by microbiological analysis and analytical techniques including observations by optical, fluorescence and electron microscopy and spectroscopy. The investigated samples showed that the amount of microbiological cells in the stained area was negligible. Chemical analyses allowed the identification of compounds responsible for the chromatic alterations.

Influence of tire rubber waste on the fire behavior of gypsum coatings of construction and structural elements

The addition of inorganic expanded aggregates, such as perlite or vermiculite is well known in gypsum plasters. However, the reuse of organic wastes in coatings like plasters and renders has been poorly studied. This paper shows the effect of tire rubber wastes on the mechanical properties and fire performance of gypsum plasters. The rubber waste was added to the mixture in mass percentages of 14.50% (C1) and 46.60% (C2). Flexural and compressive strength of plasters made with rubber wastes was visibly reduced as well as their surface hardness (Shore C). In addition, fire tests produced major damages through the entire 2 cm thickness of samples containing rubber wastes, as it was corroborated by X ray diffraction (XRD) and Thermogravimetric (TG) analysis. The heat transfer due to fire exposure modified considerably the chemical composition of plasters, since, on the non-exposed face to fire, the amount of gypsum (CaSO4·2H2O) equivalent to mass loss obtained by TG due to water released by these plasters made with rubber wastes, was 5.4-7.2 lower than that of conventional plasters. The results suggest that certain wastes may reduce the efficiency of gypsum plasters in protecting underneath construction and structural elements against fire.

Preliminary Study of the Mechanical Behavior of Gypsum Plastering Mortars with Ceramic Waste Additions

In recent years, the construction sector has generated large amounts of construction and demolition waste (CDW). In Europe, more than 50% of this waste is ceramic waste (CW). Therefore, and in accordance with the Circular Economy Action Plan, the building sector should reintroduce a certain amount of CDW into the life cycle of buildings. Many studies have sought to incorporate CDW in gypsum plaster and cement mortars for construction. However, few studies have analyzed the feasibility of replacing raw materials such as gypsum, cement, or sand with CW. A three-phase experimental plan was designed to introduce various types of CW—from new construction and from rehabilitation works—in a gypsum matrix. The viability of the new mortar and its capacity to improve the mechanical and physical properties of gypsum without additions were analyzed. In the first phase of the experimental plan, CW was added in different percentages and granulometries into the gypsum matrix to make different mortars samples, and mechanical tests were conducted. The plaster mortar with the best results for use as coating was selected. The following tests, considering the final application of the mortar, were carried out: setting time, water capillarity absorption, and adherence. A chemical and mineralogical characterization was performed on the CW. The results showed that it is feasible to replace part of the raw gypsum material with recycled ceramic material. The superficial hardness, water absorption, adhesion, and mechanical resistances of the gypsum mortars containing CW were improved compared with those of gypsums without additions.

The manufacture and origin of the Tutankhamen meteoritic iron dagger

AbstractThe Iron Age was the time when people acquired iron processing technology and is generally thought to have begun after 1200 B.C. Some prehistoric iron artifacts made of iron meteorites are dated from the Bronze Age. A nicely preserved meteoritic iron dagger was found in the tomb of King Tutankhamen (1361–1352 B.C.) of ancient Egypt. Yet, its manufacturing method and origin remain unclear. Here, we report nondestructive two‐dimensional chemical analyses of the Tutankhamen iron dagger, conducted at the Egyptian Museum of Cairo. Elemental mapping of Ni on the dagger blade surface shows discontinuous banded arrangements in places with “cubic” symmetry and a bandwidth of about 1 mm, suggesting a Widmanstätten pattern. The intermediate Ni content (11.8 ± 0.5 wt%) with the presence of the Widmanstätten pattern implies the source meteorite of the dagger blade to be octahedrite. The randomly distributed sulfur‐rich black spots are likely remnants of troilite (FeS) inclusions in iron meteorite. The preserved Widmanstätten pattern and remnant troilite inclusion show that the iron dagger was manufactured by low‐temperature (<950 °C) forging. The gold hilt with a few percent of calcium lacking sulfur suggests the use of lime plaster instead of gypsum plaster as an adhesive material for decorations on the hilt. Since the use of lime plaster in Egypt started during the Ptolemaic period (305–30 B.C.), the Ca‐bearing gold hilt hints at its foreign origin, possibly from Mitanni, Anatolia, as suggested by one of the Amarna letters saying that an iron dagger with gold hilt was gifted from the king of Mitanni to Amenhotep III, the grandfather of Tutankhamen.

Evaluating the potential use of recycled glass fibers for the development of gypsum-based composites

The concerns on the recyclability of composites are rising. Finding ways to reuse composite materials is fundamental given their huge availability worldwide. However, the intrinsic characteristics of composite materials make it hard to recover their primary constituents. Therefore, the incorporation of these materials after their typical life span into other applications is of great importance towards their circularity and valorisation. In this paper we evaluate the possibility of recycled fiberglass sheets to be used for the creation of gypsum-based composites, aiming at improving the mechanical properties when compared to conventional gypsum. We benchmark the effect of adding recycled fibers against the use of virgin ones. Neat gypsum plaster was used as the matrix and reinforced with both commercial E-glass and recycled fibers. The addition of recycled fibers into the gypsum matrix modified the material behaviour, preventing a purely brittle behaviour, and increasing the flexural strength by 66 % when 6 wt. % was added. The addition of virgin E-glass fibers not only allows for massive plastic deformation of the composite but also increases its flexural strength by nearly 290 % when a mass fraction of 12 wt. % of E-glass was added.

Effect of Chopped Carbon Fibre (CCF) on enhancing the compressive strength and density of gypsum plaster

A present study investigates the influence of employing Chopped Carbon Fibre (CCF) on the characteristics of gypsum plaster (compressive strength and Density). The study plan consists of four gypsum plaster mixtures; these mixtures are classified into two categories based on their (Water/Gypsum Plaster) ratios (0.6 & 0.7). Every set subdivided by two categories based on 0.0 and 0.3 percent of CCF volume fraction (Vf). For each admixture, three samples (50 * 50 * 50) mm adopted. It was discovered that utilaized CCF to gypsum plaster mixes enhance and improve density and compressive strength for two W/GP ratios. The rate of improving compressive strength when use CCF increase by rising ratio of W/GP. furthermore, increasing the (W/GP) ratio results in a drop compressive strength and density for Volume ratios; while the CCF behavior may reduce drop rate of compressive strength and density.

Experimental Investigation on the Thermal Properties of Gypsum Plaster-Rice Husk Ash Composite

This experimental investigation aims at evaluating the thermal properties of rice husk ash (RHA)—filled gypsum plaster composite for potential applications, as insulating materials. The thermal conductivities of composites of gypsum plaster reinforced with RHA at 0%, 10%, 20%, 30%, and 40% volume fractions were determined experimentally using Lee’s disc method. The experimental results show that integrating RHA reduces the thermal conductivity of gypsum plaster and improves its insulation capacity. The results obtained from the experiments were compared with the Rule of Mixture Model, Maxwell Model, and Russell Model. It was observed that the thermal conductivities obtained from experiments and the theoretical models decreased with an increase in the volume fraction of RHA. The errors associated with the models with respect to experimental results are on the average of 28.7% for Mixture Rule, 31.6% for Russel Model, and 18.8% for the Maxwell Model. An agricultural waste like RHA can be beneficially used for the preparation of composites and, due to improved insulation capability, these composites can be used for applications such as insulation boards and sheathing, hardboard, ceilings of roofs, decorations, etc.

Evaluating the individual, dual usage of (TGP) and (SF) additives on improving gypsum characteristics

The purpose of this study is to determine the impact of adding Tree Glue Powder (TGP) and Silica Fume (SF) powders (by weight) alone and in combination on the characteristics of gypsum plaster. The study will focus on two critical gypsum properties: compressive strength and setting time. According to the study plan, a total of twelve specimens will be utilized. The twelve specimens were divided into four groups according to their TGP and SF contents (by weight), which were (0.0 percent), (1.0 percent) for (TGP) and (0.0 percent), (1.2 percent) for (SF) respectively. Three cubic (5 × 5 × 5 cm.) specimens were used to determine the average outcome for each blend. The ratio of water to gypsum plaster (W/P) was set at (0.5) for various mixtures. It was discovered that by adding just (SF) to Gypsum plaster mixtures, compressive strength is increased while setting time is decreased. On the other hand, adding merely (TGP) to the mixtures reduces compressive strength while significantly increasing setting time. Additionally, it was discovered that when both additives (SF) and (TGP) were used, two benefits were acquired, namely an increase in compressive strength and a minor increase in setting time(as compared to the no additives reference case).

Development of gypsum composite with enhanced mechanical and durable performance using chemical admixture and zeolite

This study deals with the properties of gypsum plaster that are synthesized by adding different proportions of zeolite used as mineral aggregate. The experimental tests also characterize the effect of superplasticizers to reduce the water by gypsum ratio of plaster and latex emulsion to improve the adherence between the gypsum surface and zeolite. The compressive, flexural, split tensile strength, UPV, dynamic modulus, water absorption, porosity and sorptivity tests were conducted for the composite gypsum phase containing different zeolite percentage. Results obtained show that 20% substitution of gypsum by zeolite provided maximum mechanical strength which can be chosen as optimum. The superplasticizers compensated for the loss in the workability caused by the addition of zeolite. The addition of polymer latex reduces the water absorption of gypsum plaster by modifying the micro-morphology of the gypsum plaster.

About the study of compounds incorporating rubber tires

In this paper we have studied some physical characteristics of gypsum composites incorporated with two different tire rubber granulometry. The experimental program was formed by the following tests: consistency (mini-slump), compressive strength and scanning electron microscopy (SEM). The rubber used in the composites came from the retreading of tires with 5 and 10% incorporation in relation to the plaster mass and the two different granulometry used were denominated thicknesses (# 0.6 mm) and thick (# 1.19 mm ). The results were compared with the control paste, in which there was no incorporation of rubber. The rubbers of different granulometry stood out in different points. The thin rubber presented a compressive strength close to the value observed in the control, with an addition of 5% by mass, which may be due to its adherence to gypsum paste, which occurred in a less porous manner and with a closer interface between the rubber particles and pulp, observed through the SEM. The thick rubber presented the best results in consistency, contributing to the workability of the pulp, which was also observed in SEM, where the thick rubber presents less adherence to the gypsum plaster, compared to the composite with incorporation of fine rubber. It was possible to affirm, then, that rubber as residual material presented interesting characteristics in applications in plaster composites.

Design of an eco-friendly composite gypsum binder using different mineral admixtures

This study deals with the properties of a series of plasters synthesized by blending gypsum (GYP) with different proportions of metakaolin (MET), glass powder (GP), silica fume (SF) and zeolite (Z) used as mineral admixture. The consistency, bulk density, water absorption and porosity of the gypsum composites were determined after 7 days. This paper discusses the effect of the addition of mineral admixtures at increasing ratios and evaluates the influence of mineral admixtures on the mechanical performance of the composite gypsum binder. This paper also focuses on the design of composite gypsum binder by using the stepwise optimisation technique to determine the optimal dosage of each mineral admixture to attain maximum mechanical strength. The results highlight that the synthesized composite gypsum binder using mineral admixtures exhibited improved mechanical strength and decreased porosity when compared to the plain gypsum plaster.

Effectiveness of using organic and inorganic consolidants on the properties of friable-porous gypsum mortar

This paper essentially deals with the influence of various consolidation materials on the mechanical and micro-structural behaviour of feeble Gypsum mortar. Gypsum mortars suffer from a serious drawback of high porous nature due to the lack of proper binding property of gypsum plaster with siliceous fine aggregate. The consolidation products chosen in this study were lime water, Barium water, ammonium oxalate, polymethyl methacrylate and epoxy resin. The results obtained from these consolidation treatments were compared to that of a commercial silane-based product available in the market. From the results, it was clear that the consolidation products proved to be very effective both in terms of mechanical and water resistance property, thereby increasing the cohesion and improved the internal stability of the gypsum mortar. The cognitive results obtained were significant in choosing the best treatment for Gypsum mortar, which can be a promising technique for the renovation of historic buildings and in future artistic constructions.

Effect of the Expanded Perlite Dose on the Fire Performance of Gypsum Plasters

Effect of the Expanded Perlite Dose on the Fire Performance of Gypsum Plasters

Сравнительный анализ изучения карстовых процессов на урбанизированных территориях и месторождениях строительного гипса

Natural and anthropogenic factors leading to the collapse zones formation and methods of studying karst processes for urbanized territories and deposits of gypsum plaster are characterized. Comparative analysis shows that the study of karst processes both in urbanized areas and in deposits of gypsum plaster are similar, but their essence is different for the assessment of the karst hazard. The possibility of applying the results of studying karst processes in urbanized territories to deposits of gypsum plaster and vice versa is considered. Recommended karstological studies at all ages and stages of geological exploration are given.

Study on the Effect of Different Types of Primers on the Plastering Properties of Gypsum Plaster on Aerated Concrete Blocks and its Mechanism

Study on the Effect of Different Types of Primers on the Plastering Properties of Gypsum Plaster on Aerated Concrete Blocks and its Mechanism