RECICLAGEM DE GESSO DE DEMOLIÇÃO E INFLUÊNCIA DA ADIÇÃO DE RETARDADORES DE CURA NAS PROPRIEDADES MECÂNICAS

ResumoO gesso é um material de construção amplamente utilizado devido à sua leveza e baixo custo, mas se torna um passivo ambiental, pois os resíduos gerados na construção e demolição de edifícios são descartados incorretamente e podem causar grandes danos ao solo e às águas subterrâneas. Sua reciclagem tem sido extensivamente estudada, mas fatores ambientais e de gerenciamento no descarte foram desconsiderados. O descarte desse material, mesmo quando controlado por políticas públicas, tem sido negligenciado, levando à contaminação desse material, conforme observado pela análise qualitativa da difração de raios X. Esses contaminantes atuam durante o processo de nucleação e crescimento de cristais de gesso, alterando o tamanho e sua forma. Este estudo avalia as propriedades físicas e mecânicas da reciclagem de resíduos de gesso obtidos em recicladores credenciados por órgãos públicos em estado puro e com a inserção de álcool polivinílico e ácido cítrico como retardadores do tempo de preparação comparando os resultados obtidos com o gesso comercial. Os resultados indicam que, nos casos de adição de álcool polivinílico, há ganho nas propriedades mecânicas quando comparado ao produto comercial e melhor trabalhabilidade quando comparado ao gesso reciclado puro, enquanto com a adição de ácido cítrico, essas propriedades são reduzidas nas duas comparações.Palavras-chave: Reciclagem. PVAl. Ácido Cítrico. Gesso. ABSTRACTGypsum is a widely used construction material due to its lightness and low cost, but it becomes an environmental liability as the waste generated in the construction and demolition of buildings is improperly disposed of and can cause great damage to the soil and groundwater. Its recyclability has been extensively studied, but environmental and management factors in the disposal have been disregarded. The disposal of this material, even when controlled by public policies, has been neglected, leading to the contamination of this material, as observed by the X-ray diffraction qualitative analysis. These contaminants act during the process of nucleation and growth of gypsum crystals, altering size and their form. This study evaluates the physical and mechanical properties of the recycling of gypsum waste obtained in recyclers accredited by public agencies in the pure state and with the insertion of polyvinyl alcohol and citric acid as retarders of setting-time comparing the obtained results with commercial gypsum. The results indicate that in the cases of addition of polyvinyl alcohol there is gain in the mechanical properties when compared to the commercial product and better workability when compared to pure recycled gypsum. While with the addition of citric acid these properties are reduced in both comparisons.Keywords: Recycling. PVAl. Citric Acid. Plaster.

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Effect of Heat Setting Methods on Structures and Properties of High Strength Polyvinyl Alcohol Fibre

Materials Science Forum ◽

10.4028/www.scientific.net/msf.815.643 ◽

2015 ◽

Vol 815 ◽

pp. 643-648

Author(s):

Yin Zhu ◽

Jiong Xin Zhao

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Polyvinyl Alcohol ◽

Setting Time ◽

High Strength ◽

Single Fibre ◽

X Ray Diffraction ◽

Heat Setting ◽

Heat Treated ◽

Setting Process

The effect of heat setting methods on the structures and mechanical properties of high strength polyvinyl alcohol (PVA) fibre is studied in this article. The microstructure and mechanical properties of heat treated PVA fibre is investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and single fibre electronic tensile strength tester. Results show that the heat setting method with constant tension is a good heat setting method which can largely enhance the tensile strength of PVA fibre. During the heat setting process, the mechanical properties of PVA fibre are greatly affected by the temperature, tension and setting time. When the temperature is 220°C, tension is 5cN/dtex and setting time is 90sec, the tensile strength of PVA fibre increases from 12.0cN/dtex to 16.4cN/dtex in compare with the PVA fibre without heat setting

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Physical and Mechanical Properties of Natural Leaf Fiber-Reinforced Epoxy Polyester Composites

Polymers ◽

10.3390/polym13091369 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1369

Author(s):

Sanjeev Kumar ◽

Lalta Prasad ◽

Vinay Kumar Patel ◽

Virendra Kumar ◽

Anil Kumar ◽

...

Keyword(s):

Mechanical Properties ◽

Composite Materials ◽

Synthetic Fibre ◽

Low Cost ◽

Fibre Length ◽

Physical And Mechanical Properties ◽

Natural Fibres ◽

Risk Environment ◽

Insulation Property ◽

Natural Leaf

In recent times, demand for light weight and high strength materials fabricated from natural fibres has increased tremendously. The use of natural fibres has rapidly increased due to their high availability, low density, and renewable capability over synthetic fibre. Natural leaf fibres are easy to extract from the plant (retting process is easy), which offers high stiffness, less energy consumption, less health risk, environment friendly, and better insulation property than the synthetic fibre-based composite. Natural leaf fibre composites have low machining wear with low cost and excellent performance in engineering applications, and hence established as superior reinforcing materials compared to other plant fibres. In this review, the physical and mechanical properties of different natural leaf fibre-based composites are addressed. The influences of fibre loading and fibre length on mechanical properties are discussed for different matrices-based composite materials. The surface modifications of natural fibre also play a crucial role in improving physical and mechanical properties regarding composite materials due to improved fibre/matrix adhesion. Additionally, the present review also deals with the effect of silane-treated leaf fibre-reinforced thermoset composite, which play an important role in enhancing the mechanical and physical properties of the composites.

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Physical and Mechanical Properties of Cement Paste Were Used Partially with Fly Ash and Kaolin Waste

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.866.199 ◽

2017 ◽

Vol 866 ◽

pp. 199-203

Author(s):

Chidchanok Chainej ◽

Suparut Narksitipan ◽

Nittaya Jaitanong

Keyword(s):

Mechanical Properties ◽

Fly Ash ◽

Room Temperature ◽

Physical And Mechanical Properties ◽

Partial Replacement ◽

X Ray Diffraction ◽

X Ray ◽

Lime Water ◽

Diffraction Patterns ◽

Iron Mold

The aims of this research were study the microstructures and mechanical properties for partial replacement of cement with Fly ash (FA) and kaolin waste (KW). Ordinary Portland cement were partially replaced with FA and KW in the range of 25-35% and 10-25% by weight of cement powder. The kaolin waste was ground for 180 minutes before using. The specimen was packing into an iron mold which sample size of 5×5×5 cm3. Then, the specimens were kept at room temperature for 24 hours and were moist cured in the incubation lime water bath at age of 3 days. After that the specimens were dry cured with plastic wrap at age of 3, 7, 14 and 28 days. After that the compounds were examined by x-ray diffraction patterns (XRD) and the microstructures were examined by scanning electron microscopy (SEM). The compressive strength was then investigated.

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Features of the hydration process of the modified blended cement for fiber cement panels

MATEC Web of Conferences ◽

10.1051/matecconf/201817003030 ◽

2018 ◽

Vol 170 ◽

pp. 03030 ◽

Cited By ~ 3

Author(s):

Rustem Mukhametrakhimov ◽

Liliya Lukmanova

Keyword(s):

Electron Microscopy ◽

Mechanical Properties ◽

Blended Cement ◽

Physical And Mechanical Properties ◽

Hydration Process ◽

Cement Matrix ◽

X Ray Diffraction ◽

Structure Form ◽

Silicate Phase ◽

X Ray

The paper studies features of the hydration process of the modified blended cement for fiber cement panels (FCP) using differential thermal analysis, X-ray diffraction analysis, electron microscopy and infrared spectroscopy. It is found that deeper hydration process in silicate phase, denser and finer crystalline structure form in fiber cement matrix based on the modified blended cement. Generalization of this result to the case of fiber cement panels makes it possible to achieve formation of a denser and homogeneous structure with increased physical and mechanical properties.

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Effect of Intercalation Structure of Organo-Modified Montmorillonite/Polylactic Acid on Wheat Straw Fiber/Polylactic Acid Composites

Polymers ◽

10.3390/polym10080896 ◽

2018 ◽

Vol 10 (8) ◽

pp. 896 ◽

Cited By ~ 7

Author(s):

Qiqi Fan ◽

Guangping Han ◽

Wanli Cheng ◽

Huafeng Tian ◽

Dong Wang ◽

...

Keyword(s):

Mechanical Properties ◽

Thermogravimetric Analysis ◽

Wheat Straw ◽

Polylactic Acid ◽

Low Cost ◽

Interlayer Spacing ◽

Positive Influence ◽

X Ray Diffraction ◽

Ft Ir ◽

Ir Analysis

In this work, an easy way to prepare the polylactic acid (PLA)/wheat straw fiber (WSF) composite was proposed. The method involved uses either the dopamine-treated WSF or the two-step montmorillonite (MMT)-modified WSF as the filler material. In order to achieve the dispersibility and exfoliation of MMT, it was modified by 12-aminododecanoic acid using a two-step route. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were performed to characterize the modified MMT and the coated WSF. As for the properties of PLA/WSF composites, some thermal (using Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis) and mechanical properties (flexural, tensile, and impact) were analyzed. The results showed that the dopamine was successfully coated onto the WSF. Furthermore, Na-MMT was successfully transformed to organo-montmorillonite (OMMT) and formed an exfoliated structure. In addition, a better dispersion of MMT was obtained using the two-step treatment. The interlayer spacing of modified MMT was 4.06 nm, which was 123% higher than that of the unmodified MMT. Additionally, FT-IR analysis suggested that OMMT diffused into the PLA matrix. The thermogravimetric analysis (TGA) showed that a higher thermal stability of PLA/WSF composites was obtained for the modified MMT and dopamine. The results also showed that both the dopamine treated WSF and the two-step-treated MMT exhibited a positive influence on the mechanical properties of PLA/WSF composites, especially on the tensile strength, which increased by 367% compared to the unmodified precursors. This route offers researchers a potential scheme to improve the thermal and mechanical properties of PLA/WSF composites in a low-cost way.

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CHARACTERIZATION OF HYDROXYAPATITE/TI6AL4V COMPOSITE POWDER UNDER VARIOUS SINTERING TEMPERATURE

Jurnal Teknologi ◽

10.11113/jt.v75.5168 ◽

2015 ◽

Vol 75 (7) ◽

Cited By ~ 2

Author(s):

Amir Arifin ◽

Abu Bakar Sulong ◽

Norhamidi Muhamad ◽

Junaidi Syarif

Keyword(s):

Mechanical Properties ◽

Composite Powder ◽

Sintering Temperature ◽

Physical And Mechanical Properties ◽

Xrd Analysis ◽

X Ray Diffraction ◽

Different Temperatures ◽

Two Phases ◽

Work Interaction

Hydroxyapatite (HA) has been widely used in biomedical applications due to its excellent biocompatibility. However, Hydroxyapatite possesses poor mechanical properties and only tolerate limited loads for implants. Titanium is well-known materials applied in implant that has advantage in mechanical properties but poor in biocompatibility. The combination of the Titanium alloy and HA is expected to produce bio-implants with good in term of mechanical properties and biocompatabilty. In this work, interaction and mechanical properties of HA/Ti6Al4V was analyzed. The physical and mechanical properties of HA/Ti6Al4V composite powder obtained from compaction (powder metallurgy) of 60 wt.% Ti6Al4V and 40 wt.% HA and sintering at different temperatures in air were investigated in this study. Interactions of the mixed powders were investigated using X-ray diffraction. The hardness and density of the HA/Ti6Al4V composites were also measured. Based on the results of XRD analysis, the oxidation of Ti began at 700 °C. At 1000 °C, two phases were formed (i.e., TiO2 and CaTiO3). The results showed that the hardness HA/Ti6Al4V composites increased by 221.6% with increasing sintering temperature from 700oC to 1000oC. In contrast, the density of the composites decreased by 1.9% with increasing sintering temperature.

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Study of the Effect of PP and LDPE Thermoplastic Binder Addition on the Mechanical Properties and Physical Properties of Particulate Composites for Building Material Application

Materials Science Forum ◽

10.4028/www.scientific.net/msf.964.115 ◽

2019 ◽

Vol 964 ◽

pp. 115-123

Author(s):

Sigit Tri Wicaksono ◽

Hosta Ardhyananta ◽

Amaliya Rasyida ◽

Feisha Fadila Rifki

Keyword(s):

Mechanical Properties ◽

Compression Strength ◽

Building Materials ◽

Construction Material ◽

Construction Materials ◽

Physical And Mechanical Properties ◽

Waste Recycling ◽

Plastic Waste ◽

Particulate Composites ◽

Water Absorbability

Plastic waste is majority an organic material that cannot easily decomposed by bacteria, so it needs to be recycled. One of the utilization of plastic waste recycling is become a mixture in the manufacture of building materials such as concrete, paving block, tiles, roof. This experiment purpose to find out the effect of addition of variation of LDPE and PP thermoplastic binder to physical and mechanical properties of LDPE/PP/Sand composite for construction material application. In this experiment are using many tests, such are SEM, FTIR, compression strength, density, water absorbability, and hardness. the result after the test are the best composition of composite PP/LDPE/sand is 70/0/30 because its have compression strength 14,2 MPa, while density value was 1.30 g/cm3, for the water absorbability is 0.073%, and for the highest hardness is 62.3 hardness of shore D. From the results obtained, composite material can be classified into construction materials for mortar application S type with average compression strength is 12.4 MPa.

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Effect of TiO2 Nanoparticles on Physical and Mechanical Properties of Cement at Low Temperatures

Advances in Materials Science and Engineering ◽

10.1155/2018/8934689 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12 ◽

Cited By ~ 8

Author(s):

Li Wang ◽

Hongliang Zhang ◽

Yang Gao

Keyword(s):

Mechanical Properties ◽

Low Temperatures ◽

Cement Hydration ◽

Setting Time ◽

Physical And Mechanical Properties ◽

Xrd Analysis ◽

Cementitious Materials ◽

Strength Test ◽

Hydration Degree ◽

Time Test

Low temperature negatively affects the engineering performance of cementitious materials and hinders the construction productivity. Previous studies have already demonstrated that TiO2 nanoparticles can accelerate cement hydration and enhance the strength development of cementitious materials at room temperature. However, the performance of cementitious materials containing TiO2 nanoparticles at low temperatures is still unknown. In this study, specimens were prepared through the replacement of cement with 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, and 5 wt.% TiO2 nanoparticles and cured under temperatures of 0°C, 5°C, 10°C, and 20°C for specific ages. Physical and mechanical properties of the specimens were evaluated through the setting time test, compressive strength test, flexural strength test, hydration degree test, mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) analysis, thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM) in order to examine the performance of cementitious materials with and without TiO2 nanoparticles at various curing temperatures. It was found that low temperature delayed the process of cement hydration while TiO2 nanoparticles had a positive effect on accelerating the cement hydration and reducing the setting time in terms of the results of the setting time test, hydration degree test, and strength test, and the specimen with the addition of 2 wt.% TiO2 nanoparticles showed the superior performance. Refined pore structure in the MIP tests, more mass loss of CH in TGA, intense peak appearance associated with the hydration products in XRD analysis, and denser microstructure in SEM demonstrated that the specimen with 2 wt.% TiO2 nanoparticles exhibited preferable physical and mechanical properties compared with that without TiO2 nanoparticles under various curing temperatures.

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Magnesium-Silicon Substituted Carbonate Hydroxyapatite (Mg-Si CHA): Factors Affecting Sintering

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.694.88 ◽

2016 ◽

Vol 694 ◽

pp. 88-93

Author(s):

Ahmad Fauzi Mohd Noor ◽

Harmiza Zainudin

Keyword(s):

Mechanical Properties ◽

Single Phase ◽

Physical And Mechanical Properties ◽

Major Effect ◽

Carbonate Content ◽

X Ray Diffraction ◽

Factors Affecting ◽

Complex Process ◽

Powder Properties ◽

Properties Of Materials

Sintering has major effect on the final properties of materials such as density, porosity and microstructure. Sintering of Mg-Si CHA in particular is a complex process since changes could occur during sintering, which include phase formation, grain size, pore size and carbonate content, and this in turn affects the mechanical properties. Improved mechanical properties of Mg-Si CHA is critical in load bearing implant applications. Poor control of thermal treatment of Mg-Si CHA during sintering would cause carbonate loss, leading to partial or total decomposition of Mg-Si CHA, subsequently would affect the physical and mechanical properties. The influence of powder properties (particle size, porosity, morphology) and sintering parameters (heating rate, firing atmosphere) on the sintered Mg-Si CHA microstructure was studied using scanning electron microscopy (SEM) characterization technique. The SEM results showed that we are able to produce sintered Mg-Si CHA without cracking of the compacted pellets, while keeping the carbonate level in the amount required (2 – 8%). X-Ray diffraction (XRD) was also performed on the sintered samples and the results indicated that a single phase Mg-Si-CHA was obtained, while Fourier transform infra-red (FTIR) spectroscopy result confirmed that as-synthesized Mg-Si CHA powder was a B-type.

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Fire-Retardant Plastering Mortars Based on Exfoliated Vermiculite and Volcanic Ash

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1043.133 ◽

2021 ◽

Vol 1043 ◽

pp. 133-139

Author(s):

Tolya Khezhev ◽

Artur Zhurtov ◽

Alim Kazharov ◽

Tamerlan Zrumov ◽

Asharbek Samgurov

Keyword(s):

Mechanical Properties ◽

Volcanic Ash ◽

Cement Mortar ◽

Low Cost ◽

Fire Retardant ◽

Physical And Mechanical Properties ◽

Strength Characteristics ◽

Multifunctional Additive ◽

Solution Density ◽

Noticeable Increase

The research results on the development of fire-retardant composite cement mortar mixtures on exfoliated vermiculite and volcanic ash with the use of a multifunctional additive are presented D-5. Compositions of fire-retardant composite mortars, which make it possible to significantly improve the physical and mechanical properties of mortar mixtures and mortars, are proposed. Introduction of a multifunctional supplement D-5 in mortar mixtures makes it possible to improve the composite mortar mixtures properties and improve the solution characteristics. Replacement of finely dispersed fraction of exfoliated vermiculite d<0,63 mm volcanic ash by volume in mortar mixtures does not cause a noticeable increase in the solution density, while their strength characteristics increase. The developed composite mortar mixtures meet the requirements of GOST 28013–98 and have a low-cost price due to volcanic ash use.

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