scholarly journals FRESH STATE AND MECHANICAL PROPERTIES OF ULTRA-LIGHTWEIGHT FOAMED CONCRETE INCORPORATING ALKALI TREATED BANANA FIBRE

2021 ◽  
Vol 84 (1) ◽  
pp. 117-128
Author(s):  
Mohammed Hassan Nensok ◽  
Md Azree Othuman Mydin ◽  
Hanizam Awang
Keyword(s):  
Mechanical Properties ◽  
Fibre Composite ◽  
Physical And Mechanical Properties ◽  
Cement Matrix ◽  
Weight Density ◽  
Banana Fibre ◽  
Foamed Concrete ◽  
Sem Micrograph ◽  
Increase Surface Area ◽  
Reduced Density

For a Lightweight Foamed Concrete (LFC) to efficiently function as an energy-saving building material, its self-weight (density) should be reduced. However, the problem associated with a reduced density is a decline in strength. To improve the mechanical properties of LFC, this research attempts to integrate banana fibre into LFC composite with a focus on fresh and harden state properties. An Ultra-Lightweight Foamed Concrete (ULFC) with a density of 600 kg/m3 was produced with the inclusion of treated and untreated banana fibres. The volume fractions of banana fibre added into LFC were 0.00% (control specimen), 0.25%, 0.35%, 0.45% and 0.55%. In addition, an optimised batch mix of ULFC reinforced with 0.35% untreated banana fibre was produced. The batches were tested for rheological, physical, and mechanical properties. Findings reveal that the workability of ULFC composites decrease with increase in fibre addition. The compressive, flexural, and tensile strengths of the alkali-treated composites were higher than the untreated banana fibre composite. SEM micrograph reveals that defibrillation of bundle fibrils due to cleaning the surface amorphous hemicellulose, lignin and pectin of the alkali-treated fibre, leads to rough surfaces and increase surface area resulting in better interfacial adhesion of the fibre with cement matrix.  

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

2018 ◽  
Vol 170 ◽  
pp. 03030 ◽  
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.

scholarly journals Global analysis of DEF damage to concretes with and without fly-ash

2022 ◽  
Vol 15 (3) ◽  
Author(s):  
Nicole Pagan Hasparyk ◽  
Dioice Schovanz ◽  
Francieli Tiecher ◽  
Selmo Chapira Kuperman
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Global Analysis ◽  
Physical And Mechanical Properties ◽  
Test Method ◽  
Cement Matrix ◽  
Negative Effects ◽  
Ettringite Formation ◽  
Pozzolanic Cement ◽  
Over Time

Abstract Delayed Ettringite formation (DEF) is an internal expansive reaction that can damage concrete. DEF is strongly influenced by the temperature, above about 60-65°C, and other factors involving cement chemistry especially, but also its physical characteristics. The exposure environment over time also promotes a condition to increase deterioration from DEF. Expansions results from secondary ettringite formation are progressive and can lead concrete to microcracking impacting its performance and durability over time. Several concrete structures are pointed to be severely attacked by DEF, and test method as well a better comprehension on this pathology is necessary to promote specific and proper preventive measures to avoid future damages. Furthermore, compared to alkali-silica reaction, DEF occurs more readily and aggressively, and sometimes prematurely, depending on several factors, such as type of cement, concrete mix design, exposure conditions, among others. This paper involves an overall analysis of the behavior of concretes with two types of Portland cements (High early-strength cement and a Portland pozzolanic cement, with fly-ash) in relation to DEF process. Several data from a laboratory study where DEF was induced through a specific thermal curing procedure are presented and discussed. The analyses involved the assessment of physical, mechanical, and expansive properties besides microstructural monitoring of samples from concretes over time. These experiments allowed detecting high values of expansions from DEF (up to 1.2%) in the concrete without fly ash. The mechanical properties were severely impacted from this deleterious process; as expansions increased, losses in the mechanic and elastic properties were verified. Expansion levels in the order of 0.5% prompted remarkably high reductions and, at about 1% the losses were relevant for both strengths (tensile and compressive) and modulus of elasticity, of 60% and 80%, respectively, in the presence of cement without fly-ash. Concrete microstructure has indicated massive formations of ettringite as well as micro-cracking and the fragility of the cement matrix because of DEF. On the other hand, expansion up to 0.2% did not promote important negative effects on the properties of concrete, especially with the pozzolanic cement tested. Furthermore, an overall approach with several correlations between physical and mechanical properties was taken to obtain different levels of deterioration for a concrete presenting DEF.

Physical and mechanical properties of sulfonated aromatic copolyimide membranes

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Ahmad Rabiee ◽  
Shahram Mehdipour-Ataei
Keyword(s):  
Mechanical Properties ◽  
Chemical Structure ◽  
Physical And Mechanical Properties ◽  
Xrd Analysis ◽  
Polymeric Films ◽  
Solid Polymer ◽  
Plastic Behavior ◽  
Thermally Stable ◽  
Sem Micrograph ◽  
Ion Conducting

AbstractPhysical and mechanical properties of four series of chemically and thermally stable sulfonated copolyimides as ion-conducting ionomers for application in fuel cell membrane, depending on chemical structure of diamine monomers were studied. The physical and mechanical properties of solid polymer membranes including thermal stability, mechanical strength, water uptake, stability in water, crystallinity and morphology were evaluated. All the polymers were thermally stable. The XRD analysis and SEM micrograph revealed that the polymers were almost amorphous and hydrophobic-hydrophilic phase separation in polyimide did not occur. Use of flexible monomers such as 4,4'-oxydianiline (ODA) and 4,4'-(4-aminophenoxy) diphenylsulfone (APDS) in the hydrophobic sequences increased the plastic behavior compared to rigid polymers prepared from 4,4'-(5- amino-1-naphthoxy) diphenylsulfone (ANDS) and m-phenylenediamine (m-PDA). It was concluded that the properties of polymeric films were strictly dependent on chemical composition of monomers and molecular weight of copolymers.

scholarly journals Mechanical Properties of Lightweight Foamed Concrete Reinforced with Raw Mesocarp Fibre

2021 ◽  
Vol 30 (3) ◽  
Author(s):  
Md Azree Othuman Mydin
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Tensile Stress ◽  
Cement Matrix ◽  
Plastic State ◽  
Foamed Concrete ◽  
Applied Forces ◽  
High Flowability

Lightweight foamed concrete (LFC) is recognised for its high flowability, minimal utilization of aggregates and superior heat insulation properties. LFC is excellent under compression but poor in tensile stress, as it produces multiple microcracks. LFC cannot withstand the tensile stress induced by applied forces without additional reinforcing elements. Hence, this study was conducted to examine the potential utilisation of oil palm mesocarp fibre (OPMF) reinforced LFC in terms of its mechanical properties. Two densities, 600kg/m3 and 1200kg/m3, were cast and tested with six different percentages of OPMF, which were 0.15%, 0.30%, 0.45% and 0.60%. The parameters evaluated were compressive strength, flexural strength and tensile strength. The results revealed that the inclusion of 0.45% of OPMF in LFC helps to give the best results for the compressive strength, flexural strength and splitting tensile strength. The OPMF facilitated to evade the promulgation of cracks in the plastic state in the cement matrix when the load was applied

scholarly journals Evaluation of the Physical and Mechanical Properties of Autoclaved and Foamed Concrete Blocks Marketed in Passo Fundo/RS Brazil

2019 ◽  
Vol 8 (1) ◽  
pp. 111
Author(s):  
Richard Thomas Lermen ◽  
Djalmo Dutra Dos Santos Neto ◽  
Leonel Nadal De Oliveira ◽  
Marina Paula Secco ◽  
Alexandre Dall'Agnol ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Concrete Blocks ◽  
Foamed Concrete ◽  
Para Determinar

Os blocos de concreto celular cada vez mais vêm ganhando mercado devido as suas características de isolamento térmico, de isolamento acústico, de baixa densidade, entre outras. Uma propriedade relevante é a resistência à compressão, a qual limita algumas aplicações deste tipo de material, por exemplo, a utilização em paredes estruturais (paredes que venham a ser submetidas a deformações impostas ou a cargas de ocupação mais significativas), as quais exigem uma resistência à compressão mínima de 3 MPa. Devido ao aumento da utilização do concreto celular nas construções, este trabalho teve como objetivo a avaliação das propriedades físicas e mecânica de dois tipos de blocos celulares comercializados na região de Passo Fundo/RS, Brasil. Ensaios experimentais foram realizados para determinar as seguintes propriedades: densidade seca, a densidade saturada, os índices de vazios, a absorção de água, a condutividade térmica e a resistência à compressão foram realizados. Os resultados mostraram que o concreto celular autoclavado apresentou melhores propriedades físicas e mecânicas quando comparado com o concreto celular espumígeno, isto é, o bloco de concreto celular autoclavado teve maior resistência à compressão, menor condutividade térmica, menor densidade e poros distribuídos de forma mais homogênea, porém os valores encontrados para a resistência à compressão de ambos os blocos foram inferiores aos determinados pelos fabricantes destes blocos. Portanto, os blocos de concreto autoclavado podem ser utilizados para alvenaria de vedação nas construções, pois atingiu a resistência à compressão mínima necessária para este tipo de parede. Já os blocos de concreto celular espumígenos, em média, apresentaram valores de resistência à compressão muito abaixo (0,6 MPa) dos valores exigidos para paredes de alvenaria de vedação (1,5 MPa), exigindo que o fabricante revise a formulação dos traços desses blocos.

Study of Cement Composites Properties with Filler Based on Wood Pulp

2014 ◽  
Vol 897 ◽  
pp. 165-170 ◽  
Author(s):  
Lucia Kidalova ◽  
Nadežda Števulová ◽  
Anton Geffert
Keyword(s):  
Mechanical Properties ◽  
Building Materials ◽  
Raw Materials ◽  
Volume Ratio ◽  
Physical And Mechanical Properties ◽  
Wood Pulp ◽  
Cement Matrix ◽  
Cement Composites ◽  
Renewable Materials ◽  
Cellulosic Fibres

Sustainable building materials are based on the use of renewable materials instead of non-renewable. A large group of renewable raw materials are materials of plant origin containing cellulosic fibres which are used as filler into building material with reinforcement function of composite. This study aimed to establish the mechanical and physical properties of cement composites with organic filler, such as wood pulp. Pulp derived from wood pulping process is very interesting material as reinforcement in cement which contributes to a reduction of pollutants. In this paper, utilization of unbleached and bleached wood pulp in combination with cement matrix with emphasis on the physical and mechanical properties is studied. Varying the producing technology (wood pulp and cement ratio in mixture) it is possible to obtain composites with density from 940 to 1260 kg.m-3 and with compressive strength from 1.02 to 5.44 MPa after 28 days of hardening. The experimental results of mechanical properties indicate that cement composites with using unbleached wood pulp reaches higher values than composites based on bleached wood pulp. The percentage of water uptake increased with increasing the volume ratio of unbleached wood pulp in composite.

scholarly journals Experimental Study on Fracture Energy of Foam Concrete at Different Notch Depth

2018 ◽  
Vol 250 ◽  
pp. 03006
Author(s):  
Mohd Naqiuddin Zamri ◽  
Norashidah Abd Rahman ◽  
Zainorizuan Mohd Jaini ◽  
Zulaikha Ahmad ◽  
Siti Amirah Azra Khairuddin
Keyword(s):  
Mechanical Properties ◽  
Fracture Energy ◽  
Lightweight Concrete ◽  
Physical And Mechanical Properties ◽  
Engineering Properties ◽  
Notch Depth ◽  
Foam Concrete ◽  
Three Point Bending ◽  
Depth Ratio ◽  
Foamed Concrete

Foamed concrete is lightweight concrete formulated from a mixture of concrete mortar and established foam. Generally foamed concrete is known for its low engineering properties. Many researchers had conducted studies and more focused on the physical and mechanical properties of foamed concrete without taking into account the behavior on its fracture energy. Therefore, this study was carried out to investigate the effect of notch-to-depth ratio on fracture energy of foam concrete using three point bending testmethod. Beam specimens with V-notch were prepared at a densityof 1400kg/m3 and 1600kg/m3. Three different notch-to-depth ratios which were adopted at 0.1, 0.3 and 0.5. Fracture energy was determined using Hillerborg, Bazant and Comitee euro International du Beton (CEB) models. From the experimental results, it was shown that fracture energy decreases asthe notch-to-depth ratio increases.

scholarly journals Algorithmic model for choosing configuration parameters for robotic gripping of agricultural products

2020 ◽  
Vol 1 (6) ◽  
pp. 78-90
Author(s):  
D.K. Wu ◽  
◽  
A.L. Ronzhin ◽  
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Agricultural Products ◽  
Physical Contact ◽  
Weight Density ◽  
Urgent Task ◽  
Labor Safety ◽  
Active Research ◽  
Algorithmic Model ◽  
Vegetables And Fruits

The solution to the problem of automating the process of collecting agricultural products based on models, algorithms and multicriteria synthesis of the configuration of robotic capture and control of its software and hardware components during physical manipulations with objects of agricultural products is discussed. Performing monotonous physically difficult operations in agricultural pro-duction leads to the risk of disorders of the musculoskeletal system of workers, therefore, the use of robotic means for physical contact and manipulation with objects in agricultural production is an urgent task that ensures a reduction in the cost of production, an increase in the quality of operations performed and the labor safety of involved specialists. The variability of the physical and geometric characteristics of the fruits and the methods of their collection does not allow the creation of univer-sal robotic grippers, therefore, active research is currently underway on the design of robotic grip-pers for manipulating the fruits of individual crops, differing in weight, density, geometry, surface roughness and other parameters. The article describes the developed conceptual model of robotic gripper control, including the description of the manipulator, gripper, sensor system and the manip-ulated object of agricultural products with various forms, physical and mechanical properties. The article analyzes the physical and mechanical properties of some vegetables and fruits, methods of cutting off the fruit, which should be taken into account when developing robotic grippers. There were discussed a four-stage technique for determining the parameters of robotic gripping, including determining the characteristics of the manipulated object; characteristics of the working environ-ment; determination of the features of the manipulator on which the gripper is planned to be in-stalled, and evaluation of the efficiency of the projected gripper according to a number of criteria. The developed algorithmic model of the choice of configuration parameters for robotic gripping of agricultural products is presented. It provides, based on the analysis of the properties of the manipu-lated object, the development of requirements for the configuration and gripping control system.

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