scholarly journals Influence of nanocellulose on the hydration process of Portland cement and concrete properties

Author(s):  
V. I. Khirkhasova ◽  

The paper deals with modification of cement composite and concrete with nanocellulose in low and high density. The author presents the study results of the influence of nanocellulose on the cement composite hardening process, as well as the physical and mechanical properties of heavy concrete. The influence of the used additive on the rheological and strength characteristics of concrete is revealed. A new method is proposed to improve the material performance.

2014 ◽  
Vol 59 ◽  
pp. 550-557 ◽  
Author(s):  
J.N. Eiras ◽  
F. Segovia ◽  
M.V. Borrachero ◽  
J. Monzó ◽  
M. Bonilla ◽  
...  

2020 ◽  
Vol 3 (8) ◽  
pp. 200-208
Author(s):  
Mukhiddinov Dilshod Davronovich

This article is devoted to the study of technological properties of opokoid rocks of Uzbekistan and their influence on physical and mechanical indices of Portland cement of JSC "Kizilkumcement." Accelerated hydrolysis of Portland cement minerals and their chemical interaction with additive on principle of acid-basic interaction, which leads to increased degree of compaction and structural strengthening of formed cement composite due to rapid absorption of lime and opocy rock with developed structure, are shown.


Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 220
Author(s):  
Petar Antov ◽  
Viktor Savov ◽  
Ľuboš Krišťák ◽  
Roman Réh ◽  
George I. Mantanis

The potential of producing eco-friendly, formaldehyde-free, high-density fiberboard (HDF) panels from hardwood fibers bonded with urea-formaldehyde (UF) resin and a novel ammonium lignosulfonate (ALS) is investigated in this paper. HDF panels were fabricated in the laboratory by applying a very low UF gluing factor (3%) and ALS content varying from 6% to 10% (based on the dry fibers). The physical and mechanical properties of the fiberboards, such as water absorption (WA), thickness swelling (TS), modulus of elasticity (MOE), bending strength (MOR), internal bond strength (IB), as well as formaldehyde content, were determined in accordance with the corresponding European standards. Overall, the HDF panels exhibited very satisfactory physical and mechanical properties, fully complying with the standard requirements of HDF for use in load-bearing applications in humid conditions. Markedly, the formaldehyde content of the laboratory fabricated panels was extremely low, ranging between 0.7–1.0 mg/100 g, which is, in fact, equivalent to the formaldehyde release of natural wood.


2016 ◽  
Vol 677 ◽  
pp. 186-190 ◽  
Author(s):  
Monika Čáchová ◽  
Eva Vejmelková ◽  
Kateřina Šestáková ◽  
Pavel Reiterman ◽  
Martin Keppert ◽  
...  

This article is focused on cement based composites. Two cements differing in mineralogical composition are utilised as main binder in composites mixtures. Results of measured physical parameters of studied materials are presented. For the sake of comparison, a reference material with Portland cement was also prepared. Basic physical properties (measured by water vacuum saturation method and by helium pycnometry), characterizations of pore system (determined by mercury porosimetry) and mechanical properties are the matter of this study. Composites show various open porosity; the results of open porosity of materials containing special cements show higher values, in comparison with composite based on Portland cement. This fact of course influences other material characteristics - mainly mechanical properties.


2020 ◽  
Vol 6 (11) ◽  
pp. 84929-84951
Author(s):  
Luccas Mansur Feuchard ◽  
Cléo Márcio de Araújo Santana ◽  
Eliane Fernandes Côrtes Pires ◽  
Fernando Luiz Barbuda de Abreu ◽  
Elie Chahdan Mounzer ◽  
...  

2014 ◽  
Vol 4 (2) ◽  
pp. 69-72 ◽  
Author(s):  
Ronquim Renato Marini ◽  
Ferro Fabiane Salles ◽  
Icimoto Felipe Hideyoshi ◽  
Campos Cristiane Inácio ◽  
Bertolini Marília da Silva ◽  
...  

2019 ◽  
Vol 09 (04) ◽  
pp. 327-337
Author(s):  
Asal Soltani ◽  
Salim Khoso ◽  
Manthar Ali Keerio ◽  
Antonio Formisano

2021 ◽  
Vol 14 ◽  
Author(s):  
Menandro N. Acda

Background: High-density fiberboards (HDF) are widely used as a substitute for solid wood in furniture, cabinet, construction materials, etc. Wood fibers are often used in the production of HDF but the use of renewable materials has gained worldwide interest brought about by global pressure to pursue sustainable development. An abundant source of renewable fibers that can be used to produce HDF is keratin from waste chicken feathers. The goal of the study is to investigate the use of keratin fibers in combination with wood fibers to produce HDF. No or limited studies have been conducted in this area and if successful, it could offer an alternative utilization for the billions of kilograms of waste feather produced by the poultry industry. HDF is a high volume feather utilization that can reduce pollution and help solve solid waste disposal problems in many countries. Methods: A series of dry-formed HDFs containing varying ratios of wood and keratin fibers bonded by polyurethane resin were produced. The physical and mechanical properties of the HDFs were determined. Results : The properties of the HDFs were affected by varying ratios of wood particles and keratin fibers. Dimensional stability as indicated by low levels of thickness swelling (<4.6%) and water absorption (<10%) was observed. Internal bond (2.47 MPa), MOE (5.8 GPa) and MOR (45 MPa) values were higher or comparable to those reported in the literature. Conclusion: HDF formed using a combination of wood and keratin fibers bonded together by polyurethane resin to as much as 50% keratin fibers were dimensionally stable with stiffness and strength above the minimum requirements for general use HDF as prescribed by EN 622-5.


2021 ◽  
Vol 1043 ◽  
pp. 133-139
Author(s):  
Tolya Khezhev ◽  
Artur Zhurtov ◽  
Alim Kazharov ◽  
Tamerlan Zrumov ◽  
Asharbek Samgurov

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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