Utilization of Surface-Modified Polymer and Glass Micro-Fibers as Reinforcement in Cement Composites

2018 ◽  
Vol 760 ◽  
pp. 225-230
Author(s):  
Jan Trejbal ◽  
Zdeněk Prošek ◽  
Josef Fládr ◽  
Pavel Tesárek
Keyword(s):  
Polymer Fibers ◽  
Cement Matrix ◽  
Interphase Interaction ◽  
Bending Tests ◽  
Chemical Surface ◽  
Modified Polymer ◽  
Four Point Bending ◽  
Macro Scale ◽  
Strong Adhesion ◽  
Surface Modified

The presented work focuses on plasma modifications of polymer and glass micro-fibers (having 32 and 14 μm in the diameter, respectively) used as randomly distributed and oriented reinforcement of concrete composites. Fiber surfaces were modified by means of the low-pressure coupled cold oxygen plasma in order to attain a strong adhesion with the cement matrix. From the perspective of micro scale, an impact of modifications on both the physical and the chemical surface changes of treated fibers was examined using: (i) a wettability measurements – an evaluation of an interphase interaction between demineralized water and fibers and (ii) the SEM microscopy – an assessment of a surface morphology. From the perspective of macro scale, the interaction between the two materials was examined by destructive four-point bending tests of the cement paste containing both the reference and treated fibers (specimens having dimensions equal to 40×40×160 mm, water to cement ration 0.4) were done. It was shown that the wettability of modified fibers was increased by approx. 10 % and 70 % in the case of glass and polymer fibers, respectively. The SEM morphology analysis revealed fine roughening of treated fibers, if compared to the reference ones. The mechanical testing pointed out on a toughness increase in the post-cracking response of loaded specimens.

Utilization of Plasma Treated Polymeric Macro-Fibers as Reinforcement in Concrete Constructions

2017 ◽  
Vol 1144 ◽  
pp. 70-75
Author(s):  
Jan Trejbal ◽  
Josef Fládr ◽  
Lubomír Kopecký
Keyword(s):  
Mechanical Properties ◽  
Plasma Treatment ◽  
Treatment Duration ◽  
Negative Impact ◽  
Fiber Surface ◽  
Cement Matrix ◽  
Bending Tests ◽  
Four Point Bending ◽  
Angle Measurements ◽  
Contact Angle Measurements

Polymeric macro fibers BeneSteel having diameter equal to 480 μm and length 55 mm were treated in low pressure oxygen plasma by different treatment duration from 5 to 480 s to attain the better interaction with cement matrix (focused on both, chemical and physical bond). An effect of realized treatment was examined through fiber surface water wettability observation by direct horizontal optical method enabling contact angle measurements. Next, the pertinent negative impact of plasma treatment on fibers mechanical properties was examined by several methods. It was shown that the most effective plasma treatment duration is up to 30 s. Thus treated fibers exhibited the better wettability by ca. 110 % in comparison with reference fibers, while its mechanical properties were not negatively affected. Finally, reference and 30 s plasma treated fibers were used as randomly dispersed reinforcement in concrete specimens. Mechanical properties of these composites were examined by four-point bending tests. Specimens containing treated fibers exhibited bigger fracture toughness by ca. 30 % beside the reference ones, while the first cracking strength stayed constant in all cases.

scholarly journals PERFORMANCE OF CEMENT COMPOSITES REINFORCED WITH SURFACE-MODIFIED POLYPROPYLENE MICRO- AND MACRO-FIBERS

2017 ◽  
Vol 13 ◽  
pp. 11
Author(s):  
Jakub Antoš ◽  
Lukáš Dejdar ◽  
Jan Trejbal ◽  
Zdeněk Prošek
Keyword(s):  
Mechanical Properties ◽  
Polypropylene Fiber ◽  
Image Correlation ◽  
Cement Matrix ◽  
Fiber Types ◽  
Cement Pastes ◽  
Cracking Behavior ◽  
Inductively Coupled ◽  
Four Point Bending ◽  
Surface Modified

This paper focuses on the mechanical properties investigation of cement pastes reinforced with surface treated polymer fibers. The cement matrix was composed of Portland cement (CEM I 42.5 R, w/c ratio equal to 0.4). Two polypropylene fiber types (micro- and macro-fibers) were used as randomly distributed and oriented reinforcement in volume amount of 2 %. The fibers were modified in the low-pressure inductively coupled cold oxygen plasma in order to enhance their surface interaction with the cement matrix. The investigated composite mechanical properties (load bearing capacity and response during loading) were examined indirectly by means of four-point bending mechanical destructive tests. A response of loaded samples containing treated fibers were compared to samples with reference fibers. Moreover, cracking behavior development was monitored using digital image correlation (DIC). This method enabled to record the micro-cracks system evaluation of both fiber reinforced samples.

High selective gas sensors based on surface modified polymer transistor

2021 ◽  
Vol 91 ◽  
pp. 106083
Author(s):  
Ruxin Song ◽  
Xu Zhou ◽  
Zi Wang ◽  
Lunan Zhu ◽  
Jie Lu ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Modified Polymer ◽  
Surface Modified

scholarly journals Use of Cement Suspension as an Alternative Matrix Material for Textile-Reinforced Concrete

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2127
Author(s):  
Richard Fürst ◽  
Eliška Fürst ◽  
Tomáš Vlach ◽  
Jakub Řepka ◽  
Marek Pokorný ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Epoxy Resin ◽  
High Performance Concrete ◽  
Bending Test ◽  
Resin Matrix ◽  
Cement Matrix ◽  
Sample Type ◽  
Textile Reinforced Concrete ◽  
Epoxy Resin Matrix ◽  
Four Point Bending

Textile-reinforced concrete (TRC) is a material consisting of high-performance concrete (HPC) and tensile reinforcement comprised of carbon roving with epoxy resin matrix. However, the problem of low epoxy resin resistance at higher temperatures persists. In this work, an alternative to the epoxy resin matrix, a non-combustible cement suspension (cement milk) which has proven stability at elevated temperatures, was evaluated. In the first part of the work, microscopic research was carried out to determine the distribution of particle sizes in the cement suspension. Subsequently, five series of plate samples differing in the type of cement and the method of textile reinforcement saturation were designed and prepared. Mechanical experiments (four-point bending tests) were carried out to verify the properties of each sample type. It was found that the highest efficiency of carbon roving saturation was achieved by using finer ground cement (CEM 52.5) and the pressure saturation method. Moreover, this solution also exhibited the best results in the four-point bending test. Finally, the use of CEM 52.5 in the cement matrix appears to be a feasible variant for TRC constructions that could overcome problems with its low temperature resistance.

Comparison of results obtained by static 3- and 4-point bending and flexural vibration tests on solid wood, MDF, and 5-plywood

Holzforschung ◽  
2013 ◽  
Vol 67 (8) ◽  
pp. 941-948 ◽  
Author(s):  
Hiroshi Yoshihara
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Medium Density Fiberboard ◽  
Flexural Vibration ◽  
Solid Wood ◽  
Bending Tests ◽  
Four Point Bending ◽  
Flexural Vibration Test ◽  
The Difference ◽  
Vibration Tests

Abstract The flexural Young’s modulus of western hemlock, medium-density fiberboard, and 5-plywood (made of lauan) has been determined by conducting three- and four-point bending tests with various span lengths and by flexural vibration test. The Young’s modulus was significantly influenced by the deflection measurement method. In particular, the Young’s modulus was not reliable based on the difference between the deflections at two specific points in the specimen, although this test is standardized according to ISO 3349-1975 and JIS Z2101-2009.

Effect of Cellulose Functionalization on Thermal and Mechanical Properties of Epoxy Resin

2017 ◽  
Vol 757 ◽  
pp. 62-67 ◽  
Author(s):  
Kritsanachai Leelachai ◽  
Supissara Ruksanak ◽  
Tarakol Hongkeab ◽  
Supakeat Kambutong ◽  
Raymond A. Pearson ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Diglycidyl Ether ◽  
Cellulose Content ◽  
Thermal And Mechanical Properties ◽  
Chemical Surface ◽  
Pull Out ◽  
Fiber Bridging ◽  
Surface Modified ◽  
Modified Epoxy

In this study, diglycidyl ether of bisphenol A (DGEBA) cured cycloaliphatic polyamine was modified with functionalized celluloses for improved thermal and mechanical properties. Three different types of surface-modified cellulose, polyacrylamide-g-cellulose (PGC), aminopropoxysilane-g-cellulose (SGC), and carboxymethyl cellulose (CMC), were investigated and used as reinforcing agents in epoxy resins. The storage modulus of these modified epoxy systems was found to significantly increase with addition of cellulose fillers (up to 1 wt. % cellulose content). An improved fracture toughness (KIC) was also observed with increasing cellulose loading content with PGC and SGC. Among the surface-modified celluloses, epoxy modified with SGC was found to have the highest fracture toughness followed by PGC and CMC at 1.0 wt.% cellulose addition due to the chemical surface compatibility. The toughening mechanisms of the cellulose/epoxy composites, measured by scanning electron microscopy (SEM), revealed that fiber-debonding, fiber-bridging, and fiber-pull out were responsible for increased toughness.

scholarly journals Comparative Effects of MMT Clay Modified with Two Different Cationic Surfactants on the Thermal and Rheological Properties of Polypropylene Nanocomposites

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Meshal Al-Samhan ◽  
Jacob Samuel ◽  
Fatema Al-Attar ◽  
Gils Abraham
Keyword(s):  
Rheological Properties ◽  
Relaxation Times ◽  
Sem Analysis ◽  
Differential Scanning Calorimetric ◽  
Thermally Stable ◽  
Weight Percentage ◽  
Modified Clay ◽  
Modified Polymer ◽  
Mmt Clay ◽  
Surface Modified

Polypropylene montmorillonite (MMT) nanocomposites were prepared by melt blending using two different organoclays modified with imidazolium and alkylammonium surfactants. The imidazolium and ammonium modified organoclays were characterized by the FTIR and SEM analysis. The effect of organic clay (MMT) on the physical properties of polypropylene was evaluated, thermal and rheological properties with different filler weight percentage. Differential scanning calorimetric results showed that imidazolium modified clay (IMMT) exhibits low melting temperature compared to the ammonium modified clay (AMMT). The crystallinity analysis showed that crystallization improved in all nanocomposites irrespective of surface modification; the thermogravimetric analysis showed that the imidazolium modified polymer composites are more thermally stable than conventional ammonium modified composites. The Transmission Electron Microscopy (TEM) analyses indicated that the PP-IMMT composites displayed exfoliated morphologies compared with the intercalated structure in PP-AMMT, and the rheological analysis at 180°C showed an enhancement in the viscoelastic properties as the clay concentration increases. The melt viscosity, crossover modulus, and relaxation times were comparable for both the surface modified composites with two different cations. The imidazolium based surfactant was found to be an effective organic modification for MMT to prepare thermally stable PP/MMT nanocomposites.

Long-Term Reliability Assessment of Bioceramics for Artificial Joints Using Microdamage Monitoring by AE

2006 ◽  
Vol 309-311 ◽  
pp. 1191-1194
Author(s):  
Shuichi Wakayama ◽  
Teppei Kawakami ◽  
Junji Ikeda
Keyword(s):  
Critical Stress ◽  
Reliability Assessment ◽  
Physiological Saline ◽  
Bending Test ◽  
Unstable Fracture ◽  
Artificial Joints ◽  
Bending Tests ◽  
Four Point Bending

Microfracture process during bending tests of alumina ceramics used for artificial joints was evaluated by acoustic emission (AE) technique. Four-point bending tests were carried out in air, refined water, physiological saline and simulated body fluid. AE behavior during bending test inhibited the rapid increasing point of AE events and energy prior to the final unstable fracture. It was understood that the bending stress at the increasing point corresponds to the critical stress for maincrack formation. The critical stress was affected by water in environments more strongly than fracture strength. Consequently, it was suggested that the characterization of maincrack formation is essential for the long-term reliability assessment of load-bearing bioceramics.

scholarly journals Changes in thermal stability of lignocelluloses waste aggregates long-term incorporated in composite

2021 ◽  
Vol 900 (1) ◽  
pp. 012042
Author(s):  
N Stevulova ◽  
A Estokova
Keyword(s):  
Thermal Stability ◽  
Alkaline Treatment ◽  
Cement Matrix ◽  
Scanning Calorimetry ◽  
Alkali Ions ◽  
Thermal Gravimetry ◽  
Pre Treatment ◽  
Surface Modified ◽  
Thermal Stability Of

Abstract This paper is addressed to comparative study of changes in thermal stability of surface-modified hemp-hurds aggregates long-term incorporated in bio-aggregate-based composites with the original ones before their integration into alternative binder matrix. In this study, the effectiveness of alkaline treatment of hemp hurds compared to the raw bio-aggregates as well as in relation to their behaviour when they are long-term incorporated in the MgO-cement environment is investigated. The differences in the thermal behaviour of the samples are explained by the changed structure of hemp hurds constituents due to the pre-treatment and long-term action of the alternative binder components on the bio-aggregates. Alkaline treatment increases thermal stability of hemp hurds compared to raw sample. Also long-term incorporation of hemp hurds in MgO-cement matrix had a similar effect in case of alkaline modified bio-aggregates. The more alkali ions present in the structure of hemp hurdssamples, the more ash is formed during their thermal decomposition studied by thermal gravimetry (TG) and differential scanning calorimetry (DSC).

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