scholarly journals Bond Characteristics of Macro Polypropylene Fiber in Cementitious Composites Containing Nanosilica and Styrene Butadiene Latex Polymer

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Jae-Woong Han ◽  
Ji-Hong Jeon ◽  
Chan-Gi Park
Keyword(s):  
Bond Strength ◽  
Microstructural Analysis ◽  
Polypropylene Fiber ◽  
Fiber Surface ◽  
Cementitious Composites ◽  
Bond Properties ◽  
Interface Toughness ◽  
Latex Polymer ◽  
Styrene Butadiene ◽  
Bond Tests

This study evaluated the bond properties of polypropylene (PP) fiber in plain cementitious composites (PCCs) and styrene butadiene latex polymer cementitious composites (LCCs) at different nanosilica contents. The bond tests were evaluated according to JCI SF-8, in which the contents of nanosilica in the cement were 0, 2, 4, 6, 8, and 10 wt%, based on cement weight. The addition of nanosilica significantly affected the bond properties between macro PP fiber and cementitious composites. For PCCs, the addition of 0–2 wt% nanosilica enhanced bond strength and interface toughness, whereas the addition of 4 wt% or more reduced bond strength and interface toughness. The bond strength and interfacial toughness of LCCs also increased with the addition of up to 6% nanosilica. The analysis of the relative bond strength showed that the addition of nanosilica affects the bond properties of both PCC and LCC. This result was confirmed via microstructural analysis of the macro PP fiber surface after the bond tests, which revealed an increase in scratches due to frictional forces and fiber tearing.

scholarly journals Comparative study of hybrid fiber cementitious composites

2020 ◽  
Vol 11 (3) ◽  
pp. 1034
Author(s):  
Maria Idrees
Keyword(s):  
Hybrid Composites ◽  
Polypropylene Fiber ◽  
Styrene Butadiene Rubber ◽  
Cementitious Composites ◽  
Butadiene Rubber ◽  
Hybrid Fiber ◽  
Hybrid Fibers ◽  
Hybrid Form ◽  
Different Types ◽  
Styrene Butadiene

Different types of fibers impart specific characteristics to concrete, including crack bridging, early age crack resistance, ductility, toughness, strength, and loss of workability. It seems that if these fibers are combined, then specific characteristics of each fiber may be imparted to concrete and the desired characteristics of the concrete composite may be achieved. Thus, this investigation has been conducted to study the properties of concrete composites composed of four different types of fibers used singly or in hybrid form. The effectiveness of hybrid fibers in cementitious composites to achieve better characteristics; strengths, toughness, workability, and cost, was investigated and compared. Composites made of carbon fiber, plain steel fiber, polypropylene fiber, and glass fiber and their hybrid combinations (2, 3 and 4 fibers mixed), at constant volume of fiber 1.25%, along 4% styrene-butadiene rubber latex and 1.5% superplasticizer, are prepared and tested. The composites are compared and investigated for their feasibility in terms of their properties and cost. The comparison showed the suitability of some bi-hybrid composites, and incompatibility of tri-hybrid and tetra-hybrid composites in terms of effectiveness and feasibility.

Behavior and Design of Post-Installed Rebar Connections under Temperature

2016 ◽  
Vol 711 ◽  
pp. 783-790 ◽  
Author(s):  
Giovanni Muciaccia ◽  
Andrea Consiglio ◽  
Gianpaolo Rosati
Keyword(s):  
Bond Strength ◽  
Safety Margin ◽  
Typical Case ◽  
Design Criteria ◽  
Bond Properties ◽  
Anchorage Length ◽  
Testing Conditions ◽  
Experimental Campaign ◽  
Eurocode 2

Typical applications for post-installed rebar connections consist in overlapping joints with existing reinforcement or anchoring of the reinforcement at a slab or beam support. At cold state it may be shown by testing that a post-installed rebar system can develop the same bond resistance with the same safety margin as cast-in-place rebar. Consequently, anchorage length and lap length for post-installed rebars can be calculated as for cast-in-place according to the Eurocode 2 provisions. However, when subjected to temperature, the decay in bond properties for post-installed systems is significantly more dramatic than for cast-in-place rebars. The paper presents the result of an experimental campaign carried out on a post-installed connection using a vinylester polymer, investigating the effects on the bond strength both of the temperature and of different testing conditions. Finally, design criteria are provided and applied to a typical case study consisting in a post-installed solid slab.

Evaluation of Adhesion Properties of Modified Asphalt Binders with Use of Binder Bond Strength Test

2017 ◽  
Vol 2632 (1) ◽  
pp. 88-98 ◽  
Author(s):  
Weidong Huang ◽  
Lu Zhou
Keyword(s):  
Bond Strength ◽  
Asphalt Binder ◽  
Gel Permeation Chromatography ◽  
Crumb Rubber ◽  
Asphalt Binders ◽  
Adhesion Properties ◽  
Rubber Powder ◽  
Positive Effects ◽  
Tracking Device ◽  
Styrene Butadiene

Moisture damage is a prominent problem of asphalt pavements. The bond strength between asphalt and aggregates is a crucial factor that influences the capability of asphalt to resist moisture-induced damage. In this study, a binder bond strength (BBS) test was conducted to evaluate the effects of various modifiers and additives of different amounts on bond strength between asphalt and aggregates. Furthermore, the influence of styrene–butadiene–styrene (SBS) on adhesion behavior of asphalt binder was investigated through a gel permeation chromatography (GPC) test. Finally, the results of the BBS test were compared with the findings obtained from a Hamburg wheel-tracking device (HWTD) test, which reflected the moisture sensitivity of mixtures under wet conditions. Results indicated that gilsonite, high-density polyethylene, and polyphosphoric acid improved the bond strength of the base asphalt; SBS had no positive effects on asphalt adhesion properties; and SBS at a low amount reduced the bond strength. Ethylene bis-stearamide wax, crumb rubber, terminal blend (TB) rubber powder, and compound modifier TB rubber powder plus SBS decreased the bond strength. The GPC test results showed that SBS possibly did not actively contribute to the formation of bond strength between asphalt and aggregates. Test data for BBS and HWTD tests under wet conditions confirmed that there was no discernible correlation between these two tests when adhesion properties of modified asphalts were evaluated. However, the results of the BBS test were in accordance with those of the HWTD test when the adhesion of asphalt with different amounts of the same modifier and the mixture resistance to water damage were evaluated.

Enhancing oil-sorption performance of polypropylene fiber by surface modification via UV-induced graft polymerization of butyl acrylate

2012 ◽  
Vol 66 (12) ◽  
pp. 2647-2652 ◽  
Author(s):  
Shaoning Li ◽  
Junfu Wei ◽  
Ao Wang ◽  
Yuexia Nie ◽  
Hang Yang ◽  
...  
Keyword(s):  
Sorption Capacity ◽  
Butyl Acrylate ◽  
Graft Polymerization ◽  
Morphological Changes ◽  
Polypropylene Fiber ◽  
Fiber Surface ◽  
Water Mixture ◽  
Retention Performance ◽  
Oil Sorption ◽  
Static Contact

In order to improve oil sorption performances, polypropylene (PP) fiber was modified through graft polymerization with butyl acrylate (BA) initiated by ultraviolet (UV) radiation in isopropanol/water mixture solution. Fourier transform infrared (FT-IR) spectra, scanning electron microscopy (SEM) and specific surface area were used to characterize the chemical and morphological changes of the PP fiber surface. Static contact angle (CA) measurements showed that the hydrophilicity of original PP fiber was enhanced after graft polymerization. The grafted fiber exhibited an excellent oil-sorption, oil-retention performance, fast saturation-sorption rate and superior reusability of oil. When the grafting degree was 15.55%, the maximum oil-sorption capacity reached 18.35 g/g, while the oil-sorption capacity of original PP fiber was only 11.54 g/g. After the tenth cycle of reuse, the grafted fiber sorbent assembly only lost 30% of its virgin sorption capacity.

Bond Properties of Plain Steel Bar in Concrete with Machine-Made Sand

2013 ◽  
Vol 438-439 ◽  
pp. 20-24
Author(s):  
Feng Lan Li ◽  
Ke Fei Yu ◽  
Xin Xin Ding ◽  
Chang Ming Li
Keyword(s):  
Bond Strength ◽  
Experimental Studies ◽  
Bond Stress ◽  
Test Method ◽  
Bond Properties ◽  
Bond Slip ◽  
Ordinary Concrete ◽  
Strength Grade ◽  
Pull Out ◽  
Steel Bar

To meet the requirement of machine-made sand application in concrete structures, it is necessary to understand the bond properties of steel bar with machine-made sand concrete (MSC). Therefore, the experimental studies were carried out on the bond of plain steel bar with MSC by the central pull-out test method. Three specimens were cast as one group, 6 groups were tested considering the changes of strength grade of MSC and ordinary concrete. The bond-slip curves were measured and analyzed. The results show that the bond slip begins at the tensile side and transfers gradually to the free end before the entire slip turns up along the interface of plain steel bar and surrounded concrete, the largest average bond stress, i. e. the bond strength of plain steel bar corresponds to the initial entire slip of plain steel bar. With the increasing strength grade of MSC and ordinary concrete, the difference of slip at tensile side and free end becomes greater. Comparing that only appears in ordinary concrete with higher strength, the larger slips turn up while the bond stress reaches the largest for the plain steel bar in MSC. Larger scatter of bond strength is between specimens in the same group. Some plain steel bars yields with the beginning of entire slip along the interface.

Research on High Ductility Cementitious Composites Improved by Water-Soluble Polymer and Micro-Fibers

2013 ◽  
Vol 800 ◽  
pp. 284-289 ◽  
Author(s):  
Li Ping Guo ◽  
Wen Xiao Zhang ◽  
Bo Chen ◽  
Li Hui Zhang ◽  
Lin Hong Jin
Keyword(s):  
Basalt Fiber ◽  
Microscopic Analysis ◽  
Water Soluble ◽  
Cementitious Composites ◽  
Environmental Scanning ◽  
Electron Microscopic ◽  
Water Soluble Polymer ◽  
Bending Load ◽  
Scanning Electron Microscopic Analysis ◽  
Styrene Butadiene

The toughness of cement-based materials, related to the performance such as durability and strength, attracts much more attention nowadays. In this paper, the curve of bending load-deflection was adopted to research the influencesof polymers (dispersibility emulsion powder, PVA and styrene butadiene latex) and fibers (PVAF, steel fiber,basalt fiber) on basic mechanical properties and toughness. The results show that the PVAF pre-incorporate in cement motor could improve the toughness of cement motor. In addition, an environmental scanning electron microscopic analysis (ESEM) and hardness were adopted to analyze the microscope morphology of polymer films inside of hardened cementitious composites.

Ceramic Bonding to Biocompatible Titanium Alloys Obtained by Powder Metallurgy

2006 ◽  
Vol 530-531 ◽  
pp. 605-611
Author(s):  
M.C. Bottino ◽  
D.K. Oyafuso ◽  
Paulo Guilherme Coelho ◽  
Elisa B. Taddei ◽  
Vinicius André Rodrigues Henriques ◽  
...  
Keyword(s):  
Bond Strength ◽  
Titanium Alloys ◽  
Shear Bond Strength ◽  
Microstructural Analysis ◽  
Testing Machine ◽  
Phase Identification ◽  
Base Metals ◽  
Blended Elemental ◽  
Universal Testing ◽  
One Way Anova

The shear bond strength between a ceramic material (Titankeramik®, Vita Zahnfabrik, Germany) and two biocompatible titanium alloys was investigated. Ti-13%Nb-13%Zr (TNZ) and Ti-35%Nb-7%Zr-5%Ta (TNZT) alloys were obtained based on the blended elemental technique followed by a sequence of cold uniaxial and isostatic pressing and sintering. Characterization involved microstructural analysis (SEM) and crystalline phase identification (XRD). Subsequently, samples were machined to 4 x 4 mm with a base of 5 x 1 mm. The base metals were blasted with Al2O3 particles followed by the application of a coupling agent and opaque ceramic. After ceramic firing, the specimens were loaded in a universal testing machine (0,5mm/min). XRD revealed the presence of α and β-phases for TNZ, and peaks related to β phases and Nb and Ta for the TNZT alloy. SEM evaluation (TNZ) depicted remaining pores and biphasic microstructure formation. SEM micrographs of the TNZT alloy revealed good densification and a homogeneous β structure. Shear bond strength data (MPa) were statistically analyzed (one-way ANOVA and Tukey test, α=.05) revealing that TNZT (37.6 ± 2.91) presented significant higher values (p=0.0002) compared to TNZ (26.03 ± 2.92). In conclusion, it seems that Ti alloy composition plays a significant role on ceramic bonding.

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