Improving the Flexural Strength of Fibre Reinforced Oil Well Cementsby Addition of a Polymer Latex

1994 ◽  
Vol 370 ◽  
Author(s):  
Demosthenis G. Pafitis
Keyword(s):  
Shear Strength ◽  
Flexural Strength ◽  
Glass Fibre ◽  
Interfacial Shear Strength ◽  
Interfacial Shear ◽  
Cement Matrix ◽  
Oil Well ◽  
Pull Out ◽  
Glass Fibre Reinforced ◽  
Polymer Latex

AbstractFibre-reinforced cements are proving to be useful in various oilfield applications. Low cost and increased toughness render glass fibre reinforced cements of particular interest. In most cases, improvements in toughness are the result of extensive fibre pull-out and this can be clearly observed in electron micrographs of fracture surfaces. This observation implies that there is much scope for improving the interfacial shear strength between the hydrated cement and glass fibres.Experiments have shown that increases in flexural strength and in energy to fracture can be achieved by incorporating small amounts of a polymer latex. Improvements of a factor of four in energy to fracture have been measured when approximately 0.8% by volume of a styrenebutadiene copolymer latex is added to a glass fibre reinforced class G oilwell cement. Experimental results suggest that this effect is not due to improvements in the strength of the cement matrix but due to an enhancement of the interfacial shear strength between fibre and cement.

Microdebond test development and interfacial shear strength evaluation of basalt and glass fibre reinforced polypropylene composites

2017 ◽  
Vol 51 (29) ◽  
pp. 4091-4099 ◽  
Author(s):  
R Zykaite ◽  
B Purgleitner ◽  
W Stadlbauer ◽  
C Burgstaller
Keyword(s):  
Shear Strength ◽  
Glass Fibre ◽  
Interfacial Adhesion ◽  
Interfacial Shear Strength ◽  
Fibre Surface ◽  
Interfacial Shear ◽  
Basalt Fibre ◽  
Polypropylene Composites ◽  
Loading Rates ◽  
Glass Fibre Reinforced

Interfacial adhesion of basalt and glass fibre reinforced polypropylene composites was studied using microdebond testing technique. A focus was put on a simple approach of applying extruded thermoplastic films as a matrix material for microdroplet formation. The ability of different viscosity and thickness polypropylene films to form symmetrical droplets under a temperature range of 200–240℃ was evaluated. Emphasis was put on polypropylene matrix chemistry, silane fibre surface treatment and testing loading rate impact on interfacial performance change in polypropylene-basalt fibre and polypropylene-glass fibre microcomposites. It was found that it was possible to obtain high symmetrical droplet yield out of polypropylene films of melt flow rate 50 and 125 g/10 min and 55–85 µm thickness at 240℃. The presence of maleic anhydride grafted polypropylene coupling agent increased the interfacial shear strength significantly. Microcomposites with glass fibre had higher interfacial shear strength in comparison with the used basalt fibre, mainly due to the difference in their sizing. Various silane-based fibre surface coatings did not result in significant interfacial adhesion changes. Polypropylene-glass fibre microcomposite interfacial shear strength at 0.5, 3.0 and 10.0 mm min–1 loading rates had similar values with high maximum pull-out force scatter at 0.5 and 3.0 mm min–1 loading rates and low scatter at 10.0 mm min–1.

Effect of Flexible Polymer Coating on Interfacial Adhesion of Glass Fibre Reinforced Polypropylene

2005 ◽  
Vol 13 (6) ◽  
pp. 619-625
Author(s):  
Xiaodong Zhou ◽  
Qunfang Lin ◽  
Ruohua Xiong ◽  
Xinyu Cui ◽  
Gance Dai
Keyword(s):  
Shear Strength ◽  
Thermal Cycling ◽  
Glass Fibre ◽  
Interfacial Adhesion ◽  
Interfacial Shear Strength ◽  
Polymer Coatings ◽  
Interfacial Shear ◽  
Flexible Polymer ◽  
Glass Fibre Reinforced ◽  
Rubber Coatings

Polymer coatings were obtained by using two rubbers, cis-polybutadiene rubber and ethylene-propylene diene monomer and two block copolymer: polystyrene-block-polybutadiene-block-polyvinyltriethoxysilane and polystyrene -block-polyvinyltrietho xysilane. They were used to coat glass fibre surfaces. The effects of the coatings on the interfacial adhesion and thermal cycling resistance of composites were studied by a single-filament fragmentation technique designed to measure the interfacial shear strength of glass fibre reinforced polypropylene. The interfacial shear strength was improved by the rubber coatings, which could graft to silane coupling agents coated onto the fibre surfaces, and could undergo crosslinking under peroxide initiation. The interfacial bond strength was determined by the nature and thickness of the rubber coatings. The interfacial adhesion was also improved when using block copolymers to treat glass fibres. The rubbers and those copolymers having flexible blocks in their chain structures both produced coatings that could relieve the thermal stresses at the composite interface during temperature cycling. The interface between the composites and the flexible polymer coatings had good thermal cycling fatigue resistance.

scholarly journals A Special Single-Fibre Pull-Out Technique for Determining the Fiber/Cement Interfacial Bond Strength

2002 ◽  
Vol 11 (1) ◽  
pp. 096369350201100 ◽  
Author(s):  
J. M. Caceres ◽  
A. N. Netravali
Keyword(s):  
Shear Strength ◽  
Bond Strength ◽  
Interfacial Shear Strength ◽  
Single Fibre ◽  
Interfacial Shear ◽  
Specimen Geometry ◽  
Interfacial Bond ◽  
Interfacial Bond Strength ◽  
Pull Out ◽  
Fibre Cement

The paper discusses a simple specimen geometry to obtain the fibre/cement interfacial shear strength (IFSS). The specimens are easy to prepare and easy to test. The technique gives reliable and reproducible results. IFSS results for five different fibres with cement were measured. Most IFSS values obtained are in the range of 0.15 to 1.5 MPa. Despite the simplicity of the technique presented in this study, the results are in agreement with those obtained by several other researchers using different techniques and specimen geometry.

scholarly journals Shear Behaviors of the Intersurface between Rice Straw Rope and Dredger Fill Silt: Experimental and Mechanism Studies

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Guizhong Xu ◽  
Ji Chen ◽  
Shenjie Shi ◽  
Angran Tian ◽  
Qiang Tang
Keyword(s):  
Shear Strength ◽  
Normal Stress ◽  
Rice Straw ◽  
Immersion Time ◽  
Interfacial Shear Strength ◽  
Land Reclamation ◽  
Tensile Force ◽  
Interfacial Shear ◽  
Pull Out ◽  
Dredger Fill

The further development of land reclamation, port waterway, and wharf construction brings about proper treatments of dredger fill silt, while huge amounts of rice straw set aside in China argument rational disposal every year. Therefore, rice straw is bundled up as ropes, which represent as drainage body and reinforcement, to make eco-friendly treatment for dredger fill silt. This paper investigates the mechanical properties and validity of rice straw rope as certain treating material of dredger fill silt through a series of pull-out test, mass loss test, and tension test on specimens with different water contents and dry densities. The results reveal that peak value of interfacial shear strength rises with the increase of normal stress at the same immersion time, and in particular, it rises by up to 250.0% when the normal stress is 40 kPa. The tensile force of rice straw rope increases slowly with the rise of tensile displacement, and the failure mode changes from brittle to ductile with the rise of immersion time, which witnesses first rapid back slow degradation trend. The proper interfacial shear strength, tensile force, and reasonable degradation rate of rice straw rope make it ideal in drainage and consolidation of dredger fill silt.

scholarly journals Why Should the “Alternative” Method of Estimating Local Interfacial Shear Strength in a Pull-Out Test Be Preferred to Other Methods?

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2406
Author(s):  
Serge Zhandarov ◽  
Edith Mäder ◽  
Uwe Gohs
Keyword(s):  
Shear Strength ◽  
Interfacial Shear Strength ◽  
Traditional Approach ◽  
Interfacial Shear ◽  
Frictional Stress ◽  
Displacement Curve ◽  
Pull Out ◽  
Alternative Method ◽  
Fiber Reinforced Materials ◽  
Force Displacement

One of the most popular micromechanical techniques of determining the local interfacial shear strength (local IFSS, τd) between a fiber and a matrix is the single fiber pull-out test. The τd values are calculated from the characteristic forces determined from the experimental force–displacement curves using a model which relates their values to local interfacial strength parameters. Traditionally, the local IFSS is estimated from the debond force, Fd, which corresponds to the crack initiation and manifests itself by a “kink” in the force–displacement curve. However, for some specimens the kink point is hardly discernible, and the “alternative” method based on the post-debonding force, Fb, and the maximum force reached in the test, Fmax, has been proposed. Since the experimental force–displacement curve includes three characteristic points in which the relationship between the current values of the applied load and the crack length is reliably established, and, at the same time, it is fully determined by only two interfacial parameters, τd and the interfacial frictional stress, τf, several methods for the determination of τd and τf can be proposed. In this paper, we analyzed several theoretical and experimental force–displacement curves for different fiber-reinforced materials (thermoset, thermoplastic and concrete) and compared all seven possible methods of τd and τf calculation. It was shown that the “alternative” method was the most accurate and reliable one, while the traditional approach often yielded the worst results. Therefore, we proposed that the “alternative” method should be preferred for the experimental force–displacement curves analysis.

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