Étude en laboratoire de l'adhérence béton de resurfaçage - dalle de chaussée

1992 ◽  
Vol 19 (6) ◽  
pp. 1041-1048
Author(s):  
Minh-Tan Do ◽  
Gilles Chanvillard ◽  
Claude Lupien ◽  
Pierre-Claude Aïtcin
Keyword(s):  
Key Words ◽  
Elastic Foundation ◽  
Laboratory Study ◽  
Shear Test ◽  
Bonding Agent ◽  
Bonding Agents ◽  
Test Setup ◽  
Slab Temperature ◽  
Flexure Test ◽  
Slant Shear

This paper presents a laboratory study on the bonding of a concrete overlay to an old slab. The main variables of the study were the bonding agents and the initial slab temperature when the overlay was placed. A flexure test setup, based on the theory of beams of elastic foundation, was developed. The results obtained were compared with those of the slant–shear test. Key words: bonding agent, debonding, elastic foundation, interface, beam.

scholarly journals Evaluation of Polymer Modified Mortar and Bonding Agent for Structural Repair

2021 ◽  
Vol 7 (2) ◽  
pp. 56-62
Author(s):  
P N Ojha ◽  
◽  
Puneet Kaura ◽  
Brijesh Singh ◽  
Y N Daniel ◽  
...  
Keyword(s):  
Research Work ◽  
Test Method ◽  
Bonding Agent ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Bonding Agents ◽  
Repair Work ◽  
Structural Repair ◽  
Styrene Butadiene ◽  
Slant Shear

Polymer modified mortar is found to be suitable for structural repair and strengthening of damage structural elements. Conventional mortar is not preferred in repair of concrete since it has inferior mechanical property and durability performance. Polymer based mortar is an alternative to conventional mortar with enhanced mechanical properties. However, there are limited specifications and guidelines available for specifying PMM mixes for structural repair work. The research work aims to evaluate the mechanical performance of polymer based mortar with varying concentration of styrene butadiene rubber latex at laboratory scale. Another aspect in repair of corrosion damage structures is the bond between the substrate concrete and repair mortar. In order to study the effectiveness of bonding agents, the performance evaluation of bonding agents has been evaluated using slant shear test and pull-off test as per ASTM C 882 and EN 1542 respectively. Findings of study indicates that at 8-10 percent concentration of dry polymer solid by cement mass in polymer based mortar is the optimum dosage. Styrene-butadiene rubber based polymer mortar showed improvement in flow in comparison to normal mortar however, mixes with crushed sand shows decrease in flow which is due to presence of more fines. Slant shear and pull-off test method shows epoxy bonding agent give better bond strength as compared to SBR latex.

An Investigation to Estimate the Flouride Uptake Adjacent to a Fluoride-releasing Bonging Agent

1995 ◽  
Vol 22 (2) ◽  
pp. 113-122 ◽  
Author(s):  
S. M. Chadwick ◽  
P. H. Gordon
Keyword(s):  
At Risk ◽  
Clinical Significance ◽  
Orthodontic Treatment ◽  
Bonding Agent ◽  
Bonding Agents ◽  
Acid Etch ◽  
Fixed Appliances

Decalcification of the teeth remains a problem during orthodontic treatment with fixed appliances. It has been suggested that bonding agents which release fluoride could supply it to the area of the tooth most at risk from decalcification. The aim of this study was to estimate uptake by enamel adjacent to a fluoride releasing bonding agent. Acid etch biopsies were used to estimate the concentration of fluoride in enamel adjacent to brackets bonded with Vitrabond® and Geristore®. Results indicate that there was a significant increase in the concentration of fluoride in enamel adjacent to Vitrabond®. The clinical significance of the increase in the concentration of fluoride adjacent to Vitrabond® and the mechanism by which fluoride moves from the material into the enamel remain unclear.

scholarly journals Comparative Evaluation of Fluoride Release From Chemically Cured and Light-Cured Orthodontic Bonding Agents and Surface Alteration of Enamel: An in vitro Study

2020 ◽  
Vol 54 (3) ◽  
pp. 233-239
Author(s):  
Ashish Kumar Barik ◽  
Ritu Duggal
Keyword(s):  
Artificial Saliva ◽  
In Vitro Study ◽  
Fluoride Content ◽  
Bonding Agent ◽  
Fluoride Release ◽  
Bonding Agents ◽  
Surface Alteration ◽  
Orthodontic Bonding ◽  
Group B

Introduction: Fluoride is known to reduce demineralization and enhance remineralization which is desirable around orthodontic brackets. Material and methods: This study was carried out to determine the rate of fluoride release, fluoride content of enamel, and surface alteration of enamel from orthodontic bonding agents. Thirty extracted maxillary first premolars were divided into 2 groups of 15 teeth each. Group A—teeth were bonded with a chemically cured orthodontic bonding agent containing fluoride (Rely-a-Bond, Reliance, Itasca) and group B—teeth were bonded with a light-cured orthodontic bonding agent containing fluoride (Light Bond Reliance, Itasca). All individual sample teeth were used to estimate fluoride release and fluoride content of enamel. The same samples were also used to evaluate enamel surface alterations. The rate of fluoride release from the above 2 orthodontic bonding agents were measured in artificial saliva on day 1, 2, 3, 4, 5, 6, 7, 14, 30, 60, and 90. The fluoride content of the enamel was evaluated on day “0” and day “90” of bonding. The samples were also evaluated for the surface changes in enamel using scanning electron microscope (SEM). Results: The results showed that (a) chemically cured and light-cured bonding agent showed a dramatic decrease in the concentration of fluoride release from day “1” to day “2,” (b) the concentration of fluoride release kept decreasing from day “1” to day “90” of measurement in both the groups, and (c) SEM of the bracket margins bonded with chemically cured bonding agent and light-cured bonding agent revealed particle depositions of irregular shape and size on day “90.” Conclusion: Light-cured bonding agent (Light Bond) released higher concentration of fluoride as compared to chemically cured bonding agent (Rely-a-Bond). Light-cured bonding agent (Light Bond) showed higher increase in fluoride content of enamel than chemically cured bonding agent (Rely-a-Bond).

The enhanced performance of split-ring connections through prestressing

1991 ◽  
Vol 18 (5) ◽  
pp. 830-838 ◽  
Author(s):  
J. H. P. Quenneville ◽  
K. Van Dalen
Keyword(s):  
Key Words ◽  
Engineering Design ◽  
Laboratory Study ◽  
Laboratory Tests ◽  
Simple Technique ◽  
Douglas Fir ◽  
Limit States ◽  
Split Ring ◽  
Lap Splices

This paper examines the concept of enhancing the performance of timber connectors in truss joints by the introduction of transverse prestressing. The behaviour of lap splices of Douglas fir, with 63 mm split-ring connectors and end distances of 50, 100, 150, and 210 mm, was examined for various levels of prestress in a laboratory study. As well, the magnitude of the load that can be carried by the connection through friction between faying surfaces was also assessed for various levels of prestress. The simple technique used in the laboratory for introducing prestress is described. Results of the laboratory tests on 20 joint configurations are presented, and the experimentally determined strengths are compared with the calculated resistances using the provisions of CAN\CSA-086.1-M89 "Engineering design in wood (limit states design)." Key words: timber, connector, prestress, truss joint.

Comparison of Test Methods for High-Temperature Performance of Asphalt Mixtures

2013 ◽  
Vol 361-363 ◽  
pp. 1629-1634 ◽  
Author(s):  
Guo Xiong Wu ◽  
Xiao Ke Zhang ◽  
Rui Lin Wang
Keyword(s):  
Elastic Modulus ◽  
High Temperature ◽  
Shear Test ◽  
Asphalt Mixture ◽  
Test Methods ◽  
Asphalt Mixtures ◽  
Penetration Test ◽  
Shear Elastic Modulus ◽  
Temperature Performance ◽  
Slant Shear

Through a comparative study of high-temperature asphalt mixture performance by three methods: the standard rutting test, uniaxial penetration test on cylindrical specimens, and slant shear test, this paper displays that the shear elastic modulus gained by both cylindrical uniaxial penetration test and slant shear test can reflect well the properties of shear deformation of asphalt mixture under high temperature. However, there are certain limitations in these test methods.

Shear Deformation of High Density Aluminum Honeycombs

2003 ◽  
Author(s):  
Wei-Yang Lu ◽  
John Korellis ◽  
Terry Hinnerichs
Keyword(s):  
Shear Deformation ◽  
Shear Test ◽  
High Density ◽  
Model Parameters ◽  
Test Beam ◽  
Model Simulations ◽  
Aluminum Honeycomb ◽  
Axis Compression ◽  
Principal Directions ◽  
Flexure Test

The orthotropic crush model has commonly been used to describe the constitutive behavior of honeycomb [1]. To completely define the model parameters of a honeycomb, experimental data of axial crushes in T, L, and W principal directions as well as shear stress-strain curves in TL, TW, and LW planes are required. The axial crushes of high-density aluminum honeycombs, e.g., 38 pcf (pound per cubic foot), under various loading speeds and temperatures have been investigated and reported [2]. This paper describes experiments and model simulations of the shear deformation of the same high-density aluminum honeycomb. Results of plate shear test, beam flexure test, and off-axis compression are presented and discussed.

A FINITE ELEMENT STRESS ANALYSIS OF THE INTERFACE STRESS GENERATED DURING THE PUSH-OUT TEST

2002 ◽  
Vol 02 (02) ◽  
pp. 197-210 ◽  
Author(s):  
K. R. WILLIAMS ◽  
R. A. DRAUGHN
Keyword(s):  
Finite Element ◽  
Bonding Agent ◽  
Hard Tissue ◽  
Bonding Agents ◽  
Dental Restorations ◽  
Number Of Factors ◽  
Similar Chemical ◽  
Uppermost Layer ◽  
Set Up ◽  
Push Out

Within the dental sphere it is advantageous to be able to bond the restoration to dentine in order to avoid clinical problems such as marginal leakage with subsequent caries. Dentine bonding agents are normally employed to create an effective interface between the restoration and hard tissue with the formation of chemical links. The measurement of the bond strength between dental restorations or implants and surrounding hard tissue is generally achieved through the use of an experimental push-out test. However, these bond strengths have been found to be quite variable between laboratories even when similar chemical bonding agents have been used. This variability may be due to a number of factors including experimental differences such as, material moduli effects, specimen loading and changes in the thickness and properties of the interdiffusional zone (IDZ) that forms following polymerization of the bonding agent. In this work, these variables have been explored using the finite element method initially through a 2-D description of the geometrical set up and subsequently a 3-D discretization. The results indicate that the loading and specimen support during testing have a significant effect on the measured push-out values. Furthermore the effects of a gradually changing modulus in the uppermost rings of the IDZ can have a significant influence on the support bearing property of the bonding agent. These changes in modulus of the IDZ may be the result of fluoride leaching to bring about increases in properties and modulus. A mixed moduli IDZ where the uppermost layer is approximately double the value of the remaining material can lead to increases in push-out values of 10% or more.

scholarly journals A new concept of upflow clarification in activated sludge separation

1986 ◽  
Vol 13 (5) ◽  
pp. 517-522
Author(s):  
Arthur B. Sparling ◽  
David L. Woytowich
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Activated Sludge ◽  
Key Words ◽  
Laboratory Study ◽  
Removal Mechanism ◽  
Operating Characteristics ◽  
Activated Sludge System ◽  
Gravity Sedimentation ◽  
Settling Characteristics

An experimental investigation was conducted to evaluate a new concept of upflow clarification. A novel sludge removal mechanism that used the entire floor area for the removal of solids was incorporated in an upflow clarifier. The operating characteristics and design features of the continuous flux upflow clarifier (CFLUC) are described in detail. The laboratory study was conducted to determine the effectiveness of the CFLUC clarifier in separating sludges with different settling characteristics. The different sludge types were produced by an activated sludge system treating a synthetic dairy waste at four different food to microorganism (F: M) ratios. At low organic loadings (0.10–0.24 (g COD)(g MLVSS)−1 (d)−1), the CFLUC clarifier removed 70% of the pinpoint floe that remained during quiescent batch settling conditions. At high organic loadings (0.41–0.83 (g COD)(g MLVSS) −1 (d) −1), the CFLUC clarifier was capable of separating filamentous bulking sludges with poor settling characteristics. Based on the results of the experimental study the upflow clarifier effectively separated all sludge types over the range of organic loadings investigated. Key words: CFLUC clarifier, secondary clarification, upflow clarification, sludge blanket, bioflocculation, bulking sludge, gravity sedimentation.

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