Innovative test method for the reliable evaluation of joint sealants in concrete pavements

2021 ◽  
Author(s):  
David Ov ◽  
Rolf Breitenbücher ◽  
Martin Radenberg ◽  
Dominik Twer
Keyword(s):  
Plain Concrete ◽  
Test Method ◽  
Life Cycle Costs ◽  
Artificial Ageing ◽  
Concrete Pavements ◽  
Joint System ◽  
Relevant Element ◽  
Reliable Correlation

Joint sealants as indispensable filling systems in jointed plain concrete pavements (JPCP) are permanently exposed to various stresses during their service life, which often leads to a replacement of the sealing after approx. 7 to 10 years. Aside from seasonal unsteady climatic changes, the cyclical stresses caused by traffic and the ageing of joint sealants are especially significant. Considering the rising number of damages that occur within the overall "joint" system, an increased demand for a durable solution is requested as it is a relevant element for the life cycle costs of concrete pavements. In this context, a testing and ageing method was developed which comprises of the entire "joint" system, including the saw-cut concrete joint flanks, the primer as well as the joint sealant. This procedure depicts the decisive scenarios of in-situ stresses and allows the characterization of joint sealants. For this purpose, specimens were subjected to horizontal and vertical loads (static/cyclic) as well as to various ageing effects (temperature conditioning, UV-conditioning and freeze-thaw-cycles). After conditioning, a significant influence of the artificial ageing on the residual strength was observed in the tensile/shear tests. By comparing the artificially aged samples tested in the laboratory with extracted and in-situ aged samples, a reliable correlation was determined. Considering these system tests an initial approach was established which enables the evaluation of joint sealants in both unaged and artificially aged conditions on the basis of scientific parameters and limits.

Test Method for In Situ Electrostatic Characterization of Lunar Dust

2007 ◽  
Author(s):  
Charles R. Buhler ◽  
Carlos I. Calle ◽  
J.Sid Clements ◽  
James G. Mantovani ◽  
Mindy L. Ritz
Keyword(s):  
Test Method ◽  
Lunar Dust

Field Test Method for Residual Stress in Plain Concrete Pavements and Structures

2014 ◽  
Vol 42 (3) ◽  
pp. 20130108 ◽  
Author(s):  
Daniel I. Castaneda ◽  
Jacob D. Henschen ◽  
David A. Lange
Keyword(s):  
Residual Stress ◽  
Field Test ◽  
Plain Concrete ◽  
Test Method ◽  
Concrete Pavements ◽  
Field Test Method

Construction Practices of Short Paneled Concrete Pavements (SPCP) for High Volume Roads

2021 ◽  
Author(s):  
Sridhar Kasu ◽  
Amaranatha Mupireddy ◽  
Nilanjan Mitra
Keyword(s):  
Large Scale ◽  
Plain Concrete ◽  
High Volume ◽  
Concrete Pavements ◽  
Joint Spacing ◽  
Initial Cost ◽  
The Usa ◽  
Scale Test ◽  
State Of Research

The state of research on narrow and non-dowel short jointed paneled concrete pavements (SPCP) is gaining attention on a large scale across the different parts of the world especially in Chile, the USA, and India. The jointed plain concrete pavements (JPCP), which are designed with slab sizes around 3.5 m x 4.5 m results in thicker slabs with a thickness of paving quality concrete (PQC) layer ranging from 280-330 mm depending on load and temperature stresses on Indian highways. In addition to thicker slabs, JPCP requires dowelled joints, which increases the initial cost of pavement. In order to reduce the thickness and initial cost of construction, the use of cast-in-situ SPCP laid on a strong foundation consisting of a dry lean concrete (DLC) base, cement treated sub base (CTSB) and subgrade is being studied. The square short slabs of size: 1 m, 1.5 m and 2 m joint spacing and of thickness 180 to 220 mm were designed and constructed as two full-scale test sections of SPCP on national highways (NH-2 and NH-33) in India. Slabs were constructed by introducing an initial vertical saw-cut of 3 to 5 mm wide and to a depth of 1/4th to 1/3rd of the thickness. The adopted construction practices through field demonstration and implication of SPCP for highways is the main thrust of the paper which helps the practitioners, designers for adopting such projects in the future.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

A very rapid in situ Kikuchi technique to determine relative crystal misorientation

1988 ◽  
Vol 46 ◽  
pp. 830-831
Author(s):  
J. I. Bennetch
Keyword(s):  
Electron Beam ◽  
Analytical Techniques ◽  
Superplastic Forming ◽  
The Other ◽  
Kikuchi Pattern ◽  
Kikuchi Line ◽  
Line Analysis

In a recent study of the superplastic forming (SPF) behavior of certain Al-Li-X alloys, the relative misorientation between adjacent (sub)grains proved to be an important parameter. It is well established that the most accurate way to determine misorientation across boundaries is by Kikuchi line analysis. However, the SPF study required the characterization of a large number of (sub)grains in each sample to be statistically meaningful, a very time-consuming task even for comparatively rapid Kikuchi analytical techniques.In order to circumvent this problem, an alternate, even more rapid in-situ Kikuchi technique was devised, eliminating the need for the developing of negatives and any subsequent measurements on photographic plates. All that is required is a double tilt low backlash goniometer capable of tilting ± 45° in one axis and ± 30° in the other axis. The procedure is as follows. While viewing the microscope screen, one merely tilts the specimen until a standard recognizable reference Kikuchi pattern is centered, making sure, at the same time, that the focused electron beam remains on the (sub)grain in question.

Coherent electron nanodiffraction from clean silver nano particles in a UHV STEM

1993 ◽  
Vol 51 ◽  
pp. 1058-1059
Author(s):  
J. Liu ◽  
M. Pan ◽  
G. E. Spinnler
Keyword(s):  
Supported Catalysts ◽  
Imaging Techniques ◽  
Nano Particles ◽  
Metal Particles ◽  
Shape Structure ◽  
Dynamical Simulations ◽  
Small Metal Particles ◽  
Extract Information

Small metal particles have peculiar chemical and physical properties as compared to bulk materials. They are especially important in catalysis since metal particles are common constituents of supported catalysts. The structural characterization of small particles is of primary importance for the understanding of structure-catalytic activity relationships. The shape and size of metal particles larger than approximately 5 nm in diameter can be determined by several imaging techniques. It is difficult, however, to deduce the shape of smaller metal particles. Coherent electron nanodiffraction (CEND) patterns from nano particles contain information about the particle size, shape, structure and defects etc. As part of an on-going program of STEM characterization of supported catalysts we report some preliminary results of CEND study of Ag nano particles, deposited in situ in a UHV STEM instrument, and compare the experimental results with full dynamical simulations in order to extract information about the shape of Ag nano particles.

Characterization of the glycoconjugates of boar testis and epididymis

Reproduction ◽  
2000 ◽  
pp. 325-335 ◽  
Author(s):  
A Calvo ◽  
LM Pastor ◽  
S Bonet ◽  
E Pinart ◽  
M Ventura
Keyword(s):  
Ricinus Communis ◽  
Lectin Histochemistry ◽  
Apical Part ◽  
Seminiferous Tubules ◽  
In Situ Characterization ◽  
Intense Staining ◽  
Terminal Galactose ◽  
Boar Spermatozoa

Lectin histochemistry was used to perform in situ characterization of the glycoconjugates present in boar testis and epididymis. Thirteen horseradish peroxidase- or digoxigenin-labelled lectins were used in samples obtained from healthy fertile boars. The acrosomes of the spermatids were stained intensely by lectins with affinity for galactose and N-acetyl-galactosamine residues, these being soybean, peanut and Ricinus communis agglutinins. Sertoli cells were stained selectively by Maackia ammurensis agglutinin. The lamina propria of seminiferous tubules showed the most intense staining with fucose-binding lectins. The Golgi area and the apical part of the principal cells of the epididymis were stained intensely with many lectins and their distribution was similar in the three zones of the epididymis. On the basis of lectin affinity, both testis and epididymis appear to have N- and O-linked glycoconjugates. Spermatozoa from different epididymal regions showed different expression of terminal galactose and N-acetyl-galactosamine. Sialic acid (specifically alpha2,3 neuraminic-5 acid) was probably incorporated into spermatozoa along the extratesticular ducts. These findings indicate that the development and maturation of boar spermatozoa are accompanied by changes in glycoconjugates. As some lectins stain cellular or extracellular compartments specifically, these lectins could be useful markers in histopathological evaluation of diseases of boar testis and epididymis.

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