Long-term performance of mechanically post-installed anchor systems

2016 ◽  
Vol 20 (3) ◽  
pp. 288-298 ◽  
Author(s):  
Minho Kwon ◽  
Jinsup Kim ◽  
Hyunsu Seo ◽  
Wooyoung Jung
Keyword(s):  
Pullout Test ◽  
Reduction Factor ◽  
Test Method ◽  
Test Results ◽  
Freeze And Thaw ◽  
Comparison Results ◽  
Compressive Strength Of Concrete ◽  
Long Term Performance ◽  
Term Performance

A mechanically post-installed anchor, which is one of the most widely used post-installed anchors in South Korea, was selected to evaluate long-term usage through a pullout test. Two types of specimens were constructed: the original specimens and freeze and thaw specimens. Mechanically post-installed anchors were installed in both of them. A freeze and thaw test method was utilized to consider the long-term usage. The compressive strength of concrete during the freeze and thaw test method is reduced by about 20% compared to that of the original concrete. From the pullout test results, the pullout strength of the freeze and thaw specimen was smaller by about 50% than that of the original specimens. Furthermore, the failure mode of the freeze and thaw specimens was changed. Cone shape destruction of anchors and anchor pullout destruction occurred in the original specimens; concrete pullout destruction occurred dominantly in the freeze and thaw specimens. Based on the comparison results, the reduction factor ( λ) for long-term usage of the mechanically post-installed anchor was derived using a probability function and was proposed to modify the concrete capacity design equation.

A Method for Measuring the Creep Behavior of Pressurized Polymer Tubing

2001 ◽  
Author(s):  
Chunhui Wu ◽  
Susan C. Mantell ◽  
Jane H. Davidson
Keyword(s):  
Heat Exchanger ◽  
Strain Gage ◽  
Hot Water ◽  
Test Method ◽  
Hoop Strain ◽  
Dog Bone ◽  
Thin Walled ◽  
Long Term Performance ◽  
Term Performance

Abstract Polymer components have been proposed for use in domestic solar hot water heating systems. A polymer heat exchanger is under development for such systems. For heat transfer considerations, the heat exchanger will be comprised of many thin walled tubes. The heat exchanger must survive 10 years of service at high pressure (1.55 MPa) and high temperature (82°C). A novel method has been developed for evaluating the long term performance (creep) of the polymer tubing. Traditional creep testing, performed with dog bone test specimens can not be applied because the thin walled tubing has anisotropic material properties. Consequently, performance must be evaluated directly on the extruded tubing. The method entails wrapping a Constantan wire around the tube specimen to continuously record the hoop strain. For pressure loading of tubing, this method offers significant improvements over strain gage instrumentation. In this paper, the test method is described, an analysis of the strain transfer between the tubing and wire wrap is presented, and strain data for polypropylene tubing measured with a strain gage and wire wrap are compared. The data show that the wire measurement method can be successfully used for the characterization of long term mechanical behavior of polymer tubes.

EFFECTS OF CLAY ON PROPERTIES OF CONCRETE

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Ayub Elahi ◽  
Atizaz Ali
Keyword(s):  
Construction Material ◽  
Harmful Effect ◽  
Clay Content ◽  
Acid Attack ◽  
Concrete Properties ◽  
Compressive Strength Of Concrete ◽  
Long Term Performance ◽  
Term Performance ◽  
Different Levels

Concrete is a versatile and most prevalent construction material. Its long-term performance depends on its interactions with the surrounding environment. The standards limit the ratio of the clay in aggregates due to its harmful effect on the concrete properties. This research paper presents the effect of different levels of clay addition on the concrete properties. Various levels of clay addition for different mixes were used in this experimental study. The effect of clay addition on workability, compressive strengths permeability and acid attack of concrete mixes was investigated. It has been seen that workability decreased by increasing the clay content to the mix. A drop in compressive strength of concrete up to 12% was observed by adding clay as compared with that of control samples. An adverse effect on resistance to permeability and acid attack of concrete was noted by increasing the clay content.

An Investigation of Environmental Reduction Factor for GFRP Bar Used as Concrete Reinforcement in China

2011 ◽  
Vol 413 ◽  
pp. 399-403 ◽  
Author(s):  
Jian Wei Huang
Keyword(s):  
Reduction Factor ◽  
Fiber Reinforced Polymer ◽  
Rc Structures ◽  
Average Temperature ◽  
Reinforced Polymer ◽  
Gfrp Bar ◽  
Temperature Records ◽  
Long Term Performance ◽  
Term Performance

Currently, an environmental reduction factor (ERF) is incorporated in design codes/guidelines of Fiber Reinforced-Polymer (FRP) in reinforced concrete (RC) structures to account for the FRP long-term durability. Due to the lack of real time durability data, justification of the ERF is still necessitated. This paper presents a calibration of ERF for GFRP bar to be used in China on the basis of the prediction of GFRP long-term performance with monthly average temperature records from 32 major cities. Research results show that the ERF values vary from 0.49 to 0.58 at 100% R.H. exposure, while ERFs are greater than 0.70 for all cases being studied when R.H. is below 90%. On the basis of this study, ERF can be recommended as of 0.70 and 0.50 for application with R.H. <90% and moisture saturated exposures, respectively.

scholarly journals NNWSI Waste Form Performance Test Development

1984 ◽  
Vol 44 ◽  
Author(s):  
John K. Bates ◽  
Thomas J. Gerding
Keyword(s):  
Performance Test ◽  
Test Development ◽  
Test Method ◽  
Waste Form ◽  
Analog Test ◽  
Waste Package ◽  
Long Term Performance ◽  
Term Performance

AbstractA test method has been developed to measure the release of radionuclides from the waste package under simulated NNWSI repository conditions, and to provide information concerning materials interactions that may occur in the repository. Data from 13 weeks of unsaturated testing are discussed and compared to that from a 13 week analog test. The data indicate that the waste form test is capable of producing consistent, reproducible results that will be useful in evaluating the role of the waste package in the long-term performance of the repository.

Long-Term Performance Analysis of Geomembrane Considering Stress Cracking Resistance

2016 ◽  
Vol 879 ◽  
pp. 838-842
Author(s):  
Han Yong Jeon
Keyword(s):  
Quality Control ◽  
Test Method ◽  
Short Term ◽  
Cracking Behavior ◽  
Stress Cracking ◽  
Failure Times ◽  
Crack Behavior ◽  
Long Term Performance ◽  
Term Performance

In this study, key properties of polyethylene resin and HDPE GM were tested for comparing their stress crack behaviors. Stress cracking time was differed from each type of resins and products. The failure times of ESCR test were too long compared to SP-NCTL's. The SP-NCTL results of RWOA was failed earlier than RWA‘s, GM1’s and GM2’s. But there was no difference between each sample of the results of ESCR test within short term testing duration. The ESCR test was influenced by stress relaxation during the test. The SP-NCTL test is reasonable for verifying stress cracking behavior and construction quality control. According to this study, ESCR test is not appropriate for determining the stress crack behavior, but SP-NCTL test is better test method for predicting the stress crack behaviors of HDPE GM.

State DOT Implementation of Statistical Analysis and Percent Within Limits

2019 ◽  
Vol 2673 (2) ◽  
pp. 583-592
Author(s):  
Aaron R. Coenen ◽  
James E. Pforr ◽  
Steven A. Hefel ◽  
Barry C. Paye
Keyword(s):  
Quality Assurance Program ◽  
Limiting Factor ◽  
State Agencies ◽  
Test Results ◽  
Department Of Transportation ◽  
Wisconsin Department ◽  
Integral Role ◽  
Long Term Performance ◽  
Term Performance

Verification testing, conducted by many state agencies, should serve an integral role in a quality assurance program. Many agencies seek a balance of physical and financial resources, as resources are routinely a limiting factor. For the Wisconsin Department of Transportation (WisDOT), it is datasets collected by both the contractor (quality control, QC) and department (quality verification, QV) at differing frequencies compared in a statistically valid method that provide balance. Statistical analyses, specifically F- and t-testing, have been chosen by WisDOT to accompany a Percent Within Limits (PWL) specification for hot mix asphalt (HMA). The analyses evaluate QC and QV data variances, means, standard deviations, and so forth, and determine whether it is reasonable to assume the test results of each dataset come from the same population, that is, are representative of the same material. If comparable, the more frequent QC data are considered verified and subsequently used in PWL calculations to approximate the percentage of material within specification limits. Anything less than comparable is subject to further investigation, for example, a dispute resolution process, to determine which test results most reliably represent the physical properties of the material, and are thus justifiably used in latter calculations. Such an approach has allowed WisDOT to adjust pay in accordance with material quality and consistency, ultimately connecting pay to anticipated long-term performance. This modified system of monitoring HMA materials has motivated multiple changes to industry processes and planning, and resulted in more consistent pavements, which should reduce the potential for isolated premature distresses.

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