An Improved Test Method for the Detection on Alkali-Silica Reactivity of Aggregate

2013 ◽  
Vol 671-674 ◽  
pp. 1715-1720
Author(s):  
Jing Wang ◽  
Gu Hua Li ◽  
Jun Peng Zhang ◽  
Jun Jie Zhou ◽  
Feng Ming Sun ◽  
...  
Keyword(s):  
Test Method ◽  
Test Conditions ◽  
Alkali Silica Reactivity ◽  
Physical Environments ◽  
Test Parameters ◽  
High Alkali ◽  
Mortar Bar

Test the alkali-silica reactivity of slate aggregate in Guizhou using mortar-bar method in JTG E42-2005of China and accelerated mortar-bar method in TB/T2922.5-2002 of China. The results show that the six months expansion is 0.11% with mortar-bar method, the aggregate has low alkali activity. The 14-days expansion exceeds 0.30% with accelerated mortar-bar method, according to the TB10005-2010, the aggregate has high alkali reactivity. Obviously, the accelerated mortar-bar method is safer than the mortar-bar method, but the test parameters and test conditions of accelerated mortar-bar method have some differences with the aggregate physical environments. According to the accelerated mortar bar method, the thesis proposes an improved test method for evaluating the alkali-silica reactivity of slate aggregate.

scholarly journals Influence of Test Conditions on Sliding Wear Performance of High Velocity Air Fuel-Sprayed WC–CoCr Coatings

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3074
Author(s):  
Kaveh Torkashvand ◽  
Vinod Krishna Selpol ◽  
Mohit Gupta ◽  
Shrikant Joshi
Keyword(s):  
Wear Rate ◽  
Test Performance ◽  
Sliding Wear ◽  
Normal Load ◽  
Specific Wear Rate ◽  
Wear Behaviour ◽  
Wear Performance ◽  
Test Conditions ◽  
Test Parameters ◽  
Sliding Distance

Sliding wear performance of thermal spray WC-based coatings has been widely studied. However, there is no systematic investigation on the influence of test conditions on wear behaviour of these coatings. In order to have a good understanding of the effect of test parameters on sliding wear test performance of HVAF-sprayed WC–CoCr coatings, ball-on-disc tests were conducted under varying test conditions, including different angular velocities, loads and sliding distances. Under normal load of 20 N and sliding distance of 5 km (used as ‘reference’ conditions), it was shown that, despite changes in angular velocity (from 1333 rpm up to 2400 rpm), specific wear rate values experienced no major variation. No major change was observed in specific wear rate values even upon increasing the load from 20 N to 40 N and sliding distance from 5 km to 10 km, and no significant change was noted in the prevailing wear mechanism, either. Results suggest that no dramatic changes in applicable wear regime occur over the window of test parameters investigated. Consequently, the findings of this study inspire confidence in utilizing test conditions within the above range to rank different WC-based coatings.

scholarly journals Activity of Ceftaroline against Aerobic Gram-Positive and Gram-Negative Pathogens: Effect of Test Method Variability

2011 ◽  
Vol 2011 ◽  
pp. 1-5
Author(s):  
Diane M. Citron ◽  
Yumi A. Warren ◽  
Kerin L. Tyrrell ◽  
Ellie J. C. Goldstein
Keyword(s):  
Bactericidal Activity ◽  
Test Method ◽  
In Vitro Test ◽  
Gram Negative ◽  
Methicillin Resistant ◽  
E Coli ◽  
Minimum Inhibitory Concentrations ◽  
Test Conditions ◽  
Vitro Test

Ceftaroline is a new cephalosporin with bactericidal activity against methicillin-resistant S. aureus (MRSA) as well as gram-negative pathogens. Variations of in vitro test conditions were found to affect ceftaroline activity, with 5% NaCl inhibiting growth and/or reducing the minimum inhibitory concentrations (MICs) for E. coli, K. pneumoniae, M. catarrhalis, H. influenzae, and streptococci, while an inoculum of 106 CFU/mL raised MICs of some E. coli, K. pneumoniae, and M. catarrhalis strains.

scholarly journals Accelerated test methods for evaluating alkali-silica reactivity of recycled concrete aggregates

2021 ◽  
Author(s):  
Robert C Johnson
Keyword(s):  
Binding Capacity ◽  
Recycled Concrete ◽  
Test Duration ◽  
Accelerated Tests ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Alkali Silica Reactivity ◽  
Accelerated Mortar Bar Test ◽  
Bar Test ◽  
Mortar Bar

This thesis reports the findings of a study carried out to determine the effectiveness of Accelerated Tests in evaluating the Alkali-Silica Reactivity of Recycled Concrete Aggregates. The study evaluated the variability of the Accelerated Mortar Bar Test due to test variables as well as the single and multi-laboratory variation. The variability of the Concrete Microbar Test due to test variables and the correlation to results from Accelerated Mortar Bar and Concrete Prism Test results were also evaluated. The tests were corroborated by comparing the porosity, permeability and alkali binding capacity of samples tested by the accelerated tests. It was found that the Accelerated Mortar Bar Test provides acceptable results when the test variables, such as crushing methods and absorption values, are carried out and evaluated properly. The Concrete Microbar Test was found to underestimate the expansion of reactive aggregates. However, the same test was found to provide good correlation to the expansion results of Concrete Prisms incorporating Supplementary Cementing Materials when the test duration was increased.

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