Aggregate tests

Because of the variability of aggregate sources, aggregates should be tested to determine their suitability for use in asphalt (bituminous mixtures) or as material in base and subbase layers. Their suitability is defined in reference to geometrical, physical and chemical proper-ties/requirements. Table 2.3 summarises the main test methods. 

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Platelet aggregation test (PAT), staphylococci binding assay,... 

Although in many cases the exact mechanism for the species-dependent differences in response to certain therapeutic agents remains unclear, these differences must be examined to determine the appropriate species to be used for preclinical pharmacological evaluation of each agent. This evaluation can routinely be performed by in vitro coagulation or platelet aggregation tests prior to evaluation in animal models. 

Gold aggregation test is preliminarily carried out to judge the... 

Human fibrinogen containing fibronectin and von Willebrand factor, purified human fibrinogen, von Willebrand factor a2-macroglobulin, and fibronectin used for preadsorption to the surfaces in this study were chosen primarily because of their increased accessibility over the canine analogs. Fibronectin is very similar in structure in all mammalian species tested so far, and all types of fibronectin have similar effects on cultured cells and cross-react with antibodies elicited in rabbits to one species of fibronectin. Thus, the use of human fibronectin is probably justified. Recent unpublished data of W. J. Dodds and G. S. Johnson suggest that washed canine platelets will not respond to human factor VIII concentrates in the ristocetin-induced platelet aggregation test. From these results, the conclusions for the von Willebrand... 

The total Flakiness Index is designated as the total aggregate mass passing through each bar sieve, expressed as the percentage of the total sample mass of dry aggregates tested. 

Figure 2.1 Sand equivalent values of sands from various rocks. (From Nikolaides A. and E. Manthos, Sand equivalent of road aggregates tested with European and American standards and methylene blue results. Proceedings of the 4th International Conference, Bituminous Mixtures and Pavements , Vol. I, p. 199. Thessaloniki, Greece Aristotle University, 2007.)...

The standard size of aggregate tested in accordance with CEN EN 1097-2 (2010) is 10/14 mm size aggregate. 

When the test is carried out in accordance with the American ASTM C 131 (or AASHTO T 96 2010), the size of aggregate tested can be of maximum nominal size 37.5 mm, 19 mm, 9.5 mm or even 4.75 mm. Coarser than 37.5 mm aggregate can also be tested details can be found in ASTM C 535 (2012). 

The American LA coefficient is calculated as the difference between the initial and final mass retained on a 1.7 mm sieve and is expressed as a percentage of the initial mass of the aggregate tested. 

The reported coefficient M e of the aggregates tested (the value is rounded to the nearest whole number) is the mean value of two samples tested. The test may also be conducted without the addition of water. The reported value is designated Mds- A detailed description of the test procedure is given in CEN EN 1097-1 (2011). 

The determination of aggregate particle density between 0.063 and 4 mm using the pyknometer method is similar to the method for aggregate particles between 4 and 31.5 mm. The key difference is the amount of aggregate tested, which should not be less than 1 kg. 

Sampling of constituent materials is carried out in the central mixing plant or upon delivery of the materials on site. Aggregate testing procedures are the same as those for hot mixtures. Bitumen emulsion testing, as well as tests on the recovered bitumen, follows the requirements and test methods specified in the standard used. 

It can also be used to determine the quantity of the soluble binder in the hot mix asphalt or reclaimed asphalt. The recovered aggregate may be used for sieve analysis or other aggregate testing. 

Fimbriae were identified as the filaments responsible for developing bacterial adhesion to other cells or surfaces. Various types were distinguished, produced by E. coli, salmonella and many other types of bacteria. Typically these projections were 2 pm long and 7nm in diameter, with up to 400 per cell. When the bacterial adhesion was measured by a blood cell aggregation test, or by a microscope counting of adhering cells, the fimbriae were inhibited by D-mannose addition. 

Fowler, D.W., Allen, J.J., Lange, A. and Range, R, 2006. The prediction of coarse aggregate performance by micro-deval and other aggregate tests, International Research for Aggregate Research (ICAR) Report 507-lF, pp. 608. 

Kurtulus, A., Lee, JJ- Stokoe, K.H. 2005. Summary report - site characterization of capital aggregates test site. Technical report. Department of Civil Engineering, University of Texas at Austin. 

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