Geometrical properties determination tests

Particles with size smaller than 0.002 mm, that is, clay, might also affect cohesion of the asphalt (bituminous) mixture, as well as the mechanical behaviour of both asphalt and unbound layer in the presence of water. 

A brief description of the main tests for defining the geometrical properties of aggregates is given in the following paragraphs. 

---

Source Reproduced from CEN EN 933-1, Tests geometrical properties of abrogates — Part I Determination of particle size distribution - Sieve analysis Brussels CEN, 2(X)5.Wlth permission ( CEN). 

Source Reproduced from CEN EN 933-3, Tests for geometrical properties of aggregates - Part 3 Determination of particle shape - Flakiness index,... 

CEN EN 933-1/Al. 2005. Tests for geometrical properties of aggregates — Part 1 Determination of particle size distribution-Sieve analysis. Brussels CEN. 

An obvious challenge in testing of textured geomembranes manufactured by processes 1 and 3 is the determination of geomembrane thickness. The measurement of thickness cannot usually be performed using the standardised procedures described in Sect. 3.2.2. Sometimes individual test methods fitting to the special geometrical properties of a texture must be... 

The radiation and temperature dependent mechanical properties of viscoelastic materials (modulus and loss) are of great interest throughout the plastics, polymer, and rubber from initial design to routine production. There are a number of laboratory research instruments are available to determine these properties. All these hardness tests conducted on polymeric materials involve the penetration of the sample under consideration by loaded spheres or other geometric shapes [1]. Most of these tests are to some extent arbitrary because the penetration of an indenter into viscoelastic material increases with time. For example, standard durometer test (the "Shore A") is widely used to measure the static "hardness" or resistance to indentation. However, it does not measure basic material properties, and its results depend on the specimen geometry (it is difficult to make available the identity of the initial position of the devices on cylinder or spherical surfaces while measuring) and test conditions, and some arbitrary time must be selected to compare different materials. 

Cylindrical pellets of four industrial and laboratory prepared catalysts with mono- and bidisperse pore structure were tested. Selected pellets have different pore-size distribution with most frequent pore radii (rmax) in the range 8 - 2500 nm. Their textural properties were determined by mercury porosimetry and helium pycnometry (AutoPore III, AccuPyc 1330, Micromeritics, USA). Description, textural properties of catalysts pellets, diameters of (equivalent) spheres, 2R, (with the same volume to geometric surface ratio) and column void fractions, a, (calculated from the column volume and volume of packed pellets) are summarized in Table 1. Cylindrical brass pellets with the same height and diameter as porous catalysts were used as nonporous packing. 

Three kinds of calcite ceramics based on pure CaCOj, containing lwt%, 5wt% and lOwtyo of pure lithium fluoride LiF were evaluated. Testing samples were formed by uniaxial pressing and sintered in temperatures of 450, 470, 490, 510 and 530°C. Green density and apparent density were determined by geometrical method, relative density was calculated on the basis of calcite theoretical density (3,156 g/cm ) and mechanical properties were evaluated on the basis of compression tests. 

During the test, the load (F)- longation (AL) diagram up to the break of specimen is recorded necessary to calculate the stress ((T)-strain (s) diagram (Fig. 4.3) using the geometric conditions of specimen Aq and equipment L or Lq (Eqs. 4.1-4.3). Modem universal testing systems equipped with computer techniques are able to record stress a, time t and strains s and 8t simultaneously. For the determination of modulus of elasticity a strain rate of 1 %/min is applied and 50 mm/min are mostly used to characterize the tensile properties of thermoplastics. 

---