Penetration grading

For the low-temperature experiment the rate of extension apparatus, as described by Hajek (25) and Haas (26), was used to determine the stiffness of test specimen of SA binder based concrete mixes at — 10° and — 25°C. The asphalt cements chosen were 40-50, 85-100, and 300-400 penetration grade to cover the entire range as well as to ensure that if a difference in properties did exist, it would be noticeable. The other test variables included temperature susceptibility (obtained by using asphalts based on crude oils from various sources), SA ratio, and binder content. 

As the asphalt binder, a straight asphalt which complies with the quality requirements specified in JIS K 2207, having a penetration grade of 60 to 80, was used. 

Mix and Specimen Preparation. Most of the mixes described in this paper were prepared from a fairly one-sized medium-coarse sand with 35% voids in the mineral aggregate and with only 2%% of the material finer than No. 200 mesh. The sand grading is included in Table I. A 150/200 penetration grade asphalt was used. 

The penetration grade, softening point, and ductility of the GRT-modified bitumens were studied as a function of rubber selection, temperature, rotational speed, shearing time, order of rubber, and oil addition (Li et al 2009). It was established that a shearing time of 40 min, a temperature of 180" C, a rotational speed of7000 rpm, and a rubber concentration below 25 wt.% with oil content below 4 wt.% were optimal for carrying out the technological process for preparation the GRT-modified asphalts. 

Additionally, Table 3.5 gives the requirements of penetration-graded bitumens (asphalts) in accordance with ASTM D 946 (2009). In this case, there are five distinct grades, with the first being 40/50 and last being 200/300. 

Table 3.5 Requirements for penetration-graded asphalt cement ...

Source Reprinted from ASTM D 946, Standard specification for penetration-graded asphalt cement for use in pavement construc-tion,West Conshohocken, Pennsylvania, USiASTM International, 2009.With permission ( ASTM International). 

Measurements have shown that an 80/10 penetration grade bitumen extracted from an asphalt concrete surface layer with air voids of 8%, after 2 years in service in the latitude of Thessaloniki, Greece, showed a reduction in penetration by 20%. Bitumen (80/100) extracted from a similar bituminous mixture (cold asphalt concrete surface layer with 9% air voids) but lay in the latitude of Jakarta, Indonesia, after 1 year in service, showed a reduction in penetration of 35% to 45%. 

Figure 4.10 Heukelom chart and characteristic properties of penetration grade bitumens manufoctured from one crude. (From Shell Bitumen, The Shell Bitumen Handbook. Surry Shell Bitumen UK, 1990.)...

To empty the open testing cylinder, turn it upside down and place it with the opening down on a 0.5 1 metal box against the inner wall of an oven preheated to 160°C 5°C. Allow it to stand for 30 to 35 min for penetration grade bitumen and for residues from emulsion or cut-back and for 40 to 45 min for binders containing polymers or for rubber-bitumen. 

The binder should be selected on the basis of ambient temperature, traffic and the expected functional performance of the OGFC mixture. The selected bituminous (asphalt) binder should satisfy the requirements of ASTM D 6373 (2007) (performance-graded asphalt binder). However, other grades of asphalt binders, such as penetration grade (ASTM D 946 2009) or viscosity grade (ASTM D 3381 2012), may be suitable. 

The determination of bituminous layer thickness is carried out with respect to design ESAL and design CBR value. A number of nomographs (design charts) have been developed, for each distinct base/sub-base thickness (400, 300 and 200 mm) and for each MAAT (13°C, 16°C and 19°C), for two penetration grade bitumen (50/70 and 40/50 pen). 

Cumulative traffic (ESAL) Mean annual air temperature (°C) Penetration grade binder (pen) Layer with a certain penetration grade binder... 

The binder may be bituminous emulsion (modified or unmodified), penetration grade bitumen or polymer-modified bitumen. The use of modified bitumen emulsion or modified bitumen improves quality of construction and extends life expectancy of the treatment. 

The number range for each sample is the binder penetration grade, and the small peak at zero time is a polystyrene standard. (Reproduced from Reference 31, p. 29, by courtesy of... 

Ma, X. and I. Andreasson (2005). Predicting the effect of various ISA penetration grades on pedestrian safety by simulation. Accid. Anal Prev., 37,1162-1169. 

Manufecturers Comments Penetrating grade (low viscosity). Manufacturers Comments UV surface cure version of 648. ... 

A team from Iran [57] looked into re-using waste products from SBR and HOPE manufacturing plants as modifiers for asphalt derived from the vacuum bottom residue in crude oil production. In addition to the waste SBR and PE, they also included N-methyl pyrrolidone (as an extender) in the study. Penetration, softening point and brass tests were conducted on the vacuum bottom residue, and Marshal tests were conducted on the polymer-modified hot mixed asphalt. They found that the optimised polymer-modified hot mixed asphalt exhibited superior strength and lower flow compared to standard 60/70 penetration-grade bitumen. 

If an existing rivetted structure leaks it might be worthwhile trying one of the very fluid sealants such as Loctite 290 penetrating grade which has the ability to creep into the joint before setting. 

Anaerobic compositions are normally applied as liquids which have especially good wetting and, in some cases, penetrating characteristics. The viscosity of the latter is as low as 2 mPa while the heavy paste-like versions will have viscosities in excess of 5 X 10 mPa. The materials are normally applied before components are assembled but the penetrating grades may be used after assembly. 

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